International Correspondence Schools · Scranton, Pa. : The Colliery engineer co. · leaf 358
e center line E F oi the tunnel, and arecalled the center cut holes. The mass of rock includedby these holes is wedge-shaped and shown in plan at A inFig. 43(i. The removing of this wedge by blasting is calledbreak!njir the cut. Fig. 437 shows a longitudinal sectionthrough the center cut holes. The… … Fig. 435. Fig. 437. ^//y^^ /v/^/yyw/A^ -^»^
Railroad engineering
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