Pillar recovery drill patterns are 1.2 by 1.8 m (4 by 6 ft). Holes are 64 mm (2½ in) in diameter and vary from 7.3 to 12.2 m (24 to 40 ft) long. Fan patterns are drilled using a combination of flat and angled holes; that is, flat holes are drilled as high as the jumbo can reach, and all holes above are drilled to form a fan to cover the remaining top portion of the pillar.