Some Engineering Problems Of The Panama Canal In Their Relation To Geology And Topography

82 ENGINEERING PROBLEMS OF PANAMA CANAL. the total number of holes drilled were arranged as one continuous hole, it would be long enough to pass through the center of the earth. The amount of concrete used in the locks and dams, about 4,500,000 cubic yards, would make a pyramid 400 foot high, with a base 960 feet square. The maximum number of drills in actual use at any one time in Culebra Cut alone was 377, of which 221 were tripod drills and 156 well drills. With these over 90 miles of holes have been drilled in a single month. Drill holes were normally placed about 14 feet apart, and their usual depth was about 27 feet, or 3 feet deeper than the shovel excavation extended. The greatest number of steam shovels at any one time in the cut was 43, and the greatest monthly excavation was made in March, 1911, when 1,728,748 cubic yards of material, mostly rock, was excavated. To handle this required 115 locomotives and 2,000 cars, or about 160 loaded trains per day. Fhrough Culebra Cut for excavation purposes there were 9 parallel tracks, or about- 100 miles of track in the 9 miles of the cut. I ho doepost oxcavation. is at Gold Hill, where tho topmost part of tho slope is 494 feet above the bottom of the canal. In Culebra Cut the blasting operations necessitated about 1 pound of 45 per cent potassium nitrate dynamite to every 2| cubic yards of material.