Upper Hirst
Coordinates: 56°07′19″N 3°46′30″W / 56.122°N 3.775°W The Upper Hirst is a coal seam in central Scotland that was mined in the 1950s through to 2002, mainly to supply Kincardine Power Station, and later, Longannet Power Station, in Fife.
This was a low-quality coal, unsuitable for most other purposes, and had mostly been disregarded previously. Its low sulfur content made it very suitable for power station use.
The Upper Hirst coal is found within the Upper Limestone Group of strata, above the Limestone Coal Group, but below the Productive Coal Measures. The latter two groups of strata may be separated by up to 1000 metres. In the Central Coal Field, which is in the form of a basin, the Productive Coal Measures, if they were ever deposited, have been lost by erosion except near the centre, where they outcrop near Alloa and Clackmannan, and have been mined until recently. The Limestone Coal Group of strata have been mined only around the edge of the basin, although in the 1950s there were plans for deep mines at Airth, where two large shafts were constructed to rockhead and then abandoned, and at Gartarry Toll, which was not begun.
At Manor Powis, for example, the useful seams in the Limestone Coal Group were at a depth of about 400 metres, and included valuable anthracite; the Upper Hirst was above this and as well as being mined at mid-shaft in the old colliery, was reached by a pair of sloping adits constructed near the bank of the River Forth. The slope of the seam was followed for some distance down the dip of the basin, to the east.
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