Polymetallic ore

Polymetallic ores (from poly... and "metals") 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. The main minerals that form polymetallic ores are galena, sphalerite, to a lesser extent pyrite, chalcopyrite, arsenopyrite, cassiterite.

The formation of primary polymetallic ores took place in different geological epochs (from Precambrian to Cenozoic). Basically, such ores occur in the thickness of volcanogenic rocks of acidic composition.

Rocks containing polymetallic ores are often intensively altered by hydrothermal processes — chloritization, sericitization and silicification. Hydrothermal deposits are also of some importance. They are formed as a result of weathering processes of near-surface parts of ore bodies (to a depth of 100–200 m). These deposits are usually represented by 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 (bedded and lenticular deposits, stocks, veins, nests, complex tube-like bodies) and occurrence conditions (gentle, steep, consonant, secant, etc.).

Literature

 * Small mining encyclopedia, 2004.