Mineral Associations and Mo-W Ore Types of the Slepaya Zalezh' Orebody at the Tyrnyauz Deposit

摘要

Slepaya Zalezh', the largest orebody of the Tyrnyauz Mo-W deposit, is considered a first-priority object should mining operations at the deposit be resumed. Molybdoscheelite, scheelite, and molybdenite impregnation in mineable concentrations is genetically related to metasomatites of the productive stage overprinted on skarns, periskarn rocks, hornfelses, and marble. Ore types have been recognized based on the relative amounts of different ore-bearing metasomatite facies and protoliths acting as a diluting mass. Seven ore types have been recognized and mapped in cross section. Types I and II are characterized by predominant (70-90%) aposkarn ores after endo- and exoskarns, accordingly. Type III is characterized by approximately equal proportions of ores after endoskarns and periskarn rocks; type IV differs from type III by a decrease in periskarn rocks replenished by an increase in hornfels. Type V is dominated by ores after exoskarns and, to a lower extent (up to 25%), after marble. Type VI is intermediate between types III and IV. Type VII represents all protoliths in approximately equal proportions. Each type exhibits a stable mineral and chemical composition inherited from the protolith. The ores of each particular type have simple distinguishing features, convenient for logging and mapping, which can be used for manual picking of grab and bulk samples and preliminary ore separation. The ores exhibit narrow ranges of variation in sizes and shapes of ore mineral grains and intergrowths and concentrations of minerals harmful to flotation. The subtle differences in ore mineral concentrations between ore types enable their selective mining and blending. Maps and cross sections contain data on the spatial distribution of the associated components such as garnet and wollastonite in skarns and productive metasomatites, pyroxene-plagioclase periskarn rocks, and hydrothermally altered rocks with Cu, Au, and other mineralization.