Structural Features of the Ore Deposit of the Kawayama Mine

Abstract

The ore deposit of the Kawayama mine is comprised of veins and several veinlets of pyrrhotite, chalcopyrite and sphalerite. The veins and veinlets dip at a low angle. As seen from structural features, mine-ralizing solutions seem to have ascended-along a thrust plane. Though the thrust plane is nearly parallel to the bedding planes, it crosses the folded strata of a syncline in the country rock. Consequently the country rock forms an abnormal strike zone along the thrust. This abnormal disturbance is, therefore, a good indicator for prospecting. Also by tracing the cross thrust zone, the extent of ore deposit can be expected. The extension already prospected is 600 metres on the strike side and 1, 000 metres in the dip side.
Lenticular voids inclined at low angles and resulting from thrust movement were probably the most favorable places for the mineralization. This idea of mineralization accords very well with the field data. By making a vein contour map, it may be possible to find more hidden deposits along gently dipping thrust zones.