What makes this particular complex unusual is not just the machinery infrastructure, still readable in the surviving stonework, but a small settlement to the southwest that locals have long called the Cornish Colony, a cluster of two-storey dwellings that speaks to the importation of specialist labour from the tin and copper mines of Cornwall during the industry's early decades.

The complex spans two broad phases. The pump house and several of the mining structures date to the early nineteenth century, when the Allihies mines were being established and equipped. A pump house, used to remove water from the mine shaft, survives at foundation level beside the shaft itself. The engine house came later, a three-storey stone structure with walls measuring roughly 8.4 metres by 5.8 metres, a gabled northeast wall, and a beam support wall to the southwest, the kind of arrangement familiar from Cornish engine houses, where a large reciprocating beam engine would have driven the pumping or winding gear. Its chimney, still standing to around 15 metres, is circular in plan and built in stone, with the upper courses finished in brick. Roughly 50 metres to the northeast stands a late nineteenth-century single-storey dwelling, and a partially destroyed earlier structure lies about 30 metres further to the southeast. To the south of the settlement, a roofless powder magazine survives in a D-shaped enclosing wall, with the inner gabled magazine measuring just over 9 metres by 4 metres; powder magazines were built with thick walls and careful siting to contain any accidental explosion away from the workforce and the main workings.

The Cornish Colony itself is a partially collapsed range of two-storey houses, with one renovated building at the western end. A structure on the west side is locally identified as a schoolhouse, suggesting the settlement was intended to be self-contained. The presence of Cornish miners and their families in Allihies is well documented across the Beara Peninsula, and this site preserves the physical remains of that transplanted community in unusual detail, from the industrial plant down to the domestic and educational buildings that sustained it.