 In total seven boreholes were drilled; the deepest to 3,790 feet (1,155 metres).In early 1953 it was deduced that there was an estimated 80 million tonnes of workable coal in seams varying from 2 ft 2½ in to 7 ft 0 in (68 cm to 213 cm) in thickness.Agecroft Colliery was redeveloped by the NCB in the 1950s reusing No 3 and No 4 shafts and sinking a new shaft.