Rock Drilling, with Particular Reference to Open Cut Excavation and Submarine Rock Removal (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...in structure to the sandstone of the St. Mary's River. One dredge of the elevator type was in use and in a day of 24 hrs., all stops allowed for, the average performance was 158 cu.yds. Besides the dredge there were two outfits for breaking the rock. One was the Lobnitz rock-breaker and the other a drill barge having six drills that were lifted by steam power and guided by hand. The Lobnitz rock-breaker averaged 182 cu.yds. per day, while the drill boat averaged 81 cu.yds. per day. The cost per cubic yard drilled and blasted by the barge was 3s., while by the Lobnitz rock-breaker it was only 15. 2.$d. The cost per cubic yard for dredging by the elevator dredge, the rock being drilled and blasted by the barge, was 25. 6d., same for the Lobnitz breaker 2s. 2d. Allowing 4% interest and 2% depreciation on the dredge, valued at 19,000, the additional cost per cubic yard for removal of rock broken by the drilling and blasting would be 8.2f.; same for that broken by the Lobnitz breaker was y.id. COMPARATIVE COSTS IN ABOVE SYSTEMS (local Wages) 1 The information in this article was collected by Mr. Gilbert H. Gilbert. 180 Difference in cost per cubic yard in favor of removal of rock broken by means of the Lobnitz breaker 25 2.6d. Saving on 500,000 cu.yds. = 54,166. An interesting comparison is furnished between the above two methods of breaking rock and that by use of Ingersoll-Rand submarine drills on the St. Mary's River. Costs in cents per cubic yard of drilling and blasting, using Ingersoll-Rand submarine drills, 18.45 + 1.05 (interest and depreciation) = 19.50. The drop drills on the barge at Blyth = 72.90. Lobnitz breaker is 2.5=29.30. Saving in cost of breaking 500,000 cu.yds. by means of the Ingersoll-Rand sumbarine drill as...