File:Bulletin (1910) (14759940441).jpg

Identifier: bulletin86unit (find matches)
Title: Bulletin
Year: 1910 (1910s)
Authors: United States. Bureau of Mines
Subjects: Mines and mineral resources Mines and mineral resources Mining engineering
Publisher: Washington U.S. Govt. Print. Off. (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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nto give greatest efficiency of results in handling; and (3) the tenacityor resistance to breakage of large masses of the material. If the rock is hard the cost of drilling is increased not only by thelonger time required but also by the larger cost of sharpening drills,greater drill breakage, more frequent delay from drill bits stickingand from broken drill points obstructing and sometimes necessitatiagthe abandonment of the holes, and easier deflection of the drill holeif it crosses at an acute angle an open joint or fracture zone containingsoft or crushed rock. The degree of smallness to wliich the rock must be broken dependschiefly on the size that gives greatest economy in handhng consistentwith the capacity of the excavating machinery and the use, if any,to which the material is to be put. A steam shovel with a dipper of4 or 5 cubic yards capacity can pick up, balance, and dump on arailway car a bowlder weighing several tons. The most economical GENERAL GEOLOGY OF CANAL ZONE. 17
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AVSNOmi HI aON - la I 97348°—Bull. 86—15 2 18 EXGINEERIXG PROBLEMS OF PAXAMA CAXAL. SUCCESSION OF BEDDED ROCKS. ;c. River alluvium.,-, Pleistocene ■jb. Muds and sills.■ formation, (a. Gravel. im^tone. )^^^^^ ^^^ ^^^ limestone. tuff beds, argillite, etc. LatePleistocene. Pleistocene orPUocene. Oligocene. ^- limest^M 9. ^^-^^ JLight colored Pat„Ti (c. Clav beds. ^- formation 1^ Fine sandstone, lormation. j^ Argillite. Caimitn f*^- Sandstone. ^liXton^ JMarine limestone, many corals. clay rocks, lava flow., etc. , clay, tufis. Limy sandstone. Eocene? ■ c o O g O o Miocene? (Mostly). <y O Op j. Emperadoilimestone Cucuracha K .,„,! f„,™„^^- formation, j^and formed ^- formation. JMarine carbonaceous shale ^ conelomerate j^oarse and fine conglomerate and sandstone beds. 2 Las Cascadasl Volcanic debris, mud-lava, some flows and dikes ofagglomerate./ andesite. ^fo^m^aSH--^-^--*-SUCCESSION OF IGNEOUS ROCKS. 6. Basalt. 5. Meta-breccia. 4. Rhyolite. (7) 7^ ^?yiS 3. Andesite

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