Compressed air . o be obtained by the useof well-drilling machines it was natural thatH. S. Kerbaugh, Inc., should adopt them inconnection with the work at Safe Harbor, al-though it was an entirely different propositionfrom the Enola work. The ground to bedrilled was hard rock of a gneiss mica schistformation with a small percentage of rock varied in hardness and the seamswere at varying angles to the perpendicular. The average drilling was nineteen feet sixinches per ten-hour shift, but the rate variedgreatly, according to the location. On thewest end of the work, the rate was sixty
Compressed air . o be obtained by the useof well-drilling machines it was natural thatH. S. Kerbaugh, Inc., should adopt them inconnection with the work at Safe Harbor, al-though it was an entirely different propositionfrom the Enola work. The ground to bedrilled was hard rock of a gneiss mica schistformation with a small percentage of rock varied in hardness and the seamswere at varying angles to the perpendicular. The average drilling was nineteen feet sixinches per ten-hour shift, but the rate variedgreatly, according to the location. On thewest end of the work, the rate was sixty feetin ten iiours. while at Manns Run, where theholes were from seventy-five to one hundredand twenty-eight feet deep, the rate was elevenfeet per day. At Star Rock one hundred-footholes averaged fourteen feet per ten hours. AtBuzzard Rock, where holes were from onehundred to one hundred and thirty feet deep,the average was nine feet per ten hours. Fromthe Buzzard Rock to Brenners Hollow, in COMPRESSED AIR. 4067. SHOWING THE DIFFICULT NATURE OF THE WORK. nine thousand feet of solid rock drilling, theholes averaged from sixty feet to one hundredand thirty feet in depth, the rate of drillingbeing nine feet per ten-hour shift. FromBrenners Hollow to Safe Harbor Viaduct thedrilling was from eighty feet to one hundred and thirty feet deep: the average rate beingtwenty feet per ten hours. The drills on theSafe Harbor work for the first sixty days weresteam actuated, and after that time weredriven by comjiressed air. the size of the con-tract making it advisable to operate as far as 4068 COMPRESSED AIR.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcompres, bookyear1896
