They are the physical remains of charcoal production, an industry that once shaped woodland management across Ireland and much of Europe. Each platform, roughly nine metres by six metres, was levelled into a slope to create a flat working surface where a collier could stack and slowly burn cordwood under a covering of earth and turf, carefully tending the smouldering mound to produce the dense, carbon-rich fuel that iron-smelting and metalworking depended on.

At least 75 of these platforms have been recorded on the northern and southern sides of the Upper Lake, with a further concentration to the west and south-west of Reefert Church, the small Romanesque ruin in the valley below. A separate survey recorded around 40 comparable platforms in the same general area. References to the site appear in work by Ua Riain from 1940 and later in a study by Healy in 1972, suggesting the platforms had drawn attention from researchers across several decades. The sheer number of them points to an operation of some scale rather than casual or domestic use, though the precise period of activity is not firmly established from the available evidence.

The platforms survive because the levelling work that created them left a lasting impression in the terrain, a shallow cut into the uphill side and a built-up lip on the lower edge. Walking the paths around the Upper Lake, particularly on quieter stretches away from the main monastic site, a careful eye at ground level will pick out these subtle terraces in the moss and bracken.