1964 Volume 14 Issue 64 Pages 96-108
The Omine Mine is located at about 20 km east of Tono City, Iwate Prefecture, or about 1.2 km northwest of the Sahinai iron ore deposit of the Kamaishi Mine.
Geology of the mine area consists of Permian slate, sandy slate, sandstone and hornfels, intruded by quartz diorite and granodiorite.
The genesis of the ore deposit is intimately related to the granodiorite intrusien. The deposit is a contact metasomatic-high temperature hydrothermal cupper ore deposit, and is characterized by abundant occurrence of cubanite along with chalcopyrite.
The skarn of the ore deposit comprises four types, namely, "banded skarn", "breccia skarn", "green skarn" and "garnet skarn". The "breccia skarn" characteristically contains a large amount of microcline in its brecciated part, and the ore is found in the green-tinted interspace of the breccia. The ore, occurring in network or impregnation, or forming veinlets, has high contents of gold and silver.
Prospecting is performed by geological survey, land survey and boring, keeping a close contact with the mining team. Recently the "underground wireline method" has been adopted to the boring work, by which the efficiency has been greatly raised.
