Dry-Land Dredging

 Crevicing and Vacuum-Mining, Dry-washing
Nov 232011
 

BY MARCIE STUMPF/FOLEY

There is a fairly new method of mining out there in the mining community that is rapidly gaining in popularity, with good reason. It is called “Vacking;” and, as you might suppose, involves vacuuming material.

As a suction dredge vacuums material from the bottom of the river, this is a type of dry-land dredging. It involves using a small, lightweight unit to vacuum cracks and crevices of exposed bedrock, moss on exposed bedrock or boulders, or material in a dry wash in the desert. For this “dry land dredging,” however, there are no uncomfortable and expensive wet-suits to don, no heavy equipment to carry and then set up, and no long period of learning how to operate the equipment, or learning where to find gold.

Anyone who is familiar with mining knows that there is a much larger proportion of fine gold deposited than large gold, in almost any area. Each winter, as the rivers swell with winter rains and snows, much fine gold is washed down them. The fine gold, since it is much lighter in weight, is deposited much higher on the banks, or in the material of the river. As the high waters recede with the onset of spring and summer, much of the areas where the fine gold is deposited is left exposed up on the banks of the rivers.

The new units consist of a two-cycle gasoline engine mounted on a five gallon container, which is equipped with a suction hose and a crevice nozzle. They are very efficient at pulling the fine gold from moss, and at cleaning out crevices. Previous efforts to accomplish this by hand were slow and painstaking, and not very efficient. Collecting fine gold has always been one of the greatest challenges facing any miner, and some people spend years attempting to perfect their fine gold recovery.

Not only does “vacking” do an excellent job at recovering fine gold — it is a lot of fun! It is so fast, simple, and easy to use, that it seems to take all the work out of mining. You are still out in the great outdoors, still getting healthy exercise, but all that’s left when you remove the excess work is the fun.

Since we live and work very near a gold-bearing river, if my husband can squeeze two hours of time, he can get to his favorite spot, set up, get in most of that time mining; and still come home with enough gold to feel he has been mining. If he is dredging, that’s not enough time to more than set up and get started before he has to quit!

These units come on their own back-pack frame, and all accessories are carried right inside the unit. It is a completely self-contained unit, and includes an extra fuel bottle, a crevice tool, a gold pan, a “sniffer bottle” to remove the gold from the pan, and even a sample vial to keep it in. With all these accessories, the unit weighs just 15 lbs., so you could hike into the back country with it without undue strain.

Many wives who are not interested in dredging or motorized sluicing (high-banking) enjoy using this type of unit because it is something they can do completely on their own. The only problem we have seen develop is that when some of the husbands see that the gold recovery exceeds that of their dredge or motorized sluice, they want to use one also. Then, they either fight over the one unit, or join the growing group of “two-vack” families. Since they are such low-cost units, this is pretty easy to do.

I recently talked to one avid vack-miner who has been using one of these units for two years. He was concerned that he might possibly lose some of the fine gold out the exhaust as the unit filled, since it is so lightweight. Shortly after purchasing his unit, he fitted an elbow and extension over the exhaust, and directed it into a container of water. He has used it faithfully, and panned out the light powder that accumulated each time. He has never found even a speck of gold in it.

A crack or crevice in exposed bedrock that runs crossways to the current of the river acts as a natural riffle, catching fine gold just as the riffles of a sluice do. The moss that accumulates on exposed bedrock acts much as the carpet in a sluice, only better! It is amazing just how much fine gold can accumulate there. These are prime areas for vacking.

Areas where people have been working with motorized sluicing equipment have also proven to be good. Even if they have worked the area down to the bedrock, they have been unable to clean the area as thoroughly as it can be cleaned with a Vack, and generally, the richest areas are right on the bedrock.

The greatest demonstration I have ever seen about how gold traps in bedrock and moss, and how much work it is to recover it using conventional methods, is contained in Dave McCracken’s video, “Modern Gold Mining Techniquies.”

Although I have not mentioned finding nuggets with this equipment, it certainly does find them! Even areas that have predominantly fine gold in the high bedrock will trap nuggets during flood storms, and if they are there, this equipment will help you get to them as nothing else will.

Since you do not work directly in the active waterway, and this equipment does not put anything into the waterway, there are no dredge permits required for the use of these units, at least in the state of California.

All in all, Vacking has such a wide range of applications, in so many areas of the country, by such a wide range of people, that the gain in popularity is very understandable. It can only be expected to grow.

If you should get the Vacking bug, be sure you look for us out there, because that’s where we will be every chance we get!

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Electronic Treasure Hunting

 Electronic Prospecting, How To Find Gold
Nov 232011
 

By Jimmy Sierra

“What goes on in that metal box may be a mystery to most of us, but we all know it isn’t magic”

 

Metal detectingThe title of this article can mean different things to different people and thereby add to the mystique surrounding the entire field of metal detecting, for that is what “Electronic Treasure Hunting” is all about. The word electronic should mean the same to everyone. What goes on in that metal box may be a mystery to most of us, but we all know it isn’t magic.

The vast assortment of transistors, resistors, capacitors and various integrated circuits add up to a very sophisticated type of transmitter which broadcasts a signal through the transmitting coil of copper wire contained in the disc or loop at the front-end of the detector. This signal is affected by the electromagnetic field which is present around all metal objects. Thus, when it returns to the receiver-coil in the loop, this signal is changed. The change is interpreted by the complex circuitry in the detector box and lets us know that there is metal out there.

Depending upon the sophistication of the detector, this data can include the possible type of metal, depth of the item and even the shape or identity of the metal object. This may be an over-simplification of what goes on, but we need not worry about how it happens. Let the engineers who invent these devices handle that. The thing to remember is, metal detectors find metal. There are variables that create differences between detectors, and these variables will determine which style of detector is best-suited to the type of treasure hunting that we wish to do.

This brings us to the second part of the title of this article: Treasure Hunting. As I mentioned, this is the part that means different things to different people. To some, it means looking for dropped coins or jewelry in various places such as parks, playgrounds, backyards, beaches, picnic grounds or even old ghost towns. The locations change and the technique for searching varies a great deal, but the basic function of the detector to locate metal is the same. Some consider treasure hunting to be locating caches of buried coins or valuables, even sunken galleons. Again, the treasure and the location change, but the detector is still operated as it is de- signed, to locate metal objects.

To others, treasure hunting takes the form of searching old battle sites or ghost towns for relics of days gone by.

And yet, another select group of treasure hunters who call themselves “prospectors” direct their search for the elusive nuggets of gold, long sought by man to be used as a measure of wealth.

By now I hope it has become apparent that the common denominator linking most treasure hunters together is the electronic metal detector. The location may change and the targets may differ, but all respond to the initial function of the detector to find metal. It is only necessary to vary where we look, and to some degree, develop special skills unique to each type of treasure in order to change from coin shooter to cache hunter to relic hunter to prospector.

This might be a good time to clear up one particular misconception, one that has been brought to my attention hundreds of times over the years by those unfamiliar with treasure hunting. That is, the idea that metal detectors cannot find GOLD. This stems from some misunderstanding about the nature of gold. When I have questioned these people, I have found that most were not really sure if gold was a metal or not. Some had a vague idea that gold might be classed as a mineral. Most, however, were not sure what the difference was between a metal and a mineral.

In brief, the difference between a mineral and a metal is that a mineral is a chemical compound of more than one element, and a metal exists in its pure state as a single element. So, let’s just accept the fact that iron, copper, lead, silver, and GOLD are all metals and can be found free in that form, and that all of them can be located with a metal detector. We can surely begin to see why such mystery surrounds gold and gold prospecting, as well as treasure hunting in general.

I do not mean to imply that electronic treasure hunting or prospecting is as easy as falling off a log; only that it is not magic, and that the skills acquired while learning to hunt coins in a park with a detector are the same skills used when prospecting for gold nuggets in the Mohave Desert. The target and the location change, but the basic skill is only varied by the different types of hunting.

Up until several years ago, one of our most successful coin shooters from the Sacramento area in California had never seen a gold nugget except at the various gold shows where suction dredgers show off the treasures which they find at the bottom of streams and rivers. He had acquired the necessary skills over the years in the operation of his detector. He had learned to utilize the ability of his detector to cancel-out the ground mineralization caused by iron ore and salts which mask the ability to locate metal objects such as coins. He had trained his ear and slow searching techniques to hear those deep older coins. When he decided to give a shot to gold prospecting, he had little else to learn. He was successful right from the start. Of course, he didn’t look for the nuggets in the local park. But, he did find his first nugget in a dry streambed not more than 15 minutes from his house. He was bitten by the gold bug on that first day and will never be the same!

His biggest problem was to find a good place to hunt. He rightly concluded that the best place to start was where the old 49ers had found gold. If it was there then, it was surely there today. He was right. He began by going over the tailings left behind by old-timers. Gold was plentiful and the old methods of recovery were not perfect. Carelessness and lack of skill left plenty behind. He researched old maps and history books to seek out previous diggings. Sometimes, he went over old tailings. Other times, he searched dry washes and gulches near the diggings. Experience sharpened his skill and techniques, just as those many hours spent in the old parks had prepared him for this new approach to treasure hunting.

Averaging three days per week searching, he found more than 40 ounces of gold last year!

I do not want to paint too rosy of a picture here. The fellow mentioned above is a real experienced detectorist. He spends time hunting and looks for the right spots. Few of us will measure up to his success. But most who try their hand at treasure hunting will be pleasantly surprised at how fast they can become skilled in the use of this electronic device. Practice and patience are all that are required. Skill in tuning and operating the detector comes from reading the manual carefully and asking information from the dealer that sold the unit. Other users are a good source for acquiring special helps in learning to use the unit. I, as well as others, have written articles and books explaining in detail the tuning and searching techniques of metal detecting.

Joining up with others in a Club or association will gain you very valuable access to experience and places to hunt for golden treasure.

One of the unpredictable ingredients in the creation of a successful treasure hunter is LUCK!! The old adage that you have to be standing over a target to find it, is true. My friend and I were searching an old baseball field a number of years ago which was adjacent to an old Mission. We both found numerous coins, many silver, but all from this century. I was lucky enough, however, to find a 1778 Spanish half real dating back to the Mission Period. It was only 4 1/2 inches or so deep. It was luck. I was practicing the same learned skills as my partner and we both were successful. My old coin was there because I was standing over it.

I have a good friend with whom I prospect. We dig a lot of targets in order to find the elusive gold nugget. I have found many nuggets, most in the tiny-to-small size-range, but none really large. However, along with many smaller nuggets, this fellow has found a 6-ounce, a 9-ounce, and a 12-ounce piece of Mother Nature’s natural golden treasure. Granted, he hunts for gold nuggets a lot more than I do, but many who hunt as often as he does never find nuggets in that class. Wouldn’t you say some luck came his way? Each one of these nuggets was found with a different make and model of detector.

Many detectors are pretty equivalent in ability to find metal, but all metal detector users are not equal in skill — or in luck.

Another example comes to mind at this time: This one might seem pretty far-fetched, but it is true. A few months ago, a prospector-friend of mine called to announce that he had just found his largest nugget to date. It was a ¾-ounce piece, that’s 15 pennyweight. Now, that is a respectable nugget. Of course, he said he found it with the help of his faithful dog. You might call the dog his gold-hound at this point. While my friend was prospecting along the bank of a popular river, his dog was doing his duty near the water. As he noticed his dog scratching at the sandy shore, he caught a glimpse of something flashing in the sunlight. He went closer to investigate and spotted the aforementioned nugget with loop and all attached. Some luckless prospector had lost his prized specimen from around his neck. One man’s loss is another man’s gain, as they say. It goes without mention that this is one dog that will never want for attention again!

We have talked about learning how to use the detector, regardless of what the object of your search is. There is no substitute for expertise and skill. We have mentioned that buying the proper detector is essential and we have pointed out that a certain amount of good luck doesn’t hurt. The final ingredient is good old perseverance and perspiration.

My basic intent in this article is to clear away some of the magic from electronic metal detecting and show it as an acquired skill, which is what it really is. It is important to buy the best detector you can; one that has the ability to cancel the ground-mineralization. This is most important if you plan to use the detector for prospecting, because gold and silver are most-often found in highly-mineralized soil.

If you are going to use the detector in trashy areas (lots of man-made metal objects), you should buy a detector that has some ability to identify trash. Otherwise, you will have to dig every target that sounds off. This is not only tiring; but since you can only dig so many targets in a day, it diminishes the odds of digging good targets. You can see that this would not be important if you were relic hunting, where all items are potential treasures. But it is more important when coin hunting, where pull tabs and bottle caps are not desired, or in prospecting, where nails and tin cans left from former miners are tedious to dig and not as valuable as gold nuggets. Of course, if the area is virgin, one would not have a need for identifying trash.

Being able to identify a “hot rock” (a rock with different mineral content than the surrounding terrain) is also an important feature to be looked for in a detector to be used for prospecting. Have your dealer help you pick a detector best-suited for your needs, whether they be specialized or multi-purposed.

Good Hunting!

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Electronic Prospecting for Gold!

 Electronic Prospecting, How To Find Gold
Nov 232011
 

By Linda Haze Gabris

 

Gold nugget found while metal detectingI first wanted one when I read about a million-dollar nugget found in Australia by an “electronic-prospector.” The captivating article told about an enormous lump of gold that was unearthed by a miner using a metal detector. Several stories later, one of these devices was on my “have-to-have” list. That was years ago. In 1988 I ordered an A3B-United States Garrett Gold Hunter.

My owner’s manual promised this unique instrument would help make all of my dreams come true! Well, here I am more then a decade later with good news. I can vouch for the fact; these strange-looking gadgets really do work! During these years I have unearthed some of the best treasures to be found anywhere in the country!

First of all, an “electronic-prospector” has to redefine the word “treasure.” To me, a treasure is almost anything that lies hidden and secured by earth or water.

While there is no thrill quite as great as finding a lustrous gold nugget wedged in a crevice of bedrock, or an old coin buried deep in pine needles along the trail, one can learn to appreciate other “finds,” too! “Beeping-out” and digging up simple objects like an old tobacco tin, a horse shoe or the remains of an enamel wash dish also contribute to my own “joy of the hunt.” A heap of old rusty cans behind a tumbled miners cabin, or a scrap of metal embedded in a gravel bar, offer reminders of those who traveled ahead of us-down the golden trail. Some hunters call these items “bad beeps.” I have learned to appreciate them as interesting bits of yesterday!

The first thing to do when learning how to operate a metal detector is to read all of the manufacturer’s literature. Make yourself familiar with the features of the model that you have chosen. You will receive maximum performance from your detector by studying its manual. Even if it takes days, I suggest you don’t hit the gold fields until you understand all of your detector’s functions and features.

When you head for the hills, make certain that you bring along a spare set of batteries!

The best place to get familiar with your new machine is in a “salted” area near home. Make sure you pick a place where you will not encounter buried power lines! You can build a test plot by planting several items at various depths, from two to ten inches deep, and about two feet apart.

Using bits of colored cloths tied to little sticks, you can flag the location of the different items; a nail, ball of tin foil, bottle cap, an old fork or spoon, a couple of coins, and a gold nugget or ring (be sure to mark the location well). Note the depth at which they were buried! Now you can scan the targets and listen to the detector “beeping out” its signals. If you listen closely, you will hear different tones for each metal.

Once you can tell the difference between the sounds, study the sounds in accordance with the depths. This adds a challenging twist to your learning curve!

Using lots of patience, try hunting for items in both the “all-metal,” and “discriminate” modes. You will want to wear headphones for greatest effect. Following your manual, try both automatic and manual tuning. Work with the instrument until you understand its unique workings. Practice, as you would with a guitar, until your detector is “tuned.” After you are familiar with all your model’s features, and you know what the different types of targets sound like, you can head into the hills with confidence and great expectations!

I find the equipment needed for electronic prospecting is very simple. You will need a tool for digging out the “buried treasures” as you discover them. I use a long, narrow-mouthed spoon in areas where the earth is soft. In areas of harder soil or cemented gravel, I find a sharp-nosed pry bar works best. If I am detecting for gold in gold producing regions, I always carry a plastic gold pan and miner’s shovel. When beeping occurs in gold-bearing gravel, I shovel the “scanned-over” dirt into the pan, and then run the detector over the pan to see if I scooped up the target; or if it is still in the ground.

Once I have the target in the pan, I sift or pan out the material to see what is reading out on my detector. Don’t use a metal pan, because you won’t be able to pin-point the target.

Don’t be disheartened if most finds only pan-out as old sluice box nails or rusty bits of metal. This is to be expected in some areas. Determination and patience will eventually lead you to precious golden nuggets for your poke! You will need a leather pouch or plastic container with a tight-fitting lid to put your new-found gold in. Zip-lock bags are also good for this.

I always carry all “dug-targets” back to camp with me, so that the search area will be fresh for my next hunt (or for other detectorists!)

When a nugget has been unearthed, I usually turn off my machine and hand-work the area by test-panning surrounding gravel that could (often does!) contain particles of gold or other nuggets too small or deep for detection. Until you know the full range of your model, this is a good practice to follow. All detectors have varying ranges of depth penetration!

I have discovered the most productive areas for metal detecting gold are in the areas around old workings. Some of my most prized nuggets have been “beeped” out of tailing piles left behind by the old-timers!

I have also unearthed nice nuggets from the “spillage” around the old recovery systems from bucket-line dredges, sluice boxes, and shakers. Using my metal detector, I have stumbled upon many “clean-up” sites from big operations. A “clean-up” site is usually near water, where the heavy concentrates from an operation have been worked-down to just the gold. Concentrated material from an old recovery system contains black sand, rusty nails, bits of metals; and more often than not, a good amount of fine gold particles that were lost during the clean-up process. After my detector has sounded-out a “clean-up beep,” I pan it out before moving on.

In my years of prospecting for gold, I have not only unearthed a collection of remarkable gold nuggets, but I have also found other unique treasures. One such piece was a sad old iron that I was able to restore to good condition. This was located in a gravel bar, in the middle of the Manson, a noted gold producing river in British Columbia.

Other “treasures” include countless forks, knives, spoons, metal buttons, medals, coins, a silver-handled nail brush, and a pill box dated from the 1800’s. I have also found tons of rusty square nails, tin cans, scraps of screens, grates from old workings, and many tidbits from unknown objects.

Every target, whether it is a kidney bean-sized nugget, or a mere bean can, offers me the excitement of the dig; the thrill of discovering something that lay hidden in the earth. It is treasure; no matter how great or small! That’s what electronic prospecting is really about: The “beep” at the end of the search coil!

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Different Kinds of Sampling

 Gold Prospecting & Sampling, How To Find Gold
Nov 232011
 

By Dave McCracken

How much you need to qualify a gold deposit in advance depends upon the additional investment that will be required to gear-up for production.

Dave Mack

In placer mining, there are fundamentally two kinds of sampling:

1) Discovery: Attempting to locate a higher-grade deposit of value inside of a larger volume of lower-grade material.

2) Quantification: Extracting and analyzing smaller portions, to gain a perception of how much value exists within a larger volume.

The general concept behind sampling is to minimize investment into a specific mining property, or a particular project, until there is enough proof that a mineral deposit exists which contains enough value to justify a more substantial investment.

The kind of sampling that you should do, and how much is necessary, largely depends upon the ultimate objectives, and/or how large of an investment you will make to implement a commercial project – especially that portion of the investment which cannot be recovered and re-committed to some other project at a later time.

For example, if you are going to join The New 49’ers Prospecting Organization to gain access to 60+ miles of mineral properties in northern California, and decide to devote an extended period of time into searching for and developing high-grade gold deposits along those properties, the money you would spend outfitting yourself with a sampling dredge is something you can depreciate over the extended period. This is because the investment will not be confined to a single mining project or property. When you are done, because the dredge and gear will be accessible, you can regain some of your investment by selling the used equipment.

How much sampling would be necessary in advance of making this investment? Not so much, because most of the investment is not committed to a single mining property. Before a final decision is made, perhaps it would be worth spending a week of your time participating in a Group Mining Project, to obtain some direct exposure to the activity, and see if this is how you want to spend your time.

On the other hand, if you were considering a substantial capital investment to start up a full-scale commercial dredging program on one specific mining property out in the middle of Borneo’s rain forest, where accessibility is only available by helicopter; it would be wise to first send in a sampling-team to confirm the existence of commercial deposits that will allow you to make a reasonable return on your investment. Knowing that most of the capitalization into this kind of mining project is unlikely to be diverted to some other program at a later time, how much sampling would be enough? It should be enough to:

1) Verify that commercial deposits exist on the property; and,

2) Quantify the deposit(s) well enough to become certain that the commercial value of the project is justified.

Sampling is a careful, organized method of attempting to locate high-grade mineral deposits; and then, obtain a reasonable perception of the value they contain.

Here are a few basic sampling principles:

1) The larger the sample, the more accurately the sample results will represent the larger volume of material that has not been analyzed.

2) The more samples you take, and the closer they are together, the more accurately the average result will represent the larger volume of material that has not been analyzed.

3) To achieve an accurate result in sampling, it is vital that you thoroughly clean all of the values from sampling equipment in-between samples.

4) As mineral deposits can be found at different strata’s within a streambed, a good sampling program does not only test in different geographic locations; but also at the different layers within a streambed. This is because it can often be more commercially-productive to mine a deposit only down to a specific strata.

 

On this river in Madagascar, the gold (plentiful) was so fine, the sample material had to be dredged into a large catch basin suspended between two boats, and then processed using specialized equipment on the bank.

5) To be effective, recovery-equipment used in sampling must have the capability of concentrating the values which exist within the deposit. Where special recovery equipment is needed, and the sampling must be accomplished with portable dredging equipment, it is sometimes necessary to dredge the samples into a floating catch-container. Then the samples can be carefully processed on land.

Sizing the gold being recovered, and the gold that is not being recovered, is an important part of a sampling process.


6) Care must be taken to ensure that foreign material is not introduced into the material being sampled which can render the result inaccurate. Just as this has to do with foreign material from other geographic locations, it also has to do with material from different strata’s within the streambed, if layers are being tested independently of each other.

7) The smaller the sample being analyzed, the more the result can be thrown off by the introduction of foreign material (called “contamination.”)

8) Tailings from a sampling recovery system should be carefully analyzed to see what values are being lost; and whether steps can be taken to recover the values in a production operation.

9) Ultimately, only the values that can be recovered during production should be included in the final business projections.

10) Care must be given to measure the amount of raw volume that is excavated to extract a sample. Because the value recovered must be related back to the amount of material that was moved and/or processed to obtain the result. This relation will need to be measured against the volumes and costs associated with a potential production operation.

For example: If an average cubic meter of streambed gravel to be processed will produce $10 in gold (gold at $425/ounce), at a gross production cost of $4 per cubic meter, when a production dredge is operating at 100 cubic meters per day, you can predict a net income of $600 for each dredge participating in the program.

Sampling is generally accomplished in two steps: The first step is to locate the existence of a mineral deposit. Usually, when we use the term “preliminary sampling program,” we are talking about a project where the existence of high-grade deposits still needs to be confirmed.

The second step is to sample the deposit(s) enough to gain a perception of its value. And that’s what this article is really about; how much quantification is necessary? The answer to this question largely depends upon the additional investment that will be required to gear-up for the desired volume of production.

Where we dredge along the Klamath River in northern California, using the very same equipment and support-structure in sampling as we do in production, we do not have to do very much quantification of a deposit before launching into production. This is because just finding the high-grade is reason-enough to mine it. Although, we usually do devote several samples in an effort to find a low-grade area where we can place tailings. Then, we establish the value of the deposit as we mine it.

The reason we can do this, is that under these circumstances, there is no substantial amount of increased financial risk when we transition from sampling into production.

Local miners were recovering rich deposits in the Cambodian jungle using very primitive, low-volume methods. Here was a good place to start with a sampling dredge.

However, many situations are different from this. Some mining projects are just in the start-up phase. Some mining prospects are in remote locations. Under many circumstances, to minimize risk, it is wise to begin with portable sampling equipment to complete the preliminary sampling phase of the program.

Local miners were supporting their villages in Madagascar by digging gravel from the bottom of the river out of boats using long-handled shovels. Our sampling later proved they were digging on the strongest line of gold in the river.

In this case, the question remains how much quantification is necessary to support the evolution to the next level of operations? This will always come back to the program objectives – which often have to remain flexible, depending upon what is discovered during sampling.

Here are several different levels of quantification:

1) Doing enough additional samples to prove that a high-grade deposit justifies bringing in a larger-sized suction dredge to go into production. As part of this, it is important to work out the best type of recovery system to use, and decide how many production-shifts you will run. Night operations require special lighting equipment.

2) Doing enough samples along a stretch of river to prove that high-grade deposits are extensive enough there to justify bringing in multiple production dredges, and setting up a substantial support infrastructure.

3) Doing a series of controlled samples, an equal distance apart, along a portion of a river, to statistically-quantify the value of a mineral deposit. This is often done under the watchful eye of a consulting geologist who will certify the results in preparation for a larger-scale mining operation with the use of mechanized machinery that might float on platforms.

  

 

4) Doing a series of controlled samples, an equal distance apart, for some distance across an entire section of river, to quantify the average-value of the river gravels. This almost certainly would be accomplished under the guidance of a consulting geologist(s) who will certify the results, in preparation of financial instruments for investment bankers or a public trading company.

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Classification of Material in Sluicing

 How To Find Gold, Sluicing & Surface Mining, Video Enhanced Stories
Nov 232011
 
video subscription graphic
This story first appeared in Gold & Treasure Hunter Magazine May/Jun, 1993 on Page 45. This issue is still available! Click here.

By Dave McCracken

Classification is necessary to increase the amount of smaller particles of gold that you will trap in your recovery system.

Dave Mack

 

It takes more water velocity to move larger-sized material than it does to move the smaller-sized material through a sluice box. Yet, to the degree that the water velocity over a sluice box is increased, there may be a loss of fine gold recovery. Or, to the degree the water velocity over a sluice box is slowed down, there is likely to be an increase in fine gold recovery–as long as there is still enough flow over the box to keep the riffles concentrating.

When larger rocks are pushed through a sluice box by water force, they also create greater turbulence behind the riffles as they pass over, which may cause an additional loss of fine gold.

To improve gold recovery, it is common practice to run material through a screen to classify out the larger rocks before running the material through the recovery-portion of a sluice box. In this way, less water velocity is needed through the box, which allows for a more orderly flow, and an increase in fine gold recovery. The action of screening materials is called “classification.” Materials which have been passed through a classification screen are called “classified materials.” The following video segment demonstrates this very important point:

  • Classification Video One

The size and depth of riffles within a sluice box play an important part of this. A slower water flow might not keep a deeper riffle concentrating. A greater water flow can sometimes “boil-out” a lower-profile riffle. So as water flow is slowed down to catch finer-sized gold, it is generally necessary to use shorter riffles.

Half-inch mesh screen is commonly used for primary classification in small and medium-sized sluicing operations, because the screen is large enough to allow classification to take place quickly, yet no materials greater than half-inch in size will get into the sluice. Therefore a slower-velocity of water can be directed through the box, and fine gold recovery will be improved.

Classification for a sluicing operation can be done in any number of ways. One is to place a piece of strong half-inch mesh screen over a bucket, and shovel or pour through the screen into the bucket while sweeping the larger material off to the side. Once the bucket is filled with classified material, it can be poured into the sluice box at a uniform rate. It is better to not dump the whole bucket into the sluice all at once! This is because too much material is likely to overload the riffles and cause a loss of gold recovery.

In a situation where it is necessary to haul material a short distance to the sluice box, sometimes it is easiest to classify the material directly into a wheelbarrow and transfer only the classified material to the sluice.

Perhaps one of the best screening methods is to build a classification device that you can shovel into, and which will stand directly over the top of, and drop the classified materials into, the head of your sluice box.

The device should be built with the screen set at an angle. This way, larger material is helped to roll off of the screen as the pay-dirt is shoveled onto it. Smaller materials should fall through the screen and be directed into the head of your sluice box. This is actually a miniature model of the big classifiers used by large-scale heavy equipment bench-mining operations. A classification device such as this is rather easy and economical to build and will speed up a production-sluicing operation while screening is being done to improve gold recovery.

Any recovery system will only recover gold effectively down to a certain size-range. Most gold particles smaller in size than that will be lost with the tailings. Classification is one effective way of increasing the amount of gold that will be recovered out of the material that will be processed. As demonstrated in this following video segment, this is especially true of suction dredges; because dredges are able to increase the volume of production over other types of hand-mining activity.

  • Classification Video Two

Here is a substantial explanation of the system which we have developed to effectively recover more fine gold on our conventional suction dredges. It combines two classification screens to more-effectively separate material-feed into three size-fractions, each which is directed into a different recovery system. The smallest gold particles (which are most difficult to recover) are directed into low-profile riffles along the bottom of the sluice box which have long been proven to be very effective at trapping fine gold.

 

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Boulders & Winching Techniques

 How To Find Gold, Suction Dredging, Video Enhanced Stories
Nov 232011
 
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By Dave McCracken

There can be a lot of gold deposited under and around the boulders located within a pay-streak!

Dave Mack

 

It takes an incredible force of water to move boulders in a river. Once they are moving in a flood storm, they can deposit in low-velocity areas, just like gold does. But, since boulders do not have a higher specific gravity, mass for mass, than most of the other streambed materials, they can be washed downstream just about anywhere in the river during a major storm. So you should not only use the presence of boulders to guide you in sampling. You would be much better advised to focus your attention on the boulders that have been deposited along the common path of gold’s travel.

In shallow streambed material, you can sometimes detect where important bedrock changes are located by noting where the boulders have deposited within the waterway. For a boulder, or a group of boulders, to be found in a specific location along the river’s path, there may be a sudden bedrock drop-off, a large crevice, or some other kind of lower-velocity condition in that area which caused the boulder(s) to be deposited there. Everything in the waterway happens for a reason, even if you cannot always see what it is!

If the boulder(s) is located somewhere along the common gold path, that would be a prime spot to do some sampling. In this situation, I suggest that you do not limit your sampling to the area just behind (downstream) of the boulder, though. Go around to the upstream side of it, as well. Look for any bedrock change which may have caused the boulder to stop there. If gold has moved through that area, that same bedrock change could also have caused gold to concentrate there. Finding the bedrock change that stopped the boulder, and following the bedrock change across the waterway, is a great way to locate the common gold path.

You do not always find boulders with every rich pay-streak deposit. But, it is not uncommon to find many boulders keeping company with a good pay-streak. When you do find them, most of them will probably have to be moved out of your way as you work forward through the deposit.

MOVING BOULDERS BY HAND

There can be a lot of gold deposited under and around the boulders located within a pay-streak. To get most of the gold out from under a boulder and into your suction nozzle, usually the boulder has to be moved at least a little bit.

One of the most useful tools that can help a dredger move boulders is a 5-foot (or longer) steel pry bar. If a boulder is too large to be moved to the rear of the dredge hole by hand, it can sometimes be rotated around to one side so that you can dredge out from under part of it. Then, it can be rotated around the other way to access the remaining gold and material beneath. A long pry bar can be a big help to you in moving boulders around in this way.

The key concern while working around boulders is safety! Loose boulders in and around a dredge hole are the gold dredger’s greatest danger, especially when working alone. Boulders resting up in the streambed material are usually more dangerous than those resting on the bedrock. But, those on the bedrock can cause trouble, too, if they are loose and able to roll – particularly, if the bedrock has any slant to it.

As they are uncovered in a dredge hole, loose boulders should be moved and safely secured as a top priority. They should be placed at the rear of the hole, if possible. But, wherever they are placed, they should be positioned so they no longer pose any threat of rolling into the hole and on top of someone working there. You can place smaller rocks and cobbles under the boulders as necessary, to make certain they will not roll or slide.

If you start to uncover a boulder that is resting up in the streambed material, do not forget about it. Until it has been moved and secured safely, a loose boulder should be foremost in your mind. If it is not yet ready to be moved, and you still need to dredge around it to free it up some more, it can be useful to place an arm or a shoulder against the boulder. This way, you can feel if it starts to loosen up in the material. Do not place your arm, head, or shoulder near the underside of the boulder, however. Because, sometimes a boulder will loosen up and crash down very quickly, without much warning. Physical contact with the boulder is helpful when you cannot keep your eyes on it at every moment. The face mask limits your visual perception underwater – especially when you need to watch what is going up the suction nozzle.

The main concern here is to take all necessary precautions to keep yourself from becoming pinned or crushed beneath a boulder in your dredge hole. If a boulder pins any part of your body to the bottom, it may be difficult or impossible for you to get the necessary leverage to move the boulder enough to get out from under it. And, if you are working by yourself …? I know of two dredgers who ended their careers in just this way.

Also beware of fractured bedrock walls that tower over you. They can fall apart and drop in your dredge hole as you remove the streambed material that holds them in place. I got pinned once by a slab of bedrock that broke free of a wall as I dredged away the material that was holding it there. Luckily for me, it landed on my steel-tipped boot, and that I was dredging with another guy on that day!

The second greatest danger to a dredger usually comes from a cobble falling off the side of the dredge hole and hitting the dredger in some way — like on top of the head. This can finish off a dredger just as surely as a boulder. Or, it may cause some serious pain/injury. Fingers and other body parts can get smashed if you are not careful!

Most trouble with cobbles and boulders can be prevented simply by taking your hole apart with safety in mind. The proper method of taking a dredge hole apart has already been fully covered in my Gold Dredger’s Handbook, so I will not repeat it again here. But, as a point of emphasis, the fastest way to take apart a streambed also happens to be the safest way.

Production dredging goes very smoothly and quickly when you have some area of exposed (dredged) bedrock between the non-dredged material in front of you and the cobbles, boulders and tailings behind you. When you start uncovering a boulder in the material, you should immediately begin planning where you are going to move it, once it is ready.

If you run across an occasional boulder that you cannot move by hand, sometimes you can dredge the material (and gold) out from around and under it without having to move it out of the dredge hole. You accomplish this by moving other, smaller rocks out of the hole to make room for the boulder. In this way, if there are not too many boulders, you can keep moving forward on the pay-streak without the few boulders slowing you down very much.

But, if there are a lot of large boulders down along the bedrock, you will likely discover that at least some of them will need to be completely removed from your excavation if you expect to uncover very much bedrock with your suction nozzle. Some boulders will need to be removed to make room for other boulders as you move forward on the pay-streak. If you cannot remove the boulders from your dredge hole by hand, then you will need some mechanical assistance.

DIFFERENT TYPES OF WINCHES

COME-ALONG: A “come-along” is a portable, hand-operated winching device that can be of considerable help to a small-sized digging program. It can be used to move those boulders that are not huge, but which are too large to be moved by hand. Come-alongs range in size. I recommend a larger version of the better quality, rather than the really cheap, imported models. Come-alongs have a great accessibility factor, because you can carry one just about anywhere. Their operation is somewhat slow. But, they will give you that extra edge when you need to move just a few boulders, and you do not own or want to set up a power winch.

  • Using a Grip Puller

GRIP-PULLER: Several companies make a hand-winching device that rides along on a steel cable. There is a handle that you crank back and forth, similar to a come-along. Each time the handle is cranked in each direction, the device moves an inch or two along the cable. These units also come in different sizes. In my opinion, grip-pullers are a substantial step up from a come-along, both in pulling-power and dependability. I have used these units underwater, but find that the water resistance adds substantial work to the cranking action. Still, when you are working alone, having this device in the hole with you allows you to see what the boulder is doing while you are winching it

Where you can buy winching supplies

USING YOUR TRUCK AS A WINCH: If your vehicle can be driven to a nearby position, you can stretch a cable from the vehicle to the boulder. The proper direction of pull can be rigged up by running the cable through snatch blocks (heavy-duty pulleys) which can be anchored to trees, boulders or whatever is available. Then you can use the pulling-power of your truck to help move the boulders out of the way. Four-wheel drive vehicles work better for this, especially when they are carrying a load to increase tire traction. Suggestion: It is better to connect the cable to something on the vehicle’s frame, rather than just the bumper!

When conditions are right for it, using a vehicle to pull smaller boulders can be much faster than using a come-along. One person operates the vehicle, while a diver is in the water, slinging the boulders. Safety becomes a greater concern when more than one person is involved in the pulling and the slinging of rocks. Communication and coordination between the “puller” and the “slinger” are very important to prevent serious accidents. Suggestion: If you turn the truck around and pull in reverse, you can better-see signals from your partner, and sometimes you get better traction, especially on a 4-wheel drive vehicle. Another suggestion: It is better to keep your vehicle a respectable distance from any drop-offs (like into the waterway), just in case the boulder gets momentum in the wrong direction. I know of guy who got pulled over the side of an embankment by a boulder gone wild!

Larger-sized trucks, tractors, bulldozers, and other heavy equipment can sometimes be used to move bigger rocks with even better results.

AUXILIARY TRUCK WINCHES: Auxiliary automotive winches are also able to move small to mid-sized boulders for a dredging operation with excellent results. Some of those little winching units have a wondrous amount of power. A typical 8,000 or 10,000-pound electric winch will move a surprisingly-large boulder!

If you are going to be using an electric winch, you may want to consider installing dual batteries in your vehicle. It also helps to keep the engine running while you are winching, so the batteries can quickly regain their charge between pulls.

When using a truck-mounted auxiliary winch to pull boulders, it is a good idea to block all four wheels. This precaution helps to keep the vehicle from moving, rather than the rock you are trying to pull. The front tires should be blocked especially well. If there is an embankment to worry about, it is also a good idea to run a safety chain or cable from the vehicle to some additional anchor behind, like a tree or another truck. This will protect against losing your vehicle over the embankment if the boulder happens to roll the wrong way. Sometimes this added measure is necessary just to keep the vehicle from sliding during the pull.

Probably the best kind of auxiliary vehicle winch for dredging purposes is one that can be attached mechanically to the “power take-off unit” on your vehicle’s transfer case, if it has one. With this kind of winch, you can use the full power of your truck’s engine to pull rocks. Not only will this provide you with more pulling power, but you will not have to worry about your batteries running down.

There is also a lot of good to be said for the portable electric and hydraulic winches on today’s market. I know of many smaller-scale and commercial dredgers who use them. They are quite powerful! Portable electric winches can be framed up to (1) attach to a vehicle, (2) be taken out to the dredging site, or (3) even be floated on a platform, where there is deeper water. All that is needed is an automotive battery and a means of keeping it charged up. The portable hydraulic winches can be similarly effective. The winch controls can be extended out on a longer cable and even modified to work underwater, which can be very helpful!

LOG SKIDDERS: Most gold-dredging country is also logging country. So there are quite a few log skidders around that can be leased or hired to pull boulders for you. Log skidders are usually equipped with powerful winches. They can really do a job in pulling the larger boulders! Also, you can drive them into some pretty difficult areas. Hopefully, you can work out a deal that will be ideally suited to your operation; a deal perhaps, where you pay by the hour and have the skidder arrive at a certain time each day, or whenever you are in need of it’s services.

PORTABLE POWER WINCHES: Gasoline-powered, mechanical and hydraulic winches are available in all sizes. Generally, the larger they are, the more winching-power that they produce. But, the added size and weight also makes them more difficult to pack into some of the less accessible areas.

If you find a widespread, rich pay-streak with plenty of large boulders that need to be moved, you should set up on your dredging site the most powerful winch that you are able to haul in there. The more pulling-power you have available, the smoother and faster winching will go.

I never recommend that a dredger buy a portable power winch just because he or she will be dredging. It is probably better to wait until you know exactly what your needs are. I have worked many pay-streaks where no winching was needed at all. And, in many of the pay-streaks that did require winching, a number of the boulders were so large that the small, portable store-bought type of winch would not have been adequate for the job.

You can find some pretty heavy-duty used winches for sale at about the same cost as a lighter-weight, new portable unit. I advise waiting to see what you will need before putting your money into a winch.

Having said that, here is something to consider: Mechanical winches seldom have a control mechanism which can allow the operator to stand away from the machine where all the wrestling is going on (and in the line of fire if a cable breaks). While I have used some wonderful mechanical winches, there was never a time that we were pulling a big rock that I was not worried about something going wrong with all those tons of energy happening right next to me. There is a lot to be said about electric or hydraulic units that will allow you to step away from the danger with the controls in your hand.

WINCHING COBBLES IN DEEP MATERIAL OR SHALLOW WATER

As I have stressed in other articles about dredging, the main limiting factor to progress is in how quickly oversized material (rocks that are too large to be sucked up the nozzle) can be moved out of the ongoing excavation. In deeper streambed material, there can be so many cobbles that there is no longer any room directly behind the dredge hole to throw them. You can run into a similar problem in shallow water, where the cobbles must be lifted out of the water (where they become a lot heavier) to get them behind the dredge hole. In these types of situations, it is common to fill cargo nets with your cobbles and winch them out of your dredge hole in bulk. The following video sequence was taken in an operation where we were removing big lots of cobbles from a deep excavation in just this way:

  • Winching Cobbles

SETTING UP A HOLE FOR WINCHING

Before you start winching boulders, it is a good idea to first make sure that you have located the lower (downstream) end of the pay-streak. You do not want to winch boulders onto any part of the pay-streak that you will be working at a later time. While the winter storms could possibly move some of the cobbles and dredge tailings which were placed on a pay-streak in error, it takes much more than a winter storm to move boulders from where you winch them. Believe me; it is much better to plan ahead, so you only need to move boulders one time!

BUILDING A RAMP

It takes a tremendous amount of winching-power to pull a boulder up and over another boulder from a dredge hole. The direction of pull is all wrong, and the second boulder will act like a barrier. The winching is much easier, smoother, and far less dangerous, if a ramp is built so the boulders will have an inclined runway to be pulled along. Cobbles can be used to make an effective boulder ramp. Therefore, an important part of setting up your dredge hole for winching is to construct a ramp/runway that can be used to easily remove the boulders, without them encountering difficult obstructions.

It can be really tough to pull a boulder out of a hole without a ramp.

Cobbles can be used to make an effective ramp for winching boulders out of a dredge hole.

One approach to setting up your hole is to dredge around a number of boulders as much as possible to free them up for winching. This way, more boulders can be pulled out of the hole once winching is begun. Then you can come back later to clean up the bedrock with your dredge.

To perform winching effectively, you will need plenty of air line attached to your hookah system. This is because it is necessary for the diver to sling each boulder and follow it to its final destination where he will disconnect it. Then, the sling and cable must be pulled back and attached to the next boulder. Since this process requires a lot of movement, depending upon the distance involved, you may need to attach an extension onto your air line to accomplish this smoothly.

FEASIBILITY OF MOVING BOULDERS

A dredging operation that requires a lot of boulders to be winched is going to move slower than if little or no winching is required. A winching operation almost always requires the involvement of at least one other person, sometimes even two or more. Those “extra hands” will usually expect to get something for their active participation in your dredging project. So you will find that when you need to use a winch, you will be moving slower through the pay-streak, and it will usually cost more to run the operation. Therefore, a pay-streak that has lots of boulders usually needs to pay pretty well to make the additional effort worthwhile.

The following video segment will give you a look at an organized winching program where multiple persons were involved:

  • Winching Boulders

Sometimes, you may discover an excellent pay-streak, but find that it lies beneath many boulders that have to be moved. Even though there may be plenty of gold under the boulders, after figuring the time and expense involved in winching, you may conclude that the gold recovery, though excellent, is still not sufficient to make the project economically feasible. Big boulders are not easy to move. Moving them takes time and money; more, sometimes, than the gold is worth. So, to avoid getting bogged down in an unworthy project, keep track of your daily expenses and your daily gold recovery. Then you will have some basis for calculating whether it is financially worthwhile to continue dredging in that specific location.

If your winching helpers are not full-timers on your dredging operation, and if the location is not too remote, you might arrange to have them arrive at a certain time each day to help pull boulders. That way, you can spend the morning setting up the hole to winch as many boulders as possible. Then, when your help arrives, the boulders can all be winched out of the hole at one time. After winching is completed for the day, you can let your winch helpers go, while you go back down and clean up the hole with your dredge. This way, you are not paying helpers to stand around with nothing to do while you are dredging. It can make a difference.

SETTING UP A WINCH FOR OPERATION

When you are using a portable power winch to move boulders in a dredging operation, the winch must be set up on a solid and stable foundation. It takes a tremendous amount of force to move a boulder. Sometimes, the boulder will move quickly. Or, sometimes, the sling will slip off the boulder, causing the cable to suddenly go slack. Maybe the boulder will loosen up and roll the wrong way, causing a sudden, heavy stress on the cable. When these things happen, and they do happen, you do not want your winch bouncing around or sliding off the platform. That could be extremely dangerous! The winch must be stable!

The winch also should be anchored to a solid object behind it which will hold its position much more securely than the boulders that are to be moved. A fair-sized tree, or a large boulder, directly behind the winch platform can work well for this purpose.

Also, the cable or chain being used to anchor the winch must be considerably stronger than the winch’s capability to pull. The last thing you need is your anchor chain or cable breaking while you are pulling a large boulder! This could cause the winch, and the winch operator, to be yanked off the platform, resulting in a serious accident. Undamaged, heavy-duty truck tow chains with the adjustable end-hooks are excellent for anchoring a winch. Make sure you get chains that are strong enough.

Your winch should also be anchored to a point which is lower than it is. If the winch is anchored from a low point, when boulders are being pulled, the winch will be held down more solidly onto the platform. If the winch is anchored to a higher point, during pulling the winch can be lifted off its platform. This can also be dangerous.

Sometimes, you will not be able to find a good location for your winch along the streambank. You prefer a location where the winch can be set up to directly face the boulders to be pulled, and which provides a level, solid foundation with a properly-located, fixed object from which to anchor the winch. But if that is not available, you can almost always find an acceptable foundation somewhere between two large objects along the bank. The platform may require a little concrete work to get it right. The winch can be anchored to one of the objects, while the other object can be used to attach a snatch block (heavy-duty pulley). The cable can then be run from the winch, through the snatch block, to the boulders that need to be moved. One advantage to this rigging setup is that if the cable does happen to break under a great strain, it will be less likely to fly directly at the winch and its operators.

Positioning the winch between two anchors on the bank,
because there is no easier way to get a straight pull with the winch.

When you set up a winch, it is usually best to position it so the boulders will be pulled as much as possible in the desired direction. The boulders will also need to be pulled far enough away from the dredge hole that they will not have to be moved again at a later time. Often, you will not be able to set up the winch in a position where you can directly pull the boulders in the desired direction. For example, you may want to pull them downriver, rather than toward the stream bank. This situation is most commonly corrected by using directional-change snatch blocks. A snatch block (pulley) can be anchored at a point from the exact direction that you want to pull boulders. The cable then runs from the winch, through the snatch block, to the boulder. In this way, you can usually move the boulders in any direction that you desire from a stable winching position along the bank.

Setting up the proper direction of pull by anchoring a snatch block directly downstream in the river.

Directional-change blocks for winching should be very heavy-duty. They need to be stronger than the cable being used, or the capability of the winch to pull. The best pulley is one that can be quick-released from the cable. This way, you do not have to feed all the cable through the block to get rigged for winching. Good winching pulleys are generally available at industrial equipment supply stores and at marine equipment shops. Directional-change blocks can be attached to trees or boulders with the use of additional cable, chokers or heavy-duty chain. You will find that a few extra tow chains (long ones) and chokers will come in very handy when setting up a winching operation. Chains which have the end-hooks on them are best, so you can adjust their length to meet your needs.

To minimize damage to the environment, you can place pieces of wood between the cable or chain and the trunk of any tree that you use as an anchor. When you anchor a directional-change block to a tree or boulder, you are almost always better off anchoring to a low point. This will reduce the chances of rolling the boulder over or pulling down a tree.

When you use a cable to anchor a winch or directional-change block to a boulder, set it up so that the pull will not cause the cable to become pinched (between two boulders or between a boulder and the bedrock) or be pulled into the material underneath the boulder. Otherwise, after the winching, you may have trouble retrieving your cable without having to move the anchoring boulder as well.

At times, you may need to set up a directional-change block, to pull boulders in a desired direction, but cannot find a downstream boulder that is large enough to use as an anchor. In this case, you can run an additional cable out from a fixed object further downstream on the opposite side of the waterway, and attach your directional-change block to the cable. Then, by increasing or decreasing the length of the cable, you can position the block right where you want it.

Setting up a directional-change block by extending it out on a cable from the other side of the waterway.

It is not a good idea to winch boulders with rope, even the smaller boulders being pulled by your truck or a come-along. When you use rope for winching, the rope stretches even if it is doubled-back multiple times for extra strength. And, it stretches. And, it stretches. Then, it breaks. Such breaks can be dangerous when working around boulders. Also, it can quickly exhaust your supply of rope. Rope is just not strong enough for the job. Steel cable is best. You might get a deal on good, used steel cable from the scrap metal yards. Call around to find out who has it when you need it. Scrap yards usually sell it at scrap prices, by the pound, even if it is in good condition.

The cable you use on your winch should always be considerably stronger than your winch’s pulling capacity. The last thing anyone wants to see is a bunch of out-of-control steel cable flying wildly back in his direction. Faulty or worn cable should be replaced immediately and never used thereafter for winching.

Winching boulders involves an incredible amount of force. So does hauling logs by cable. Similar cables are used in logging operations to pull trees to the loading area. I have heard stories of logging cables snapping, flying back, and cutting a man in two. You are dealing with a similar amount of force when winching the larger boulders in a dredging operation.

WINCHING SIGNALS

During a winching operation, it will be necessary to have a diver in the water to set the sling on the boulders. The diver will also need to remove the sling from each boulder after it has been moved, and then return the sling and cable back to the dredge hole for use in moving the next boulder. This process will continue until all the boulders for that stage of the dredging operation have been moved.

Unless the diver is slinging boulders and operating the winch (a very slow way to go, unless the controls to the winch are in the water with the diver), another person must operate the winch, truck or other device that will be doing the pulling. Once you have more than one person involved in the operation, communication becomes a critical part of the process.

If the winch is a smaller one, or if a truck is being used to pull boulders, and the pulling position is in sight of the target boulders, the job might be accomplished with only one winch operator. On the other hand, in a normal two-man operation, if the winch operator is unable to maintain constant eye contact on the area where the winching is taking place, perhaps a third person will be needed to help with the communication. Each situation will be different. Since this need for immediate and accurate communication is a safety matter which requires on-site judgment, you will have to decide how many people are needed to winch safely.

Sometimes a truck can be turned around to pull backwards, and the driver can directly see and simultaneously carry out the diver’s signals. The controls on an electric winch will often allow a second person to be positioned well enough to see what is happening where the rocks are being moved.

While a boulder is being moved, the diver can watch its progress and signal the winch operator to stop pulling and/or give slack on the line so the boulder sling can be adjusted, if necessary, to successfully complete the movement as planned. The main point is that the diver must be able to communicate to the winch operator quickly and without error. The greater the pulling-power and/or speed of the winch, the more important it is that these signals be accurately received and acted upon quickly. Imagine that you are using a powerful winch to pull a large rock with a heavy steel cable and solid anchoring objects. If your boulder gets jammed against something else in the dredge hole so that it will not move, and you continue pulling with great force, something is eventually going to give. And, it might not be the boulder! This uncertainty is what you want to avoid.

If you are using a winch that does not automatically feed the cable evenly onto the drum, the operator will sometimes need to manually guide the cable. Otherwise, on hard pulls, if the cable starts crossing itself and is allowed to pinch itself on the drum, it may become damaged and thereafter be dangerous for further winching. For this reason, the winch operator may need to focus some attention on the winch, rather than on the diver. In this type of situation, it is wise to include an additional person to help relay communication. Someone needs to be watching for the diver’s signals at all times.

Gasoline-powered winches make noise. So does a gasoline-powered hookah-air system supplying air to the diver. The diver also usually has a regulator in his mouth. With all of this noise present, and the diver having his mouth full, verbal signals are usually not very dependable – especially, if there is a substantial distance between the diver and the winch operator. For these reasons, I have often found visual signals to be more trustworthy, particularly when there is a person positioned at the winch to relay the diver’s signals to the winch operator.

In shallow water, hand signals can usually work pretty well. You really only need three of them: “PULL” , “STOP” and “GIVE SLACK ON THE CABLE”. I highly suggest you take a look at the standard set of signals that my partners and I use in our own dredging operation. These can be found in a special video segment included with an article I wrote about teamwork. Otherwise, create your own signals so that they can be quickly and clearly understood, and one signal cannot be confused with another. There is also a section on winching and signals in my video, “Advanced Gold Dredging & Sampling Techniques.” You might want to check it out to get some ideas.

At times, you may be faced with the need to winch boulders out of a dredge hole located in deeper water. In this case, the diver will be heavily weighted down to stay on the river-bottom. He may also be some distance from the streambank. In this setting, it may be nearly impossible for the diver to surface to give timely signals to the winch operator. The process of getting up to the surface can simply take too long! When this is your situation, and if the water is not moving too fast, you may consider using a buoy, tied to a rope that is anchored near the dredge hole, to relay your signals. I personally have found the best and safest signals to be: (1) buoy underwater means, “PULL” (2) buoy floating at the surface means, “STOP PULLING” and (3) buoy bobbing up and down in the water means, “GIVE SLACK”.

This method of buoy-signals is relatively safe. If the buoy is anchored a short distance from the boulder, in order to pull the buoy underwater and hold it there, the diver would have to be away from the boulder on the “PULL” signal. If the buoy is floating, the diver can be anywhere, which is why it is the best choice for the “STOP” signal. You need to make certain, however, that nothing is allowed to snag the buoy’s rope (like the pull cable or an air line) which could pull the buoy underwater and cause a false “PULL” signal!

One other safety note:All divers must always watch their own hookah air lines during winching, to make sure an air line (or the signal rope to the buoy) is not snagged up in the cable or rolled over by the boulder as it is moved.

BOULDER SLINGS

When slinging boulders, try to make sure the pull cable will not rub too heavily or get crushed against other boulders. It is always best to protect the pull cable and let the boulder sling take the pounding. The boulder sling is going to be pounded anyway. Because of this rough duty, boulder slings should be replaced or repaired periodically.

One type of boulder sling often used out in the field is a long, heavy-duty tow chain with end-hooks which allow the chain to be quickly and easily adjusted to any length. This system gives you a fast set up. Just wrap the chain around the boulder in the proper place, connect the end-hook to give you the right fit, and she’s ready to go.

Tow chain boulder sling with end hook.

However, some boulders are smoother and rounder, which makes it more difficult to get a good “bite” with a sling made out of chain. Every time you start to pull, the boulder might move just a little and then the chain slips off. You can waste a lot of time working on a single boulder in this way; it can get quite frustrating.

Logging cable-chokers are also useful for making a cable sling that will tighten up on the boulder as you pull. This may improve the situation, but still not work problem-free on smooth, round rocks.

For round and smooth boulders, I have found the best remedy to be an auxiliary “boulder harness.” This homemade boulder harness consists of heavy cable, chain, steel pipe and cable clamps. It is very easy to construct. The sections of steel pipe slide onto the cable to protect it and to keep the cross-chains properly positioned. The harness is set up like a lasso. It pulls tighter around the boulder as stress increases on the line. And, it generally works well in pulling even the most difficult boulders.

How to put together an excellent boulder harness for winching.

PULLING BOULDERS

Some boulders come easy and some do not. A lot of the problem is in breaking the boulder’s initial suction/compaction in the streambed. If your winch does not have the power to pull a boulder the way you have slung it, sometimes you can break the boulder free by using a rolling hitch A “rolling hitch” is rigged by slinging the boulder backwards, then running the chain or cable over top of the boulder. This places the winch’s pulling-power along the most-leveraged position on the boulder. This will sometimes free a stubborn boulder by rolling it.

How to sling a rolling hitch.

When pulling boulders up and out of a dredge hole, you should pull them some distance away from the hole. Otherwise, if there are more boulders to be moved, they may begin backing up along your ramp and block the passage of any more boulders. This could require you to move them all again, which is a time-waster that you can avoid with proper planning in the first place. For example, take a look at the image at the beginning of this article. That is a top view of a winching operation we did on one of our Group Mining Projects a short while ago. See how we were pulling the boulders back well out of our ongoing excavation?

If you are dealing with relatively deep streambed material and a lot of boulders, you may want to set up an adjustable, directional-change block behind the hole. This way, the boulders can be winched out of the hole in several different directions. This will prevent them from backing up so quickly.

Setting up an adjustable directional-change block to pull boulders in several different directions.

Once the dredge hole has been opened enough, some of the boulders can be winched or rolled to the backside of the hole, rather than taking them up the ramp. Winching will start to go faster when you get to this stage. Depending upon the situation, it may be necessary to winch some of the boulders up the ramp and out of the hole to prevent too much jamming. Be sure to keep access to the ramp free and clear. Otherwise, you may get closed in with too many boulders in the rear of your hole. The more boulders that are jammed up, the more difficult it can be to clear them out of the hole.

Sometimes, when you have winched your boulder to its destination, it will end up on top and pin your sling underneath. If you are using a tow chain as your sling, you can usually just unhook it and have the winch pull it out from underneath the boulder. But, if you are using a sling made of cable, you may not be able to pull it out from under the rock without damaging the harness. For this reason, it is a good idea to have a second sling on hand to help move the boulder off the other harness when this happens.

DIVER’S SAFETY

A diver will be safest by staying well away from the area where a boulder is being winched, and the path it will be taking as it is being pulled. The forces involved in winching are more than enough to cause a very serious accident. Since the diver is underwater, the winch operator sometimes cannot see what is happening where the bolder is located.

What can happen down there, though, is when the diver sees the boulder getting hung up on things as it is being pulled along, he wants to move in and help it along with his pry bar. The less power that your winch provides, the more the diver will naturally feel the need to help the boulder along in this way. Never forget that your safety margin is considerably reduced when you get near a boulder while it is being pulled! A safer course of action would be to stop the pulling and reset the harness, or reset the direction of pull, or improve the boulder ramp, or find a stronger winch for the job. Or, you can increase the pulling power of your existing winch by double blocking…

DOUBLE BLOCKING

“Double blocking” is accomplished by attaching a snatch block to the boulder sling, running the pull cable through that block, and then back to the last directional-change anchor. This type of rigging will nearly double the amount of pulling force that can be exerted against the boulder by the winch and pull cable.

Double blocking back to the last directional-change anchor
will nearly double the winch’s pulling power against the boulder.

If even more power is needed, another block can be set up on the line to run the pull cable back to the boulder sling. The pulling force of any winching device can be increased by continuing to double block in this way. There is a disadvantage to all this rigging, however. It takes much more cable to pull boulders any significant distance. Also, it is equally more difficult for the diver to pull the boulder sling and cable back to the dredge hole after each boulder has been moved. With all that cable going back and forth, it can get pretty complicated – especially if you are dealing with a limited amount of visibility. Quick-release snatch blocks are a must when double blocking. This way, you can detach the pulleys from the cable without having to feed it all the way through.

Actually, one double block is not that hard to manage as long as you have enough cable. It is when you double block a second time that it starts getting difficult to keep track of which cable is going to where? But, this alternative is available to you if you need the extra pulling power to move a particularly large boulder.

Directional-change blocks, by themselves, do not give you an increase in pulling power. For a power increase, the cable must be doubled back so that the boulder is moved only half the distance that the winch is pulling on the cable.

 

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Cold Water Dredging

 How To Find Gold, Suction Dredging
Nov 232011
 

By Dave McCracken

As far as I’m concerned, if you are going to spend a lot of time dredging in cold water, a hot water system is definitely the way to go!

Dave Mack

Cold Water 1
“Photo by Tim Cook”

Can you recall ever standing alongside an unheated swimming pool or just next to the water’s edge on the beach, trying intently to muster the nerve to jump into the cold water? Perhaps you even tried to build up to the big leap by counting, “One, two, three.. .jump!” — only to find yourself still standing at the edge of the water after the countdown and feeling like your body is not quite under your control. This can often be the case when you are dredging in cold water. The key to successful cold water dredging is having the proper equipment — particularly those items needed to keep your body from getting too cold and uncomfortable.

Wetsuits

Wet-suits are designed to allow water to get inside the suit. Your body-heat then warms the water up, insulating you from the colder water that remains outside the suit. In really cold water, the main problem with a wet-suit is that initial frigid shock which shocks your body as the initial cold water rushes into your suit when you first enter the water. This happens again every time you re-enter the water after knocking out a plug-up in the jet tube or every time you take a break. This “cold water shock” has an accumulative affect on the body; and even the toughest people often find ourselves going “one, two, three” on the bank and have trouble making our bodies jump back into the water.

Some wet-suit divers lessen the pain of cold water shock by having a hot tub of water on the bank. They pour the hot water into their suits just before re-entering the water to help bring up their body temperature. Hot water systems that provide a steady flow of warm water into a wet-suit are even better — but we will address that topic below.

There are different types of wet-suits, some which are designed especially for cold water use. Cold water wet-suits are usually made of thicker rubber, have few or no zippers, and almost always have the hood directly attached to the wet-suit top. There is also the “shortie,” which is like a pullover wet-suit sleeveless T-shirt with or without a hood attached. A shortie can be worn underneath or over top of a regular wet-suit to create added warmth. In addition to the added thickness of rubber around your upper torso, a hooded-shortie prevents a lot of the cold water shock from running down your neck and back!

Important note: The more rubber you add for insulation from cold water, the more lead you must add to your weight belt(s) so you can remain firmly anchored to the bottom of the waterway when you are dredging. Also: The more rubber that is added around your upper body, arms and shoulders, the more constrained your arms and shoulders will be. Dredge work underwater is mostly stomach, arms and shoulder-work (movement). Therefore, adding more rubber increases the amount of effort required to get the work done. Effort in dredging is like money in your wallet. You only have so much. So it must be managed as efficiently as possible. Because, once you have used it up, your day is over.

Dry-suits

For cold water dredging or diving, dry-suits are definitely a step above wet-suits (when there is not a hot-water system). A dry-suit is designed to keep all of the cold water out. Basically, there are two different types of dry-suits available on the market: Those that use the rubber or nylon shell as insulation, and those that require additional insulation to be worn inside the suit. Both types work well; it is a matter of individual preference as to which kind is best for you.

Dredging activity is very hard on any type of suit. There are many different models and makes of dry-suits available. Some are designed more for sport diving rather than dredging and hard work. Dry-suits generally are quite a bit more expensive than wet-suits. However, you cannot rightfully put a price on comfort and warmth when you are spending many hours underwater working for a living. If you are cold and uncomfortable, you will not get in as much dredging time; and you will not make as much gold (money). So, my advice is to spend the extra money on getting a quality dry-suit if you are going to buy one.

Dry-suits generally require more maintenance than wet-suits. Mainly, the seals at the extremities and the zipper must be properly maintained. Most dry-suits have zippers which should be coated with bees wax every several uses and sprayed with silicone each time the suit is used. The seals should be sprayed just before each use. This allows them to slip on more easily, and prevents unnecessary stretching. The zipper is the heart of a dry-suit and must be handled with care. You have to be careful not to get sand in it, and not to sit on it or rub it heavily while moving rocks around in the dredge hole. I always glue a rubber flap over my dry-suit zippers to further-protect them from dredging wear and tear. Most manufacturers stress having a second person zip it closed rather than doing it yourself. This is because it is difficult to pull the zipper straight when it is behind you, as many dry-suit zippers are. If you damage the zipper, the suit is no good until you get the zipper replaced.

You will find that even the smallest puncture holes in a dry-suit need to be patched when diving or dredging in extremely cold water. Otherwise, you are constantly uncomfortable with cold water entering the suit from that location.

Hot Water Systems

Cold Water 2As far as I’m concerned, if you are going to dredge long hours in cold water, a hot water system is definitely the way to go! Water is usually heated with a heat-exchanging device mounted to the cooling or exhaust system of the dredge motor. The dredge pump is tapped to provide a water supply, which runs through the heat-exchanger, then through a steam trap/mixing tank, and then down through a hose to pour a constant volume of warm water into the dredger’s wet-suit. Some dredgers are using propane continuous-demand hot water heaters, but most use heat exchangers mounted to their engine exhaust systems.

Hot water heat-exchangers are available on the market. They are also reasonably easy to build. Most homemade exchangers are built with a long length of copper tubing which is either wrapped around the existing exhaust system or is coiled inside a separate housing through which the engine’s exhaust is channeled.

Photo By Tim Cook

The key to a hot water system is to provide an abundance of hot water. If you do not have plenty of hot water for all of the divers working on a system, then you will most likely end up pumping cooler water into each diver’s suit, which can be worse than having a wetsuit with no hot water system.

Hint: You can never have too much hot water — because you do not necessarily have to use it all.

Most ordinary wet-suits are adequate as hot water suits — particularly with the addition of a hooded shortie vest. Dry-suits normally do not make good hot water suits, unless they are modified. This is because the seals prevent the hot water from exiting the suit. After a while, all the excess water inside the suit cools down and makes the diver cold. Removal of the seals on a dry-suit would probably make it a good hot water system (as long as it is a tight-fitting dry-suit) — but this seems a waste of money when a far less expensive wet-suit will accomplish the same purpose.

The main problem dredgers can have with a hot water system is being scalded by extreme hot water or steam. This problem can largely be solved by adding a steam trap to the system. Some prefer to call this a “mixing tank.” A mixing container can be made out of PVC plastic tubing. One of the primary purposes of the mixing container is to be a holding tank for water and steam. So, if extreme hot water or steam is created in the system, it will have a chance to mix with the warm water in the tank before being pumped down to the diver. The mixing container should be mounted vertically on your dredge with the input coming from the top, and the output to the diver being on the bottom of the container. This way, steam is prevented from being pumped directly to the diver(s). Some systems contain a low-pressure relief valve at the top of the container to allow air and steam to release.

mixing containerThe mixing container must be large enough to absorb a shot of extremely hot water, but not so large that it allows the water to cool down before it is pumped to the diver. The mixing container allows the diver to feel the rise in water temperature much more slowly, so that the hot water hose can be removed from the wetsuit before it gets uncomfortably hot. Sometimes, the water can be so hot coming out of a heat exchanger, that a special steam hose must be used. In fact, just for safety, I always use heat hose on the connection from the heat exchanger to the mixing tank.

If the water coming out of the heat exchanger is too hot to pump directly to a diver — which is often the case — a source of cold water can also be tapped from the pump and directed into the mixing tank through a valve. By regulating the amount of cold water, you can adjust the temperature of the water being pumped down to the diver. This also increases the volume of warm water available to all of the divers.

Warm water is usually pumped down to the diver through the same kind of hose being used for air line. The hot water line and air line are usually taped together to prevent tangling and additional underwater confusion. The hot water line can be slipped into your wet-suit down through the neck. I usually poke a hole in my wet-suit near my chest where it is easy to slip the hot water line in and out of my suit.

Or, in extremely cold water, you can devise a splitter system which will direct some of the warm water to your chest, hood, each bootie, and each glove. This is the best way to do it if you are dredging in ice cold water. However, sometimes the splitter system can be avoided simply by having a hot water system which provides so much volume, that the warm water is forced out into these same extremities.

When dredging in ice cold water, if you do not have warm water directed to your hands, it is usually necessary to use three-finger wet-suit mittens. Otherwise, your hands can go numb from the cold. Three finger mittens are bulky; they prevent you from picking up larger cobbles with one hand, and they generally slow you down. With a good source of hot water to the hands, you can often get by with a good set of slightly-insulated rubber work gloves with the openings loosely rubber-banded around your wrists to prevent cold water from entering.

Dredge with snow on the decksAuthor was developing some of the early hot-water heaters on his first dredge in 1981 while working in the frigid waters of the Trinity River in Northern California.

It is necessary to warm up your dredge engine to normal operating speed for at least several minutes to properly set the temperature of the water directed to the divers from the mixing container. Once you get the temperature working right for you, you normally do not need to make any further adjustments on subsequent dives, as long as you are running the motor at the same RPM.

If you stand around for a few minutes with hot water pouring into your suit, there is usually no shock at all when entering the cold water. As a matter of fact, it can be a pleasure to enter the cold water after you run your body temperature up to the uncomfortable stage when you begin sweating.

A hot water system should be removed from the dredge when not being used, like during the warm summer months. Otherwise, the heat and vibration will tend to wear the heat-exchanger out unnecessarily. Also, even when not in use, if a hot water system is attached, water should be allowed to flow through it any time the engine is running. This will prevent unnecessary overheating of the heat-exchanger.cold water 3

Photo by Tim Cook

If you are tapping your dredge pump for a supply of water, be sure the water output is either closed off or underwater when priming your pump. Otherwise, there may be an air leak which can prevent priming.

The nice thing about a hot water system is that it will supply a continuous feed of hot water into your suit. This way, your body’s energy reserves are not being constantly used up to keep warm. As a result, you can be comfortable and get in more dredging time.

Important note: You can also be so warm that your body doesn’t want to work — like being in a hot shower. The solution to this lies in the amount of cold water you valve into the mixing tank, or how far down you zip your wet-suit jacket! Believe me, “too warm” is a much easier problem to solve underwater than “too cold.”

A common question people ask is, “Should I get a hot water system, or a dry-suit?” The answer to this lies in what you intend to do. I suggest having both systems available, depending upon your activity. For production dredging and sampling in extremely cold water, I would use a hot water system. For swimming across the river to stretch a rope, or for swimming down the river with mask and snorkel to look at the bottom in extremely cold water, I would recommend a dry-suit.

Other Things To Know About Cold Weather Dredging

If you are working in freezing temperatures above water, there are certain things that should be done on your dredge each day before knocking off. Your pump should have a drain plug tapped into the bottom. This way, you can drain the water at the end of each day to prevent your pump from freezing solid. It is not a bad idea to bring some hot water with you everyday in a thermos, because sometimes the pump will freeze even with the water drained. Be careful not to crack the pump housing by pouring too much scalding water directly over it when it is freezing cold.

Also, in freezing weather, the concentrates and water must be completely cleaned out of your recovery system at the end of each day. Otherwise, they will freeze solid and prevent the system from working until it thaws out the following day — if it thaws!

If you are not going to process them directly, your concentrates from the day should be stored well underwater to prevent them from freezing on the bank. Your mask, hood and gloves should be brought back to camp each evening and kept warm. Otherwise, you have the misery of putting them on when they are ice cold — unless you have a hot water system on your dredge.

Winter Dredging

Eric Bosch and author displaying nuggets pulled while diving together.

Dave and Eric holding nuggetsEven if you are able to handle most of the cold water problems with the use of good equipment, another factor winter dredgers often have to deal with is higher and faster water. While the higher water will allow you to mine further up on the edges of the river, in many areas it will prevent you from mining out in the faster and deeper water areas-which may provide easy mining during the summer months. If, due to the faster, higher water, you are not able to get out and sample in certain sections of the river, you will not be able to run a full testing program on that section of river; and you will miss pay-streaks. So, it can also be more difficult to locate deposits during the faster and higher water months of the year.

On the other hand, if the river edges are paying, the winter months may be the only time they are available for dredging. The location of deposits are going to vary from one place to the next.

While wet-suits, hot water suits and dry-suits do make for good insulation underwater, they generally provide poor insulation to the cold air above water when you are wet. Therefore, it is good to have a warm winter jacket to wear over your diving suit while taking breaks on the surface.

Tents in the snowAs a side note on this, my commercial dredging buddies and I ate many hurried lunches on deck during the winter months (even while it was snowing) while the dredge continued to run at operating speed (with a rock placed over the suction nozzle to slow the water in our recovery system), pumping warm water into our suits.

If you are mining in extremely cold conditions, it really helps to have a warm and comfortable camp. A person can put up with some pretty cold and miserable conditions if he or she knows there is a warm shower and hot meal coming later that evening. There are few things worse than freezing all day and then going back to stay in a wet and cold camp!

Author’s campsite during his first several years as a gold prospector.

How Tough Are You?

It takes a pretty tough person to dredge in extremely cold conditions. Even with the best equipment, there is still a substantial amount of cold water exposure on your hands and face. You spend quite a bit of time working on the dredge, tying off lines, swimming the river, cleaning up concentrates, making repairs, etc. This all adds up to exposure which can be painful or uncomfortable. Some people are gung-ho enough to dredge in extremely cold water on a short-term basis. Few people are willing to do it long-term.

We all have the potential to be tough enough to dredge in extremely cold water. What it always comes down to is whether or not we desire to be that tough! A lot of people think they are, and then realize they are not willing to do it!

Talk is cheap!

I was mining with several guys in 34-degree water one winter. One of the divers and I were sampling for a new deposit while the other two guys were actively dredging out a rich deposit we had already located. They were recovering several ounces of nugget-gold each day, while we were knocking out sample holes. One day, we helped get the production operation started and then headed out to do our sampling. We soon realized we forgot our lunch, turned around and drove back to where our partners were dredging. We had not been gone fifteen minutes, and they had already gotten out of the water and were in the truck with the heat turned on — drinking hot coffee! These were tough guys; that water was cold!

A partner and I were dredging in Alaska in October when things started to freeze. We’d had a very good season, but I wanted to put more ounces into my bottle before returning home. Ice had already formed on the edges of the river, and my partner had been ready to leave weeks before. I was determined to spend one more week dredging, because the gold was good and I had plans for what I was going to do with it. One day, with a week to go, I could not make my body go underwater again. “One, two, three, go!” — but my body refused. So, it just wasn’t worth it, anymore! I walked over and tugged on my partner’s air line and asked him if he was ready to go — home, that is. We were on the road later that afternoon in a warm truck with the heat blasting. In that area of Alaska, three feet of snow fell that night!

There is a point where the body just takes over and says, “No!” And, this is probably the point where it is smart for you to listen.

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Cleaning up

 Crevicing and Vacuum-Mining, How To Find Gold
Nov 232011
 

BY JUDE COLLEN KENDRICK

 

This is a picture that you will seldom see – me getting up at 5:30 a.m. full of excitement – to vacuum! Yet, I spent some of last summer and almost all of this past winter, doing just that. It wasn’t “dust bunnies” I was after, however; it was gold!

A few Decembers ago, I wrote a Christmas dry-washing article about the Mojave Desert. I said that I had made a portable vack machine to clean off the caliche (cement-like material) shelves that one encounters out in the desert. But it was not until last summer on the Klamath River near Happy Camp in California that I actually used the vack machine for what most people use them for, which is crevicing.

I knew about crevicing, of course, but it just wasn’t my thing. In fact, on several of my surface mining (motorized sluicing) trips there would be lots of prospectors around the creeks crevicing and getting gold. I cannot recall, though, at that time seeing anyone with a vack. They all had store-bought or homemade tools to get the gold out of all the nooks and crannies. On the Klamath, I borrowed a Mack-Vack made by Pro-Mack in Happy Camp, because I did not have the space to bring my motorized sluice along. My little portable vack that I had made was in the “equipment graveyard.” I had brought gad bars and digging tools, so I was set up to crevice. I will admit that I was not very enthusiastic about it at the time. I like to see dirt flying and lots of material running through my equipment. But it did not take long to change that lack of enthusiasm!

The bedrock around the area where I was on the Klamath broke apart fairly easily. I walked around trying to find the right kind of hard-packed gravel between the seams of these massive slabs. I had only used the vack for a while and had only about half of the 5-gallon bucket filled (not much material, I thought). Yet, when I panned it out, there was a beautiful match head-sized nugget. Now, this type of prospecting wasn’t bad at all!

Kay Tabbert and her husband Chuck, both members of The New 49’ers, were in the same area at the time. Chuck was busy dredging while Kay, with only her little hand tools, a whisk broom and dustpan, was crevicing on some bedrock not far downriver from me. All of a sudden I heard Kay calling for Chuck (and anyone else around). So I walked over to see what was going on. I could not believe it. Kay had separated a rock about the size of a melon, and in the crevice, stuck to one side, were 7 beautiful large flakes of gold! Just like that! I could not get back to my area fast enough!

I had dredged for years and I knew just how to spot the places where the water would deposit gold. It was really no different from working in the water – I just did not have to get my hair wet! I was feeling a little impatient, though, as I never did wait to fill up an entire 5-gallon bucket with material using the vack machine. But what I did pan produced great little “clinkers” of Klamath gold.

Unfortunately, I only had about seven days last summer up on the Klamath. But, I had five months this winter to play in the dirt. Lucky for me, I got “hooked” on vacuuming crevices!

I was prospecting Quartzsite, Arizona and the surrounding areas. The desert had a lot of rain this past summer and everyone was hoping that the washes would “pay off!” I decided to sell my beloved “Nick’s Nugget” dry-washer, as I knew I was going to be out prospecting alone a lot. As great as it was, it was too heavy and clumsy for me to manage on my own. I purchased a small dry-washer combo (with the vack option) from my friends Bob and Linda Taylor. This was great. One engine ran both and I could carry everything in one trip.

Hunting for bedrock in the desert is certainly not like on the rivers. It definitely does not expose itself as much. Yet in many places it is not deeply hidden. I was finding many places in washes where people had dug down to bedrock and had not even touched it with a whisk broom. So, guess what I did? They had already done the heavy work. I just sat there and vacked up the gold!

Finding new places to vack was not easy, as I have said. I have known for years, from experience, that the gold in the deserts isn’t always where it is supposed to be. What would look like great bedrock on the rivers often means nothing in the desert, mostly due to the lack of water volume and movement in the deserts. When I arrived at Quartzsite I met up with Al Powell, who is also a New 49’er member that I met briefly while on the Klamath. Al and I were finding “perfect” looking bedrock, in established gold areas, that produced nothing. We were always shocked, because all the “recipes” for gold were there. We could have found more gold in downtown Quartzsite! We were not giving up, however!

I decided to take five days and go off to find a hot spot for Al and me to work. I found a very small ravine below a heavily mined area that had a large section of bedrock exposed. It took two days of pulling “Buick-sized” rocks to work myself down to where I was getting some nice gold. After the fourth day, I showed Al my gold and took him out to the spot so we could clean it out together. Well, I suppose I did my job too well; as except for some small flecks, Al and I vacked all day and got nothing large. “OOPS! Sorry, Al!”

The weather in the desert turned nasty, with off and on heavy rains that went on for days. Consequently, all of the dry-washers around the desert were silenced. The ground in places was damp as deep as eight inches down, which forced people to grab their gold detectors and head out nugget-shooting until things dried out. Yet, Al and I were not held back; we were still out there, in a new area, with our vacks. We didn’t have any trouble bringing up the damp gravel, although the two of us looked like “mud pies” at the end of the day.

I had, from the beginning, been running my vack materials through my dry-washer so I would not have to pan as much concentrate. Even the damp material did not present much of a problem, as Al and I just ran everything through the dry-washer two or three times. I am sure that the people driving by during those wet days who saw the dry-washer running, said to themselves, “They are crazy!” Well, that is a whole other story, but we did have our pretty desert gold to look at all the way back to our desert “sanitarium!”

I would recommend purchasing a vack to anyone, even as a backup to your usual motorized sluice or dry-washer. And, now, when “housework” day comes each week, I won’t dread using the vacuum; I will just be practicing! Good Luck!

 

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Capturing Gold Nuggets

 Electronic Prospecting, How To Find Gold
Nov 232011
 

By Richard Doherty

“With the new instruments available today, millions of gold nuggets are within reach of the intelligent, properly equipped, electronic prospector.”

 

Hand full of beautiful gold nuggetsWhen I first heard about picking gold nuggets from the surface, or close to the surface of the ground, I really didn’t think it was feasible.

I made some halfhearted attempts at locating some of the precious yellow beauties with no success and much frustration. Finally, I buried a gold nugget down in the ground and attempted to locate it with my new detector. To my surprise, it wouldn’t detect the nugget, so I moved it closer to the surface and still couldn’t detect the target. It was almost on the surface by the time I was able to receive a very light audible signal. That did it! I quit!

Still, the idea of locating a gold nugget with an instrument really intrigued me, so I stayed in touch with the advances of metal detectors. In the meantime, I continued my more conventional prospecting activities in Arizona, where I was fortunate enough to associate with other prospectors who knew about gold deposition.

Years later, the metal detector industry began to develop detectors that would deal, at least somewhat, with the highly-mineralized ground associated with gold deposits. So I purchased one of the most advanced detectors on the market and went in hot pursuit of the elusive yellow nuggets. Hour after hour, I combed the ground; I searched everywhere the gold “had to be!” If it was there, I wasn’t finding it, so I pressed on.

Scorpion made from gold nuggetsFinally, after many, many frustrating hours, the first nugget succumbed to my detector, minutes later, another. I really got excited, and I decided to share this new-found activity with my friends. I helped them learn what I had learned, and then we developed new methods and techniques. Detectors were getting better, and I purchased the latest equipment, knowing that I needed every edge that I could possibly acquire.

We sorted out which instruments worked best and figured out how to get the most from the ones we decided to work with. Nuggets began to fall on a regular basis, and more friends became interested. We turned them on to the equipment we were using and the techniques we had developed. They began to find gold nuggets almost immediately. This surprised me; because after all the heartache I went through to locate my first nugget, my friends were quick to pick up what we had already learned.

Gold nugget hunting is not like coin hunting at all; it is a specialized field and requires specialized equipment and techniques. Once learned, it is easy. As you do it more and more, nuggets will yield to your detector more consistently.

First, there are three “musts” for any degree of success. Not one of them is any more or any less important than the others, because they are dependent upon each other:

1. The correct instruments must be selected. Selection is based upon the instrument’s performance relative to the size and purity of the gold and type of ground that will be searched.

2. Knowledge regarding the use of your instrument must be thorough.

3. Knowledge about where the gold is located. Most of this information is gathered through research and talking with others who already know.

Your degree of success depends upon how diligently each one of these three “musts” is followed, and it is that simple. If you decide to approach finding gold nuggets in this manner, it is not a matter of, “Will I find a gold nugget?” It is only a matter of when, how big, and how many!

Huge rough nuggetIt has never before been more possible to locate your own gold nuggets with the aid of a metal detector, than it is right now. It is not that there is more gold out there. In fact, each day, there is a little less. However, with the new instruments available today, millions upon millions of beautiful gold nuggets are now within easy reach of the intelligent, properly-equipped electronic prospector. You don’t need tons of equipment to haul around, nor do you need many thousands of dollars to get started. The exercise is mild; the air is fresh; and the pursuit of your own gold nuggets is done at your pace — no one else’s.

I would also like to mention some of the myths surrounding electronic prospecting. It is difficult to place these in any order, so I will just mention them according to the frequency of times I am asked:

“Are there still gold nuggets out there to be found?”

“Will a metal detector really find gold?”

“Didn’t the ‘old-timers’ get all the gold?”

“Why isn’t everybody doing it?”

“Isn’t all the land claimed up?”

“Don’t I need a specialized vehicle or mode of transportation to get to the gold?”

“Isn’t it hard work?”

“How can I find gold nuggets when I know nothing about geology, mining, mineralog, or electronics?”

“Won’t a detector find fool’s gold?”

Please don’t let these questions, objections or myths stop you from gathering your own gold. It’s a whole new exciting, profitable activity, and you can do it!

Public awareness is definitely on the increase, and hundreds are getting into the activity of capturing gold nuggets from the earth. There are pounds of gold being taken daily, and there is no reason why you cannot be taking your share!

Frustration and lack of confidence is the primary cause of failure. The reason most electronic prospectors fail is that they purchase inadequate equipment or don’t learn how to use it properly.

Hunting coins and hunting nuggets with a detector are quite different. Coins are a flat-sided target. Many nuggets are not. Also, many flat nuggets will slip sideways into a crack or crevice in the bedrock, which leaves very little target-area available from the surface. Shape, size, and lack of the “halo” effect can cause a gold nugget to remain a difficult target.

Of course, there are exceptions to this. Not too long ago, I found a 5/8-ounce gold nugget that was about one inch deep, lying flat. It sounded-off like a quarter! I was amazed to retrieve a beautiful nugget which was shaped like an eagle’s head!

Nugget hunters know how important good equipment is. I was speaking with a professional electronic prospector the other day, showing him a new detector. Before I could tell him what the detector cost, he said it didn’t matter anyway; because he was willing to spend any amount of money on the detector if it was significantly better than the one he was using. You see, he knows that good equipment will pay for itself, especially with the price of gold nuggets as they are.

I know coin hunters who dream of finding their first gold coin. Most never do. However, electronic prospectors, who follow the basic guidelines, will find hundreds of gold nuggets.

Where is the gold? This brings us to another reason why now is an excellent time to get started in this fascinating activity. There are clubs and various types of associations which you can join where you will meet other people who prospect. Some of these organizations provide mining properties for their members to prospect. The folks who run clubs are usually quite particular about the mining properties which they own, and they are also knowledgeable about which claims they should stake or purchase. One of the easiest and fastest ways to find gold is to join one of these clubs. Some even provide training programs or organize group mining projects where you can gain immediate, valuable hands-on experience. Talk with other members and the staff to gain information as to where you might begin your prospecting. This is the best way I know of to get started in any type of gold prospecting today.

As you prospect on these claims and talk with others, you will begin to get a “feel” for where the gold is and why it is there. Gold seems to be a lot easier to find if you already know it is there. If you are not sure, it could cause you to search halfheartedly, and that is not conducive for locating nuggets. You must know the gold is there; you must know how to operate your equipment; and you must know that your equipment will get the job done. If you have these three criteria well in hand, you will surely find your own gold. After that, it’s just a matter of spending some time doing it and improving your skills.

In the beginning, it may take you a minute or longer to recover a target you have established; but soon, these targets will be coming out of the ground so quickly that you will surprise yourself. My average recovery time per target is between fifteen and thirty seconds, depending upon digging conditions. I have seen it take as long as 30 minutes to extract a target, but these are more unusual conditions.

In Quartzsite (Arizona) last year, we had occasion to dig in some very old material that was as hard as concrete. This material had been deposited millions of years ago. There was no man-made metal present. But the gold was there! My detector sounded off, and we knew what it was; so we started to excavate. It was hammer and chisel time! You must be very careful not to scar the nugget, so digging has to be carefully-done. Almost 30 minutes later, out came a beauty. It weighed just over ½-ounce. It was detected under 13-inches of highly-mineralized, concreted earth and rock.

As you uncover a valid target, it will usually develop into a clearer signal or stay about the same. If it stays the same, you may also have passed over an area that is highly mineralized. Or perhaps there was some kind of hot fire in that spot during some time in the past. Sometimes, ashes will read very slightly on the detector. But the signal does not develop as you dig down on it.

If the signal disappears altogether, you have either moved the target, or you may have had a piece of rusting ferrous material that fell apart when you moved the soil. A magnet comes in handy to quickly isolate ferrous targets; it can be a real time saver!

Bullets, nails and other foreign metallic targets are some of the items you will learn to deal with. At first, they are nothing but a nuisance. However, let’s take a closer look at this: If you are digging metal of this nature, not only does it hone your recovery skills, but it tells you that the area has not already been searched-out (every smart, responsible detectorist has a container along to remove small metal trash-targets from the playing field).

If there are no previous dig-holes, you may be the first person to detect that area. But if there are dig-holes, and you are still finding metal, it tells you someone else did not do a thorough job. If they left trashy metal in the area because they were using an electronic discrimination mode, they certainly will have left nuggets behind, too! You will pick up the nuggets your predecessor left, because electronic discrimination seldom can be used effectively while nugget hunting. Only under certain conditions would you use discrimination, and that would be after many hours of experience. Even then, you could make costly mistakes. My advice is to not use electronic discrimination while hunting gold nuggets.

Meters, gauges, bells and whistles do not make a good nugget-hunting detector. I personally feel about the only function they serve to the nugget hunter is to add weight to the instrument — which is the last thing you need. Although I will admit that there are other good prospectors around who disagree with my opinion.

The following is a list of recommended reading material which may call for reading and re-reading. This is not a complete list, but the material suggested here is a must:

Willie Merrill wrote a book called, THOSE ELUSIVE NUGGETS; and he not only knows what he is talking about, he shares his knowledge in a very free manner. I have read the book no less than five times. Each time, I learn something new. Our minds are not always ready to accept all information the first or second time through.

Another book of importance is ELECTRONIC PROSPECTING by Roy Lagal and Charles Garrett, which will also require more than one reading. This book goes into the many avenues of electronic prospecting.

Any magazine articles written by successful electronic prospectors are definitely worth reading. Hundreds of articles could be written on the subject of electronic prospecting, and each one of them will have some hot tips for you. .

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Defining Acceptable Ground

 Gold Prospecting & Sampling, How To Find Gold
Nov 232011
 

By Dave McCracken

It is important to define for yourself how much gold you need to recover to make the effort worthwhile.

Dave McCracken

 

It is a very good idea for you to define for yourself what amount of gold is minimally acceptable for you to recover on a daily basis. It might be a half-ounce per day. It might be more. Or it might be less, depending upon the size of the dredging or other mining equipment you are using, your operating expenses, and how much gold you need to recover to make the effort worthwhile. The main point here is that you should set some minimum standard. If you are recovering that much gold on a daily basis, you will stick with it. If your daily averages start dropping below that point, you will start sampling around for better ground.

There are several good reasons for doing this. One is that if you do not know about how much gold is acceptable to you, and what is not acceptable, you can waste a lot of time “going on hoping” (for some undefined target) while you continue to dredge in low-grade material, rather than sample around for something better like you should. Another good reason is that you need to determine how far to each side and how far to the rear to dredge into the lower-grade material along the boundaries of a pay-streak. I covered this subject more thoroughly in another article.

Perhaps the best reason that you need to define a minimum acceptable level of daily gold for yourself, is so you can take in the better, and much better, and tremendously-better pay-dirt as a bonus when you find it. This could be on a regular basis if you become good at sampling. If you do not take on the good finds as a bonus, you can find yourself comparing the good finds with the acceptable finds; and pretty soon the acceptable finds may not be acceptable any more! This is especially true when you are dredging up a high-grade pay-streak.

I know of a guy that was new to gold dredging, who was into a very large pay-streak which was paying him a little more than half-ounce per day for every day that he went out and dredged. He was happy with this. That was well more than an average day’s wages in the profit he was making over top of expenses, and gold prices have been going up to make that even better. Everything was going along just fine until one day when he uncovered a bedrock up-cropping and pulled six ounces of beautiful gold out of a single pocket in the bedrock just in that one day. The following day, he was back into the half-ounce amounts again. Only that was no-longer good enough. He quit shortly thereafter. He left the area, never came back, and I have not heard of him since.

What happened? He got spoiled from the incredible feelings generated from uncovering really valuable golden treasure. This causes something which is often referred to as “gold or treasure fever.” Once the extreme high-grade was finished, he could not go back to recovering just half-ounce of gold per day, anymore. It is kind of like losing the person you love. Nobody else will do.

If you stick with gold prospecting long enough to get good at sampling, there will always be greater highs. But if the greater highs are the only thing that is now acceptable pay-dirt, you will find yourself frustrated a lot of the time.

If you define for yourself what is acceptable as pay-dirt, as you continue to get better at sampling, you will find that there is a surplus of acceptable ground available to you. Therefore, you will be able to upgrade your minimum acceptable levels a degree or two as time goes along.

If you are willing to mine every bit of acceptable ground that you can get into, and are willing to accept the bonuses as they are uncovered, and just treat them as a bonus, you will be making more gold more of the time – and you will find more bonuses, too

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