炭壁圧出対策

抄録

Yotsuyama Mine is one of the three mines in Miike Colliery. Retreating longwall mining system is exclusively employed and the mechanized faces are equipped with sheeld supports and a double ranging drum shearer. The working faces are developed in the Upper, Main and in the selected area of the Lower Split of the Upper Seam. In 1977, the mine experienced an extraordinary phenomenon in a face worked in the Upper Seam West 35th District where the cover of depth was 550 meters, the deepest cover of the colliery at that time. The phenomenon was very similar to outburst. Since then, mine has experienced such severe phenomena very often in the area especially where the seam is immediately covered with hard sandstone and/or the face is very close to the rib of or beneath the residuall pillars. The mine, therefore, has established its own preventives tackling on the problem. This report presents the mine's overall preventives taken to keep the safety and the production.