How To Use hard coal In A Sentence
- Coal body is watered by deep hole high pressure above mid-hard coal seam to soften the harder coal so as to improve the working efficience. It's a new way for mechanization mining in harder seam.
- Anthracite -- The name anthracite, or hard coal, is applied to those dry coals containing from 3 to 7 per cent volatile matter and which do not swell when burned. Steam, Its Generation and Use
