Scientific American Supplement No. 822, October 3, 1891 by Various
page 15 of 161 (09%)
page 15 of 161 (09%)
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on separately, permitting the battering rams to work at a greater
distance from the wall face. The time consumed in thus pulverizing the rock by repeated blows was naturally found to be increased. It was found more convenient to use only a single row of battering rams. The production was from about seven to eleven cubic meters (9.2 to 14.4 cubic yards) per hour. Toward the close of September, after it had been demonstrated that the "Derocheuse" was capable of accomplishing with celerity and economy the result for which it was designed, it was purchased by the Suez Canal Company. During the month of September, an experiment, the details of which were carefully noted, extending over a period of sixteen days, gave the following results: Crew (33 men), 140 hours. 2,012.50 francs $402.50 Coal, @ 87.50 francs ($7.50) per ton 787.50 francs 157.50 Oil and supplies 220.00 francs 44.00 Fresh water, 16 days 210.00 francs 42.00 Sundries 42.50 francs 8.50 ---------------- --------- Total expense for removing 764 cubic meters (999.2 cubic yards), 3,272.50 francs $654.50 Average, 4.28 francs per cubic meter ($0.65 per cubic yard). This result cannot be taken as a universal basis, because after a year's use there are numerous repairs to make to the plant, which would increase the average net cost. This, besides, does not include the cost of removal of the dredged material, nor the depreciation, the interest and the insurance. |
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