Gold mining in the United States has taken place continually since the discovery of
gold at the Reed farm in North
Carolina in 1799. The
first documented occurrence of gold was in Virginia in 1782.[1] Some minor gold production took place in North
Carolina as early as 1793, but created no excitement until the discovery on the
Reed farm in 1799.[2]
US gold production
greatly increased during the 1980s, due to high gold prices and the use of heap
leaching to recover gold
from disseminated low-grade deposits in Nevada and other states.
Anyone who pans for gold hopes to be rewarded by the
glitter of colors in the fine material collected in the bottom of the pan.
Although the exercise and outdoor activity experienced in prospecting are
rewarding, there are few thrills comparable to finding gold. Even an assay
report showing an appreciable content of gold in a sample obtained from a lode
deposit is exciting. The would-be prospector hoping for financial gain,
however, should carefully consider all the pertinent facts before deciding on a
prospecting venture.
Only a few prospectors among the many
thousands who searched the western part of the United States ever found a
valuable deposit. Most of the gold mining districts in the West were located by
pioneers, many of whom were experienced gold miners from the southern
Appalachian region, but even in colonial times only a small proportion of the
gold seekers were successful. Over the past several centuries the country has
been thoroughly searched by prospectors. During the depression of the 1930's,
prospectors searched the better known gold-producing areas throughout the
Nation, especially in the West, and the little-known areas as well. The results
of their activities have never been fully documented, but incomplete records
indicate that an extremely small percentage of the total number of active
prospectors supported themselves by gold mining. Of the few significant
discoveries reported, nearly all were made by prospectors of long experience
who were familiar with the regions in which they were working.
The lack of outstanding success in
spite of the great increase in prospecting during the depression in the 1930's
confirms the opinion of those most familiar with the occurrence of gold and the
development of gold mining districts that the best chances of success lie in
systematic studies of known productive areas rather than in efforts to discover
gold in hitherto unproductive areas. The development of new, highly sensitive,
and relatively inexpensive methods of detecting gold, however, has greatly increased
the possibility of discovering gold deposits which are too low grade to have
been recognized earlier by the prospector using only a gold pan. These may be
large enough to be exploited by modern mining and metallurgical techniques. The
Carlin mine near Carlin, Nev., is producing gold from a large low-grade deposit
that was opened in 1965 after intensive scientific and technical work had been
completed. Similar investigations have led to the more recent discovery of a
Carlin-type gold deposit in Jerritt Canyon, Nev.
Many believe that it is possible to
make wages or better by panning gold in the streams of the West, particularly
in regions where placer mining formerly flourished. However, most placer
deposits have been thoroughly reworked at least twice--first by Chinese
laborers, who arrived soon after the initial boom periods and recovered gold
from the lower grade deposits and tailings left by the first miners, and later
by itinerant miners during the 1930's. Geologists and engineers who systematically
investigate remote parts of the country find small placer diggings and old
prospect pits whose number and wide distribution imply few, if any,
recognizable surface indications of metal-bearing deposits were overlooked by
the earlier miners and prospectors.
One who contemplates prospecting for
gold should realize that a successful venture does not necessarily mean large
profits even if the discovery is developed into a producing mine. Although the
price of gold has increased significantly since 1967 when the fixed price of
$35 an ounce was terminated, the increases in the cost of virtually every
supply and service item needed in prospecting and mining ventures have kept
profit margins at moderate levels, particularly for the small mine operator. In
general, wide fluctuations in the price of gold are not uncommon, whereas
inflationary pressures are more persistent. The producer of gold, therefore,
faces uncertain economic problems and should be aware of their effects on his
operation.
Today's prospector must determine
where prospecting is permitted and be aware of the regulations under which he
is allowed to search for gold and other metals. Permission to enter upon
privately owned land must be obtained from the land owner. Determination of
land ownership and location and contact with the owner can be a time-consuming
chore but one which has to be done before prospecting can begin.
Determination of the location and
extent of public lands open to mineral entry for prospecting and mining
purposes also is a time consuming but necessary requirement. National parks,
for example, are closed to prospecting. Certain lands under the jurisdiction of
the Forest Service and the Bureau of Land Management may be entered for
prospecting, but sets of rules and regulations govern entry. The following
statement from a pamphlet issued in 1978 by the U.S. Department of the Interior
and entitled "Staking a mining claim on Federal Lands" responds to
the question "Where May I Prospect?"
There are still areas where you may prospect, and if a discovery of a
valuable, locatable mineral is made, you may stake a claim. These areas are
mainly in Alaska, Arizona, Arkansas, California, Colorado, Florida, Idaho,
Louisiana, Mississippi, Montana, Nebraska, Nevada, New Mexico, North Dakota,
Oregon, South Dakota, Utah, Washington, and Wyoming. Such areas are mainly
unreserved, unappropriated Federal public lands administered by the Bureau of
Land Management (BLM) of the U.S. Department of the Interior and in national
forests administered by the Forest Service of the U.S. Department of
Agriculture. Public land records in the proper BLM State Office will show you
which lands are closed to mineral entry under the mining laws. These offices
keep up-to-date land status plats that are available to the public for
inspection. BLM is publishing a series of surface and mineral ownership maps
that depict the general ownership pattern of public lands. These maps may be
purchased at most BLM Offices. For a specific tract of land, it is advisable to
check the official land records at the proper BLM State Office.
Successful gold mining under present
conditions is a large-scale operation, utilizing costly and sophisticated
machinery capable of handling many tons of low-grade ore each day. The grizzled
prospector with a burro is no longer a significant participant in the search
for mineral deposits, and the small producer accounts for only a minor share of
the total production of metals including gold.
Some degree of success in finding
gold still remains for those choosing favorable areas after a careful study of
mining records and the geology of the mining districts. Serious prospecting
should not be attempted by anyone without sufficient capital to support a long
and possibly discouraging campaign of preliminary work. The prospective gold
seeker must have ample funds to travel to and from the region he selects to
prospect and to support the venture. He must be prepared to undergo physical
hardships, possess a car capable of traveling the roughest and steepest roads,
and not be discouraged by repeated disappointments. Even if a discovery of
value is not found, the venture will have been interesting and challenging.
Locations of important gold-producing
districts of the United States are shown in some of the reports of the
Geological Survey listed at the back of this pamphlet. Geological agencies of
the principal gold-producing States where additional information may be
obtained also are listed. Information may be obtained, too, from U.S. Bureau of
Mines State Liaison offices located in the capital cities of most States.
Placer Deposits
A placer deposit is a concentration of a natural
material that has accumulated in unconsolidated sediments of a stream bed,
beach, or residual deposit. Gold derived by weathering or other process from
lode deposits is likely to accumulate in placer deposits because of its weight
and resistance to corrosion. In addition, its characteristically sun-yellow
color makes it easily and quickly recognizable even in very small quantities.
The gold pan or miner's pan is a shallow sheet-iron vessel with sloping sides
and flat bottom used to wash gold-bearing gravel or other material containing
heavy minerals. The process of washing material in a pan, referred to as
"panning," is the simplest and most commonly used and least expensive
method for a prospector to separate gold from the silt, sand, and gravel of the
stream deposits. It is a tedious, back-breaking job and only with practice does
one become proficient in the operation.
Many placer districts in California
have been mined on a large scale as recently as the mid-1950's. Streams
draining the rich Mother Lode region--the Feather, Mokelumne, American,
Cosumnes, Calaveras, and Yuba Rivers--and the Trinity River in northern California
have concentrated considerable quantities of gold in gravels. In addition,
placers associated with gravels that are stream remnants from an older erosion
cycle occur in the same general area.
Much of the gold produced in Alaska
was mined from placers. These deposits are widespread, occurring along many of
the major rivers and their tributaries. Some ocean beach sands also have been
productive. The principal placer-mining region has been the Yukon River basin
which crosses central Alaska. Dredging operations in the Fairbanks district
have been the most productive in the State. Beach deposits in the Nome district
in the south-central part of the Seward Peninsula rank second among productive
placer deposits of Alaska. Other highly productive placers have been found in
the drainage basin of the Copper River and of the Kuskokwim River.
In Montana, the principal
placer-mining districts are in the southwestern part of the State. The most
productive placer deposit in the State was at Alder Gulch near Virginia City in
Madison County. Other important placer localities are on the Missouri River in
the Helena mining district. The famous Last Chance Gulch is the site of the
city of Helena. There are many districts farther south on the headwaters and
tributaries of the Missouri River, especially in Madison County which ranks
third in total gold production in the State. Gold has been produced at many
places on the headwaters of the Clark Fork of the Columbia River, particularly
in the vicinity of Butte. Placer production from the Butte district, however,
has been over-shadowed by the total output of byproduct gold recovered from the
mining of lode deposits of copper, lead, and zinc.
Idaho was once a leading
placer-mining State. One of the chief dredging areas is in the Boise Basin, a
few miles northeast of Boise, in the west-central part of the State. Other
placer deposits are located along the Salmon River and on the Clearwater River
and its tributaries, particularly at Elk City, Pierce, and Orofino. Extremely
fine-grained (or "flour") gold occurs in sand deposits along the
Snake River in southern Idaho. Placers in Colorado have been mined in the
Fairplay district in Park County, and in the Breckenridge district in Summit
County. In both areas large dredges were used during the peak activity in the
1930's.
The most important mining regions of
Oregon are in the northeastern part of the State where both lode and placer
gold have been found. Placer gold occurs in many streams that drain the Blue
and Wallowa Mountains. One of the most productive placer districts in this area
is in the vicinity of Sumpter, on the upper Powder River. The Burnt River and
its tributaries have yielded gold. Farther to the west, placer mining
(particularly dredging) has been carried on for many years in the John Day
River valley.
In southwestern Oregon, tributaries
of the Rogue River and neighboring streams in the Klamath Mountains have been
sources of placer gold. Among the main producing districts in this region are
the Greenback district in Josephine County and the Applegate district in
Jackson County.
Minor amounts of placer gold have
been produced in South Dakota (the Black Hills region, particularly in the
Deadwood area, and on French Creek, near Custer) and in Washington (on the
Columbia and Snake Rivers and their tributaries).
In addition to these localities,
placer gold occurs along many of the intermittent and ephemeral streams of arid
regions in Nevada, Arizona, New Mexico, and southern California. In many of
these places a large reserve of low-grade placer gold may exist, but the lack
of a permanent water supply for conventional placer mining operations requires
the use of expensive dry or semidry concentrating methods to recover the gold.
In the eastern States, limited
amounts of gold have been washed from some streams draining the eastern slope
of the southern Appalachian region in Maryland, Virginia, North Carolina, South
Carolina, Georgia, and Alabama. Many saprolite (disintegrated somewhat
decomposed rock that lies in its original place) deposits in this general
region also have been mined by placer methods. Small quantities of gold have
been mined by placer methods in some New England States. Additional placer
deposits may be discovered in the East, but prospecting will require substantial
expenditures of time and money. The deposits probably will be low grade,
difficult to recognize, and costly to explore and sample. Moreover, most of the
land in the East is privately owned, and prospecting can be done only with the
prior permission and agreement of the land owner.
Lode Gold
Lode gold occurs within the solid rock in which it was
deposited. Areas likely to contain valuable lode deposits of gold have been
explored so thoroughly that the inexperienced prospector without ample capital
has little chance of discovering a new lode worth developing. Most future
discoveries of workable lode gold ore probably will result from continued
investigations in areas known to be productive in the past. The districts in
which such new discoveries of gold may be possible are too numerous to be
listed in detail in this pamphlet. Some of the famous districts are: in
California, the Alleghany, Sierra City, Grass Valley, and Nevada City
districts, and the Mother Lode belt; in Colorado, the Cripple Creek, Telluride,
Silverton, and Ouray districts; in Nevada, the Goldfield, Tonopah, and Comstock
districts; in South Dakota, the Lead district in the Black Hills; and in
Alaska, the Juneau and Fairbanks districts. Deposits in these districts
generally are gold-quartz lodes.
Prospecting for lode deposits of gold
is not the relatively simple task it once was because most outcrops or
exposures of mineralized rock have been examined and sampled. Today's
prospector must examine not only these exposures, but also broken rock on mine
dumps and exposures of mineralized rock in accessible mine workings. Gold, if
present, may not be visible in the rock, and detection will depend on the
results of laboratory analyses. Usually, samples of 3 to 5 pounds of
representative mineralized rock will be sent to a commercial analytical
laboratory or assay office for assay. Obviously, knowledge about the geological
nature of gold deposits and particularly of the rocks and deposits in the area
of interest will aid the prospector.
There are many publications of
interest to those seeking more information about gold. The following list is
representative. Anyone contemplating a prospecting venture or mining operation
should consult some or all of these and other publications as well to become
better informed on this fascinating and challenging subject. Many papers, maps,
and articles on gold and related heavy metals were published on the results of
investigations conducted in the mid- to late-1960's by the U.S. Geological
Survey and the U.S. Bureau of Mines. Titles and instructions for ordering many
of these appear in the publication catalogs of each agency. Some may be out of
print but may be consulted in libraries of the two agencies, and in many city,
college, and university libraries.
In 2007 the United States produced approximately 240 tonnes of
gold, making it the fourth-largest gold-producing nation, behind Australia, South Africa, and China.[3]Most gold produced today in the US
comes from large open-pit heap leach mines in the state of Nevada. The US is a net exporter of gold.[4]
Vast
gravel deposits from ancestral rivers within the Sierra Nevada contained large
quantities of placer gold, derived from the weathering of gold-quartz veins.
Gold mining evolved from hydraulic mining of unconsolidated placer deposits in
the early days of the Gold Rush, to underground mining of hardrock deposits,
and finally to large-scale dredging of low-grade gravel deposits, which in many
areas included the tailings from upstream hydraulic mines.
Underground
mining of placer deposits (drift mining) and of hardrock gold-quartz vein
deposits produced most of California's gold from the mid-1880s to the 1930s.
Another important source of gold from the late 1890s to the 1960s was
gold-bearing sediment, which was mined using dredging methods. More than 3.6
billion cubic yards of gravel was mined in the foothills of the Sierra Nevada,
where the dredging continued until 2003.
