Postlethwaite on Eskdale mining

JOHN POSTLETHWAITE ON ESKDALE'S MINES

As it happens, there has been a great deal of historical, geographical and archaeological research on the mines and quarries of Eskdale in recent years (for example, check out "Mines of the Lake District Fells" by John Adams, for a basic but not short list of Eskdale's mines). However, John Postlethwaite was writing when the Eskdale mines were pretty much at their peak [such as it was] so "Mines and Mining in the (English) Lake District" (1877; 3rd edition 1913) serves as a contemporary source, as much as an historical summary.

IGNEOUS ROCKS: ESKDALE GRANITE
This is the largest exposure of granite in the Lake District, covering an area of about forty-eight square miles. It is generally rather coarse, but in some parts fine grained, and consists of quartz, containing numerous liquid cavities, orthoclase, oligoclase and plagioclase felspar, dark-brown and black mica (muscovite and biotite) haematite, chlorite, calcite, perthite, apatite and tourmaline.
The felspar is more or less impregnated with haematite, which gives a reddish tint to the rock, and that tint is more apparent on a weathered surface than where it has been recently fractured, as the haematite, when liberated from the decomposed felspar, spreads over the whole face of the rock. There is, however, a small area near Waberthwaite, where the haematite is altogether absent, and the rock being fine grained and light-grey in colour, is very like Aberdeen Granite. There is another exposure of the granite at Wasdale Head, which is probably connected with the larger mass. It measures about a mile in length by half-a-mile in width.
Near the foot of Wastwater the granite is in contact with the Buttermere and Ennerdale granophyre for a distance of nearly half-a-mile.

The following is an analysis of Eskdale Granite

Silica	73.573
Alumina	13.750
Lime	1.064
Magnesia	.396
Potash	3.512
Soda	4.315
Ferrous oxide	2.103
Ferric oxide	.615
Phosphoric acid	.012
Sulphuric acid	-
Carbonic acid	trace
Carbonaceous matter and Water	.660
	100.000

There is a very full and complete description of the Eskdale Granite by A.R. Dwerryhouse, D. Sc., F.G.S., in the Quarterly Journal of the Geological Society. Vol. LXV., page 55.

...near the sea coast, is The Eskmeals Granite Company's Quarry, opened about 30 to 35 years ago. The output, consisting of granite kerbs, channels, setts, macadam, and crushed granite for footpaths, has reached a total of about 25,000 tons per annum. The Company has efficient machinery, consisting of Stonebreakers, Rotary Screens, Cubing Mills, Steam Loco. Cranes, Compressed Air Rock Drills, and Aerial Ropeway, the motive power being suction gas. Concrete Flags are also made, and some dressing and polishing is done.

MINES IN THE IGNEOUS ROCKS OF THE LAKE DISTRICT
In the Eskdale Granite there are a great number of veins of haematite iron, some of which have yielded a good deal of ore, and the grass-covered mounds in Red Gill, on the southern side of Eskdale Valley, prove that some of them were worked in early times. About 42 years ago, the Whitehaven Iron Mine, or Nab Gill Mine, as it is commonly called, was opened; it is situated on the northern side of the valley, close to the village of Boot. The bearing of the vein is north-west and south-east, and its hade is towards the north-east. Six levels have been driven into the mountain, at various elevations, the lowest being about 110 fathoms below the highest point where ore has been worked out to the surface. A number of small deposits of ore were stoped in levels Nos. 4 and 5, but they were not driven so far as the point where the best deposits were found in the levels above. These deposits in the upper levels were of considerable extent, and some of them were worked out to the surface.
A considerable quantity of ore was raised at the South Cumberland Mine, on the southern side of the valley, opposite Nab Gill, and on the direct course of its vein. Some ore was also obtained near the King of Prussia Inn, a little lower down, and on the northern side of the valley. These mines were considered sufficiently productive to warrant the construction of a narrow gauge railway from Ravenglass to Boot, which was opened in 1875. In 1874 the Eskdale Mines yielded 4,187 tons of ore, value £5,233 15s. 0d., being an average price of 255. per ton; in 1875 the yield was 6,769 tons, but the average value fell to 15s per ton, and in 1876 Eskdale produced 9,135 tons, value £5,481 0s. 0d., at an average price of 125. 6d. per ton. At this low price of ore the mines ceased to be remunerative, and were closed to await better times. The unfavourable state of the market has also prevented the further development of a good deposit of ore that has been partially opened at Brant Rake.