Transactions, Volume 178

Abbadia alteration andesite anorthosite argillized average bands beds biotite block bodies breccia calcite carbonate cent chalcocite chalcopyrite chert chromite cinnabar clay concentration copper core crystals deflection deposits depth diabase diamond drilling dikes dolomite drill holes east exploration fault fissures fluorescence footwall formed fractures Fresnillo gabbro galena gangue geologic geologists grade grains granite greenstone hanging wall hematite Hill hypogene igneous Ilmenite indicated intrusive iron formation limestone lode magma magnetic magnetite manganese ment mercury metal miles minerals mining district Mount Isa occur outcrop oxide plagioclase porphyry present production pyrite quartz monzonite quartzite range replacement samples scheelite sericite shaft shale shear shows siderite silica silver silver-lead-zinc slate solutions sphalerite Steep Rock Lake stoping strike structural sulphide Superdip surface Survey temperature thick tion tons U. S. Geol ultraviolet vein vertical volcanic wall rock wedge width zinc zone