The Bronze Age British miners would have used fire-setting mining techniques, but with the arrival of the Romans the cavern was extended and more extensively mined. According to the Clwyd Powys Archaeological Trust, before the hill was landscaped for the current golf course, at least ten shafts were visible on the southern part of the hill, together with a large number of shallow pits and shaft-mounds. The main entrance to the mine is still the Ogof. A number of Roman artefacts have been found in the mine including a number of bones and burials, and a hoard of 30 first and second century silver coins of Roman currency found in 1965 by some schoolboys, now conserved at the National Museum of Wales. The mine was probably abandoned c. 200 CE.