li ery ▁on ▁the ▁Manchester ▁Co al field . ▁It ▁accessed ▁the ▁coal ▁se ams ▁of ▁the ▁Middle ▁Co al ▁Me asures ▁laid ▁down ▁over ▁ 3 0 0   mill ion ▁years ▁ago ▁in ▁the ▁Car bon ifer ous ▁Period ▁and ▁over lain ▁by ▁P ermo - Tri ass ic ▁rocks . ▁A ▁ ▁layer ▁of ▁all uv ial ▁depos its ▁consisting ▁of ▁cl ay , ▁sand , ▁gra vel ▁and ▁mar l ▁overlay ▁the ▁rock . ▁The ▁coal ▁se ams ▁di pped ▁at ▁ 1 ▁to ▁ 4 . 5 ▁towards ▁the ▁south . ▁The ▁W ors ley ▁Four ▁Foot ▁mine ▁was ▁reached ▁at ▁a ▁depth ▁of ▁ ▁and ▁the ▁Ar ley ▁mine ▁at ▁ 3 3 6 0 ▁feet ▁( 1 0 2 0 ▁m ). ▁ ▁History ▁The ▁Cl if ton ▁and ▁K ears ley ▁Company ' s ▁coal ▁res erves ▁were ▁becoming ▁de ple ted ▁in ▁the ▁Ir well ▁Valley ▁at ▁a ▁time ▁when ▁demand ▁for ▁coal ▁on ▁the ▁Lanc ash ire ▁Co al field ▁was ▁at ▁its ▁highest ▁and ▁in ▁ 1 9 0 7 ▁its ▁subs idi ary ▁company ▁s ank ▁a ▁ ▁bore ▁hole ▁at ▁Ast ley ▁Green , ▁north ▁of ▁the ▁Bridge water ▁Canal ▁to ▁investigate ▁un t apped ▁res erves ▁of ▁the ▁conce aled ▁coal field . ▁The ▁company ▁acquired ▁the ▁min eral ▁rights ▁for ▁ ▁of ▁land ▁accessing ▁an ▁estimated ▁ 1 4 0 ▁million ▁tons ▁of ▁coal ▁under ▁Ch at ▁M oss ▁stretch ing ▁beyond ▁the ▁Liverpool ▁and ▁Manchester ▁Railway ▁and