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Show NEW IDEA IN EXCAVATING Hydraulic Mining Cartridge Is Said to Be the Most Powerful Yet Devised. It Is often hard, and sometimes dangerous, dan-gerous, to use ordinary explosives for mining and excavating in confined spaces, a fact that has led to the development de-velopment of the hydraulic miniug cartridge as a safe and effective substitute. sub-stitute. The cartridge consists of a steel cylinder containing numerous small pistons that expaud when water is injected Into them with a hand pump. After drilling a deep enough hole, the workmen Insert the cylinder, and then set to work at the hand pump. The tiny pistons expand until their free extremities bear against the mass of rock with constantly-Increasing force, and the rock Is gradually fractured under the tremendous pressure. pres-sure. The operation, it is said, Is not only cheaper than the ordinary blast, but disintegrates a larger area of rock. |