Holes are drilled

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• mining — /muy ning/, n. 1. the act, process, or industry of extracting ores, coal, etc., from mines. 2. the laying of explosive mines. [1250 1300; ME: undermining (walls in an attack); see MINE2, ING1] * * * I Excavation of materials from the Earth s… …   Universalium

• Drill bit — For the fictional character, see Drill Bit (Transformers). For the cancelled skyscraper nicknamed Drill bit, see Chicago Spire. For the types used in drilling wells, see Well drilling. From top to bottom: Spade, lip and spur (brad point), masonry …   Wikipedia

• Printed circuit board — Part of a 1983 Sinclair ZX Spectrum computer board; a populated PCB, showing the conductive traces, vias (the through hole paths to the other surface), and some mounted electrical components A printed circuit board, or PCB, is used to… …   Wikipedia

• 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

• Percolation test — A percolation test (from percolation , colloquially called a perc test) is a test to determine the absorption rate of soil for a septic drain field or leach field . The results of a percolation test are required to properly design a septic system …   Wikipedia

• Butt joint — For the geometry in welding, see Butt joint (welding). A butt joint is a joinery technique in which two members are joined by simply butting them together. The butt joint is the simplest joint to make since it merely involves cutting the members… …   Wikipedia

• Costa Rican Jade Tradition — Jadeite is presumed one of the most precious materials of [Pre Columbian] Costa Rica. It, along with other similar looking greenstones ( ex. chalcedony, serpentine, and green jasper) were cherished and worked upon for years. It was used to… …   Wikipedia

• Costa Rican jade tradition — Jadeite is presumed one of the most precious materials of Pre Columbian Costa Rica. It, along with other similar looking greenstones ( ex. chalcedony, serpentine, and green jasper) were cherished and worked for years. Jadeite was used to decorate …   Wikipedia

• Underground mining (hard rock) — A three dimensional model of an underground mine with shaft access Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals, mainly those containing metals[1] such as ore containing gold …   Wikipedia

• screw — screwable, adj. screwer, n. screwless, adj. screwlike, adj. /skrooh/, n. 1. a metal fastener having a tapered shank with a helical thread, and topped with a slotted head, driven into wood or the like by rotating, esp. by means of a screwdriver. 2 …   Universalium

• Cave digging — is the practice of enlarging undiscovered cave openings to allow entry. Cave digging usually follows a search of mountains and valleys in karst topography for new caves. Often it takes place underground in places where a large passage has clearly …   Wikipedia