After heavy rains in May 2002, a collapse of the 1776 excavation shaft caused a hole to form in the top of the hill. English Heritage undertook a seismic survey of the hill to identify the damage caused by earlier excavations and determine the hill's stability. Repairs were undertaken but the site remained closed to the public. As part of this remedial work English Heritage excavated two further small trenches at the summit and made the important discovery of an antler fragment, the first from a secure archaeological context at the site. A radiocarbon date of c. 2490–2340 BC dates the second phase of the mound convincingly to the Late Neolithic.