| Rock sex | Unidirectional tensile strength (MPa) | rock name | first time mining Q0 | repeated mining | |
| Q1_ | Q2_ | ||||
| Firm hard | ≥90 80 70 60 | Very hard sandstone, limestone and clay shale, quartz veins, very hard iron ore, compact granite, amphibole, diabase Hard limestone, hard sandstone, hard marble, not hard granite | 0.0 0.0 0.05 0.1 | 0.0 0.1 0.2 0.3 | 0.1 0.4 0.5 0.6 |
| Middle hard | 50 40 30 20 >10 | Harder limestone, sandstone and marble Ordinary sandstone, iron ore Sandy shale, flaky sandstone Hard clay schist, not hard sandstone and limestone, soft conglomerate | 0.2 0.4 0.6 0.8 0.9 | 0.45 0.7 0.8 0.9 1.0 | 0.7 0.95 1.0 1.0 1.1 |
| Weak | ≤10 | All kinds of shale (not hard), compact marl, soft shale, very soft limestone, anthracite, ordinary marl, broken shale, bituminous coal, hard topsoil-granular soil, compact clay, soft sandy clay, loess, humus, loose sand | 1.0 | 1.1 | 1.1 |