Its walls, over a metre thick, enclose an interior measuring roughly five and a half metres by three and a quarter, and a circular stone chimney, standing around ten metres tall, occupies the north-east corner. These are the remains of a manganese mining complex at Aghatubrid Beg, a site that speaks to an industry most people would not associate with this part of Ireland at all.

Manganese ore was extracted across parts of County Cork during the nineteenth century, when the metal was in demand for steel production and the manufacture of bleaching agents. The engine house at Aghatubrid Beg is a compact but well-built structure: the north wall is gabled, and a beam support wall to the south would have helped carry the weight of whatever machinery was housed inside, most likely a steam-driven pump used to keep the mine workings clear of water. That circular chimney, still standing at roughly ten metres, served the engine's boiler. To the west of the building, a spoil heap survives, the accumulated waste rock pulled from the ground during extraction, a low mound that marks the footprint of the operation as plainly as the standing stonework does.