At present, several methodologies for calculating the economic efficiency of R&D in various sectors of the national economy have been developed, but the problem has not yet been solved in general. Most of the methodologies are based on a single formula ...
Drilling of boreholes in comparison with sinking of mine workings allows to explore placer deposits of minerals with less time and money. The main type of mechanized sinking of exploration wells in gold-bearing placers in the USSR and abroad is percussion drilling.
The question of the correct determination of the economic efficiency of geological exploration, despite its obvious importance and relevance, has not been finally resolved. In industrial practice for this purpose is used the value of costs per unit of explored mineral reserves, ie, the cost of exploration of a unit of reserves. Е. О. Pogrebitsky economic efficiency of exploration work in percent is defined as the ratio of the cost of exploration to the value of extracted products...
The studied Ural rock crystal deposit is confined to a large lens of dolomite marbles of northeastern dip and northwestern declination. The average thickness of the lens is 200 m and its length is 800 m. In the northeast it is in contact with the apophysis of the Caledonian-Hercynian granitoid massif, in the southwest - with crystalline schists of presumably Riphean age and minor detritus of the massif. Industrial targets at the deposit are crystal nests.
Extensive literature is devoted to the iss.s of hydrothermal alteration of host rocks at domestic deposits of rock crystal. Since the majority of rock crystal deposits are confined to quartz-bearing rocks, it is natural that sandstones, quartz-mica schists and various granitoids have been the main focus of attention of researchers. However, significant commercial accumulations of rock crystal are also known in carbonate rocks. Such is the case of one of the deposits in the Urals, which was studied for several years by V. D. Eshkin, who published a number of works on its geology, genesis and on the question of hydrothermal alteration of the host rocks.
The main task now facing quartz geologists is a thorough analysis of structural control The deposit, like most rock crystal deposits in adjacent areas, belongs to the northwestern strike-slip fault zone. The thickness of the zone reaches 500 m, its length - the first kilometers. The disturbance is characterized by lenticular-block structure, typical for similar formations in metamorphic rocks. The entire zone is composed of concordant lenses of quartz-mica schists and marbles of the Manya Formation (Pz, Cm) and lenses of Hercynian granodiorites ...
According to the existing theory, rock crystal deposits are formed in at least two consecutive stages: a) formation of quartz bodies; b) formation of crystal nests. For the formation of quartz bodies, the source of Si02 is a magmatic source, for the formation of crystal nests - host rocks or previously formed quartz bodies .
