underground equipment
1Underground mining (soft rock) — refers to a group of underground mining techniques used to extract coal, oil shale and other minerals or geological materials from sedimentary ( soft ) rocks. Because deposits in sedimentary rocks are commonly layered and relatively less hard,… …
2Underground living — refers simply to living below the ground s surface, whether in naturally occurring caves or in built structures.Besides its obvious novelty, underground living offers additional benefits when compared to living in traditional buildings, such as a …
3Underground 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 …
4Underground Electric Railways Company — The Underground Electric Railways Company of London Limited (UERL) was the holding company for three of the new deep level tube underground railway lines constructed in London in the first decade of the 20th century. It was established in 1902 by …
5Underground Electric Railways Company of London — Geographic map of the UERL s three deep level tube lines in 1907 Part of a series of article …
6Underground nuclear testing — Preparation for an underground nuclear test at the Nevada Test Site in the 1990s. Nuclear weapons …
7Underground economy — The underground economy or black market is a market consisting of all commerce on which applicable taxes and/or regulations of trade are being avoided. The term is also often known as the underdog, shadow economy, black economy or parallel… …
8underground film — motion picture made and distributed outside the commercial film industry, usually as an artistic expression of its maker, who often acts as its producer, director, writer, photographer, and editor. Underground films usually display greater… …
9Underground mine ventilation — Schematic of underground mine ventilation Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove noxious gases (typically NOx, SO2, methane, CO2 and CO). The source of …
10Underground mine — A mine where coal is produced by tunneling into the earth to the coalbed, which is then mined with underground mining equipment such as cutting machines and continuous, longwall, and shortwall mining machines. Underground mines are classified… …
