Polymetallic ore

Polymetallic ores or multimetal ores are complex ores containing a number of chemical elements, among which the most important are lead and zinc. In addition, polymetallic ores can contain copper, gold, silver, cadmium, sometimes bismuth, tin, indium and gallium.^[1] The main minerals that form polymetallic ores are galena, sphalerite, to a lesser extent pyrite, chalcopyrite, arsenopyrite, cassiterite.^[1]^[2] They are most commonly formed from sulfides but also include oxides.^[1]^[3]

The three main families of sulfide polymetallic ores are identified as volcanogenic massive sulphide family, the sedimentary exhalative family, and the Mississippi Valley type family. The classification of lead-zinc deposits in particular has been varied and resulted in a number of different organizations schemes.^[1] The term "polymetallic ore" also includes nodules, principally Manganese nodules, that do not form as terrestrial deposits but as concretions on the ocean floor.^[3]^[4]

Rocks containing polymetallic ores are often altered or formed by hydrothermal processes — chloritization, sericitization and silicification.^[5]^[6] These deposits are often iron hydroxides containing cerussite PbCO₃, anglesite PbSO₄, smithsonite ZnCO₃, calamine Zn₄[Si₂O₇] [OH]₂×H₂O, malachite Cu₂[CO₃](OH)₂, azurite Cu₃[CO₃]₂(OH)₂. Depending on the concentration of ore minerals, a distinction is made between solid or disseminated ores. Ore bodies of polymetallic ores are distinguished by a variety of sizes (having a length of several m to km), morphology (lenticular bedding deposits,^[7] stockwork, veins,^[8] nests, complex tube-like bodies) and occurrence conditions (gentle, steep, consonant, secant, etc.).^[9]

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Polymetallic ore

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Literature

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