Winding Engine House on Site of Grenville United Mine

The winding engine house, also known as a "whim," is located on the site of the former Grenville United Mine in Troon. It is likely from the late 19th century and is currently derelict. The structure is built from slobbered killas rubble with granite quoins, featuring a bob wall made of granite blocks, window arches, and the upper stage of a chimney constructed from polychrome brick. The building has a rectangular plan oriented east-west, with the bob wall on the east side and the foundations of the former winding drum in front of it. A circular chimney is attached at the south-west corner.

This building is smaller than the nearby pump engine house and includes round-headed openings, such as a driver's window in the bob wall (though the wall beneath this has collapsed) and a small cylinder door in the rear wall. There is a vertical tie-plate at the west corner of the north side. The chimney is intact, tapered, cylindrical, and consists of two stages with a cornice. The foundations of the winding drum are partly in disrepair. This engine house functions as a partner to the pump engine house located approximately 50 meters to the north-east, creating an interesting group of structures on a prominent site near the road. It is part of a series of mines that exploited the Great Flat Lode.