Back — The roof or upper part in any underground mining cavity. Backfill — Mine waste or rock used to support the roof after coal removal. Barren — Said of rock or vein material containing no minerals of value, and of strata without coal, or containing coal in seams too thin to be workable.
The congressman's tour of Luby Equipment Services' facilities and a panel discussion took place on May 30 and was arranged by the Associated Equipment Distributors (AED), a trade group representing companies that distribute, rent and support equipment used in construction, energy, agriculture and other sectors.
This article is about the tier-60 degradable equipment available to free-to-play players. For the pay-to-play, non-degradeable version, see Dragon equipment. Corrupt dragon equipment is a set of armour and weapons that shares the same stat bonuses as the corresponding pieces of regular dragon...
A. Abutment - In coal mining, (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides, which act as abutments of the arch of strata spanning the roadway; and (2) the weight of the rocks over a longwall face is transferred to the front abutment, that is, the solid coal ahead of the face and the back abutment, that is, the settled packs behind the face.