A local geology group, which is part of Crewkerne & District U3A, were given a guided tour of the old Meldon limestone quarries near Okehampton on the edge of Dartmoor. Quarrying began there about 1790 when the limestone was needed for building and agricultural purposes. During the group’s tour they saw two of the old kilns where charcoal was burnt with limestone, to form quicklime, which the local farmers would take back to their farms in wagons. Members learnt of the uses for quicklime which is relatively cheap to produce and can be used with mortar and plaster for building and to improve the quality of the soil.
Once the workings at the quarries on the east side of the river had reached a depth of 40 metres and were exhausted, they were flooded to form Meldon Pool. Geology group member Liz Randall said: “Second World War US military vehicles were reputedly dumped in this pool. The only structures surviving from the quarry on the other side of the river are a lime kiln, part of a winching system and a ruined weigh-house building.” In the later 19th Century, the London and South Western Railway company constructed a track which spanned the West Okement river at Meldon. This involved making a cutting and building a viaduct. Finding that the stone in the cutting was suitable for railway track ballast, the railway company established a quarry nearby, which closed in 1994 and is now privately owned.
The geology of the area was of particular interest as Liz explained: “Dartmoor has many granite domes formed 250 million years ago when molten magma intruded upwards into older rocks. The dykes and veins of the rocks contain lead, copper, arsenic and aplite.” The Crewkerne geology group discovered that aplite at Meldon was used for making glass but the glass produced was of an inconsistent quality and the project was abandoned.