On the Iron Ore and Associated Deposits of the Kamaya Mine, Iburi Province, Hokkaido, Japan

Abstract

The iron oxides and iron sulphides of the Kamaya mine, located about 12 km northeast of Datemonbetsu, Iburi Province, Hokkaido, are of hydrothermal origin. In this area liparitic tuff and tuff breccia sediments of the Miocene Toyoura formation have been intruded by propylite, nevaditic liparite and andesite dikes, and later covered by flows of two-pyroxene andesite lava.
The iron ores are generally irregular, massive deposits within the nevaditic liparite and breccia tuff. These ore bodies consist of reddish brown iron ore and some blackish iron sulphide. Ore and associated minerals are quartz, iron ore (hematite), pyrite, marcasite, and sericite.
The most characteristic feature of the iron ores is their higher iron content and lower combined-water content than so-called "limonite" in the zone of oxidation. The ore is red to reddish black, has a micaceous luster, and gives a reddish brown streak. In thin section this iron ore is opaque and ussually associated with quartz. Its X-ray powder pattern is very similar to that of artificial Fe₂O₃. Chemical analysis gives Fe₂O₃, 88.40% ; H₂O (+), 0.34% ; H₂O (-), 1.72%; and insoluble residue, 8.33%; total. 98.79%.