Pentremawr Colliery was a coal mine, located in the Gwendraeth valley in Carmarthenshire, South Wales.
Due to the angle and depth of the anthracite in this part of Wales, Pentremawr was a slant mine, and hence access and extraction of the coal did not need a shaft.
In 1927, Pentremawr Colliery Company Ltd. was absorbed into the Amalgamated Anthracite Combine, with records showing that 1,007 men employed.
The company ploughed in money to fix problems associated with the initial local geological fault, resulting in the discovery of the 8-foot-thick (2.4 m) Big Vein seam in 1939.
Opposed by local residents and Llanelli MP Nia Griffith and AM Helen Mary Jones, the scheme is subject to planning permission.