Thursday, July 31, 2008

Weight Measurements for Gold Miners


Whether you are a novice to mining or an old timer at recovering gold, sooner or later the time will come when you'll want to weigh your finds and find out just how much of the yellow metal you have. If you don't have one already, buy yourself a scale (either the older balance type pictured above or one of those new-fangled digital models) and use the following as a guide:

24 grains = 1 pennyweight

20 pennyweights = 1 troy ounce

12 troy ounces = 1 troy pound

If you are one of those miners who prefers the avoirdupois weight system, here is a troy-to-gram conversion chart:

1 grain = 65 milligrams

1 pennyweight = 1.555 grams

1 troy ounce = 31.104 grams

1 troy pound = 373.248 grams

Remember, gold's symbol on the Periodic Chart of the Elements is Au (from the Latin word for gold, "aurum"). Gold is a noble metal with a very high density and specific gravity, which means it is typically quite heavier than the other elements around it including water and larger, less dense rocks, sands, or gravels. Gold rarely if ever tarnishes and is highly malleable (soft enough to be flattened, shaped, or worked) and extremely ductile (can be drawn into very thin wires or "threads").

There you are. A morsel or two of information on gold measurements that may prove helpful.

(c)  Jim Rocha (J.R.)  2008

Wednesday, July 30, 2008

5 Tips for Novice Gold Miners


1. Educate Yourself

Take the time to learn all you can about gold and gold mining BEFORE you rush out the door gold pan in hand. As in any pursuit, there are many fine points to be considered and studied in gold mining, small-scale or otherwise. For a newcomer to placer mining these include the geology of gold, stream hydraulics, deposition physics, mining history, and a good understanding of placer gold mining equipment, tools, and recovery processes. Whew! Sounds like a lot to learn, doesn't it? In some ways it is, but not all of this is meant to be learned overnight. And if you take the time to learn something about gold and gold mining first, you'll be a much more successful miner in the long run.

2. Stick to Basic Tools and Equipment

If you're a gold mining novice, it makes absolutely no sense to spend hundreds or perhaps even thousands of dollars on fancy and costly mining gear like motorized dredges or highbankers. Keep it simple and learn how to walk before you run. A good gold pan, a few hand tools, and a 5-gallon bucket for carrying gold-bearing gravel are about all you need to find a bit of gold early on. Buy the fancy gear later, after you have the basics down, feel more confident about your mining knowledge and abilities, and are ready to move more material and get more gold.

3. Keep Your Expectations in Check

As a would-be gold miner, maintaining a positive outlook is an asset. But remember, this is 2008, not 1849, and the likelihood of you (or I for that matter) striking it rich gold mining is slim indeed. Unfortunately, many newcomers have visions of gold pans overflowing with flakes and nuggets and it can be quite sobering for them when the realization sinks in that gold mining is, for the most part, very hard work for very small returns. Let's do a bit of math. Even the most experienced recreational or small-scale miners these days average between 1-3 pennyweights per day. Hmmm...there a 20 pennyweights in a troy ounce of gold. Why, that's only about 1/10 of an ounce of gold per day! Get the picture? Keep your expectations in check and you'll be a happier, less frustrated miner because you understand that recreational mining is not some "get-rich-quick" scheme but a love and an avocation that can pay a bit back in return.

4. Learn How to Sample Properly

Using proper sampling techniques, methods, and approaches is the most important thing you can do to ensure your chances of successful gold recovery out in the field. Many newcomers to recreational mining fail to realize this and race around willy-nilly grabbing dirt and gravel from here and there, with no rhyme or reason to their madness and very little gold gained in the process. But you, you're different. You understand that a systematic sampling approach is your best bet to finding good gold values, perhaps even those hidden paystreaks or pockets that others have missed. Use proper sampling techniques and you'll be well on your way to becoming a miner with a reputation for getting the gold.

5. Watch, Listen, and Observe

You can learn more in a day from an experienced miner than you could in a month from a dozen prospecting or gold mining books. And, truth be told, most experienced placer miners are more than willing to help newcomers get a handle on things, if they open their ears and don't become royal pains in the proverbial rear. So put your fragile ego aside and learn to watch, listen, and observe. See how other miners work, what little "tricks of the trade" they employ, and what sorts of tools and equipment they use.

If you follow these tips conscientiously, I guarantee you'll graduate from good ol' Greenhorn University magna cum laude.

(c)  Jim Rocha (J.R.)  2008

Tuesday, July 29, 2008

Nugget Shooters Hit It Big in Alaska

The Big Ones Keep Turning Up

So you thought exceptionally large gold nugget finds were a thing of the past? Not in Alaska, where the big ones keep turning up to detectorists, nugget shooters, and large and small-scale placer miners.

Many of these beautiful finds are taking place in areas where old bucket-line dredges worked gold-bearing gravels.The bucket dredges tended to work straight channels and paying material was often pushed or dumped to either side as they progressed forward. Savvy nugget hunters who work these tailings are, in many instances, having a field day. (NOTE: The detectors mentioned most often are the Minelab series and the Fisher Gold Bug 2.)

Here are just a few of the larger Alaskan nugget finds in troy ounces. Most of these have been found since 1983 (many medium nuggets of 1/4 ounce-3 troy ounces and "smaller" nuggets weighing less than 1/4 troy ounce are being recovered regularly in the more productive areas):

294 oz., near Ruby
122 oz., Ganes Creek
62.5 oz., Ganes Creek
42 oz., Nolan Creek
33.85., Ganes Creek
8 oz., near McGrath

Productive Areas

Notice how the name Ganes Creek keeps turning up in this list? Although by no means the only spot in Alaska that continues to produce large nuggets, it is one of the best known (and open to detecting, dredging, and highbanking for a fee). Other productive areas are near Chicken and Ruby, the Hammond River, Crow Creek, McGrath, and Moore Creek, to name a few. Like Ganes Creek, some of these areas can be hunted or mined on a "pay-as-you-go" basis. (A simple web search can provide you with additional details).

So if that golden dream is chipping away at your resolve or you are just plain tired of working your rear off all day for a pennyweight or two, perhaps an Alaskan adventure may be just what the doctor ordered. Maybe you'll come home with the find of a lifetime or, at the very least, with a larger nugget than you ever dreamed of finding in the Lower 48.

I know one thing.....late at night when my own bedrock dreams take hold, I can hear the call of the wild in my ears....so who knows? Maybe I'll see you on Ganes Creek.

(c)  Jim Rocha (J.R.)  2008

Monday, July 28, 2008

Placer Mining Equipment: the Spiral Wheel Concentrator

No matter how efficient the type of placer mining equipment you employ, there will always be a small percentage of very fine or "micron-sized" flour gold left in your black sand concentrates after you've removed the larger gold pieces (i.e., nuggets, coarse flakes, "pickers," etc.). Often, this very fine gold is nearly invisible to the naked eye and seems to defy any and all attempts to recover it.

One very effective way to accomplish this task is by using a "spiral wheel " concentrator. What's a spiral wheel concentrator? In essence, it is a motorized "automatic" panning system designed specifically for fine gold recovery from black sand concentrates.

How does it work? The spiral wheel concentrator works on the same principle as a gold pan, but is designed and configured to maximize gold recovery far beyond that of a pan by using a specific set of operating parameters or recovery elements, including:

  • optimum recovery angles,
  • adjustable water flow,
  • centrifugal forces,
  • continuous action,
  • double angle riffles,
  • recycling tub, and
  • multi-speed rpm recovery rate (in some models).
The basic components of a spiral wheel concentrator are the spiral wheel (or pan) itself, a 12-volt pump and motor powered by a car battery, an adjustable water flow sprayer or washer, a support stand, a recycling tub, the pan's center recovery "cup," and assorted tubing or hoses.

What are the advantages of a spiral wheel concentrator?

Efficiency (up to 95% gold recovery to about 500 mesh size)
Portability (typically weighs 20-30 pounds and can be broken down, transported, and set up easily)
Running Time (usually 6-8 hours on a full battery charge)
Can Use Recycled Water (the recycling tub uses as little as 3 gallons of water, an asset in dry placer areas)
High Processing Rate (up to 100 pounds of black sand concentrates per hour)
Sturdy and Dependable (if maintained properly)
Ease of Clean Up (most models use a gold recovery "cup" that can be easily removed from the center of the pan or wheel and then replaced after the gold has been removed from the cup)

There aren't many disadvantages to using a spiral wheel concentrator but at least two items should be addressed:

1) Cost (as low as $200.00 on up to $500.00-$700.00 depending on the brand and type of spiral wheel concentrator you are interested in. For someone with good mechanical and fabrication skills, building a spiral wheel concentrator might prove to be a cost-effective and challenging do-it-yourself project)

2) Function (spiral wheels are made for recovering fine gold from black sand concentrates and are not designed for use and abuse as primary pieces of mining equipment like a highbanker or sluice box. Although they can function as such, only small amounts of gold-bearing material can be "fed" into them AFTER it has been screened or "classified" to a very small mesh size first)

There are other effective means of recovering fine gold from black sand concentrates such as mini-sluices and bowl concentrators like the "Blue Bowl," and these may provide the grist for another post later on.

Take care and good luck.

(c)  Jim Rocha (J.R.)  2008

Friday, July 25, 2008

Six Bedrock Sniping Tips



Bedrock crevicing or "sniping" for placer gold in a drywash or stream can be a rewarding experience for recreational miners. Sniping doesn't require lots of expensive equipment, but what it does require is knowledge, experience, patience, persistence, and perseverance.

You're already ahead of the game if you possess the last three attributes and experience will, of course, come with time. So it's up to me to provide you with some gold sniping tips to speed up the entire process and point you toward success. Here goes:

1. Search for areas of bedrock with minimal amounts of overburden: if you're like me, you have neither the time nor the inclination to shovel off 5 or 6 or 10 or 15 feet of overburden to get to the good stuff on bedrock. Granted, the closer bedrock is to the surface the more likely it has been worked, but just the opposite can be true as well.

2. Choose rough, highly fractured bedrock over smoother, more water-worn bedrock: the smoother and more water-worn a section of bedrock is, the easier it is for placer gold to be swept out of shallow potholes and cracks in high water flow conditions.

3. Focus on fractured bedrock where the cracks, fissures, and crevices run perpendicular to the stream flow: these types of cracks and crevices will trap gold much more effectively than fissures running parallel with the direction of the stream flow. Makes sense, right?

4. Check large boulders or other large obstructions sitting atop bedrock for cracks and fissuring: these types of obstructions can be good gold traps as well if they have cracks or fissures. Clean these crevices out the same way you would if they were part of the bedrock.

5. Clean out even the smallest, shortest, and narrowest cracks and crevices on bedrock: these are the crevices that others will bypass either from laziness or from assuming they carry little gold. Trust me, just the opposite is true in many instances.

6. Remove every bit of material from a crack, crevice or fissure: the best gold will be at the bottom of even the smallest crack or crevice. Your "sniping" work is not complete until that crack or crevice is so clean it shines.

There you have it. 6 simple tips for increasing your gold recovery rate from bedrock.

(c)  Jim Rocha (J.R.)  2008

Tuesday, July 22, 2008

Gold in the Southwest: Arizona, Part IV

Here is the fourth and final post in my series on placer gold locations in Arizona. I'll finish things up by covering Yuma County:

Yuma County: Nearly every watercourse and area of bench gravel in the Tank Mountains contains placer gold. Very coarse placer gold can be recovered using drywashers at the east foot of the mountains, especially in locations below the Puzzles, Golden Harp, Ramey, and Regal Mines.

If you travel about 30 miles northeast of Dove into the old Castle Dome District there are many old hard-rock mines and placers that once produced decent gold values. Southeast of the old Big Eye Mine gold placers can be found in area gravel deposits.

There were very rich placers in all the gulches and some terraces about 2 miles west of Dome. Monitor Gulch was one of the richest of these. Additional placers containing good placer gold values can be found in the drainage canyons around Muggins Peak. In fact, it would be worthwhile to check any bench or gulch gravels within a 8-10 mile radius of Muggins Peak, as the likelihood of getting "color" is quite good.

There is a 60-acre parcel of gold-bearing gravels in the Kofa District 27 miles southeast of Quartzite. Be advised, however, that bedrock in some areas here is buried under as much as 70 feet of overburden!

The "Potholes" Placers exist on both sides of the Colorado River not far from Laguna Dam. Many of the bench gravels and drainages north and west (California side) and north and east (Arizona side) of the dam contain gold. I worked this area with a drywasher many times and can confirm that decent gold values can be recovered in these placers. Additionally, it is said that placer gold can be found in bedrock depressions and tributary gulches all along the Colorado River in this area.
On the La Posa Plain outside of Quartszite are the Plomosa Placers, drywashing territory carrying decent gold values. Other gold placers in the area can be found at La Cholla, Middle Camp, and Oro Fino. Rich placer gold "seams" can be found in some of these placers at bedrock.

Six miles east of the of the Colorado River along the west side of the Dome Mountains extensive placers can be found. In fact, all the area washes, gulches, and arroyos carry varying amounts of placer gold that can be recovered using a drywasher. Especially rich placers were onced worked nearby at Goodman and La Paz Arroyos.


The Trigo Placers are about 20 miles from Quartzite at the west foot of the Dome Rock Mountains. Arroyos and ancient bench gravels in this area contain placer gold in the form of coarse, flat grains. Nearby, additional placers can be worked in low-laying areas near the Kofa Mountains (these placers were once quite rich in terms of gold values recovered).

In Harquahala Gulch southeast of Salome placer gravels were worked extensively in the late 1800s. And again, all drainages in the Tank Mountains should be sampled for placer gold.
I hope these "information-rich" posts on Arizona placer gold districts and locations have proven helpful to you.

(c)  Jim Rocha (J.R.)  2008

Sunday, July 20, 2008

Gold Mining Safety Tips

In my previous post I covered some of the risks involved with recreational or small-scale placer gold mining and now its time to list a few tips for making your mining endeavors safer:

Crushing Injuries:

When working around or under large rocks or boulders keep your body and extremities positioned away (as much as possible) from areas of potential collapse. Or, better yet, brace or "shore up" the area you are working by replacing those areas already dug or "cleaned out" with some of the larger rocks you moved out previously. This helps to counterbalance the "imbalance" created by removal of material underneath such obstacles and can prevent potential rolling or collapse.

Always stay aware of what you are doing the entire time and don't assume that a big boulder won't move on you....I nearly had my right hand crushed on a recent trip to the North Yuba River in California's Motherlode in just such an incident. NEVER ever crawl partway underneath a large boulder or obstruction to get at gold-bearing material, no matter how good that dirt may look. If you have to, use a prybar or a "come along" to move that nuisance out of the way, or get someone to help you. Again, be safe and work smart, on the surface or underwater (if you are dredging).

Heat Exhaustion:

Gold mining, for the most part, requires a great deal of hard physical effort that is not for the faint of heart. Add this to the fact that many mining activities are performed under the hot sun, and it is easy to see that serious trouble can be just around the next corner. Use your common sense when working in areas where high daytime temperatures can occur or are the norm. Keep yourself well hydrated, periodically take rest breaks in the shade or in your tent or RV, and stay out of the sun during the hottest time of the day.

Know the the warning signs of potential heat exhaustion and take action immediately if these symptoms appear: fatigue, weakness, feeling faint, nausea, severe headache, dizziness, muscle cramps, or sudden irritability. Be especially careful in desert or dry gold areas where excessive heat and lack of water and shade can prove problematic.

Dehydration:

Remain well-hydrated when out in the field conducting mining activities by drinking plenty of water or "Gatorade" type sports drinks (these replace lost electrolytes). Sodas and juice are OK too, but they don't do as good a job at quenching your thirst. Avoid consuming alcoholic beverages when mining. Aside from the fact alcohol will negatively influence your decision making processes if you drink enough of it, you'll dehydrate at an accelerated pace.

Hypothermia:

If you're mining in colder climates or at elevations where the weather can turn nasty quickly in the fall or spring, make sure you are dressed for the occasion. One good way of doing this is to "layer" by wearing successive layers of light-to-warm clothing that can be added or removed as required. Take along a warm hat and gloves, as well. I never was much on cold-weather mining, but if you are, make sure you are prepared for any eventualities.

Drowning:

There are a number of ways of reducing the possibility of this life-threatening event: use the "buddy system" when deep-water dredging; avoid trying to cross fast-flowing or deep streams, especially if you are carrying mining gear or wearing waders; and by being a decent swimmer if you decide to "cool off" by diving or swimming in the cold waters of a mountain river. Again, avoid alcohol consumption and use plain old common sense.

Slips and Falls:

When mining (especially in locations with water) wear boots, work shoes, or tennies (not good for preventing crushing injuries, by the way) that have a "gripper," non-slip type of sole. Many of the rocks and bedrock surfaces along a gold-bearing stream can be as slippery as ice. Don't be in a hurry, watch where you step, and where possible, support yourself with items such as prybars, long-handled shovels, a walking stick, or something similar.

Animals, Reptiles, and Insects:

The best advice I can give you here is "leave those wild critters alone!" They are called wild for a reason and are not meant to be poked, prodded, or otherwise manhandled. Avoid potential snake bite by being vigilant and careful when reaching behind, moving, or stepping over rocks, logs, or boulders during mining activities or when hiking to a new site. If necessary, wear insect repellant to keep those pesky little flying nuisances at a distance.

Being Trapped/Asphyxia:

Stay out of old mines, "coyote" holes, or the vertical tunnels or shafts the old timers dug to get at bedrock gold in streams or drywashes. Despite your curiousity, remaining above ground in the fresh air and sunshine is a "far, far better thing to do."

Sun Damage/Skin Cancer:

This one is essentially a "no brainer." When out and about (especially at higher elevations or in the desert Southwest) cover up by wearing long pants (have you ever tried to mine in shorts and bare knees? OUCH!), a long-sleeved shirt, and a wide brimmed hat of some sort. "Slather" all exposed body parts with high SPF sunscreen lotion. You may not appear as the mining stud or studette you'd like to be, but you won't have a plastic surgeon carving away on you later either (something I know about personally).

"Valley Fever"/Respiratory Problems:

Wear a dust mask or lightweight half-face respirator when working in dry placers, especially if you are goinng to be running a drywasher to get your gold. Even a kerchief or piece of cloth tied behind your head and used in this manner (like the bad guys in an old western movie) is better than directly breathing in dust, fine silica, or bacteria.

Final Word of Advice:

The absolute best safety tip I can give you is this, use the "buddy system." If something does go awry, one of you can help the other and vice versa. This is especially true for deep-water dredgers who spend the bulk of their time mining fully immersed in water. Remember the old adage, "two heads are better than one."

(c)  Jim Rocha (J.R.)  2008

Thursday, July 17, 2008

How Gold Deposits are Formed


As most of you already know, gold typically occurs in fractured "host" rocks (granite, schist, quartz, etc.) as veins or lodes. The Sierra Nevada Batholith (the source of the California Motherlode Region's gold) is a good example of this sort of deposit on a grand scale.

Most lodes are formed when super-heated fluids composed of various chemical constituents circulate through mineralized zones containing gold (Au), chemically bond with it, and then transport it to new locations in the earth's crust. The physical differences of various types of rock as well as the chemical composition of the fluids driven into and around them account for the vast array of various types of lode gold deposits, some of which are outlined below:

1) "Smoker" Au Deposits: These deposits occur wherever superheated waters spring up from vents ("smokers") in the ocean floor which are typically created by tectonic activity along the earth's crust. When this happens, metal-rich minerals including small amounts of gold are deposited in the zone where the superheated, auriferous water is mixed with the cold seawater it makes contact with.

2) High-Sulphur Hydrothermal Au Deposits: Hydrothermal gold deposits usually form when gold-laden water is superheated by magma (molten rock) in the shallowest layers of the earth's crust along lines of past volcanic activity. The chemical fluids in these sorts of deposits are sulphur rich, something that caused many an old timer to call these types of gold ores "sulpherets." (The gold deposits found near Summitville, CO are a good examples of high-sulphur hydrothermals.)

3) Low-Sulphur Hydrothermal Au Deposits: These deposits are very similar to the previous deposit type, with gold forming under similar conditions in similar regions. The main difference is, of course, that the mineralized chemical fluids involved are low in sulphur. (Gold ores found near Round Mountain, NV are low-sulphur hydrothermals.)

4) Microscopic or "Invisible" Au Deposits: Formed when specific chemical interactions take place between super-heated fluids and sedimentary rock, "invisible" deposits derive their name from the micron-sized gold particles that typify them. But don't let the terms microscopic or invisible fool you. These types of deposits can be very "rich" in terms of gold values (but require massive operations to mine). (The Carlin and Meikle Mines in Nevada are good examples.)

5) Uplift or Batholith Au Deposits: Typified by the extensive gold deposits of California's Motherlode Region, batholiths form when extensive fracturing of the earth's crust occurs and tremendous uplift takes place as mountain ranges rise (i.e. the Sierra Nevada Mountains). As this uplift takes place, mineralized hydrothermal fluids flow into rock fractures and cracks, usually of a quartzitic nature (these superheated fluids are created by extremely hot metamorphic rocks buried deep beneath the earth's surface).

6) Greenstone Belt Au Deposits: These are very ancient gold deposits geologically speaking (older than 2 billion years), and no longer form on the earth today. However, examples of these ancient deposits can be found in Australia, Canada, and Africa in various locations.

7) Placer Au Deposits: Over the course of millenia, fine gold, flakes, and nuggets are worn away from their source lodes by heat, cold, pressure, and erosion and begin "migrating" into low-lying areas such as benches, streambeds, gulches, washes, and the ocean floor. These easily worked deposits are called "placers" and they are the bread and butter of most recreational or small-scale miners.

So there you have it. You've just completed the basic Bedrock Dreams Geology 101 course.

Congratulations!

(c)  Jim Rocha (J.R.)  2008

Tuesday, July 15, 2008

Placer Mining Equipment: the Suction Dredge

Placer Mining Equipment: the Suction Dredge

The suction dredge is the single most efficient piece of mining equipment for recovering placer gold from a river or stream. Dredges can process large amounts of auriferous ("gold-bearing") material and are quite good at recovering everything from "pinhead" flour gold and small flakes on up to large nuggets. Essentially, dredges are just gasoline-powered "vacuum cleaners" that can be floated on pontoons or used from a stream bank (the latter being the usual province of highbankers or very small dredges).

Dredge Categories: Suction dredges are typically categorized according to the diameter of the unit's intake hose, which can be as small as 2 inches and as large as 8-10 inches or more. However, most recreational or small-scale placer miners in the United States use dredges with intakes of 2.5, 3, 4, or 6 inches, since these are the types most commonly sold by suppliers. The larger the diameter of the dredge's intake hose, the more material it can process (usually expressed in terms of cubic feet per hour).

Requirements and Limitations: One thing all dredges have in common (regardless of their intake hose diameter) is that they require large volumes of water to operate correctly and efficiently. Obviously, larger dredges with wider intake hoses require greater volumes of water while smaller dredges with corresponding smaller intake diameters can be successfully employed on smaller streams carrying much less water.

Dredge Components: The standard components for most dredges are:

1) Gasoline engine(s) providing power for the unit;

2) Water pump or "venturi" jet creating suction and expelling water;

3) Intake hose and suction nozzle acting as vacuum "attachments;"

4) Sluice box(es) for processing auriferous gravels and trapping the gold;

5) Pontoons, inner tube(s), or other flotation devices for supporting the dredge on the water's surface;
and

6) Breathing apparatus such as a "hookah" line for diving underwater.

Types of Dredging: There are essentially three main types of dredging activities:

1) Deep water where diving experience is a must, the dredger is fully immersed in water reaching depths of 15-20 feet, and he or she is using an air line ("hookah") to breathe;
2) Shallow water where diving experience is not mandatory and the dredger is (typically) only partially immersed in water depths of 2-5 feet; or
3) Surface dredging where overburden is shallow or bedrock is nearly exposed and cracks and crevices can be easily vacuumed.

Advantages: There are a number of advantages associated with using a suction dredge:

1) Large volumes of auriferous material can be processed rapidly;
2) Dredges are extremely efficient "gold grabbers;" and
3) They can be extremely cost-effective if operated properly in productive areas.

Disadvantages: Often, with every advantage comes a concurrent disadvantage. Dredges are no exception to this rule:

1) Fairly substantial initial financial outlay ($1,000-$6,000 depending on the dredge type and size);
2) Like all things mechanical dredges require a certain amount of maintenance and repair, and they can break down ;
3) They are often bulky and cumbersome to transport or carry and require additional tools, gasoline, and materials that must also be transported or carried.

Safety Concerns: Safety concerns should be first and foremost in any dredger's list of important items, since there are some inherent dangers involved with running the larger intake dredges at greater depths. I recommend the "buddy system" for those placer miners who will be working fully immersed underwater. Hookah breathing lines can twist, kink or foul and large rocks or boulders beneath the surface can suddenly shift or move, trapping the dredger. Be smart and be safe. No amount of gold in the world is worth your life, pure and simple.

Permits: I can't think of one state in the U.S. that does not require an annual permit for operating a suction dredge (and highbankers with a suction nozzle). Before you dredge any location, make sure you have researched any and all permit requirements for that area and that specific location. Save yourself from potential legal hassles and fines, OK?

(c)  Jim Rocha (J.R.)  2008

Monday, July 14, 2008

Gold in the Southwest: Arizona, Part III



Here is the third Bedrock Dreams installment on gold placer areas in the State of Arizona. In this post I begin by listing placer districts and locations in Pinal County:

Pinal County: Erratically distributed placer gold has been found at the west foot of the Slate Mountains.

The once famous Canada del Oro Placers can be found about 4 miles south of Oracle near the northwest base of the Santa Catalina Mountains. Nearly all the arroyos, drywashes, and gulches in this area contain good gold values, even though this area has been worked hard over the years.

Santa Cruz County: Near Harshaw both elluvial and alluvial placer gold has been reported in a condensed 1-square mile area between Sonoita Creek and Alum Canyon.

Six miles north of Nogales, placers of the same name can be found in Guebabi Canyon.

The Oro Blanco Placers are located in the Rusy and Oro Blanco region. These placers were once very rich, especially in Oro Blanco and Viejo Gulches. Also check the nearby hillsides as they contain bench and terrace placer gold deposits.

Additional rich placers were once worked near the mouth of Warsaw Creek and a few miles north of the Mexican border.

If you travel 9 or 10 miles south of Patagonia about 5 miles north of the Mexican border, you will find the Patagonia Placers, extensive gold placers that were once heavily worked and proved very productive in terms of gold values.
Near the old Mowry Mine additional placers can be found in Mowry Wash. These placers are in ancient Quaternary Period gravels and were also quite rich. Other low-laying areas and drainages around and below the Mowry Mine contain placer gold values as well. Many of the nuggets recovered in this region were in excess of 2 troy ounces and were quite coarse.

The Palmetto Placers consist of nearly 320 acres of Quaternary Period gravels about 6 miles northwest of the old Three "R" Mine.

Over 100,000 troy ounces of lode and placer gold were produced in the Ruby area in the vincinity of the Old Glory, Austerlitz, and Margarita Mines.

The Tyndall Placers were rich ground at one time at can be found at the base of the Grosvenor Hills southwest of Salero.

Yavapai County: In the Black Canyon District (Bradshaw Mountains) productive placers were once worked near the Agua Fria River below the old Howard Mine. In and along Black Canyon small placers still produce gold and nearly all the watercourses and drainages in the region will carry some placer gold as well.

In American and Mexican Gulches between Arrastra Creek and Cleator there are fairly extensive placers that were once highly productive.

The famous Humbug Creek Placers extend for some 20 miles along Humbug, French, and Cow Creeks. Fine and flake gold can be recovered from overburden gravels here that are sometimes more than 20-feet deep. If you can get to bedrock though, expect to recover some very coarse gold and nuggets.

North of Black Canyon City near Bumblebee, rich placers were once worked in gravel bars.

The Weaver-Rich Hill District continues to be very "rich ground," producing many placer gold nuggets, especially for savvy electronic propsectors and nugget shooters. IMPORTANT NOTE: To the best of my knowledge, the Rich Hill area is completely claimed up, so please be careful not to trespass there.

Placer gold can be found in the Eureka Placers along Burro Creek and in nearly all the area gulches, washes, and bench gravels (some 18 miles northwest of Hillside Station).

There is placer gold in Placerita, French, and Cherry Gulches as well as in Blind Indian and Mill Creeks southeast of Kirkland.

Very productive placers were once worked along Model Creek in Peeples Valley.

Near Pine Flat, almost all the watercourses and drainages in the area of the old Cumberland Mine contain placer gold.

Nearly every creek in the Prescott area contains placer gold.

The upper reaches of Granite Creek contain the Granite Creek Placers, which were heavily worked beginning in 1860.

In New England Gulch (5 miles south of Prescott) very rich placers existed until they were "worked out." Additionally, all the benches, drainages, watercourses, gulches, and washes in this region contain some placer gold.

The Hassayampa-Groom Placer District is on the west slopes of the Bradshaw Mountains. These placers produced thousands of troy ounces of gold.

Rich placer ground can also be found at Rock Springs below the old Maggle Mine.

(In the fourth and final installment of this series of posts on Arizona placer gold locations, we will finish up with Yuma County.)

Take care until then.

 (c)  Jim Rocha (J.R.)  2008

Saturday, July 12, 2008

Getting the Gold: Some Thoughts on Crevicing

Proven Method for Getting Gold

A proven method of getting gold in a streambed is by crevicing, or "sniping" as many placer miners call it. You may not be able to move cubic yard after cubic yard of gold-bearing gravel like you would with a suction dredge or highbanker, but what crevicing lacks in quantity can often be compensated for in terms processing ease, mobility, and potential returns for minimal monetary outlay.

Let's face it. Not all of us can easily expend thousands of dollars for placer gold mining equipment like large suction dredges, trommels, higbankers or various and sundry other high-end pieces of motorized or mechanized gear. Additionally, not all of us want the multitude of hassles associated with transporting, packing, maintaining, and operating this equipment. What we want is a more direct approach that requires little except a modicum of placer mining experience and knowledge of stream hydraulics and gold deposition physics. And, a few hand tools that are easily carried in a backpack or 5-gallon bucket. Finally, most of us realize we are not going to "strike it rich" out there and just want to get some gold and have a good time doing it. This is where a good crevicer or "sniper" steps in.

A Question of What Works Best

In an earlier post I discussed some of the issues and equipment involved with underwater sniping for gold but in this post I want to stress that crevicing or sniping can be done without using snipe tubes, snorkels, face masks, or wetsuits. It's all a question of what suits your gold-mining temperament. Some folks love getting wet and muddy while others like it high and dry. Some want to break their backs getting at the gold while others prefer taking it slow and easy. If you are a retired person or a current (or prospective!) AARP member, you probably know what I am talking about here.

Above-the-waterline or drywash crevicing can fill all these voids and, if done well, can provide the "sniper" with endless opportunities for recovering decent amounts of fines, flakes, and small nuggets and even the occasional hot "paystreak." Why is this so? Because a good sniper is only going to be processing material that has already been "concentrated" by stream hydraulic action (though this may become more problematic in dry placer areas). Let me give you a hypothetical example:

You run six 5-gallon buckets of auriferous bench gravel through your sluice box and recover 1.5 pennyweights of gold after clean up. Meanwhile, your prospecting buddy who is an avid sniper has been busy cleaning out a small bedrock crevice that looked promising. After leaving the crevice sparkling clean your partner pans out 1.5 pennyweights of placer gold. The gold recovery was equal between you two, yet who had to move more dirt at greater physical effort?

In the final analysis, whatever works....well, works! You don't always have to be some placer mining "magnate" hauling a trailer, gas cans, "come alongs," and a 6" dredge. If you're not trying to make a living at placer gold mining (and most don't), mine your way, not someone else's way.

(c)  Jim Rocha (J.R.)  2008

Gold in the Southwest: Arizona, Part II



Here is the second of my Bedrock Dreams posts on Arizona placer gold districts and locations (many of which are dry placers, by the way). This post begins with placer mining areas in Maricopa County, which includes the Phoenix urban area:

Maricopa County: There are minor placer gold deposits from lode mines in the Cave Creek District, less than a hour's drive north of Phoenix.

Approximately 45 miles northwest of Phoenix are the San Domingo placers. Old Woman Gulch, a tributary of San Domingo Wash, is an extensive placer area that was once known for producing large, coarse nuggets. Additionally, just about all the smaller washes in this region carry heavy black sands and fine placer gold.

The Hassayampa Placers can be found less than 10 miles southeast of Wickenburg and below the mouth of San Domingo Wash. These placers have been very productive over the years and continue to produce placer gold for small-scale and recreational miners.

In the drainages around and near the Vulture Mine, gold can be recovered by drywashing gravels and by working the older tailings piles.

Mohave County: The Lewis Placers, known for producing coarse gold, are just a few miles southwest of Kingman.

About 6 miles southeast of the Lewis Placers are the Lookout Placers which contain widely disseminated but coarse wire gold.

The Gold Basin Placers can be found by an unpaved road branching off Highway 93 (somewhere near the north end of Red Lake Place). These placers are extensive but have also been worked hard by other miners using drywashers.

You can find the King Tut Placer District by driving 70 miles north and west of the Gold Basin Placers. These placers are nearly 8 miles in length and have produced quite a bit of placer gold over the years.

In the Silver Creek area there are many small placers downstream from the old U.S. Highway 66.
Many small to medium-sized gold placers can be found near Pierce Ferry, an area accessible from Highway 93 north of the Chloride turnoff.

The Chemehuevis Placers are located in the foothills of the Mohave Mountains about 18miles southeast of Topock.

The "Old Spanish Diggings" can be found near the Red Hills at the southwest foot of the Mohave Mountains. Additionally, this area contains Printer's and Dutch Gulches, placers that were once very rich.

Pima County: Gold placers can be found along Arivaca and Las Guijas Creeks in the Las Guijas Mountains. In the pediments at the north foot of the mountains large scale placer operations were once conducted and most of the drainage courses here contain some placer gold.

Approximately 6 miles west of Continental you can find numerous dry placers along the upper course of Amargosa Arroyo. Some placer gold also exists in thin hillside gravels here as well.

The Greaterville District lies about 35 miles southeast of Tucson. Nearly all the gulches, washes, arroyos, terraces, and benches here contain placer gold. The most productive areas were located in and along the following gulches: Boston, Kentucky, Harshaw, Sucker, Graham, Louisiana, Hughes, and Ophir.

Seventy miles north and west of Tucson are the Quijotoa Placers, a very extensive placer area covering nearly 100 square miles. However, some of these placers may be on Pima Indian land, so be careful not to trespass.

Abundant and coarse placer gold was once recovered south of Pozo Blanco, about a mile from the west foot of the Quijotoa Mountains. Many smaller placers were worked a few miles north of this location as well.

Placers along the north slope of Alder Canyon in the Santa Catalina Mountains once produced abundant placer gold in the form of flat, coarse pieces.

Approximately 5 miles southeast of Baboquivari Peak (in the mountains of the same name) you can find placer gold in the benches and gravel bars (Baboquivari Placers).

At Papago, 30 miles southwest of Tucson, rich gold placers were once worked along Ash Creek.

The Old Baldy Placers lie some 60 miles south by southeast of Tucson at the northwest base of the Santa Rita Mountains in Madera Canyon. These placers were once extensively worked and may prove problematic since significant amounts of overburden cover the paystreaks here.

(c)  Jim Rocha (J.R.)  2008

"Reading" a Stream: Drywashes



In earlier posts on the subject I covered some of the basics of placer gold deposition as it relates to stream courses with continual water flow. Drywashes can, however, pose a different set of problems for the small-scale miner.

Intermittent Flow Means Intermittent Gold

In drywashes or other stream courses with only occasional or intermittent water flow the basics of gold deposition and stream hydraulics still apply to some degree, but at the same time these stream "reading" factors can become quite problematic or downright frustrating to prospective placer miners. Why is this? The answer is, in essence, quite simple and direct.

In arid or desert placers where water flow is essentially restricted to sudden thunderstorm downpours, brief seasonal flooding, or other intermittent events, the bulk of the stream course's placer gold is in a transitional state. Granted, significant amounts of gold may still be found on bedrock, behind larger obstructions, or in low pressure portions of the streambed but in a drywash there is nearly the same likelihood that pockets or paystreaks of gold will be scattered throughout the stream course at various points, levels, and depths that seem to defy conventional logic governing gold deposition in running streams.

Think Outside the Box 

For example, in areas that only receive rain during sudden torrrential downpours from thunderstorms in the summertime, drywashes acting as drainages for higher elevations are usually in a flash flood state, with tons of rock, gravel, and other debris being swept downstream with great force and speed. This includes placer gold. When, just as suddenly, this flash flooding stops, the placer gold that was in suspension just seconds earlier is deposited wherever it is "dumped" at the moment stream hydraulic action ceases.

So, placer gold in drywashes can frequently be found in erratic pockets and paystreaks that often do not conform to the physics of gold deposition in a running stream with consistent hydraulic action. This creates a new set of problems for any miner attempting to "read" a drywash. Often, drywashes pose a "hit-or-miss" type of placer mining that can either be immensely rewarding or just as frustrating. When it comes to gold deposition in dry placers, thinking outside the box is a definite asset.

(c)  Jim Rocha (J.R.)  2008

Use Your Gold Pan First: Part 2

One of the most important things you can do to improve your chances of successful gold recovery is to use your gold pan to sample thoroughly BEFORE operating any piece of mining equipment (i.e., dredge, dry washer, sluice box, highbanker, etc.).

Yes, stream hydraulics and the principles of gold deposition physics will dictate, to a great degree, where you will begin your search for gold, but unlike the examples of would-be miners I mentioned in my earlier post on this subject that you CANNOT afford to be lazy and assume that good gold values will be recovered just because you are working the gravels of an inside bend or other low-pressure or likely gold deposition area. USE YOUR GOLD PAN FIRST. Sample, sample, sample.

I've covered proper sampling in some earlier posts in Bedrock Dreams and I suggest you read these because I am not going to "re-plow" the same ground here. But what I am going to do is give you a few hints and tips on how to effectively employ your gold pan before running large amounts of material through a piece of mining equipment, whatever that may be.

Here's what I look for when performing my preliminary sampling with a gold pan, regardless of whether I am sampling a gravel bar; the area behind large, low-pressure obstructions; bedrock; bench gravels; or any other likely looking spot:

1) If there is no gold in the pan: If I find nothing in a certain number of test pans at different depths and locations I don't waste another second but move on to another likely looking location for additional sampling.

2) There are pieces of oxidized iron or lead in the pan but no gold: Definitely worth a second look and additional sampling. Bits and pieces of oxidized iron, old nails, rusty conglomerates, shot, and deformed lead fishing weights are good indicators that I'm on the right track since they tend to follow the same deposition patterns of placer gold. However, I must qualify this somewhat. They DO NOT guarantee I will find placer gold along with them, especially if I am unlucky enough to be sampling areas that have already been worked over pretty well.

3) There is gold in the pan along with pieces of oxidized iron, lead, and coarse black sands: Ok, now we're talking. If a reasonable number of test pans hold up with consistent results, this may be a very good location to set up my equipment and start running larger amounts of material.

4) How coarse is the gold in the pan? Am I finding a few microdots of flood or flour gold, small flakes, or a chunky piece I can pick up with my fingers? Here's the way I tend to assess things: If I'm finding lots of flood gold as opposed to an occasional flake or two or even a chunkier piece, I'll work the area showing the most gold. If I am getting a nice chunky piece or two per pan, or every third pan or so, I will make that my area to work hard by processing as much material as I can with the appropriate piece of mining equipment. It's a judgment call of sorts. Do you want to recover lots of fine gold or would you rather try to recover the heavier pieces even though they are less frequent?

In the final analysis, you must decide which area you are sampling is giving you the best gold "showing" and the best potential gold return recovery rate for the estimated amount of material to be processed. As you can see, this not an easy task most of the time and requires knowledge, foresight, experience, good sampling techniques, and a bit of luck thrown in for good measure. One thing I can tell you for sure is that a haphazard or half-hearted sampling approach won't cut it in the long run. You'll come up short the majority of the time.

"USE YOUR GOLD PAN FIRST!"

Good luck out there.

(c)  Jim Rocha (J.R.)  2008

Placer Mining Equipment: the Highbanker


Placer Mining Equipment: the Highbanker

A highbanker (also known in some mining circles as a power sluice) is a piece of placer mining equipment used for processing auriferous gravels located some distance (typically up to 100 feet away) from a stream or water source. By using a motorized pump and tubing or hose, the highbanker is able to send a large volume of water onto the unit's hopper (classifying screen) and through the sluice box to recover gold.

Highbanker pumps can be either electric (12-volt battery) or gas driven, although the gas-driven models seem to be the most prevalent out in the field. Some highbankers are also designed and constructed to re-circulate water so they can be employed in situations where there is little, or even no water at all (the miner uses jerrycans of water and a recirculation tub). Highbankers in this latter case are typically electrically driven.

Additonally, some gas-driven highbankers have the capacity to be used as a suction device, much along the lines of a small suction dredge. Obviously, the highbanker unit remains out of the water and on dry ground, but an intake hose and nozzle of 2.5"-3" diameter can be employed directly underneath the stream surface to "vacuum up" gold-bearing gravels or to clean bedrock surfaces. (I used to run a "suction" type highbanker quite frequently, so I am very familiar with them and highbankers in general.)

Highbankers are typically employed in one of two ways: 1) gold-bearing gravel is shoveled onto the hopper screen or 2) a suction nozzle is used underwater to vacuum up gold-bearing material. That's essentially it. Otherwise, the highbanker functions much in the same fashion as a regular sluice box, with a steady flow of water washing the barren and lighter materials down and away from the riffles out the lower end, while trapping the heavy black sands and gold in miner's matting or indoor/outdoor carpeting, and behind the riffles themselves.
Main Advantages of a Highbanker:
  • Can process gold-bearing gravels located some distance away from a water source (you bring the water to the gravel, not the gravel to the water)
  • Reasonable portability and ease of set up
  • Able, in most instances, to operate (for limited periods of time) using recycled water
  • Some models can "double up" for use as a suction device with small diameter intake hose and nozzle attachment
  • Additionally, some models have a "garden hose" attachment that can be used for cleaning light overburden from bedrock cracks or crevices
  • Extremely efficient gold-trapping ability, including very fine or "flour" gold
  • Easy clean up of gold-bearing concentrates
  • Overall versatility
What are the downsides to using a highbanker? Few come to mind. But they can be quite expensive ($1,200.00-$2,200, estimated) to purchase new and like anything mechanical, they can be balky at times or even break down on you. So if you don't have good mechanical skills make sure you have a back-up plan (a regular sluice box or rocker or?) out in the field. Additionally, please note that the highbanker suction hose diameter is fairly small and rock jams can be a real pain in the rear at times. Just so's you know...

I've know a number of recreational placer miners over the years who designed and constructed their own highbankers, and those home-made models did a pretty good job of getting the gold out in the field. However, building a highbanker will be much more difficult and costly than constructing a home-made sluice box or rocker. So be realistic about your "do-it-yourself" abilities before taking this task on.

(c)  Jim Rocha (J.R.)  2008

Gold in the West: Utah



Extensive Gold Mining History

Like most western states, Utah has a fairly extensive gold mining history that includes both lode and placer gold discoveries. So if you are a would-be placer miner living in Utah, this post may point the way for you.

Although gold was first discovered in the State of Utah in 1858, Native Americans defending their turf prevented miners from exploiting this discovery near Clifton until 1869. Also known as the Gold Hill District, discoveries in and around Clifton were not very extensive but moderate amounts of lode and placer gold were produced there.

They May Have Become Rich

The largest and most extensive placer gold discovery in Utah's history occurred in 1863 when extensive deposits of the noble metal were located in Bingham Canyon in the Oquirrh Mountains of Salt Lake County. The Bingham Canyon placers produced over $1.5 million in placer gold at a time when gold was selling for around $20.00 per ounce. (Although I have no idea of its current status, the Bingham Canyon area sounds like a likely starting place for prospective gold miners in Utah).

In 1870 the Mercur placer gold district in Tooele County was established. But many miners staking claims at the site there were disheartened by the low returns in their pans and the scarcity of water for mining, and extensive placer mining operations were soon abandoned in favor of other districts. The irony here is that some 20 years later the Mercur District would produce nearly half a million ounces of gold, most of it from lode mining. Had some of the original miners held onto their claims they may have become rich men. So it goes in the world of gold mining...

"Rich Diggings"
A frenzied stampede of placer miners "rushed" the San Juan River area (and its feeder streams) in the winter of 1892-1893 on unsubstantiated rumors of "rich diggings" in the area. After nearly 2,000 would-be miners endured great hardships and even bloodshed, the San Juan placer rush was declared a "humbug" because the gold in the region was mostly very fine or "flour" gold, something miners of the day mostly scoffed at unless they could pan it by the pound.
Placer mining in Utah continued right into the 20th Century, with new finds and new districts springing up in places like Tushar, Henry, La Sal, the Abajo Mountains, and along the Colorado and Green Rivers and their tributaries.
So there you have it, a condensed history of placer gold mining in Utah.

Now get out there and find some of that yellow metal.

(c)  Jim Rocha (J.R.)  2008

Placer Gold Sampling, Part II



The Sampling Process

In an earlier post I discussed the overall importance of proper sampling and the general principles involved in establishing a successful approach. Now we'll examine the sampling process itself, primarily from the small-scale, hand tool approach which most recreational placer miners would employ. Sampling by suction dredge is, in some respects, a different ball game so I will relegate it to another post at a later time.

Please note that the following sampling approaches are useful in both wet and dry placer locations. Additionally, each of these approaches is contingent on the premise that the sampler has chosen a likely area for placer gold deposition based on stream structure and hydraulics, and the physical laws governing depositional physics.

Sampling Approach 1, Lateral or Perpendicular

This approach involves taking a series of samples in a lateral sequence perpendicular to the flow of the stream (or wash). There is no solid dictum regarding a starting point (i.e., extreme left, right, center, etc.) along this lateral line, but I tend to start my sampling sequence in low-pressure areas of the stream where material is being deposited, directly behind large obstructions such as boulders, or where bedrock is visible or sitting under shallow overburden. This then becomes my starting point and I will subsequently take samples at consistent intervals and depths from this central location.

Sampling Approach 2, Parallel

In this approach a sequence of samples is taken in a likely area parallel to the direction of the stream or wash flow. This method is particularly useful in evaluating the gold values contained in areas such as gravel bars (inside bends) or low-pressure areas studded with smaller obstructions. It can also be effective in determining the overall consistency of pockets or paystreaks laid down in the direction of the stream flow (something which does occur, although not as frequently as deposits or paystreaks deposited across the stream flow).

Sampling Approach 3, Grid

This approach employs a grid pattern for sampling and can be very effective in determining the gold values contained within a localized area of the stream or wash. The first step is to lay out the boundary of a large box or rectangle. Samples are then taken from each of the four corners of the box and, if needed, from midway points along each side of the box. The interior of the box can then be gridded out into smaller boxes for more detailed (and accurate) sampling.

Sampling Approach 4, Diagonal

Here a sequence of samples is taken diagonally across the stream or wash. Though similar in function to Sampling Approach 1 (lateral), this approach combines sampling elements of both the lateral and parallel (Sampling Approach 2) approaches and can reap the same benefits as these if applied conscientiously.

Sampling Approach 5, Getting Struck by Lightning (not for serious miners)

This is what I term the "getting struck by lightning" approach. Invariably you will see it being employed by novices to the world of recreational mining or by those who are just too lazy to do it the right way. In this approach there is no rhyme, reason or logic to the way samples are taken. The sampler simply runs to and fro in a haphazard manner, grabbing a pan full of dirt here and another there, paying no attention at all to stream hydraulics or deposition physics. Or alternatively, the individual plops down in one location from where he or she cannot be budged and then proceeds to spend the entire day searching for the "big one" in that very same spot. Later, this same person will complain bitterly about the lack of gold in that particular stream or wash and tell everyone else what a lousy location it is. (Of course, some people actually get struck by lightning, but how many do you know personally?)

Make sure you tag or identify all your samples or employ some means of distinguishing which ones came from what locations and at what depths. One way this can be done is by placing the samples in small or medium plastic bags (such as trash bags) and using a piece of tape and a Sharpie or Magic Marker to number or identify them. Pan or process each sample carefully and note how much gold each contains and whether the better gold values are associated with the following:

large amounts of coarse black sands,

pieces of rusty (oxidized) iron or nails,

conglomerations of oxidized metal, or

lead shot or fishing weights.

Additionally, pay close attention to where the best samples are coming from and what sample depth appears to be the most productive. Once you have performed all aspects of one of these systematic sampling approaches, you should have a clear idea where to start your actual mining procedures and what piece of mining equipment is best suited for maximum gold recovery.

(c)  Jim Rocha (J.R.)  2008

Nugget Shooting (Historical Perspective)

(Fisher Gold Bug 2.)

Nugget Shooting is Popular

Nugget shooting with a metal detector has seen tremendous growth in popularity over the past 25 years. And today many small-scale miners and electronic prospectors are enjoying increased success in this endeavor by recovering placer gold nuggets from areas once considered "worked out."

Most Older Detectors Were Multi-Purpose

Prior to the late 1980s or early 1990s there were few, if any, metal detectors on the market specifically designed for electronic prospecting or nugget hunting. Most detectors of the era were multi-purpose machines designed primarily for hunting coins in parks, school grounds, and around older homes. These machines could also be used on beaches and to search for gold, but they did not function very well in areas of high salt concentrations or black sands, and often failed miserably in areas of extensive iron mineralization where placer gold is typically found. Additionally, most were of the Very Low Frequency (VLF) or Transmitter/Receiver (TR) types. These detector's circuits and their associated operating frequencies did well in their basic coin hunting modes, but were not conducive to detecting and pinpointing small gold nuggets out in the field.

Much More Sophisticated

Today, these gold detecting machines are much more sophisticated in terms of design, circuitry, and operating frequency and many have the capacity to not only detect the smallest gold nuggets, but small flakes and grain-sized pieces. Additionally, most of the modern machines employ very effective ground balancing/ground canceling features for use in highly mineralized areas, which used to be the bane of early nugget hunters. Experienced nugget shooters in Australia and the continental United States (especially Arizona) continue to recover many nice pieces of placer gold, and in recent years some large finds have turned up in the Alaskan goldfields, particularly in old bucket dredge tailings.

Are You a Nugget Shooting Expert?

I myself have done some nugget shooting over the years without much success. Yes, I was using a VHF detector (Fisher Gold Bug 2 and Whites Goldmaster) in areas known for producing nuggets. I've found plenty of BB shot, tiny bits of metal and wire, and other metallic odds and ends, but never a nugget. Perhaps I need an intensive course in nugget shooting taught by an expert.

But don't let my lack of success prevent you from swinging a good machine over gold-laden ground. You may end up an expert yourself. If you do become successful at it, give me a call OK? You can show me the ropes.

(c)  Jim Rocha (J.R.)  2008

Southern California Placer Areas: Randsburg



Randsburg Gold District

The Rand or Randsburg gold district lies along the Kern County-San Bernardino County line near the tiny mining town of Randsburg, approximately 40 miles Northeast of Mojave and about 30 miles due north of Kramer (Kramer Junction). I am very familiar with the area since I once belonged to a mining group that worked two 20-acre placer claims at Randsburg.

Placer gold was discovered at Goler Wash in the El Paso Mountains (about 15 miles west of Randsburg) in 1893. This discovery triggered a mini-gold rush in the area and soon prospectors and miners began fanning out throughout the area in their search for new diggings. This led them to new placer gold discoveries in the broad, alluvial fan that sits below the present-day town of Randsburg. Soon, hundreds of would-be placer miners were running these gold-bearing gravels through their "puffer" type dry washers.

Over $20,000,000 in Gold 

The placer gold discoveries at Randsburg were quickly followed up to their source in the mountains above town, where hard-rock mines like the Yellow Aster, Black Hawk, Buckboard and many others contributed to an estimated gold output of more than $20,000,000. That's a lot of zeroes, especially when much of the district's production occurred when gold was fixed at $35.00 per troy ounce or less.

The Randsburg placers are very easily accessed by just about any vehicle but keep your eye out for claim markers and notices, as well as No Trespassing signs. You may want to check with a few of the locals in the town of Randsburg first, to get a drift on what areas may be open to recreational mining. This district is essentially a high desert area that is bone dry, so you will have to work the gravels first with a dry washer and then pan the concentrates with water you bring along for that purpose. I've not heard of Randsburg as an electronic nugget hunter's paradise, but this may be due to the tremendous amount of small metallic trash in the area.

Sample First

I suggest you do some good sampling before setting up and running any equipment. Like most desert placers, the gold at Randsburg is erratically distributed throughout the low-lying drainages of the large alluvial fan below the town. The placer gold here is quite coarse and ranges in size from fines to small flakes or nuggets. In some instances it may show traces of copper (more orange in color) or conversely, silver (paler gold color).

Red Mountain and Johannesburg

Also nearby are the old mining communities of Red Mountain and Johannesburg ("JoBurg"), which you will drive through if you take the road north from Kramer to Randsburg. Most of the mining here is of the hard-rock variety so you will see lots of old mining headframes and equipment lying around. I drove through this area last June (on my way to the North Yuba River) and was surprised to see at least one active lode mine working at Red Mountain. However, I have never heard much about placer gold in the Red Mountain district so I suspect it probably was not as extensive as the placers around Randsburg (although there are some workable placers at Joburg).

Mind the Heat (and the Cold)


Do to the excessive daytime temperatures, you want to avoid this general area at the height of summer, of course. It's a great place to mine in the Fall, Winter, or Spring, although in the winter it can get quite cold during the nighttime and early morning hours. It can even snow in this area. So be advised and make sure you bring the appropriate clothing, camping gear, and so on with you. Oh, and one last thing. Bring plenty of water.

Take care.

(c)  Jim Rocha (J.R.)  2008

Placer Gold Sampling, Part I



Do It Right the First Time

Sample, sample, sample.The importance of thorough sampling techniques in successful placer gold mining operations (whether large or small) cannot be overstated. Even newcomers to recreational mining seem to understand this concept intuitively and will take pan fulls of gravel from various locations in a streambed in their search for color. This approach, however, is usually performed in a "helter-skelter" fashion where luck is the main qualifying factor and stream hydraulics, deposition physics, and proper sampling techniques take a back seat.

With that in mind, here are some basic sampling principles:

1) Make sure you have the appropriate knowledge and experience of the physics of placer gold deposition and stream hydraulics before sampling. This entails a clear understanding of how gold moves and is distributed in a streambed and the effects of water flow on gold deposition in terms of force, speed, pressure, current, eddy, and so on. Without a good working knowledge of these principles you are setting yourself up for potential failure and lots of frustration.

2) Since most gold placers are composed of many layers and materials (assorted sands, gravels, rocks, boulders, clays, bedrocks, and "false" bedrocks) your samples should be relatively large in number and quantity. For example, 10 samples will give a better overall indication of potential gold values in a specific location than just 2 from that same location. The same is true of quantitative samples. Five pounds of sampling material from one location will provide more accurate test results than one pound from that same location.

3) Some placer gravels will contain gold that is consistently distributed throughout streambed gravels. If you are lucky enough to locate one of these evenly distributed placers, you can lower your sample numbers and quantities. But when sampling placers where the gold is unevenly or erratically distributed (like those in dry areas or with low annual water flow) you should increase your sample numbers and quantities to ensure a reasonably accurate estimate of the gold values present.

4) During sampling, pay close attention and take note of what types of stream materials are included your samples. Ask yourself these types of questions because they are flashing red lights that should not be ignored:

Are you finding greater amounts of gold in sample pans containing pieces of lead shot or fishing weights?

Does an increased amount of gold in your sample pans seem to be associated with increased amounts of rusty (oxidized) metal such as old square-headed iron nails or conglomerations of rusty iron that have been fused together?

Are your best sample pans those that contain the greatest amounts of very coarse black sands?

5) Remember that, in most instances, your best gold values will appear in samples taken from just above or directly on bedrock (or false bedrock layers in certain locations).

Basic Elements of an Effective Sampling Program:

1) Research the mining history of the area you want to work:

What did the old timers find in terms of gold values and where were the best gold values located?

Was the gold coarse and nuggety, or was it primarily recovered in grains and small flakes?

What materials were associated with the best paystreaks and pockets?

Were the best-producing areas upstream, downstream, on bedrock, in nearby "benches" or elsewhere?

2) Closely study the terrain around you for unique or unusual physical characteristics (colors, changes in vegetation, rock slides, large boulders or obstructions, etc.). The topography and geology around you can provide important clues to where the best gold values may be and where you should start your sampling.

4) Choose the sampling method that works best for you in terms of location and that requires the least amount of hassle and expense. For must of us that means a pick and shovel or small hand-held digging/crevicing tools. In other instances it may mean using core augers, drills, or even heavy equipment.

(c)  Jim Rocha (J.R.)  2008

Use Your Gold Pan First: Part 1

Want the best piece of advice that nearly 30 years' worth of placer gold mining experience can give you?

"USE YOUR GOLD PAN FIRST!"

That's it? Yes, that's it in a nutshell. If you've read some of my other posts here at Bedrock Dreams you've heard me emphasize these three issues concerning the gold pan:

a) It's a prospecting tool, not a piece of mining equipment; and

b) It's the single most important sampling tool in your entire arsenal of gold mining gear; and

c) It's the standard tool used for "cleaning up" (i.e., panning) gold-bearing black sand concentrates out in the field.

Let's take a closer look. Unlike suction dredges, dry washers, sluice boxes, high bankers, trommels or rockers, a gold pan is not designed to process large amounts of auriferous gravel. In fact, an expert panner working full tilt can only effectively process approximately one cubic yard per day of gold-bearing material. With a rocker box this amount of material is just about doubled, with a sluice box tripled, and so on, up the line, depending on the type of mining equipment used, how well it is set up and employed, and the knowledge and hard work of its operator.

What does that tell you? What it should tell you is that the gold pan is the least effective of all these pieces of mining gear in terms of the sheer amount of material that can be processed using it. So it is best employed in the roles it was designed for: prospecting, sampling, and clean up. One, two, three. And it is these first two items about gold pans that require closer examination.

Getting to the Heart of the Matter

So here is where we get to the heart of the matter about gold pans. Over the past 30 years I've seen any number of recreational placer gold miners lug all sorts of fancy and expensive (and quite often heavy and cumbersome) pieces of mining equipment streamside and then, without further adieu, spend an hour or two (or longer) setting up and fiddling with or "fine tuning" things. Once they are satisfied that their gear is running at optimum performance, they set to work with a vengeance, shoveling or vacuuming up vast amounts of dirt and gravel in an impressive display.

All well and fine, right? Well, no actually. Why? In the instances outlined above I was amazed (or better yet, horrified) by the fact that these individuals performed little, if any, real prospecting or sampling before setting up their equipment and running large amounts of material.

Panning's a Waste of Time?

On one occasion, the miner in question told me bluntly that "panning was a waste of time" because he was working an inside bend gravel bar and that's where the gold should be! In another incident a miner told me it didn't pay to pan samples as long as you were in a gold-bearing area and knew gold was there. And, in yet another situation, a would-be miner expressed his frustration and disappointment at the low gold returns in his concentrate clean up after running material for hours. Yet I observed this same person take only two sample pans (one of which contained a couple of microdots of flour gold) before setting up and going to work.

(c)  Jim Rocha (J.R.) 2008

California's Motherlode: Where Did All That Gold Come From?



One of the World's Richest Gold Zones

California's Motherlode Region was one of the richest and most extensive gold-bearing zones ever discovered, on this continent or any other. Over 150 miles long and more than 50 miles wide at most points, the Motherlode produced staggering amounts of placer and lode gold. Nearly 30 million troy ounces (approximately $10 BILLION in today's dollars) were recovered from the California goldfields from 1849-1860 alone, not counting the additional millions of ounces that resulted from sporadic production thereafter, right up to today.

Where did all that gold come from? How did it become so concentrated? What was the source of these unbelievably rich placers and lode veins? The answer, my friend, can be found in three words. Sierra Nevada Batholith.

Birth of a Gold Region

Nearly 200 million years ago gigantic "bubbles" of molten rock began forming far beneath the earth's crust where the Sierra Nevada Mountains of California would one day emerge as the pre-imminent high ground overlooking the fertile valleys below. When these bubbles finally broke the surface of the earth's mantle they spewed molten lava in every direction, but in some instances these same bubbles became "trapped" beneath the surface where they, in turn, cooled in place creating what modern-day geologists call the "Sierra Nevada Batholith." What is the Batholith? A huge body of granitic rock underlying nearly 25,000 square miles of California and part of Nevada.

As the Batholith was formed and as it cooled in temperature, many different minerals were either trapped or "squeezed out" of it through chemical precipitation, heat, and intense pressure. Much of this "mineralization" or natural refining process took the form of streaks and veins of natural gold, much of it contained within quartz or quartzitic host rock which, in turn, was "hosted" by the granite of the Batholith itself.

Riches Beyond Belief

Even by modern geologic standards, the gold mineralization of the Batholith was striking and held the possibility of riches beyond compare. Where nature allowed, for the most part, a gold concentration of 5 parts per billion in most areas of the earth, in and along the Batholith gold occurred at concentrations as high as one hundred million parts per billion. Much, much later, this "richness" would provide the foundation for one of the largest human migrations in history, the California Gold Rush.

But for eons the Batholith's gold deposits remained hidden away, stored underground far below the earth's surface. Approximately 4 million years before the arrival of the 49ers in California, the crust containing the Batholith began to shudder, crumple, and then lift upward in dramatic fashion. As the Batholith rose thousands of feet into the air, so did the quartz veins, stringers, and pockets containing all that gold. Then the forces of erosion went to work.

Time and Nature Do Their Work

During decades of intense cold glaciers scoured some of the gold out of its host rock, the gold was "freed" during more temperate times as large volumes of water thundered downslope as melted snow or as heavy rains sluiced the flanks of the Sierra Nevadas. Intense heat expanded rock while freezing temperatures contracted the very same rock. And as it did so, cracks or air pockets were formed, allowing new avenues of escape for the golden metal contained within. And so it went for eons, the gold (because of its weight and density) finding its way eventually downslope into the lowest part of ravines, gulleys, bench gravels, and streambeds, accumulating in pockets or paystreaks of just a few ounces or tens of thousands of ounces.

Then one day in 1849, at a place called Coloma, James Marshall's eye was caught by the glimmer of a few golden bits of metal laying atop the bedrock of a newly constructed millrace. The rest, as they say, is history.....

(c)  Jim Rocha (J.R.)  2008

Gold in the Southwest: Arizona, Part I



Gold Booms in Arizona

The Spanish "colonistas" were the first to mine precious metals in Arizona in any sort of serious or organized fashion, working mines in the southern part of the state near Arivaca as early as the 1700s. Although these early deposits were primarily silver lodes, some small gold placers and lode veins were worked here as well. Additional placer deposits were worked by the Spaniards around this time at "the Potholes," a placer district near Yuma that covered areas on both the Arizona and California sides of the Colorado River.

The first real gold mining boom in Arizona took place in 1858 when the rich La Paz Placers near the Colorado River (near modern day Ehrenberg, AZ and Blythe, CA) were discovered, triggering a substantial "rush" to that locale. Other significant gold discoveries followed in 1864 when large placer deposits were discovered along Lynx Creek, eventually forming the economic and population base for the town of Prescott. Not long after the Lynx Creek discoveries, Henry Wickenburg (for whom the Arizona town is named for) located the now-famous Vulture gold mine, one of the richest in the state's history.

There were many other gold discoveries in Arizona that followed, some significant, some less so. Either way, Arizona has proven itself to be a gold prospector's and miner's "paradise" over the years, and this continues today. Arizona has a very active recreational gold mining community, with numerous prospecting clubs and groups that have their own claims in various gold-producing locales. Additionally, in recent years Arizona has gained a growing reputation as an electronic prospector's or nugget hunter's haven, with many beautiful placer nuggets recovered from some of the state's old, "worked out" goldfields.

Here is a partial list of Arizona placer gold districts and locations (additional placer listings will follow in subsequent posts since there are far too many placer districts and locations in Arizona to list here):
Cochise County: Near Bisbee (primarily a copper mining district) many small gold placers were worked in the upper reaches of Gold Gulch.
Most of the arroyos, washes, terraces, and benches in the Dos Cabeza Mountains contain coarse placer gold (part of this area is known as the Teviston Placers).

Drywashes in and around the Gleeson area offer placers that are reported to contain gold ranging from very fine right up to coarse nuggets.
Rich placers were worked in gravels on the east and west sides of Pearce Hill (the Pearce Placers).
Gila County: Many rich placers were once worked along the upper reaches of Pinal Creek in the Globe District.
Small placer deposits can also be found in the Apache Mountains in small gulches draining into Richmond Basin.
In area gulches near Castle Dome, placer ground can be found.
Near Payson some free gold can be recovered in minor placers.
Graham County: The Gila River Placers have produced some rich placer deposits of flake and wire gold. These placers exist in the streambeds, the bench gravels, and the terraces of this area.
Numerous gold placers also exist between Bonita and Spring Creeks (Neel, Smith Boyls, Hammond, Serna, and Colvin Placers).
Greenlee County: Near Clifton along the San Francisco River, bench gravels contain placer gold. Additionally, there are placers along the lower part of the river near the mouth of Eagle Creek as well as in the streambed of Chase Creek.
Placer gold was, at one time, recovered by hydraulicking operations near Oroville.
 
(c)  Jim Rocha (J.R.)  2008

Placer Gold in the California Deserts: a Brief Chronology

The following is a brief chronology of placer gold discoveries in the California desert regions. This list is by no means all inclusive or comprehensive, but it may provide some background information and "food for thought" for you recreational placer miners out there:

1779: Spanish settlers begin working extensive and fairly rich placer deposits on both sides of the Colorado River not far from present day Yuma, Arizona and Winterhaven, California. These desert placers yielded many nuggets and much coarse gold. Many recreational prospectors still work this area, known as "the Potholes" District.

1842: Francisco Lopez and two friends discover placer gold on the extreme western edge of the Mojave Desert, only 30 miles from present-day Los Angeles. This area, Placerita Canyon, was worked extensively for 3-4 years until abandoned.

1850: Jefferson Hunt finds flakes and pea-sized nuggets in a desert placer at the southern end of Death Valley near Salt Spring.

1860: Placer and lode gold is found by Dennis Searles and others in Death Valley's Panamint Mountains and by 1861 the Telescope Mining District is established.

1861: Placer gold is discovered high in the Piute Mountains and then lode gold is disocered near a new gold camp called "Kelsoe," forming what would eventually become the Mt. Sinai District. Later, this brief-lived boomtown is known as Claraville.

1862-1863: At the eastern edge of the Owens Valley gold placers and lode gold are discovered at Bend City, San Carlos, and Owensville. A bit farther south, placer gold is found at various locations in the El Paso Mountains.

1863: Captain Pauline Weaver and others find the rich dry placers at La Paz, just across the Colorado River from modern day Blythe, California and just a few miles north of Ehrenberg, Arizona. Many very large placer nuggets are recovered from these placers until they are "played out." Many recreational miners still work this area.

1879: Placer and lode gold are found in the hills above Oro Grande in the eastern Mojave, not far from present day Barstow.

1888: Although placer and lode gold were discovered in the Cargo Muchacho Mountains near modern-day Tumco, California by the Spaniards over a century earlier, it wasn't until this date that extensive mining operations began here and in the nearby Pichacho Wilderness area west of the Colorado River.

1893: New and even richer desert gold placers are found in and around the El Paso Mountains in the high desert east of Los Angeles. The first of these finds, Goler Wash is soon supplanted by new placer discoveries (and the inevitable lode gold mining) at Randsburg and Johannesburg.

1903: Paying placer ground is discovered in the Neenach area about 14 miles west of present-day Lancaster, California.

(c)  Jim Rocha (J.R.)  2008

Gold in New England: Maine



Like its neighboring state of New Hampshire, the State of Maine also provides placer gold mining opportunities for the recreational or small-scale gold miner. In Maine, placer gold occurs in streambed gravels and atop or near bedrock (as it does in many other locations in the United States). And, like New Hampshire, most of the gold in Maine is derived from ancient glacial detrital deposits, although some incidence of vein gold has been documented in the state.

Here is a list of placer gold areas in Maine:
Swift River and tributaries near Byron in Oxford and Franklin Counties
Sandy River from Madrid to New Sharon in Franklin County
South Branch of the Penobscot River near Sandy Bay, Bald Mountain, and Prentiss in Somerset County
Gold Brook near Chain of Ponds and Kibby in Franklin County
Gold Brook near Chase Stream in Somerset County
Gold Brook near Appleton Township in Somerset County
Nile Brook near Dallas and Rangeley in Franklin County
Kibby Stream near Kibby in Franklin County
St. Croix River near Baileyville in Washington County
Placer gold mining or panning activities in Maine do not require a permit as long as the following restrictions are understood and followed:
  • Mining activity is confined to sandy or graveled stream beds that are not heavily vegetated.
  • There can be no disturbance of stream banks.
  • Mining activity is limited to the use of gold pans, sluice boxes of less than 10 square feet, or suction dredges with a hose diameter of 4 inches or less.
  • Mining or dredging permits are not needed unless the equipment exceeds the above-listed sizes or dimensions.
 However, much of northern and eastern Maine, including the unorganized townships, is under the jurisdiction of a State agency called the Maine Land Use Regulatory Commission (LURC). The LURC applies greater restrictions on any type of recreational mining where motorized equipment is used. So you may want to check with this agency before you fire up your gold dredge in these areas. Additionally, do your research up front and avoid trespassing onto private property in your zeal to find those fines, flakes, and small nuggets.

So there you go. If you live in Maine and want to try your hand at a bit of prospecting, gold panning, or recreational mining there's nothing holding you back.

Be safe out there.

(c)  Jim Rocha (J.R.)  2008