They are, in fact, the physical remnants of a charcoal-making industry, each platform once serving as a levelled working surface where timber was slowly burned under controlled conditions to produce the dense, hot-burning fuel that pre-industrial ironworking and other crafts depended upon. These so-called hearth platforms or pitstead platforms were created by cutting into a slope to produce a flat, roughly oval area where a carefully constructed mound of wood could be covered in turf or earth and smouldered for days at a time under the supervision of a collier.

The platforms at Lugduff are recorded in two separate surveys. The earlier count, published by Ua Riain in 1940, identified 75 oval platforms, each measuring approximately nine metres by six metres, distributed at irregular intervals on the northern and southern sides of the Upper Lake and to the west and south-west of Reefert Church. A later survey by Healy, published in 1972, documented a further 40 platforms of similar form in the same general area. The total number and their distribution across the valley suggest a sustained and organised operation rather than occasional or opportunistic use. Glendalough, though best known for its early medieval monastic remains, evidently supported industrial activity of this kind at some point in its history, though the precise period of use for these platforms is not recorded in the available sources.