Saturday 18 July 2009, North west Branch Trip to Coldstones Quarry [SE 125 641]. Leader Ian Dossett: Reporter: David Green

摘要

Coldstones Quarry, lies about a kilometre to the east of the moorland village of Greenhow, and is developed in thick Carboniferous limestone of the Alston Formation. The limestone is surrounded by sandstone and shale of the Millstone Grit Group which is beautifully exposed on the upper benches. Garnet Vein and Sun Vein cut across the quarry and as new benches are developed there is an unparalleled opportunity to examine mineralisation which is typical of the mid-Pennine lead mining fields. When blasting cuts the veins, mineralised blocks are stockpiled for transportation to Cavendish Mill in Derbyshire, where they are processed to recover fluorite. The stockpile is reduced by a few hundred tons a month (depending on the weather as the rock is better transported dry). It has provided rich pickings for society members over many years.