APPLICABILITY OF THE RECENT CUTTING MACHINES IN UNDERGROUND DIMENSIONAL STONE QUARRIES

摘要

With increasing demands of the society for protection of the nature, open pit dimensional stone quarries are facing the rising costs for environment, and numerous obstacles raising from demands of local and regional authorities for limited exploitation and rising demands for closure the actual open pit quarries. Over the last decades underground exploitation, the method of "room and pillar" is widely improved especially in layered limestone as well in marble deposits. To preserve the productivity as well the cost and safety of mining works, the planning of the underground spaces must be done by use of various parameters of rock mechanics and engineering geology. Being the blasting undesirable for quarrying of dimensional stone blocks, the machine industry has started to supply new excavating machines based on dry or wet cutting technology. A significant development has been made on cutting tools and on extending the life of new types of tools such as widia, diamonds and special polycrystalline hard tools called "stratapack". New chain cutter machines have capability of front, back vertical and horizontal cuts, cutting up to the length of nine meters, and with permissibility of cost efficient production of the stone or marble blocks. This article will present the last decade experience of developing underground "room and pillar" exploitation with irregular distribution of the pillars in layered limestone deposit using the modern chain cutters.