AUSZUEGE AUS DEM UNTERSUCHUNGSVORHABEN Nr. 1 ###>EXTRACTS FROM STUDY PROJECT No. 1 udy of the consequences of the development of mining techniques the intensity of physical effort with the transition from conntional production at the face (coalwinning with explosive arges and pneumatic pick, steel props, caving) to production at chanized faces (coalwinning by machine, powered support, caving)