There are mines of lead-ore, of a good quality, on the Western side of this county which have been very productive. The Bog Mine in the parish of Wentnor, and the White Grit Mine, in the parishes of Shelve and Worthen, adjoin the Stiperstones: they are high hills, with bare and ragged summits, resembling the ruins of walls and castles.
They are a “granulated quartz, much harder than common sandstone, but apparently not stratified”. The Bog Mine has been worked to a depth of 150 yards, a solid lump of pure ore of 800 lb. has been gotten there: the vein is in some parts three feet thick, and generally bedded in white spar. One ton of this ore will run 15 cwt. of lead, besides slag. Dr. Townson says, “these mines are in argillaceous schistus, and produce galena lead ore, sometimes spatous lead ore (measuring lead ore crystallized in the form of spar) and blende”.
The ores at the White Grit Mine, are the common galena, and the steel-grained ores; sometimes the white spatous-ore, and considerable quantity of black-jack. The ores from this mine are not smelted separately; they differ much in their product and little experiment has been made to ascertain it. I have been informed that they produce from 10 to 13 cwt. of lead from a ton
of ore and rarely more. (Mr. Pennant in his “Welsh Tour” says that the common kind of lead ore, usually named potters ore, yields from 14 to 16½ cwt. of lead - from 20 cwt. of the ore, but the last produce is rare).
At Snailbach, in the neighbourhood of the same hills, but nearer Shrewsbury, lead has been gotten for a long time. “The vein was in some parts 4 yards wide. The vein stones are heavy spar, mixt with calcareous spar and quartz. The ore here is the common galena and the steel grained, and sometimes the white spatous ore” (Quoting from “Townsons Tracts”). It has been worked to the depth of 180 yards. The matrix of the ore is crystallized quartz and carbonate of lime. The ore is (1) Sulphuret of lead, both galena and steel ore, which latter contains silver, (2) Carbonate of lead, crystallized, (3) Red-lead ore (said to have been discovered by Raspe, a German) and (4) Blende or Black-jack.
Lead ore has been met with in other places in this part of the county. As far West as Llanymynech, lead is found in small quantities, and copper, which the Romans are supposed to have worked to a great extent. Tools, judged to be Roman, have been found in these mines, and some of them are preserved in the library of Shrewsbury Free School.1