| Webster's Online Dictionary |
| Expressions | Domain | Definition | |
| Half headers | Mining | Term applied to material that amounts to a large cap piece. They are used by sawing a header in two and placing one or more timbers under the half header on the same side of the track. Two timbers are generally placed under the half header and the end allowed to extend out over the haulage. The term half header should not be applied to regular cap pieces. (references) | |
Source: compiled by the editor from various references; see credits. | Top | ||
