THE BRETBY TUNNELLING MACHINE. (INCLUDES PLATES.)

Keywords: NATIONAL COAL BOARD, NCB, BRETBY, TUNNELLING, MACHINERY, ROCKS, CUTTING, HEADS, MOTORS, TRANSMISSION, ANCHORS, UNITS, METHODS, DEBRIS, DISPOSAL, VENTILATION, DUST, SUPPRESSION, HYDRAULIC, CIRCUITS, CUTTERS, ROLLERS, POWER, LAYOUT, ELECTRICAL, EQUIPMENT, AUTOMATIC, CONTROL, SYSTEMS, SAFETY, INTERLOCK, MONITORING, TESTING, FACILITIES, TESTS, PERFORMANCE, TRIALS, PROJECTS, APPRAISAL, OPERATIONAL, USE, HARD, TUNNELS, COAL, MINING, MINES, PROTOTYPES, DESIGN, STUDIES, THRUST