There are at least seventy-five of them on the northern and southern sides of the Upper Lake alone, each measuring roughly nine metres by six metres, arranged at irregular intervals across the hillside. They are the physical remains of charcoal production, a once-common industrial process in which timber was stacked over a carefully prepared flat area, covered with earth and turf, and burned slowly over days to drive off moisture and volatile compounds, leaving behind dense, high-carbon charcoal suited to smelting and smithwork.

The platforms themselves, sometimes called hearths or pitsteads, were levelled into the slope to create a stable working surface for the charcoal burner, or collier, and the shallow oval impression they leave behind is often the only evidence that the process took place at all. Ua Riain noted the Lugduff platforms as early as 1940, and Healy's later study identified a further forty similar examples. The concentration around Reefert Church and the Upper Lake suggests the site was in active industrial use over a sustained period, though precisely when remains unclear from the available evidence. The proximity to Glendalough, with its monastic history and likely demand for metalworking, gives the platforms a plausible context, but the connection is not firmly established in the record.