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Bit Application Chart
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For contacts : Bulgaria |
Series |
Rock type & Rock Properities |
14 |
Extremely hard, non-abrasive, very fine grained, competent, glassy quartzite, jasperite, chert , irone stone |
10 - 12 |
Very hard, non-abrasive, fine grained, diorite, granite, gneiss, quartzite |
9, 9+ |
Hard, competent , slightly abrasive, granite, gneiss , quartzite |
8 |
Hard, moderately abrasive, fine to medium grain , competente to fractured, granite, pegmatite, skarns , quartz, silicified volcanics |
6 |
Medium hard, comp. to fractured, moderately abrasive, basalt, diorite, gabro |
4 |
Medium soft, abrasive, competent or fractured, dolomite, weathered granite, serpentine |
2 - 3 |
Very abrasive - soft or hard, unconsolidated, coarse grained, conglomerate, sandstone ,limestone, concrete |
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