Engine House at Sw595307 Leeds Shaft Great Work Mine and Associated Remains

The engine house at Leeds Shaft Great Work Mine, built around 1829, is a ruin made of granite rubble walls with dressed granite quoins and jambstones. It features a granite ashlar bob wall and two granite keyed round brick arches, with wooden lintels elsewhere. The building has a rectangular single cell plan and is three storeys high over a basement pit, with a thicker bob wall on the south side. The south bob wall includes a central round-arched ground floor opening, known as the plug doorway, and the ashlar masonry is reinforced with later iron bands. The second floor has weather boarding, and the gable has been removed. The north wall mirrors the south with a similar ground floor arched opening, referred to as the boiler doorway, and has a smaller opening on the first floor above it, along with small holes for second floor beams and a window opening with missing masonry above the lintel. There are two irregularly placed openings on each side wall. The foundations of other structures are nearby. This engine house is notably old and originally housed a 60-inch pumping engine, which was rebuilt in situ by Harvey in 1857 and operated until the late 1890s. It was classified as a 'high duty' engine, meaning it exceeded the average efficiency of pumping engines in Cornwall, as recorded in Lean's monthly statistics.