A Description of some remarkable “Heaves” or Throws in Penhalls Mine

Abstract

This mine is situated in the parish of St. Agnes, in the county of Cornwall, and stands on the sea-coast, three or four hundred yards from the edge of a bold precipitous cliff rising to a height of 300 feet above the sea-level. Pryce, in his valuable old book ‘Mineralogia Cornubiensis,’ and Carne and Hawkins in papers read some forty years ago before the Royal Cornwall Geological Society, together with many other writers, refer to the heaves of the celebrated Pink lode, which is now a part of Penhalls Mine. A paper was also read in 1815 before this Society, by Mr. John Williams, entitled “Account of some Remarkable Disturbances in the Veins of the Mine called Huel Peever,” the appearance of the lodes in which mine present the nearest approach to the dislocations in the Penhalls district. The nature of the ground or “country” is a light-grey, distinctly stratified “killas” (the clay-slate of many geological writers, though not a cleaved rock) with a pretty regular dip towards the north of from 20° to 25°. In the.immediate neighbourhood of the workings the ground is traversed by:— 1. Four or five tin-lodes, varying from 4 feet to a few inches in width, dipping north at about the same angle as the killas, and composed of the oxide of tin, with a little iron and copper pyrites in the middle,—the walls or outsides, locally called eapel, being a hard grey killas with quartz and schorl. The only distinction between the different lodes