精选优质文档-倾情为你奉上SHAFT AND DRIFT EXCAVATION BY BLASTING AND SHAFT SUPPORT1 APPLICATION OF BLASTING IN SHAFT AND DRIFT EXCAVATION1.1 FRAGMENTATIONFragmentation is the breaking of coal, ore,or rock by blasting so that the bulk of the material is small enough to load, handle and transport.Fragmentation would be at its best when the debris is not smaller than necessary for handling and not so large as to require hand breaking or secondary blasting .Energy must be supplied to rock by di
