Placer mining is a kind of surface, open-pit mining. When you think of this kind of mining, you usually think of early Gold Rush prospectors. In this type of mining you will find alluvial minerals. Prospectors, another name for miners, were looking for gold. They might find it in flakes, nuggets, or gold dust. Gold is found in veins like the ones in the palm of your hand.
The gold had to be separated from the rock around it. Sometimes water erosion helped it along by wearing away the rock so that the gold flowed with the water into the nearby rivers. When this happened, it would travel with the water until it reached parts of the river where the water slowed down—like bends in the river.
The chemical properties of gold make it heavy and therefore it will drop to the bottom when the current is not strong enough to carry it. With this understanding, the early prospectors were able to make an underground mineral into a surface mineral.
Since surface minerals are easier and cheaper to reach, they are more sought after. When a prospectors found a spot they wanted to mine by a they would stake out their claim.
Prospecting For Gold Gold In USAAnyone 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.
(USGS - read entire article)
Locating Gold And Other MineralsTechnology has taken much of the guesswork out of mining, mountain ranges are still notoriously difficult environments in which to hunt for valuable minerals. Various methods used to draw a picture of the underground environment, including the measurement of gravitational and magnetic fields, are easily thrown off by factors such as changes in topography height, surrounding temperature, and barometric pressure.
Now Prof. Lev Eppelbaum of Tel Aviv University's Department of Geophysics and Planetary Sciences has developed a new method for processing and analysing complex environments in the face of these challenges. Combining new physical-mathematical approaches with their own advanced software -- which brings together all available analysis in the same three-dimensional image -- the researchers were able to overcome the difficulties posed by mountainous regions, successfully uncovering new mineral reserves.
(Science Daily - read entire article)
How To Mine Placer Gold 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.
(ICMJ - read entire article)
Sluicing Instructions After you have located a promising deposit of gold-bearing gravel, walk along the stream bank and look for a place where you can set up your sluice box. You should search for a spot where the current is moving quite swiftly. Once you find such a place, set your sluice box directly in the current so that the box is filled with water almost to the top.You can often compensate by placing the sluice box so that the upper "input" end is slightly higher than the lower "discharge" end. If the sluice box is somewhat unstable in the current, position a few rocks around the outside of the trough to brace it.
Sometimes you will not even need the "rock brace," as the first few buckets of gravel placed into the sluice box will provide just enough stability to weigh it down.
(ICMJ - read entire article)