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An anthracite pile in Trevorton, Pennsylvania. Anthracite derives from the Greek anthrakítēs (ἀνθρακίτης), literally "coal-like". [9] Other terms which refer to anthracite are black coal, hard coal, stone coal, [10] [11] dark coal, coffee coal, blind coal (in Scotland), [7] Kilkenny coal (in Ireland), [10] crow coal or craw coal, and black diamond.
The region lies at the northern edge of the Ridge-and-Valley Appalachians, and draws its name from the vast deposits of anthracite coal that can be found under several of the valleys in the region. The Wyoming Valley is the most densely populated of these valleys, and contains the cities of Wilkes-Barre, Greater Pittston, and Scranton.
The reserve list specifies different types of coal and includes countries with at least 0.1% share of the estimated world's proven reserves of coal. All data are taken from the German Federal Institute for Geosciences and Natural Resources (BGR) via BP; all numbers are in million tonnes. [1]
Mining operations in Alberta produce lower and higher ranked coal. Low-ranked coals include subbituminous coal, brown coal, and lignite; high-ranked coals include bituminous coal and anthracite or hard coals. [3]
A rock with high economic value from Pennsylvania is anthracite coal. Before mining began, there was an estimated 22.8 billion tons of anthracite in Pennsylvania. In 2001, 12 billion tons still remained in the ground, most of which was not economically feasible to mine. [3]
Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F). [ 24 ] Although coal is known from most geologic periods , 90% of all coal beds were deposited in the Carboniferous and Permian periods. [ 25 ]
The types of coal found in New Zealand include lignites, sub-bituminous, bituminous and semi-anthracite coals. [3] However, the geology of many coal fields can be complex, with significant structural tectonic disturbances caused by many fields being found near the boundaries between the Pacific and Indo-Australian tectonic plates that run through the country. [3]
Its quality is ranked higher than lignite and sub-bituminous coal, but lesser than anthracite. It is the most abundant rank of coal, with deposits found around the world, often in rocks of Carboniferous age. Bituminous coal is formed from sub-bituminous coal that is buried deeply enough to be heated to 85 °C (185 °F) or higher.