 |
| |||
| hard ground; solid bed; tough rock | |||
| hard rock; rag stone; good ground; good rock; ironstone; resistant rock; secure rock; whin; whinstone; bur; burr; iron stone | |||
| hard formation (категория буримости); hard rock (категория буримости) | |||
| competent formation; hard formation; ragstone | |||
| competent rock | |||
| |||
| coherent rocks; solid beds | |||
| hard strata | |||
| крепкая порода: 38 phrases in 11 subjects |
| Construction | 1 |
| Drilling | 2 |
| Geology | 4 |
| Makarov | 1 |
| Mining | 15 |
| Oil / petroleum | 3 |
| Oil and gas | 3 |
| Oilfields | 1 |
| Road works | 1 |
| Sakhalin R | 2 |
| Technology | 5 |