Can we theoretically calculate in which areas the gold ore is located, determine the amount of its reserves in a particular deposit in order to decide whether it is profitable to build a mining enterprise here? Indeed, exploration, drilling of deep wells and exploratory mines take years and not one thousand dollars. Are there any signs by which the presence of a precious metal in the depths of the earth is guessed? Alas, mankind has not yet invented a single universal “recipe” for the search for gold deposits. Although long since thought about this issue.
Gold ore requires intuition, intuition, almost art from the geologist. In one locality, nuggets and dendrites almost sparkle underfoot, while in another there are all the accompanying signs, and in the rock there is no trace of precious metals. The study of the processes occurring in the bowels of our planet at a depth of several tens of kilometers allows us to understand the question of the origin of this substance, which is desirable for people.
The magmatic activity of the Earth drives hot solutions through microcracks and large faults in rocks, which leave sediment from
feldspars, quartz, sulfur compounds with various metals on the walls of these stone channels. Gold ore, platinum and silver may also be among them. Nuggets often have silver impurities. If white metal is more than 25%, such a stone is called electrum. There is also native silver, which contains an admixture of gold. These are kustelites, where yellow metal can be up to 10%. A study of the chemical composition of the solution, which brought precious metals from the lower layers of the
earth's crust to a depth of 5-7 kilometers to several tens of meters, shows that they must be sought in a sulfide and chloride environment.
But this knowledge does not bring us any closer to the practical result: a theoretical search for a gold deposit. There are many chloride and sulfide sources, but not all of them have the desired metal. It can be assumed that the substance of interest to us was formed from the sediments of ancient alluvial seas buried beneath a multi-kilometer thick earth. There, under the influence of high temperatures and pressure, it was melted into liquid magma, passed through cracks and faults, and hardened in the form of ore or nuggets. But this scientific hypothesis still does not give us practical benefits.
Let’s try to go the other way: to determine the list of minerals with which gold ore most often adjoins. Its companions are other precious metals - silver, platinum, palladium, iridium, ruthenium, osmium and rhodium. Also, less noble rocks are found in close intergrowth with inclusions of gold: quartz, argentite, pyrite, galena, adularia, albite, amethyst. But the trouble is that these satellites most often do not have a single golden grain, and therefore can not serve as a guide for us in finding the cherished vein.
Gold was mined in Russia for a long time in alluvial deposits, that is, where it was washed to the surface by streams. And when other search tools and development technologies were invented in other countries, we still had troughs and sieves with gold digger tools. Fortunately, there are still a lot of these deposits in our open spaces. When they were exhausted in the Urals, huge accumulations of placers were discovered in Siberia and the Far East.