Abstract
The Study summarizes the consequences of comprehensive research on the mechanization of longwall faces which has been carried out at Taiheiyo Coal Mining Company's Kushiro Colliery since 1950 to this day.
Due to the crucial economical circumstances surrounded Japanese coal mining industry being affected by import of abundant and cheap priced crude oil from OPEC, the coal mining companies inevitably challenged to restructure their constitution by way of, for instance, mechanization of longwall faces and / or rejuvenation of underground structure.
At Kushiro Colliery, it was tried to introduce the powered supports to their thin seam(#2) and medium height seam(Lower Seam) on the experimental basis at the beginning, and as a final goal, it was also challenged to introduce multipass double wing mining method with 4 longwall faces where UU shaped Frame type with 12 legs powered supports were installed.
As a Part-1 of the report, the author describes mainly the results of measurement and analysis for roof lowering phenomena under heavy earth pressure. The results of analysis are reflected for the design of the powered supports, in particular, stroke of the hydraulic legs.
