Machines which completely free the mineral from the seam

EFIXED CONSTRUCTIONS E21Mining E21CMINING OR QUARRYING

E21C27/00Machines which completely free the mineral from the seam

E21C27/01specially adapted for removing overhanging coal E21C27/02solely by slitting E21C27/04by a single chain guided on a frame with or without auxiliary slitting means E21C27/06with a slewing frame E21C27/08with additional means for cutting the mineral into blocks E21C27/10by both slitting and breaking-down E21C27/12breaking-down effected by acting on the vertical face of the mineral E21C27/122with breaking-down members having a striking action E21C27/124with rotatable cutters provided with breaking-down members E21C27/126with slitting and breaking-down members situated in parallel on an intermediary level E21C27/128with breaking-down members functioning on the slitting level E21C27/14breaking-down effected by force or pressure applied to side of slit E21C27/16with means for both slitting and breaking-down E21C27/18by both slitting and planing E21C27/20Mineral freed by means not involving slitting E21C27/22by rotary drills with breaking-down means, e.g. wedge-shaped drills E21C27/24by milling means acting on the full working face E21C27/26by closely adjacent cutter chains acting on the full working face E21C27/28by percussive drills with breaking-down means E21C27/30by jaws, buckets or scoops that scoop-out the mineral E21C27/32by adjustable or non-adjustable planing means with or without loading arrangements E21C27/34Machine propelled along the working face by cable or chain E21C27/35Ram-ploughs E21C27/36Machine self-propelled along the working face E21C27/38Machine stationary while planing in an arc E21C27/40Machine and its planing tool making alternative step-wise movements along the working face E21C27/42combined with scraper or collector box E21C27/44Planing knives E21C27/46by percussed planing means