July 29, 2021
1. f=20, The hardest, or ultra hard. i.e., the densest, toughest quartzite, basalt and various other particularly hard rocks.
2. f=15, Very hard. Very hard granite, quartz porphyry, siliceous schist, relatively hard quartzite, the hardest sandstone and limestone.
3. f=10, Hard. Firm Dense granite, very firm sandstone and limestone, quartz-veins, firm conglomerate, very firm iron ore.
4. f=8, a little Hard. Firmness Firm sandstone, limestone, marble, dolomite, pyrite, and unstable granite.
5. f=6, Relatively hard. general sandstone and iron ore
6. f=5, a Relatively hard. sandy shale and shale sandstone.
7. f=4, Moderately hard. firm argillaceous shale, unstable sandstone and limestone, soft gravel.
8. f=3, Various kinds of unstable shale and dense marl.
9. f=2, Relatively soft. Weak shale, very soft limestone, chalk, salt rock, gypsum, anthracite, broken sandstone and stony soil.
10. f=1.5, Relatively soft. gravel soil, broken shale, bonded gravel, gravel, solid coal, hardened clay.
11. f=1.0, Soft. Soft dense clay, soft bituminous coal, hard impact soil, clay-soil.
12. f=0.8 Soft. Soft sandy clay, gravel, loess.
13. f=0.6, Soil, Humus, peat ,Soft sandy soil, wеt ѕаnd.
14. f=0.5, Loose. sand, mountain gravel accumulation, fine gravel, loose soil, mined coal.
15. f=0.3, Quicksand-like. quicksand, swamp soil, water- bearing loess and other water-bearing soil.
|Contact Person :||Mr. Bill, George, Michael|