抄録
The Kishu copper mine is located in the northern part of the Kumano coalfield in the outer zone of Southwest Japan. Veins of xenothermal type occur in the Miocene sediments, which contain coals and fine particles of dispersed carbonaceous matter. The coals were formerly worked at the Yakushi, Miyai and Shiko coal mines near the Kishu mine. The samples studied were collected from the underground of the Kishu mine, old mine dumps and cores of two boreholes.
The Miocene sediments were intruded by the Kumano Acidic Rocks and the related igneous rocks in the middle Miocene time. Vitrinite near the contact with the intrusive bodies was converted to natural coke with mosaic, flow and spherical structures. The structures of coked vitrinite indicate that vitrinite was of bituminous rank at the time of intrusion. It is apparent from the general pattern of the isoreflectivity lines in the area that the hydrothermal mineralization followed the intrusion and altered bituminous rank of vitrinite to anthracite which ranges in maximum reflectivity from 3 to 6.5 percent.
