Powder Mills, Dartmoor, Devon, 1967.. Abandoned buildings associated with the former gunpowder works on Dartmoor, seen through a cluster of windswept trees. Gunpowder was commonly used for blasting in mines and quarries, as well as for military purposes, until the late 19th century when it was superseded by high explosives. The site at Powder Mills was established in 1844 by George Frean and remained in use until 1897. Amongst the surviving buildings are grinding mills, blending mills, incorporating mills, gunpowder processing buildings and charge magazines.