roof strata

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• Roof —   A building element that provides protection against the sun, wind, and precipitation.   *** (coal)   The rock immediately above a coal seam. The roof is commonly a shale, often carbonaceous and softer than rocks higher up in the roof strata.… …   Energy terms

• Strata Florida Abbey — (in Welsh: Abaty Ystrad Fflur ) is a former Cistercian abbey situated just outside Pontrhydfendigaid, near Tregaron in the county of Ceredigion, Wales. The abbey was originally founded in 1164. [http://www.archivesnetworkwales.info/cgi… …   Wikipedia

• roof bolt — noun Mining a tensioned rod anchoring the roof of a working to the strata above. Derivatives roof bolting noun …   English new terms dictionary

• Windblast — is a term commonly used in mining to describe a sudden rush of air or gas due to the collapse of a void.CausesWindblast is common in longwall coal mines, especially those whose roof strata are competent, and do not cave immediately behind the… …   Wikipedia

• tunnels and underground excavations — ▪ engineering Introduction        Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …   Universalium

• auger — /aw geuhr/, n. 1. Carpentry. a. a bit, as for a brace. b. a boring tool, similar to but larger than a gimlet, consisting of a bit rotated by a transverse handle. 2. See earth auger. 3. a device consisting of a shaft with a broad helical flange… …   Universalium

• coal mining — Coal was very important in the economic development of Britain. It was used as fuel in the factories built during the Industrial Revolution and continued to be important until the 1980s. The main coalfields are in north east England, the north… …   Universalium

• Underground mining methods —   A drift mine is driven horizontally into coal that is exposed or accessible in a hillside. In a hydraulic mine, high pressure water jets break the coal from a steeply inclined, thick coalbed that would be difficult to mine with the usual… …   Energy terms

• Coal mining — Men leaving a UK colliery at the close of a shift Surface coal mining in Wyo …   Wikipedia

• dome — domelike, adj. /dohm/, n., v., domed, doming. n. 1. Archit. a. a vault, having a circular plan and usually in the form of a portion of a sphere, so constructed as to exert an equal thrust in all directions. b. a domical roof or ceiling. c. a… …   Universalium

• PILLAR — (Heb. עַמּוּד; from the root ʿmd, to stand ), a column that stands perpendicular to the ground and generally serves to support the beams of a roof. In this article no distinction will be made between pillar, column, and post. The pillar is used… …   Encyclopedia of Judaism