Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Pyrophyllites and dickites are produced in Dado mine. The pyrophyllitie ores produced in the central mineralized zone and dickite ores are produced in the outer parts. Ores consist of pyrophyllite, dickite, quartz, pyrite, diaspore, sericite and ferric oxides. Pyrophyllite is the most abundant mineral in pyrophyllite ore and dickite is the most abundant one in dickite ore. Coarse and fine grained pyrites are contained in the dickite ores. Coarse grained pyrites should have been produced on earlier stages and higher temperature than fines, and the mineralization should have been continued after pyrites formation. Great reduction of temperature and pressure on the ore deposits are inferred after pyrites formation. Dickite ore has lower contents of Al2O3 than pyrophyllite ore because dickite ores have more quartz. The chemistry of mineralizing solutions was simple, and it maintained during the whole mineralization stages except for the reduction of temperature and pressure. The sulfur of pyrites is inferred to be igneous origin based on sulfur isotope compositions, but the fine grained pyrites might have the influence of sedimentary origin somewhat.