Distribution of Some Minor Elements in Sulfide Ores from the Hitachi Mine, Ibaraki Prefecture, Japan

Abstract The contents of some minor elements in copper-bearing ores from the Fujimi ore deposit No 5, the Hitachi mine, were determined. The selenium content in 46 samples was found to vary from 0.5 to 117 ppm. Though selenium seems to be concentrated in the ores rich in chalcopyrite, that is not always the case, as there are pyrite-rich ores with higher selenium contents than those rich in chalcopyrite. The average value of the atomic ratio of Se/S in the pyrite ores was calculated to be 3.48×10−5; this value was larger than those found for the ores from the Minenosawa and the Chichibu mines, and about the same as those found for the ores from the Nakase, the Ashio, and the Hanaoka mines. The variations with depth in the atomic ratios of Se/S and Co/Ni are closely related to each other. The atomic ratio of Se/S increased with an increase in that of Co/Ni. It has been concluded that selenium is concentrated in the pyrite ores of the high-temperature-type rather than in those of the low-temperature-type. The mercury content was small in general, but a large content of mercury was observed at the depth where the values of the atomic ratios of Se/S and Co/Ni were at their maxima.