Basic Gold Prospecting & Exploration Methods

Basic Gold Prospecting & Exploration Methods

Gold Prospecting and exploration that is a search for precious metals deposits is not a simple process because big deposits were discovered a long time ago. There are several places with important content of precious metals waiting for skill prospectors. The large mining companies of the world are focused in big deposits and the small deposits are attractive for small miners and perhaps their interest for gold prospecting is the most valuable tool for exploring new deposits.

Gold prospecting is a very widely disseminated throughout nature and may be found in any geological formation from the oldest rocks to the deposits that are still being formed, but in common with other metals, it is more likely to be found in the oldest rocks and in those places where the earth crust has undergone the most extensive changes such as elevations, folding, tilting, faults, and also volcanic action, with resulting changes in the composition and texture of the rocks.

New Technology In Gold Prospecting

The current technology is very important in development new project and exploration of new deposits begins with the selection of a target area. This is followed by reconnaissance exploration in which satellite remote sensing; geological mapping and seismic techniques are used. In turn, this is followed by detailed geophysical studies and later, a detailed drilling, sampling, assaying and mineralogical study. Gold deposits are sought with many techniques, but they are based on geochemical studies. Commonly more than one method is employed. With these methods, the geologist is looking for anomalies. Perhaps, the most important techniques are photogeology and seismic techniques.

The modern gold prospector has advantages that to some extent make up for the increased difficulty of finding ore deposits. One advantage is greatly increased knowledge about the geologic factors that localize ore deposition. The search for new deposits has become a complex undertaking, and the prospector should be as well-informed as possible. The prospector should acquire the ability to identify not only ore minerals but also common rocks and their minerals, as well as many kinds of geologic structures. This knowledge is best acquired by academic training, but much can be learned from studying reference books.

The first technique used in a gold prospecting venture is geological inference. The prospector studies reports, geologic maps, and cross sections of a region to pinpoint areas where there are structures, rocks, and minerals with which ores are usually associated. These areas warrant further exploration. Topographic maps or aerial photographs of these targeted areas are obtained and used in plotting information, such as locations for sampling.

Gold Prospecting Equipment

Can be used in many ways, according to the minerals sought and the methods employed in the search. Its effectiveness depends in large measure on the operator’s awareness of its applications. For example, radiation counters not only detect radioactive minerals for the uranium prospector, but can also be useful to placer prospectors. Some placer deposits contain both gold and heavy radioactive minerals , the radiation counter points out gold concentrations . A “black light” (ultraviolet lamp), commonly used in gold prospecting for fluorescent ore minerals such as scheelite (a tungsten ore), is also useful in detecting fluorescent rock-forming minerals such as calcite, barite, or fluorite, which can be indicators of associated metallic minerals.

Geochemical Gold Prospecting

Geochemical gold prospecting is based on systematic measurement of chemical properties of rock, soil, glacial debris, stream sediment, water, or plants. The chemical property most commonly measured is the content of a key trace element. Zones in the soils or rocks of comparatively high, or anomalous, concentrations of particular elements may guide the prospector to the elements in rocks or soils that constitute a geochemical anomaly (different from normal). The actual amount of the key element in a sample may be very small and yet constitute an anomaly if the sample’s concentration is high relative to the concentration of the surrounding area. For example, if most samples of soil are found to contain about 0.00001 percent (0.1 parts per million, or ppm) silver, but a few contain as much as 0.0001 percent (1 ppm), the few “high” concentrations are geochemical anomalies. Plots of analytical results on a map may indicate zones to be explored further.

Geochemical anomalies are classified as primary or secondary. Primary anomalies result from outward dispersion of elements by mineral-forming solutions. High concentrations of metals surround the deposit, and the dispersion of metals laterally or vertically along fractures or faults may result in a “halo” surrounding the deposit. Halos are especially useful in gold prospecting because they may be hundreds of times larger than the deposit they surround and hence are easy to locate.

Where You Can Gold Prospecting

A stope is a section of a mine where miners removed the vein material. They are often large areas in size, but they tell a prospector that the vein was rich enough to be worth extracting at this point. Sometimes these stopes come right to the surface and you will have a narrow working that may go along the Outcrops of quartz. vein but be open for some distance down dip on the vein. Obviously these open stopes are quite dangerous, but often small workings or hillside slopes below these open stopes can be quite productive because the vein from this rich area shed bits of mineralized material downhill.

Mill tailings are the material that was crushed to a fine powder in order to extract the valuable minerals in the vein. Occasionally, when the mill was poorly operated, these mill tailings can contain very fine gold. This is not, however, the normal situation. Even if the tailings are not productive, their existence indicates the mine from which they came was productive and should have some interesting material in the dumps.

Gold Prospecting & Exploration Methods

Many mine dumps have visible sulfide ore on their dumps. These sulfide ores can be rich in some districts and mark the better ores where you may gold prospecting closely associated with the sulfides.

There are many times when you have used Google Earth to look for old mines that were not marked on maps or the information that was on the map did not sufficiently describe the location. Either out in the field or when looking at aerial photographs like those available on Google Earth, one can often follow faint old roads to their end and there will be the mine you are looking for. Not every old road leads to a mine even when the old road is in an old mining area—sometimes old roads lead to springs that were used by ranchers, etc. But it is an interesting and useful technique for finding obscure, old mines.