mica-bearing
41Dartmoor tin-mining — The wheelpit at Huntingdon mine The Dartmoor tin mining industry is thought to have originated in pre Roman times,[1] and continued right through to the 20th century. From the 12th century onwards tin mining was regulated by a Stannary Parliament …
42Litchfieldite — is a rare metamorphosed igneous rock. It is a variety of nepheline syenite and is composed of two near pure phases of feldspar, albite and microcline, with predominance of the first one, plus nepheline, sodalite, cancrinite and calcite. The mafic …
43climate — /kluy mit/, n. 1. the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years. 2. a region or… …
44geology — /jee ol euh jee/, n., pl. geologies. 1. the science that deals with the dynamics and physical history of the earth, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is… …
45silica mineral — Any of the forms of silicon dioxide (SiO2), including quartz, tridymite, cristobalite, coesite, stishovite, melanophlogite, lechatelierite, and chalcedony. Various kinds of silica minerals have been produced synthetically. * * * Introduction… …
46electric generator — ▪ instrument Introduction also called dynamo, any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. Generators also produce the… …
47Effective porosity — The term effective porosity lacks a single or straightforward definition. Even some of the terms used in its mathematical description (“Vcl” and “Vsh”) have multiple definitions. However, it is most commonly considered to represent the porosity… …
48Copper mining in the United States — US primary copper production 1900 2008. Source: USGS …
49Australia — /aw strayl yeuh/, n. 1. a continent SE of Asia, between the Indian and the Pacific oceans. 18,438,824; 2,948,366 sq. mi. (7,636,270 sq. km). 2. Commonwealth of, a member of the Commonwealth of Nations, consisting of the federated states and… …
50mining — /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… …
