Process of Gold Mining
Various miners have employed different methods for mining of gold from ancient times. These are in the form of gold panning, dredging, sluicing, metal detecting, hard rock mining and byproduct recovery. Panning of gold is an age-old process making use of a shallow pan which is kept in the river water and filled with the gravel and sand with gold in it. After submerging it in water, it is shaken so that the heavy gold particles settle down, and the rest float and are thrown away. Planning is usually done in placer deposits which are present near water bodies like streams. But the disadvantage is that it is very time-consuming. However, it is a good method for finding gold deposits
Metal detectors are used in mining for gold. These have sensors which will be able to detect the presence of gold even if it is about one meter below the ground. As this can be carried around quite easily, it is quite a convenient method.
Some gold prospectors use a sluice box for mining on a small scale. It is a channel with riffles at the bottom. These rifles allow the gold to drop away from the suspended particles. The less dense material flows out of the box which is placed in a stream where the water is flowing. Many commercial gold prospecting companies use screening plants which remove boulders and gravel and then the remaining material is placed in the sluice box. They need to make use of earth-moving equipment which is powered by diesel such as excavators, bulldozers, and rock trucks.
Mining for gold can also be done with the method of dredging which necessarily makes use of suction dredges which also contain sluice boxes with pontoons. It has a suction hose held under the water level and is quite economical. It does not cause harm to the environment, and there is no deforestation or water wastage as the water can be reused.
Other kinds of mining of gold involve hard rock gold mining which is performed in cases where the gold is trapped in rock and not loosely found. Gold can also be mined from substances where the principal product may be something else such as copper and gold is only a byproduct.
Problems of Gold Mining
Gold mining involves extensive travel as the prospector has to explore the natural resources to find mineral deposits. Mining underground in pits also can be quite dangerous. Most of the underground mines are humid and dank, and some can even be extremely hot and even noisy. Some of the mines also have water up to a few inches. Of course, nowadays the underground mines do have electric lights, but the miners still wear caps with lights to illuminate certain very deep areas. At places, the roofs are low, and here the miners have to crawl o their hands and knees and even on their stomachs.
Gold mining can also entail other associated dangers in the form of electric shocks, a sudden collapse of the cave roof, some poisonous gasses or chemicals and so on. Even the weather might be a problem in some cases when gold mining has to be done in heavy snow or ice conditions. Gold miners need to be very sturdy as they need to do a lot of hard work like stooping or lifting heavy objects.
Mines have improved in the conditions these days as a lot of security measures have been taken and also, the equipment used is of a high standard. But many miners are exposed to a lot of dust generated in gold mining and this may affect their lungs and cause them serious problems. Their safety must be the major priority undertaken in the process of gold mining.
Gold mining can be done either in the hard rock deposits or the placers. The hard rocks are the primary deposits, and here the amount of gold is naturally more, but gold mining in the places is cheaper and also simpler. It is economical to mine for gold even if it is as little as 0.2 gr/t Au. In fact, there are even some great players having millions of ounces of gold, and this was true in the days of the gold rush in the nineteenth century such as the California Gold Rush and the Colorado Gold Rush.
The gold found in placer deposits is usually of the particulate type and is loosely located and hence has to be liberated by several natural processes. Hence, the grinding costs are quite low, and so even very low grade can be treated quite economically.