Transactions . shape of the orebody. A timber line was then stood, so ar-ranged that the chutes came around the outer walls of the stope. Thesechutes (fourteen in number) were about 25 ft. ( m.) on centers. Thetimber line was made of sawed timber 10 m. ( cm.) square, and laggedwith 2-in. plank. The posts were 8 ft. long and the caps 7 ft., giving 5by 8 ft. in the clear. Waste was poured down the two central fill holes VOL. LXIII.—20. 402 GEOLOGY AND MINING METHODS AT PILARES MINE and spread level around the timber line. After leveling, the ore wasbroken around the two fill holes, taking
Transactions . shape of the orebody. A timber line was then stood, so ar-ranged that the chutes came around the outer walls of the stope. Thesechutes (fourteen in number) were about 25 ft. ( m.) on centers. Thetimber line was made of sawed timber 10 m. ( cm.) square, and laggedwith 2-in. plank. The posts were 8 ft. long and the caps 7 ft., giving 5by 8 ft. in the clear. Waste was poured down the two central fill holes VOL. LXIII.—20. 402 GEOLOGY AND MINING METHODS AT PILARES MINE and spread level around the timber line. After leveling, the ore wasbroken around the two fill holes, taking off 7-ft. cuts, slicing upward tomake a cone. The men stood on the broken ore and mined up each timeuntil the cone was the full size of the stope and ran up at a 35° angle,after which the ore was mucked into the chutes. These chutes were thestandard mine chutes, being 5 ft. ( m.) square and covered with grizzlybars made of 8 by 8 in. sawed timber, spaced with 12 in. ( cm.) open- Limit Commercial Ore. ;^-^r^HORIZONTAL PLAN K 50= ^ Barren Rock Fig. 11.—Shrinkage stope showing shovelways. ings. Fill was now dropped through the fill holes until it spread out in anatural, elliptical shaped cone and its edge reached to the chutes. Ashort floor of 2-in. plank was laid next the chutes and extended 6 ft. upthe cone to assist in mucking the ore on the next cut. Mining now startedup all around the bottom of the cone, using stoping machines. The orewas rapidly broken up the slope to the two central fill holes, using drillholes 8 ft. long. Just enough ore was now mucked into the chutes toallow another cut to go up the cone. This was repeated until four cutshad been taken. Then the stope was mucked clean, the chutes raised20 ft. ( m.) and enough fill put in to again reach the back. There W. ROGERS WADE AND ALFRED WANDTKE 403 was a slight amount of fill that had to be hand spread between the chutesand the outer walls of the orebody. The accompanying illustrationsshow two stag
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
