On the site of the former Marine Colliery at the southern end of Cwm is a large steam-pumping engine built by Hathorn Davey of Leeds in 1893 and formerly used at the colliery. It was installed there when the colliery was completed, in a chamber beneath the winding engine on the downcast shaft. The engine could deal with 50,000 gallons of water per hour when working at seven strokes per minute. It has a 68-inch low-pressure cylinder with a 10 feet stroke and engine cost £4,630 to install. The engine was rescued during site clearance operations and relocated to one side of a new car park, set on a concrete plinth. It is built entirely of cast iron, and has been thoroughly painted since re-erection.The engine is a scheduled ancient monument regarded as of national importance as a rare colliery-pumping engine surviving intact from the late 19th century.