Resources

(This article was originally published by the Bureau of Mines in 1971. While some of the information is dated, there is still a lot of good stuff in it for those who want to learn the basics and some of the terminology. -- Scott Harn, Editor/Publisher, ICMJs Prospecting and Mining Journal.)

How to Mine and Prospect for Placer Gold

By J.M. West

Foreword

This Bureau of Mines publication, Information Circular 8517, was released in 1971. Since that time, changes in Federal regulations have made it possible for individuals to purchase, hold, sell, and otherwise deal with gold. Also, please note that mercury has been identified as a hazardous substance and should only be used under controlled conditions and not released into the environment.

Contents

Abstract

Introduction

Acknowledgment

History of placer gold mining

Where to look for placers

Other things you need to know

How to look for placers

Evaluation: Should you invest and mine?

How to go about mining

Problems you should anticipate in placer mining

Recovering your gold and selling it

Selected bibliography with notations

Abstract

Increased leisure time and increased interest in the out-of-doors is leading more and more families to experiment with placer mining of gold, and sometimes even to going on into small-scale production. This Bureau of Mines report supplies basic information on areas of occurrence, equipment needed, prospecting, sampling, mining, and regulations concerning the possession and sale of gold. Selected references are given for further study.

Introduction

Placer gold has tantalized many a person who has tried his luck and skill in the hope of striking it rich. Separating gold from embedded materials is basically simple, and can be done effectively on nearly any scale, depending upon the deposit and the capital available for investment. The final product is consistently in demand at a relatively stable price. Historically, however, one must be advised that rewards for the majority of small-scale miners--those who operate "on a shoestring"--have been depressingly small.

First of all, the placer miner must know where placer deposits are located and he must have the technical knowledge to extract the gold. Additionally, he must face problems of land ownership, water supply, and water pollution, all of which have grown in complexity with the population. The costs of labor and equipment are relatively high now, although this may not seem significant to an individual mining a small deposit. Secondhand equipment may become available at relatively low cost because of a slowdown in construction or as surplus at the end of a war. By taking advantage of such opportunities, one can sometimes make an otherwise unprofitable operation successful, at least as long as the equipment holds up.

To the novice or "weekend prospector," the more complex features of placer mining may seem hard to comprehend. At any rate, the novice is often more interested in the recreational values offered by gold placering than in its profitability. Thus, the search for and discovery of even a small grain or nugget of gold is an achievement worth considerable effort. As a start, the beginner may gain some benefit from visiting one of the many pan-for-a-fee tourist establishments typically found in gold-mining areas.

The small-scale miner may sell his gold, but often he keeps it as a souvenir, or for use in some kind of jewelry, or in the hope that its value will appreciate. Seldom is a placer gold venture truly profitable when all costs are considered under existing circumstances. On the other hand, an individual or a family can gain a great deal of pleasure and satisfaction from the experience of producing your own gold. Producing your own, even on a small scale, involves a number of problems which this publication attempts to discuss. Because the subject is so extensive, the reader is referred to other reports in the bibliography for more detailed information.

Acknowledgment

For many years, three Bureau of Mines Information Circulars written by E. D. Gardner and C. H. Johnson in 1934 and 1935 have been a basic reference on gold placering. However, it was realized after several reprintings of the initial volume of the series that the general presentation had become dated and often went beyond the scope of the usual requests for information. This report has borrowed heavily from the Gardner and Johnson material because of its adaptability, and the author wishes to acknowledge that source in particular, although many other sources have been used in preparation.

History Of Placer Gold Mining

Placer gold mining in the United States spans a period of nearly 200 years. Earliest mining took place in the Eastern States and particularly in the southern Appalachian region during the late 1700's and early 1800's, but the richer deposits were soon exhausted, and interest turned to the West. The earliest production of any note in the West was from the Old and New Placer Diggings near Golden, Santa Fe County, N. Mex. These deposits were worked as early as 1828. A few other deposits were mined in the succeeding years until the first discovery of major importance, that of James Marshall on January 24, 1848, on the American River at Coloma, Calif. This discovery was a major factor in the rapid settlement of the West and triggered the first of the great gold rushes in the United States. Because of the lure and excitement of gold mining, prospectors spread throughout the West and in subsequent years many more rich placer gold deposits were found. A selected listing of discoveries subsequent to Coloma follows:

1848-49

California

Trinity and Klamath Rivers

1849

Nevada

Gold Canyon

1852

Oregon

Montana

Grants Pass district

Gold Creek

1857

Nevada

Six-Mile Creek

1858

Arizona

Colorado

Gila City

Cherry Creek, Ralston Creek, Platte River

1858-60

Washington

Blewett Pass (northern and central parts of State)

1859

Colorado

Clear Creek, Blue River, Arkansas River

1860-61

Idaho

Clearwater River, Pierce City, Oro Fino, Elk City, Florence, Warren

1862

Montana

Idaho

Arizona

Bannock, Alder Creek

Boise Basin

La Paz district

1863-64

Arizona

Utah

Weaver Creek, Lynch Creek

Bingham Canyon

1864

Montana

Helena

1867

Nevada

New Mexico

Tuscarora district

Elizabethtown district

1874-75

South Dakota

Black Hills, Deadwood Gulch

1876-77

Nevada

Copper Mountain (Charleston district), Osceola

1881

Nevada

Spring Valley

In Alaska, gold occurrences were reported as early as 1848, and gold was found in the Yukon region about 1878; but not until the fabulously rich finds in 1897-98 in the Yukon's Klondike (in Canadian territory) did placer miners really begin to exploit the Alaskan deposits. In rapid succession, miners stampeded in 1898 to rich discoveries in the Nome area of Alaska, then in 1902 to the Fairbanks area; the Fairbanks placers were among the last of importance to be discovered.

Any history of placer mining would be incomplete without a word on dredging, which marked a major turn in operational efficiency. Dredging offered a way to handle tremendous quantities of material at a low unit cost and made it possible to mine where gold values were as little as a few cents per cubic yard.

Probably the first successful bucketline dredge in the United States was operated in 1895 on Grasshopper Creek near Bannock in Beaverhead County, southwestern Montana. Others quickly followed, until by 1910, use of dredges had grown so that in California alone about 100 were in existence, of which 63 were reported in operation.

The first gold dredging in Alaska occurred about 1903, and the number of Alaskan dredges grew, until in 1914, 42 were in operation. The peak number of active dredges, 49, was not reached until 1940; World War II then interrupted most operations. Costs rose beyond profitable levels after the war, and only a few of the deactivated dredges were returned to service.

All gold dredges of any significance in the United States have been shut down, and most have been dismantled or sold abroad. Placer gold production today is primarily a byproduct of washing sand and gravel for use as an aggregate in the construction industry. Commercial placer mining by other means continues only at a few locations.

California and Alaska have accounted for more than three fourths of the total production of record. A large share of the overall production, it should be added, has come from dredges. 

Where To Look For Placers

Placers can be found in virtually any area where gold occurs in hard rock (lode) deposits. The gold is released by weathering and stream or glacier action, carried by gravity and hydraulic action to some favorable point of deposition, and concentrated in the process. Usually the gold does not travel very far from the source, so knowledge of the location of the lode deposits is useful. gold also can be associated with copper and may form placers in the vicinity of copper deposits, although this occurs less frequently.

Geological events such as uplift and subsidence may cause prolonged and repeated cycles of erosion and concentration, and where these processes have taken placer deposits may be enriched. Ancient river channels (referred to as the "Tertiary channels" in California) and certain river bench deposits are examples of gold-bearing gravels that have been subjected to a number of such events, followed by at least partial concealment by other deposits, including volcanic materials.

Residual placer deposits formed in the immediate vicinity of source rocks are usually not the most productive, although exceptions occur where veins supplying the gold were unusually rich. Reworking of gold-bearing materials by stream action leads to the concentrations necessary for exploitation. In desert areas deposits may result from sudden flooding and outwash of intermittent streams.

As material gradually washes off the slopes and into streams, it becomes sorted or stratified, and gold concentrates in so-called pay streaks with other heavy minerals, among which magnetite (black, heavy, and magnetic) is almost invariably present. The gold may not be entirely liberated from the original rock but may still have the white-to-gray vein quartz or other rock material attached to or enclosing it. As gold moves downstream, it is gradually freed from the accompanying rock and flattened by the incessant pounding of gravel. Eventually it will become flakes and tiny particles as the flattened pieces break up.

Some gold is not readily distinguishable by the normal qualities of orange-yellow to light yellow metallic color and high malleability, where it occurs in a combined form with another element, such as tellurium. Upon weathering, such gold may be coated with a crust, such as iron oxide, and have a rusty appearance. This "rusty gold," which resists amalgamation with mercury, may be overlooked or lost by careless handling in placer operations.

As mentioned before, the richest placers are not necessarily those occurring close to the source. Much depends on how the placer materials were reworked by natural forces. Streambed placers are the most important kind of deposit for the small-scale operator, but the gravel terraces and benches above the streams and the ancient river channels (often concealed by later deposits) are potential sources of gold. Other types of placers include those in outwash areas of streams where they enter other streams or lakes, those at the foot of mountainous areas or in regions where streams enter into broader valleys, or those along the ocean front where beach deposits may form by the sorting action of waves and tidal currents. In desert areas, placers may be present along arroyos or gulches, or in outwash fans or cones below narrow canyons.

Because gold is relatively heavy, it tends to be found close to bedrock, unless intercepted by layers of clay or compacted silts, and it often works its way into cracks in the bedrock itself. Where the surface of the bedrock is highly irregular, the distribution of gold will be spotty, but a natural rifflelike surface favors accumulation. Gold will collect at the head or foot of a stream bar or on curves of streams where the current is slowed or where the stream gradient is reduced. Pockets behind boulders or other obstructions and even moss-covered sections of banks can be places of deposition. Best results usually come from materials taken just above bedrock. The black sands that accumulate with gold are an excellent indicator of where to look.

It should be kept in mind that each year a certain amount of gold is washed down and redeposited during the spring runoffs, so it can be productive to rework some deposits periodically. This applies chiefly to the near-surface materials such as those deposited on the stream bars or in sharp depressions in the channels. The upstream ends of stream bars are particularly good places for such deposits. Where high water has washed across the surface by the shortest route, as across the inside of a bend, enrichment often occurs.

A rifflelike surface here will enhance the possibility of gold concentration. In prospecting areas with a history of mining, try to find places where mechanized mining had to stop because of an inability to follow and mine erratic portions of rich pay streaks without great dilution from nonpaying material. Smaller scale selective mining may still be practical here if a miner is diligent.

Placer gold occurs in so many areas that it would be impractical to try to identify each of them here. One of the best recent publications covering individual districts and areas is U.S. Geological Survey Professional Paper 610, Principal Gold Producing Districts of the United States, published in 1968 (9) . Also, a series of reports is being written describing the individual placer gold deposits of various States or portions of States, to be published as Geological Survey Bulletins. 

Specific locations and names of mines can often be found on the detailed maps prepared by the U.S. Forest Service, the U.S. Bureau of Land Management, the U.S. Army Corps of Engineers, or the U.S. Geological Survey. Various State agencies may also have appropriate maps on hand.

California

California has led all other States in placer mining and as would be expected has many gold-producing areas of interest, particularly including the deposits on the Feather, Mokelumne, American, Consumnes, Calaveras, and Yuba Rivers and their tributaries (2, 4-6, 9). These rivers reach into the famous Mother Lode area of the Sierra Nevada Mountains from which much of the gold is derived. Deposits are also found in the drainages of the Trinity and Klamath Rivers in northern California and at scattered points in the southern part of the State. Ancient Tertiary channels and gravels of the Sierra Nevada Range have been especially productive sources of gold, and maps have been published by the California Division of Mines and Geology showing approximate routes of these features. Two U.S. Forest Service maps that the prospector would find of particular value in considering the Sierra deposits are of (a) the Downieville, Camptonville, and Nevada City districts, Tahoe National Forest; and (b) the Foresthill and Big Bend districts, also in the Tahoe National Forest. Maps covering the Trinity and Klamath National Forests of northern California might also be of interest.

Alaska

Most of Alaska's gold production has come from placers, principally those in the Yukon River Basin, although deposits are known on nearly all major rivers or their tributaries (22, 33). Beach deposits in the Nome district have been notably productive, as have the river and terrace or bench placers in the drainages of the Copper and Kuskokwim Rivers. Climatic conditions play a great part in mining in Alaska, and the season for hydraulic operations of any kind is relatively short.

Northwest States (Montana, Idaho, Oregon, and Washington)

Montana's principal placer mining districts are in the southwestern part of the State (15). The Helena mining district and the many placers along the Missouri River in the vicinity of Helena and upstream are among the more important areas. The headwaters and tributaries of the Missouri in Madison County, particularly near Virginia City and Bannock, are noted for early placer production. Placer gold has also been produced on the headwaters of the Clark Fork of the Columbia River at a number of points.

The Boise basin, northeast of Boise, Idaho, is most noted for the dredging of placers (21). Other well-known placer areas lie along the Salmon River in Lemhi and Idaho Counties and on the Clearwater River and its tributaries, particularly in the vicinities of Elk City, Pierce, and Orofino. Placer gold is also found along the Snake River, but this is commonly fine-grained or "flour" gold that is difficult to recover.

Oregon's placers are located mainly in the southwestern part of the State, on tributaries of the Rogue River and on streams in the Klamath Mountains (16). Main gold-producing areas are the Greenback district in Josephine County and the Applegate district in Jackson County. Placer gold also occurs in many of the streams that drain the Blue and the Wallowa Mountains in northeast Oregon. The Sumpter area and the upper Powder River have had important production. Other areas include the Burnt River and its tributaries and the John Day River Valley.

Washington is not noted for placers, although gold has been found along a number of its streams, including some on the western slope of the Cascade Mountains. Generally, the few productive placers have been confined to the north-central part of the State.

Nevada

Nevada has not been a large placer gold producer, although lode gold deposits - potential sources - are widely distributed throughout the State (27). The problem has been chiefly one of too little water. In the past, dry washers were used extensively, as well as other methods that were very conservative of water. Producing areas were largely found in the western half of the State and included American Canyon and Spring Valley in the Humboldt Range, Pershing County, and the Manhattan and Round Mountain areas of Nye County. Placers were also worked below Virginia City and in northern Elko County near Charleston. Signs of limited placer diggings may be seen in many parts of the State.

Colorado

A few important Colorado placers of the residual type are found on slopes and hillsides in the immediate vicinity of gold veins. However, placers in Colorado are generally confined to narrow canyons below lode gold mining areas within the Rocky Mountains in a belt which extends northeast across the western part of the State. Almost every gold district has had some placer production. Many of the streams emerging from the Front Range, the headwaters of the South Platte River, and the Arkansas River and its tributaries as far upstream as California Gulch contain placer gold. Historically, placers were mined first and led to development of Colorado's rich lode deposits.

Other States

Among the other Western States, placer mining has been limited to only a few localized areas. In South Dakota, the Black Hills (particularly the Deadwood area) and French Creek, near Custer, have been productive sources. Arizona (32) and New Mexico (30) placers are in some instances related to copper deposits that carry gold.

In the Eastern States some of the streams draining the eastern slopes of the southern Appalachian Range have yielded gold (32 17). Saprolite deposits (rock decomposed at the original site) have been a source of placer gold in Georgia (13) and the Carolinas (29. Generally, the eastern placers are sparsely distributed and the gold is low in grade. Thus, few serious efforts have been made at mining them since the early 1800's. Nevertheless, many locations offer possibilities for small operations intended primarily for recreational purposes.

Other Things You Need To Know

Staking Claims on Open Lands

Instructions on staking claims and filing for patents can be obtained from the U.S. Bureau of Land Management. In addition to Federal regulations, individual States also have certain requirements pertaining to the location of claims on public lands. Information on these requirements is available from the State agency that deals with mining. Claims for mining can only be staked on lands of the public domain.

Lands in areas generally subject to location for mining, such as National Forests, may be open or closed depending on whether the land has been withdrawn for some special purpose. The status of the land can usually be determined by local inquiry to the U.S. Forest Service, or it can be checked at the Land Offices of the Bureau of Land Management or at the County Assessor's Office. The status of land being considered for mining should be established before any significant investment of money or labor has been made. This will insure that the ground is open to location so that the prospector can stake a valid claim and protect his investment.

When entering any land to examine for or attempt to mine placer gold, a person should determine if it is privately owned, previously located by claim that may still be valid, or possibly held under patent, which conveys the right of private ownership. Under any of these conditions, the unauthorized intruder is trespassing and has no legal rights to the gold he may produce. Usually some sign or indication of ownership is evident, or a local resident can supply the information necessary to determine ownership, but in any event one takes his chances when the status of land is uncertain. At the worst, the land may be protected by a shotgun. Active claims should be clearly marked, and records may be checked in the respective County Courthouse to determine approximately where and when they were located. It should be added that, however necessary, such checking can be tedious.

The basic laws on location of mining claims in the public domain are contained in the General Mining Laws of 1872. Placer claims generally can be located on lands that would be classified as locatable if they contained vein or lode deposits. Neither the beds of navigable lakes and rivers nor lands below high tide are subject to mineral location. However, new claims can be located over abandoned earlier ones, although the new locator may be called upon to establish that the earlier claims were, in fact, abandoned at the time of relocation.

Mining locations may be made by U.S. citizens, by those who have declared their intention to become citizens, by an association of qualified persons, or by a domestic corporation. A location may be made by a minor who has reached "the age of discretion," and without regard to the sex or residence of the locator. A person may make valid locations as an agent for other qualified parties who may not have even seen the ground. No limit is placed by Federal statutes on the number of locations that may be made, and claims may be amended and boundaries changed at any time, provided such changes do not interfere with the rights of others.

Generally, a placer claim is established by posting a notice of location upon a tree, a rock in place, a stone, a post, or a monument. This must contain the name of the claim, name of locator or locators, date of location, number of square feet or acreage claimed, and sufficient description of the claim by reference to some natural object or permanent monument to identify the claim, following which the boundaries of the claim must be marked so they may be readily traced. Requirements for marking of boundaries vary somewhat by State. A location may not exceed 20 acres for any one person nor 160 acres for an association of persons, and claims should conform as nearly as practicable with the rectangular subdivision characteristic of the U.S. system of public land surveys.

At least one discovery of mineralization is required per claim (20 to 160 acres) "that would justify a person of ordinary prudence in the further expenditure of time and money, with reasonable prospect of success in developing a profitable mine."  A discovery implies a certain amount of excavation to show that the required mineral is indeed present, although State laws vary somewhat on this point. A minimum annual expenditure in labor and improvements of $100 must be made to hold possession of a mining claim, and evidence to this effect must be duly recorded by the appropriate county recorder. Such work is generally known as "assessment work." Provisions are also made for millsites on nonmineral land. Since September 2, 1958, the requirements for assessment work may be satisfied by conducting geological, geochemical, and geophysical surveys under the supervision of a qualified expert.

Unpatented claims may be bought and sold, but their use is restricted to mining purposes only. Any use of the surface for purposes unrelated or foreign to mining is unauthorized. Ownership of both the minerals and lands prospected and developed is attained by the process of patenting. Prior to patenting, the claim holder has possessory rights only to the minerals. A number of requirements must be met for a patent, which is obtained through the U.S. Bureau of Land Management. These include proof of discovery of valuable minerals, expenditure of at least $500 in labor and improvements, payment for filing application, publishing costs, and other items.  Specific information on placer mining patent applications and on adverse claim procedures in the case of contested rights can be found under parts 3863 and 3870, title 43, of the Code of Federal Regulations pertaining to mining claims under the General Mining Laws of 1872. (Note: For assistance regarding location of mining claims on the public domain, the Bureau of Land Management of the U.S. Department of the Interior should be consulted.)

Public Law 167, enacted July 23, 1955, provides for multiple use of the surface of public lands. This does not alter the validity of gold placer locations based upon sufficient evidence of discovery. It does set up procedures whereby the Government agency responsible for administering surface resources can challenge a mining claimant. In this way the question of surface rights is cleared so that the fullest use can be made of the land.

Under Public Law 359, enacted August 11, 1955, mining is permitted on lands which have been withdrawn from location or reserved for power development and for other purposes, provided certain steps are taken. In this case, permission to mine must be obtained from the Secretary of the Interior. Claims located before the date of the act on a power withdrawal are relocatable. Lands accorded to Indian Reservations are not subject to claim under U.S. mining laws. (From June 18, 1943, to May 27, 1955, an exception was made for the Papago Indian Reservation, but such free mineral entries were then curtailed (43 CFR 3825, formerly 3635).) One wishing to prospect or mine on Indian lands must obtain a lease from the Secretary of the Interior; application for the lease should be made through the reservation superintendent.

On State-owned lands, application for prospecting or mining lease should be made to the appropriate State authority. Regulations on granting such leases vary by State. Mining claims can be located on private stock-raising homestead lands where the Government has reserved rights to minerals, although certain limitations are specified to protect the homesteader and to provide reimbursement for damage to crops or to tangible improvements. Taylor Grazing Act lands are also subject to location.

Privately owned lands are usually leased or may be purchased outright for mining purposes. Normally a lease will carry a royalty provision on the mineral production as a percentage of the gross or net value received from sales. Many different arrangements are possible, depending upon the requirements or bargaining positions of the potential lessor and lessee.

The recent completion of studies of mining laws by the Public Land Law Review Commission and recommendations by the Commission can be expected to result in changes in regulations that could affect placer location procedures or mining rights. Information on such changes as they occur will become available from the Bureau of Land Management, U.S. Department of the Interior.

Problems With Water Rights, Water Supply, and Stream Pollution

The need for a good, dependable, and plentiful supply of water increases geometrically with the scale of operation in placer mining. Panning gold requires very little water and can be done in a small tub if necessary. At the other extreme, the hydraulic monitor, once in use, employed large flows of water under high pressure, and sluicing at a large operation could consume virtually all the water that might be available. One thing the placer miner must keep in mind is the seasonal nature of stream flow. This affects both the supply of water and also the problems of pollution for downstream users and damage to stream ecology.

Various means are used to divert and impound water. Channels, pipes, and flumes can be constructed to conduct water where it is wanted. If supply at a continuous flow is limited, storage must be provided, and placer operation is then restricted to periodic activity and depends on the capacity of the reservoir. A simple tank may make a suitable reservoir for a small operation. Pumps are commonly used now where power is cheap enough, and the recirculation enables use of a smaller supply of water.

The question of water rights has always been important to the placer miner and is a complex subject in itself. Legal authorities should be consulted in case of any doubts or disputes. It has been common practice in placer mining to measure water requirements in terms of "miner's inches," which can be converted to rate of flow by the approximate factor of 40 inches to 1 cubic foot per second (the legal conversion in Arizona, California, Montana, and Oregon; other States vary). One cubic foot of water is equivalent to about 7.5 gallons. Thus, a miner's inch converts to 11.2 gallons per minute.

Water flows are measured in cubic feet per second and storage is measured in acre-feet, the latter being equivalent to a l-foot depth of water spread across an area of 1 acre. Measurement of flow is usually done with a calibrated weir, but flows can be estimated by average velocity or by other methods if the quantity is large. A term used to describe the effectiveness of water in hydraulic operations is its "duty," which is usually expressed as the number of cubic yards of gravel washed per miner's inch per 24-hour day. Water duty will vary greatly with the mining situation.

States where placer mining has been important in the past, such as California, have enacted detailed and quite strict laws regarding stream pollution from placer operations. Such laws require the construction of a settling pond or ponds of sufficient size to clarify the water used in mining before it is discharged into the stream. Furthermore, they may require that aluminum sulfate and lime or some similar clarifying substance be added to the effluent to avoid rendering the water in the stream unfit for domestic water supply purposes.

Regulations regarding stream pollution may vary with the stream and the particular portion of the State, so the appropriate control agencies should be consulted. In California, the California Debris Commission and the California Department of Fish and Game regulate discharges from mining operations. The California Fish and Game Code curtails mining operations in the Trinity and Klamath River fish and game district between July 1 and November 30, "except when the debris, substances, tailings, or other effluent from such operations do not and cannot pass into waters in the said district." Federal and State water resource and water quality control agencies may also have something to say about placer mining discharges, and it is wise to check with them before undertaking any sizable project.

Legislation in California that closed down hydraulic mining on the Sacramento River and its tributaries goes back many years. An act entitled "Protection of Domestic Water Supplies From Pollution of Placer Mining Operations" covering the watersheds of the Sacramento and San Joaquin Rivers (A. B. 2006) was passed in 1941, requiring a permit for placer mining from the California Debris Commission and compliance with a number of provisions specifically aimed at dredging.

Who Can Advise You

There are many sources to which the novice placer miner may turn for information. Probably the first should be the particular State agency dealing with geology, mining, conservation, or development. Universities with geology or mining departments will have knowledgeable people who can be consulted. A readily accessible source of information is the reference section of your public library. Professional engineers and consultants may be contacted through professional organizations or directly, by telephone.

Federal agencies most concerned with the problems of placer mining are the Bureau of Mines, the Geological Survey, and the Bureau of Land Management, Department of the Interior. Generally, the Bureau of Mines is best equipped to handle technical or statistical questions; the Geological Survey provides information on geology and deposits; and the Bureau of Land Management is involved in land ownership and evaluation problems. The Forest Service, Department of Agriculture, is a good source of information on placer mining sites and regulations within the National Forests. Furthermore, the prospector is well advised to inquire at the local ranger station of the National Forest in which he intends to prospect for guidance and to inform the ranger of his intent.

County offices, including that of the County Recorder, can often supply useful information on claim staking and placer locations within that county. Forms for location notices are normally available at the County Courthouse in mining localities or may be purchased at a stationery store. Questions about possession and sale of gold come under the purview of the Department of the Treasury.

How To Look For Placers

Once decided on the area of search and armed with some knowledge of the characteristics of deposits to look for, then you are ready to explore. Most areas are relatively settled today and are accessible by car, or at least lie within a few miles of a road. A possible exception is Alaska, where an aircraft or boat might be needed to reach the site. Regardless of the type of transportation, you will need adequate supplies and equipment to sustain you and your companions for an extended stay in the field. With a gold pan for each and setting out from a base camp it should be possible to determine within several days if the potential for the area is good.

Equipping Yourself

Camping and outdoor recreation in general have become so popular that many commercial sources of equipment and information are now available. Some stores appeal to the budget-minded, while others, such as the specialty shops for camping supplies, have a wider selection of usually more durable products. Books on camping are available at the library, and reliable merchants will recommend the equipment best suited for a particular use. Many of the comforts of home can be found in the ordinary camp today. Backpacking has benefited from developments in lightweight materials and foods. The amounts and types of goods and equipment selected will depend on the remoteness of your location and accessibility of a resupply point. The prospector might wish to travel with a mobile home, trailer, or camper, or he might simply pack his gear on his back and head up the trail. A few suggestions are in order here, but the individual must do much of his own planning, since requirements and tastes vary so greatly.

Basic Equipment

Among the essential implements needed for prospecting are a pick; a long-handled, round-pointed shovel; and a gold pan, preferably a 10- or 12-inch-diameter pan which can usually be purchased at hardware stores in gold-mining areas. A small prospector's pick is also useful, and a magnet and a small amount of mercury should be carried to separate the gold from black sand after panning. Specialty stores and manufacturers can provide the more elaborate equipment, such as skindiving gear, ready-built sluices, and mechanical gold separation devices, if desired.

In some cases, a bucket or wheelbarrow may be needed to transport materials to the washing site, and in addition, a heavy 1/4- to 1/2-inch-mesh screen is handy to separate out coarse materials. A small screen cut to nest in the upper part of a gold pan can be useful for the same purpose in panning. A gold pan the same size as the one used for panning will make a most efficient nesting screen if a close pattern of holes is drilled in the bottom. Holes usually should be 1/4 to 3/8 inch in diameter, depending on the average size of the material being sampled. Distance between holes should be about the same as the diameter of the holes. In some areas these pans can be purchased readymade. For weighing gold, a small balance scale graduated in milligrams may be desirable. A compact, folding type of balance is available for this purpose.

A compass will be needed for establishing claim lines and for finding your way out of the woods if lost. Adequate maps should be carried. A hand magnifying lens is helpful in identifying minerals. Bags may be needed to carry out samples; plastic bags are the best because samples may be damp. A rocker may be transported to the site either assembled or in a knocked-down condition. If mining is planned, lumber and other materials to build a sluice may be carried to the site. (See construction details under respective headings.) More elaborate equipment such as pumps, pipes, hoses, and light plants might be taken in by pack animals if desired.

Personal gear includes a good pair of boots, sturdy clothing, weatherproof gear, sleeping bag, tent, and such other things as one might want for comfort and sanitation. A foam pad or air mattress adds comfort to sleeping. A length of rope is useful for many purposes around camp, from raising the food out of reach of animals to extracting a car from a mudhole. For hiking, all necessary equipment for the period away from camp should fit into a manageable backpack of some kind.

An ax, a flashlight, a knife, and matches are almost indispensable. (Fires in the National Forest should be made only in designated areas or after consulting the local forest ranger.) A water bucket is often required, and a good crosscut saw will be found useful. Guns and fishing equipment can be taken to supplement the food supply and to provide some additional recreation. Guns are seldom necessary for protection from animals. A canteen with a 2-quart or larger capacity is advisable in many areas, depending on dryness of the climate. You will need water-purification tablets where streams are contaminated, whether by grazing stock or for other reasons. A miner's lamp, which consumes calcium carbide, is sold at some hardware stores and can be used for a serviceable light, although most people when away from electricity prefer gasoline or propane lamps. A carbide lamp will also be useful for any underground work. The special miner's safety lamp is recommended wherever air may be bad. Stoves that burn gasoline or pressurized gas are in wide use in camping and even gas refrigerators may be taken along "to cool the beer." (For low-budget operations, a swift-running stream will serve this same purpose well.) For any length of time in the field, an oven for baking is a valuable amenity. A reflector oven for use next to a campfire can be made of light sheet metal and will give excellent results, also serving as a place to keep food warm.

Supplies

Freeze-dried foods are generally good and easy to carry and prepare, although somewhat more expensive than most other foods. For estimating pack weights, about 2 pounds of dehydrated and freeze-dried foods is needed per person per day. Canned foods should be avoided when backpacking because of their weight, but they are otherwise satisfactory. Disposal of empty containers should be done with consideration to others who may follow and wish an uncluttered landscape; burial is usually recommended.

Suggested food supplies for a prospector's camp include the following: bacon, beans, cheese, salt, baking powder and soda, coffee, tea, onions, potatoes, fruits, corn. peas. raisins, rice, flour, crackers, cereals, butter or margarine, powdered milk, eggs, pancake and waffle mix, sugar, syrup, and fresh meat and vegetables as practicable. Many other items can be added to the list, but these are most of the basics. Utensils should include a variety of dishes, silverware, a sharp knife, spatula, can opener, frying pan, coffee pot, and several different sizes of pots and pans. Towels, both paper and cloth, soap, scouring pads, and metal or plastic tubs or basins will be needed for cleaning up.

Extra clothing should be included in your supplies for warmth and for changes. Mosquito netting may be a virtual necessity in some areas, and adequate amounts of a good insect repellent should be packed.

Probably the most troublesome and at times the greatest hazard in the wilds today is the bear. People may argue which type of bear has the meanest temperament, but any type may leave your camp a shambles when in search of food, and under certain circumstances any bear will attack a person. Placing food out of reach or in a secure container will help reduce the attraction. Fortunately, most bears will turn and run when frightened by loud noises. Other wild animals are seldom dangerous except when provoked, but smaller ones such as packrats can inflict considerable damage on camp gear and foodstuffs. Poisonous snakes, spiders, ticks, scorpions, and the like should be treated with traditional caution; their presence should be anticipated in most areas. Learn to identify and avoid poison oak and poison ivy' Knowledge of first aid is essential for dealing with emergencies that might arise on an outing, and a study or review of the subject should be included in any preparations.

Some of the personal hazards faced in the out-of-doors include twisted ankles, lacerations from falling in brush, falls from slippery rocks or crude bridges when crossing streams, breaking through floors in old building ruins, and falls or cave-ins in old mine workings. Beware of bad air in any old workings' Danger of drowning is always present when working around the deeper streams or pools when placer mining.

Many types of first aid kits and equipment are on the market. The choice of kit is one of size and variety of content. A snakebite kit is usually a separate accessory and should be carried, even though it is rarely put to use. Disinfectants, aspirin, fungicides, bandages, and similar items should be included. For areas of considerable sunshine, tanning lotion, sunglasses, and a hat are needed, and salt tablets should be taken as designated to prevent heat prostration. Wearing a safety hardhat and safety glasses may be advisable at times.

Panning for Gold

The standard gold pan is made of stiff sheet iron and is 16 inches in diameter at the top and 2-1/2 inches deep. The rim is flared outward at an angle of about 50 degrees from the vertical. Smaller pans are used for testing, and it is advisable for most panners to use either a 10- or 12-inch size for handling ease. Probably the 12-inch is the most widely available. Frying pans or other cooking utensils may also be used for washing out gold but are less effective. Before any kind of container is used for panning it should be cleaned thoroughly and all grease should be burned out. New pans generally are greasy and should be heated over a fire until this coating is gone. Even a rusty pan, if clean, can be used satisfactorily. In fact, the roughness due to the pitting of the rust may assist in holding back the gold.

There are different techniques and subtle variations in the art of panning--experience teaches which is best. Those with wide experience and much practice can recover the most gold with the least effort. It is sometimes said that good panning technique lies in the action of the wrists. After much practice the good panner should be able to save even the very fine gold that may be nearly but not quite free from the black sands.

The pan usually is filled level with the top, or slightly rounded, depending somewhat upon the nature of the material being washed and the personal preference of the panner. It is then submerged in water. Still water 6 inches to 1 foot deep is best. While under water the contents of the pan are kneaded with both hands until all clay is dispersed and the lumps of dirt are thoroughly broken. The stones and pebbles are picked out after the fines are washed off. Then the pan is held flat and shaken under water to permit the gold to settle to the bottom. The pan is then tilted and raised quickly -- still under water -- so that a swirling motion is imparted and some of the lighter top material is washed off. This operation is repeated, occasionally shaking the pan under water or with water in it until only the gold and heavy minerals are left. With proper manipulation, this material concentrates at the edge of the bottom of the pan. Care must be taken that none of the gold climbs to the lip of the pan or gets on top of the dirt.

Nuggets and coarse colors of gold can now be picked out readily with a tweezer or with the point of a knife. Cleaning the black sand from the finer gold is more difficult, but can be carried nearly or entirely to completion by careful swirling of the contents as described above, always watching to see that none of the colors are climbing toward the lip. This part of the operation usually is done over another pan or in a tub so that if any gold is lost it can be recovered by repanning.

The concentrates should be dried, and the black sands (composed largely of magnetite) can then be removed by a magnet or by gently blowing them on a smooth flat surface. If there is an excessive quantity of black sand, the gold usually is amalgamated by putting a portion of a teaspoonful of mercury in the pan. In sampling work, extra care should be taken to see that no fine colors are lost. When mining, however, additional time needed to insure that all colors are saved probably is not justified because the value they add is so small.

A word should be said here about other minerals that you may see in your gold pan. Pyrite ("fool's gold," an iron sulfide) and mica are often mistaken for gold by the novice. Pyrite, which is usually a brassy yellow to white color, will shatter when struck with a hammer and becomes a black powder when finely ground. Mica, which may have a bright, bronzy appearance, is distinguished by its light weight and flat, platy cleavage. Both minerals are common in gold areas. Other minerals that will collect with the gold and black sands because of high specific gravity include ilmenite (iron-titanium oxide), hematite (nonmagnetic iron oxide), marcasite (an iron sulfide), rutile (titanium oxide), scheelite (calcium tungstate), wolframite (iron, manganese tungstate), tourmaline (boron and aluminum silicate), zircon (zirconium silicate), chromite (iron and chromium oxides), and cinnabar (mercury sulfide). If present in sufficient quantity, these latter minerals may have some economic significance, although efforts to recover them as byproducts are seldom worthwhile.

Native platinum, elemental mercury, lead shot, and similar materials are also occasionally found in the pan.

Evaluation: Should You Invest And Mine?

This question becomes more difficult to answer as the size of the planned operation increases. Estimation of the amount of gold recoverable and the overall costs of investment and mining is no simple matter and calls for highly experienced engineering skills for any moderate- to large-scale project. Elaborate procedures of sampling and evaluation cannot be followed by the small-scale operator because of the cost. Thus, his decisions must be based on a variety of factors, not the least of which is intuition. Needless to say, many mistakes have been made, with much resultant waste of money and effort. Do not let what started out as a recreational activity become your master instead of your servant.

Sampling Techniques

Many methods of sampling are possible, including the simple panning of gravel from surface exposures, churn drilling, test pitting and trenching, shaft sinking, and drifting. As an aid in tracing possible gold-bearing channels, geophysical techniques have been employed with some success, but proper use of the typical instruments involved is generally reserved to experts. Moreover, interpretation of results is seldom adequate to provide any quantitative estimates, although the information gained can be useful in planning an exploration program.

For a thoroughgoing discussion of exploration and sampling techniques the reader is referred to the recent Bureau of Land Management publication by John H. Wells, entitled Placer Examination: Principles and Practice (31). Wells' description of panning is particularly recommended.

Panning and rocking (described later) are the basic means of determining the recoverable gold content of placer materials. A fire assay, sometimes made on a concentrate, provides a relatively complete estimate of the gold content of the material, but a poor estimate of how much gold can actually be extracted by conventional washing methods. Thus, placer gold is seldom assayed, except to determine its fineness (measure of gold purity, see p. 37). In estimating the value of gold in the pan after washing a quantity of gravel, the technique of counting nuggets and "colors" is normally followed. Generally, pieces worth more than 5 or 10 cents are considered as nuggets; smaller particles are colors. When skill is developed in estimating the various sizes of particles, a good degree of consistency can be achieved in the results.

Where samples can be obtained across a section of the bank exposed along a creek, it is good practice to cut a vertical groove or channel of fairly consistent width and depth. The sample may be cut from top to bottom, or in segments comprising several different samples if the bank shows distinct changes in materials. Bars may be sampled by digging a vertical hole, clear to bedrock if possible, and panning the product. For surface mining of "skim bars," sampling consists of simply taking a panful from a favorable point and visually estimating the amount of similar material in the vicinity. Clearly, there is not much accuracy in any of these methods, but the deposition of gold in such locations is bound to be erratic anyway. More representative sampling is usually possible in the larger deposits where deposition and size of gold particles is more uniform or consistent.

Calculating What You Might Have

For the small-scale miner, sampling will usually be limited to taking a panful here and there and possibly running a larger sample through a rocker or sluice if panning discloses any gold. If colors are found, a record should be made of the number and estimated size of colors per pan and the approximate location. The sampling then progresses until one is assured the prospects are good enough to warrant a mining operation of some sort.

A scale of sizes and approximate values of colors based on pure gold at $35 an ounce is as follows:

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