It looks, at first glance, like nothing more than a crack in the rock face. But this unassuming hollow is catalogued as part of the Mount Gabriel Prehistoric mining complex, a cluster of 31 copper mines that together represent one of the most significant concentrations of Bronze Age mining activity in Ireland.

Mount Gabriel, the mountain overlooking Schull on the Mizen Peninsula, was first recognised as a site of prehistoric industry by researchers working in the mid-twentieth century. This particular working at Skeagh was first recorded by Jackson in 1968, and when archaeologist William O'Brien examined it in 1984, he found a suspect working rather than a confirmed mine. There were no spoil dumps nearby and no stone mauls, the rounded boulders that Bronze Age miners used to pound and grind ore from the rock face, and which turn up at confirmed sites across the Gabriel complex. Without those diagnostic traces, the question of whether this is a small infilled mine or simply a natural fissure has never been fully resolved. It sits 17.4 metres south of a companion site on the same geological sequence, and the two are considered together when the broader complex is assessed. O'Brien's detailed study of the Gabriel mines, published in 1994, lists this site as mine 23 in his catalogue, placing it within a tradition of copper extraction that dates to the Bronze Age, roughly three to four thousand years ago.

The entire Mount Gabriel complex is a National Monument in State care, and the individual sites within it share that protected status. What makes a visit to this particular spot unusual is precisely its ambiguity: it is a place where the evidence for prehistoric activity is present but unresolved, a small opening in ancient stone that may or may not be the work of human hands reaching back three millennia.