Ravelrig Quarry is a major source of aggregate for Central Scotland and has been operated by Tarmac Ltd since inception in 1984. The rock that is being extracted and processed is dolerite. It is part of a composite sill that was intruded into strata of the West Lothian Oil-shale Formation about 325 million years ago. In a few locations, the base of the sill, and contact with the underlying sediments has been exposed. As operations progress, restoration of slopes with overburden is scheduled to cover these contact locations. Discussions have taken place with Lothian & Borders GeoConservation, proposing to modify restoration contours where practical and safe to do so, allowing a section of this contact to be preserved.