How to Increase Your Gold Finds

     From a prospectors standpoint, the metal detector may be one of the most significant breakthroughs of the twentieth century. It is believed that the first metal detector was discovered accidentally in 1925 when a radio engineer in the United States noticed a metal water tank was causing interference with his field experiments. These original detectors were nothing short of clumsy giants. They required large heavy batteries and often a wooden wheelbarrow to cart them around in. Even the BFO (beat frequency oscillator) type of the late 1960’s were extremely limited in depth penetration and the amount of ground mineralization they could handle. Consequently, electronic prospecting (or nuggetshooting) really didn’t gain momentum until the invention of the light-weight VLF (very low frequency) detectors of the early 1970’s. Since then metal detectors have come to play an important role in many different fields such as archeology, military mine detection, security, geology, criminal investigations, as well as a wide variety of industrial uses. However, this article will primarily focus on the use of the metal detector as a prospecting tool. The tips contained within can be applied across the board, regardless of which type of detector you happen to be using.

     Among the best areas to search for gold nuggets with a metal detector are those where placer gold has been recovered in the past. There is a difference between hardrock and placer gold deposits. Hardrock mining is the process of working mineral veins from the earth’s crust. Veins which carry gold or a variety of other precious metals are referred to as lodes, and are commonly associated with quartz. Usually the pCenter of gold in these veins are microscopic or are chemically combined with other elements within the ore (i.e., sulfides). These types of veins are not well suited to search for with a metal detector, since it requires that a metallic target have a large enough surface area to generate sizable eddy currents and establish a secondary field; thereby allowing detection. In other words, if the minute gold pCenter are scattered throughout the vein or chemically altered in some way, they may not create a large enough disturbance to be picked up by the detector. Another problem could be the depth at which the vein is positioned. If it is buried beyond the capability of the detector you will never be able to find it.

     Don’t let me give you the impression that it is impossible to detect hardrock veins because this is not true. Free-milling gold veins, especially the shallow epithermal type can be found throughout the western United States. Over the years epithermal deposits have been an important source of both hardrock and placer gold; the state of Nevada has been home to some classic examples. Even though finding veins with a detector is a difficult business, diligent prospectors with a keen eye do occasionally discover shallow gold-quartz hardrock veins. My father came across a reef (or vein) not long ago in the tropical goldfields of the Northern Territory, Australia and recovered 2.5 ounces of crystalline gold from one hole! If you are interested in learning more about detecting for hardrock gold or drywashing, I would strongly suggest reading some of the books written by my friend Jim Straight. Jim has accumulated a wealth of knowledge about prospecting and his books have proven themselves to be an invaluable source of information (see references).

     It is for the reasons listed above that recreational prospectors and especially detectorists, are primarily interested in the location of nuggets (i.e., those pieces of gold too large to fit through a 10 mesh screen). Placer gold can be loosely defined as free pCenter of gold (i.e., dust, flakes, nuggets, etc.) that have eroded away from the original lode, and have been deposited elsewhere by the forces of nature. By far the most powerful agent for moving gold is water. Pieces of eroded gold will be dispersed down a hillside by rain storms, snow melt off, wind, etc., until they eventually find their way into a river or other water channel. The gold will then be swept up by the running water and redistributed and concentrated downstream. Because of its massive weight, gold has a tendency to become deposited in specific locations; which we will discuss later.

     There is a considerable amount of eluvial gold to be found in the desert areas of Mexico and the western United States; primarily Arizona, New Mexico, Nevada, Utah, and southern California. While the geology varies from state to state, they all have one thing in common; an arid climate. A vast majority of the gulches, gullies, washes, etc. that bisect the goldfields remain dry throughout most of the year. Monsoonal flash flooding and wind erosion become the principle weathering processes and means for transporting gold. However, these short lived torrential downpours and dust storms are nowhere near as powerful or efficient classifiers as a constantly running river, therefore desert gold has a tendency to become scattered rather than concentrated. Lack of water prevents much of the gold from agitating down to bedrock; consequently nuggets will be found throughout the entire gravel strata. It is for this reason that the soil, rock, and other angular rubble found within desert (or dry-placer) gravels remains largely unsorted. Many times large nuggets (weighing several ounces) can be located only inches from the surface!

     An important aspect of the dry-placer environment is that it greatly hampers gold recovery. Throughout the years insufficient water has prevented large scale hydraulicking, dredging, and sluicing of rich desert gravels. Methods such as drywashing, winnowing, and dry panning had to be utilized instead. As most of you already know, water is the crucial ingredient needed for successful gold recovery. Without it, overall efficiency of any operation can at best be described as ‘mediocre.’ The most productive areas have been worked to some degree by the old-timers without water; as a result they lost much of their gold. Because of the lack of water, harsh climate, isolation, and insufficient recovery systems, a majority of these locations were abandoned and have remained largely unnoticed until recent times. Nowadays with the advent of the modern metal detector, these dry-placer areas are once again yielding substantial quantities of nuggets. The metal detector is an effective tool for working desert regions. It is lightweight, relatively inexpensive, has the ability to find pieces smaller than 1 grain, and is by no means dependent upon a water supply.

     Dry-placer areas of the West are ideally suited for metal detecting. Not only are the conditions (geological and environmental) present for large surface nuggets and shallow patches, but there are hundreds upon hundreds of acres of public lands available to prospect and claim. This provides the nugget shooter with a definite advantage, because it greatly broadens his or her search area. These vast regions of relatively unexplored back country may prove to harbor sizable amounts of detectable gold. It’s just a matter of getting out there and swinging the coil! However, you should be aware that there are certain areas which are closed to mineral entry such as: military land, Indian reservations, state monuments, national parks, private land, wilderness areas, and wildlife refuges.

     Gold deposits have been found in every one of the western states. Tracking down these locations is not all that difficult as long as you are willing to do a little research. There have been many “ Where to Find Gold ” books written on this subject and believe it or not they can sometimes lead you right to the nuggets. Other sources can be found at public and university libraries. You can obtain geological reports from the Bureau of Mines. They offer specific information about the minerals discovered in various states and counties. Due to their popularity, many of them have been reprinted and can be purchased from prospecting shops. Topographical maps, which are put out by the Geological Survey of the Department of the Interior, can be useful in locating small prospects, mine shafts, tailings, etc. Another powerful new tool is the Internet which has rapidly become one of the most influential mediums for the exchange of knowledge among global prospectors. There are entire web sites and forums dedicated to helping the small miner locate precious metal deposits. Joining a prospecting club is also a good way to gain access to proven gold bearing property and meet new friends. Probably the most simple and inexpensive source of information comes from other prospectors. Not all prospectors are secretive; some are willing to share their knowledge if you are friendly and willing to listen. Talk with these people and find out where they are hunting. Maybe if you get to know them they will not mind if you do a little detecting in their areas. Whether you’re prospecting the dry washes of the rugged Sonoran Desert or an alluvial fan in northern Nevada, one thing should be kept in mind; make sure the area has some record of placer production. Some districts have been very rich in lode gold, but have only given up minimal amounts of nuggets. As mentioned before check old bulletins, prospecting books, maps, surf the web and talk with other hunters. Your chances of finding gold greatly increases if you search within the vicinity of known nugget bearing areas.

     Now that we have done our research and chosen a gold bearing area to visit we must decide where to begin searching with our metal detector. Whenever exploring a new goldfield I strongly recommend that you always start off hunting in the gulches, gullies, and washes. The reasoning behind this statement is simple. We know that our location has produced placer gold in the past, therefore it must have ( at least at one time ) contained numerous gold bearing veins. During the course of time this auriferous material has been slowly eroding down the steep hillsides in an attempt to reach equilibrium with nature. These gulches, gullies, and washes represent the point of lowest energy (excluding the center of the earth), consequently the eluvium (rocks, boulders, soil, etc.) and gold collects in seasonal water channels. We must keep in mind that the original landscape has been altered due to natural weathering processes which have been occurring for many, many years. Entire hillsides have eroded, waterways have changed course, and boulders have been tumbled. Therefore, if there is any gold in the area, there is a high probability that a few pieces will have made their way into one of these washes.

     Before going any further it is important to mention that desert waterways vary considerably, both in appearance and size. According to Straight, “ Gulches are narrow steep “ V ” shaped depressions, often full of brush and difficult to work. Gullies are a wider, less steep version of a gulch. A wash is a larger “ U ” shaped depression. If large (wide, deep) enough, it is called a canyon. Both gulches and gullies feed into washes.” Throughout this article you will notice that I use the term “ wash ” to describe any dry watercourse found within an arid region, regardless of its size or appearance. This may not be the best use of terminology, but just for the sake of this article lets label them all as washes.

     Another benefit of wash hunting is that it allows you to mentally limit your search area. For example, a wash could be anywhere from five to thirty feet wide; whereas a hillside may be much more vast. Trying to cover such an enormous amount of ground can seem overwhelming and may leave you feeling frustrated. They are just too big and time consuming. So unless you know of a particular hill that is a carrier, I would suggest sticking to the washes.

     One of gold’s amazing natural properties is its high specific gravity. When comparing gold to most other elements found in the environment we notice that is extremely dense and heavy. Gold is 19,000 times denser than air, 19 times denser than water, more than 3 times denser than quartz, and twice as dense as lead! Because running water is scarce, desert gold will not concentrate in the same manner as the alluvial or “ stream placers ” of the California Mother Lode. However, because of gold’s amazing weight we are still able to make specific predictions about where it is most likely to accumulate. Once a nugget is removed from the original lode and finds its way into a wash, it will eventually be acted upon by the movement of water. If the water velocity is high (i.e., during a flash flood) the nugget may be swept downstream for a considerable distance, until it reaches an area where the water pressure slackens and it can come to rest. If the water velocity is slow the nugget may only travel a very short distance before dropping out.

     Remember gold is dense! It doesn’t want to move and it will take the shortest path possible between any two given points. Gold can be found virtually anywhere in a wash, however it does have a tendency to hug the inside bends. This occurs as a result of the difference in water pressure created whenever flowing water is forced to change direction. The centrifugal force causes a much greater flow of energy towards the outside bend, which creates a lesser force towards the inside; thereby allowing our nugget to drop out there. Whenever you are prospecting a wash you should always thoroughly detect the inside bends; especially those with exposed bedrock.

     Another situation in which you are likely to encounter deposits of nuggets are areas where a narrow wash suddenly widens. A wide wash is able to handle a much larger volume of water, therefore the water flow will slow down. This becomes particularly important during periods of high water. As we already discussed heavy elements (such as gold) will drop out wherever the water flow slackens. Unfortunately, so will gravel, rock and other overburden. This accumulation of material creates additional depth and you will have to compensate accordingly in order to maximize your chances of hearing a faint target. Pay extra special attention to overlapping and slow down your coil sweep speed. Remember, those sections of a wash which have abrupt changes in width could contain possible pay-streaks.

     Gold nuggets can be trapped by obstructions and various changes in the bedrock. Things like large boulders and tree roots are quite capable of stopping gold in its journey downstream. If a boulder is lying directly in its path the gold will have no choice but to either wedge underneath it , or go around it. The protruding boulder causes the water to flow much slower behind it. Any gold that makes it around the boulder may become concentrated on its downside because there is insufficient force to keep it moving. Whenever you encounter one of these boulders it is always a good idea to sweep your search coil around its base. If it is not too large you may want to roll it out of the way and detect the virgin ground underneath. Tree roots and clumps of shrubs can also act as natural nugget traps. Occasionally pieces of gold will become entangled in these roots and will remain there for many years until eventually the plants dies and is washed downstream. Interestingly, I have a friend who uncovered a shiny 8 dwt. nugget simply by gathering dirt from uprooted trees situated on the banks of Lynx Creek, Arizona! So next time you get a signal from those tree roots be sure to investigate it, just don’t damage the tree in the process.

     Bedrock (also called country rock) is the outermost layer of the earth’s crust. Once a nugget or any other object hits bedrock it must stop there. This is very important for the detectorist because many times the washes found in dry-placer regions have bedrock that is shallow or even exposed. Since all metal detectors have a limited depth ability, it is beneficial to hunt areas that are close to bedrock, because the nuggets will be within detectable range. The morphology of the bedrock will most certainly change depending upon the composition and geological conditions that are prevalent in the area you are searching (granite, schist, slate, etc.). The appearance will also vary from place to place (i.e., color, texture, etc.). I generally classify bedrock as being one of two types: rough or smooth.

     Rough bedrock is sometimes called “ Nature’s perfect sluice box, ” and it is highly regarded among electronic prospectors because of its excellent nugget trapping ability. Jagged decomposed outcrops full of deep cracks and crevices make it virtually impossible for the gold to escape. If a nugget wedges itself within one of these cracks it will remain there until the bedrock breaks down or a lucky hunter comes along and removes it. Whenever you encounter areas such as this, slow down and focus your efforts on the cracks. If you receive a signal in a crack first, remove the gravel, sand, rocks, etc. with your pick or hand. Then close your eyes and gently blow into the crack with your mouth. This will clear away any excess material and hopefully expose the nugget. If you still don’t see the nugget use a flat head screwdriver to scrape any other material and blow it out again. You might also consider fitting your pick with a super magnet. As you’re digging, periodically rub it into the crack. If the target is a piece of ferrous trash it will quickly be removed, saving you from unnecessary work. Fortunately, if you are digging up the bedrock and the signal persists, your chances of it being gold greatly increases. You may also notice concentrations of black sand ( magnetite and hematite ) in these cracks. Black sands are heavier than ordinary sands and settle in much the same way as gold. The presence of black sand in a crack is a good indicator of gold, but just like everything else it is not a definite guarantee.

     Smooth bedrock will have a slick polished look, almost as if someone has taken an electric sander to it (and in a sense this is what has actually happened). Smooth bedrock started out as being rough but because of the sheer amount of water, sand, rocks, and boulders that have scoured its surface it has lost the original texture. Usually smooth bedrock will be found in the lower ends of a wash or at the edges of drop-offs; like waterfalls. Most of the time the nuggets will hit these areas and just slide right on by, although this is not always the case. I remember one occasion when I received a signal from a very smooth section of bedrock. There didn’t appear to be any sign of a crack, but I decided to dig anyway. After 20 minutes of prying and chipping I discovered a flat 38 grain nugget! It seems that at one time a crack had existed which originally trapped the nugget, but over time it had pinched shut and was smoothed over, vanishing without a trace. However, this is somewhat of an exception as most of my gold has come out of the rough bedrock. If time is of the essence, your best bet is to bypass the smooth stuff and concentrate on the rough sections.

     The final thing I would like to briefly mention is thick brush. Because water tends to collect and pool in desert washes it is not surprising that they are often full of vegetation. I do not particularly enjoy hunting in the brush, and I am assuming that neither does anyone else. Your arms get scratched up, your clothes get snagged, it is very difficult to swing the coil, and they’re likely to contain rattlesnakes or other desert critters. So normally when a person reaches a brushy spot, they walk around it and commence detecting in a more open area. This is exactly why I will hunt the brush. These places are tough to detect, so chances are they are virgin, and there is no telling what they may be hiding. I found this out the hard way when a friend picked up a quarter ounce nugget behind me in a thicket of brush. It was a tough lesson to learn, but it has paid off greatly since then. Try working the brush sometime, I think you will be surprised at what you find.

     Thus far we have only briefly discussed the methods used by early miners to process auriferous desert gravels. However, old-workings can be extremely productive places to search with a metal detector. By far the most popular piece of equipment used in the recovery of desert gold was the drywasher. Arid regions presented many new challenges for the placer miner. The first prospectors used or needed very little equipment, other than their eyes. Most of the nuggets were laying on the ground in plain view. Early prospectors (armed only with a crevicing tool) could simply walk along a wash and inspect the bedrock for exposed nuggets. However, these rich surface bonanzas quickly played out, and the miners needed an inexpensive device that could effectively process and recover coarse gold from dry gulches without the use of water; hence the evolution of the first primitive hand operated drywashers.

     Experimental prototypes slowly began showing up on the world’s goldfields. According to Straight, “ In 1897, Thomas A. Edison designed a dry process machine for saving gold in New Mexico. Later the Australian method of dry-blowing was introduced to areas like Quartzsite, Arizona and Manhattan, Nevada. They came in all shapes, sizes, and brands such as the “ Mexican air jig ” and the “ Hungarian dry washer. ” Then in the 1920’s, W. H. Harris first experimented with a hand cranked continuous (blast) current of air. ” Ultimately giving rise to the “ continuous blast ” type of gasoline powered machines still being used today.

     In its simplest form a drywasher consists of a grizzly (mesh size varies) supported by a frame which is fitted with an adjustable riffle tray. Hand cranked models typically use a system of bellows to move (or vibrate) the material across the riffles, while blower-motor powered models are equipped with a fan offset by a spinning counter-weight. Air is pushed through a hose by the blower which then causes the unequally weighted fan to spin, effectively shaking the riffle tray. Basically all the models do the same thing, it’s just a matter of how they accomplish it. As dirt is shoveled into a drywasher, the larger overburden is immediately screened off while the smaller material passes through and enters the riffle tray. This process leaves two distinct piles (or tailings) which we will label as either coarse or fine. The coarse pile forms at the front of the drywasher, this is where the larger rocks and nuggets that wouldn’t fit through the screen will be located. The fine pile will be produced towards the back of the drywasher, this material has already been processed and probably will not contain any large nuggets.

     As its name suggests, the drywasher was designed to recover gold from dry dirt. This is where many miners both then and now encounter problems. If the dirt is not absolutely dry (or at least close to it) the drywasher begins losing gold. If small pieces of gold are intermixed with moist material, they will have a tendency to slide over the top of the riffles instead of properly agitating down and becoming trapped. Big nuggets will most likely be caught, but tiny flakes could be lost amongst the fine tailings. Shoveling dirt too quickly into the unit only worsens the problem. Now the riffle tray will become overloaded and backed up with material, and once again the gold will have an opportunity to escape. The only solution is to remove the dirt, allow it to dry under the sun or over a fire, and then run it slowly through the drywasher.

     Even if the material is completely dry we still can’t be sure that we are not losing large nuggets off the grizzly. At first it would seem as if an ounce or even half ounce nugget would immediately stand out on the screen, but this is not always the case. Drywashers produce large amounts of dust pCenter which can impair vision. The nuggets can also be coated with a layer of dirt or mud, they may even be encased within a chunk of clay. Therefore it is relatively easy for a nugget to slip by unnoticed, especially if someone is not paying close attention.

     Fortunately for us, the old-timers didn’t have access to metal detectors, so it is very possible that they lost quite a few of those prize chunks in their tailings. It is for this reason that the coarse piles should always be thoroughly hunted. If you encounter a coarse pile take some time to first carefully grid the entire surface. Then use a pick or rake to scrap down 1-3 inches and recheck it. This will allow your detector to gain additional depth. Continue this process until the entire pile has been leveled. Undoubtedly you will encounter some metallic trash such as wire fragments, lead, staples, etc. Be patient and dig all your targets, because you never know if the next signal is going to be that 3 ounce lunker!

     A majority of the drywash piles I’ve seen have been situated on the banks of washes. It seems that in order to prevent the accumulation of worthless overburden the freshly dug material was carried and processed a short distance away from the actual operation. As far as the old-timers were concerned this material had already been worked, so there was no need to let it pile up around their hole. As you might imagine, erosion has taken its toll on these tailings piles. Some of them are only moderately scattered, while others have been completely swept away. Those that have survived may be overgrown with brush and can be very difficult to identify. Carefully scan the banks, searching for anything that looks out-of-place. Usually they will appear as oddly classified humps, and with a little practice you will have no trouble identifying most of them out in the field. If you do happen to come across one of these drywashing sites; especially those containing older trash such as square nails, soldered tin cans, broken bottles, and tobacco cans; be sure to investigate them with the detector.

     Also remember to detect the actual hole from which the material was removed. Many times prospectors will labor for days digging all the way down to bedrock and then forget to clean out the cracks. Here-in lays a golden opportunity! Use your detector (preferably with a smaller search coil) to carefully inspect the newly exposed bedrock for overlooked values. I have found as many as four decent sized nuggets in one abandoned drywash hole!

     Hopefully you will find these tips useful in your pursuit of the elusive yellow metal. Metal detecting can be a wonderful pastime. It provides the perfect opportunity to get some exercise, enjoy nature, and spend time with family or friends. In my opinion, it isn’t how many nuggets you find, but how much fun you have in the process. I wish you the best of luck with all your prospecting...

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