Conveyor belt for aggregate at Tunstead limestone quarry. Limestone is a major mineral product which has vital industrial and environmental applications. Quarrying remains an important industry in this part of Derbyshire, and this quarry is the largest producer of limestone in the Peak District. Along with the adjacent Old Moor Quarry, it produces around 5.5 million tonnes of limestone annually, making it the largest producer of high purity industrial limestone in Europe.