<報文>秋田県明又鉱山産鉱石の単体分離度について

概要

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Akarimata mine with copper and iron sulphide deposit is in the northern part of Akita Prefecture. This region mainly consists of green tuff, propylite, propylitic tuff breccia, altered andesite of miocene members and sediments of paleozoic with many dykes of andesite and intrusive diorite. The deposit is shallow-seated fissure filling copper and iron sulphide veins. The ore minerals are mainly pyrite, pyrrhotite, chalcopyrite and a small amount of sphalerite and magnetite. The mineral paragenesis of this deposit is very interesting because it has the characteristic mineralization of pyrrhotite and the microscopic unmixing ore textures which are known to be found very little in tertiary vein deposit. Of the ore minerals, chalcopyrite contains sphalerite stars and vermicular pyrrhotites, and sphalerite also contains chalcopyrite and pyrrhotite emulsions formed by unmixing. The metallic ores are paragenised, as seen in Fig. 1. The ores were crushed by gyratory crusher and sized grains were observed under a reflecting microscope to determine the degree of liberation. The liberation ratios of the ores are 44.82% in 48 mesh, 73.85% in 100 mesh, 83.33% in 150 mesh and more than 92% under 200 mesh, as shown in Table 1,Figs. 3 and 4. The ores of Akarimata are more difficult to liberate into monomineral grains than the ores of usual tertiary vein-type deposits.
東北大学の論文
1960-01-30