The gangway is not driven continuously, but after being driven about 55 feet on either side of the shaft, the breasts are started 25 feet from the shaft, a pillar being left to protect it. The breast is then opened up to the face of the gangway, and when one ore-breast is worked out, the gangway is driven ahead about 30 feet, and a new breast is opened and worked out before commencing a third. The air-hole is first driven to the surface, then the breast is opened to its full width of 6 feet. The thickness of the bed of ore here varies from 4 to 6 feet, depending upon the thickness of the partings of clay and slate. The clay and slate are left on the bottom, which is made sloping to allow the ore to roll down to the shute; this is 6 feet wide and 4 feet long and heavily timbered. Small props or sprags are hitched into the cement, and wedged with a lid on the clay side to prevent falls of rock. The holes are drilled by hand in the clay-partings. They vary in depth from 1 to 4 feet, and the charge of dynamite is varied correspondingly, according to the amount of ore it is desired to throw down. The loose ore is wedged down with crowbars and picks, and is then freed from any adhering clay and thrown down the shute. It is there loaded into boxes holding about half a ton each, which are pushed to the shaft on a truck. The ore-boxes have four rings at the corners, to which are attached four chains, suspended from the wire hoisting-rope. At the top of the shaft the boxes are detached and placed on a truck, which is run to the dump. Thirty cars, averaging 15 tons, are extracted in a day of two shifts, the day-shift working nine hours and the night-shift eleven. The pay of the miners is 5_s._ per shift. The cost of mining the ore averages 7_s._ per ton. The ore, as it comes from the mines, is free from refuse, great care having been taken to separate slate and clay from it in the working places. It is hauled in 2-ton wagons to kilns, which are situated on a hill-side for convenience in charging. The platform upon which the ore is dumped is built from the top of the kiln to the side of the hill. The ore is first spalled to fist-size and freed from slate, and is then carried in buggies to the charging-hole of the kiln.