 A new headgear and winding engine were built at the Deep pit shaft ; ventilation was by means of two axial @-@ type fans installed in an underground chamber . After 1947 a 460 @-@ yard ( 420 m ) tunnel 55 yards ( 50 m ) below ground level was driven to the Stuart Street Power Station , to provide coal direct from the colliery . A conveyor within the tunnel delivered 200 long tons ( 224 short tons ) of small coal an hour to the power station 's bunker . Most of the developments begun by Manchester Collieries were completed after nationalisation in 1947 by the National Coal Board ( NCB ) . After modernisation and reconstruction , coal was extracted by <unk> mining using coal @-@ cutting machinery and conveyors . This type of mining creates a void or <unk> into which the roof is allowed to collapse . At Bradford , which had no spoil heap , the <unk> was infilled with spoil or waste . As there was insufficient spoil to fill the void , some was brought from other pits . The NCB incorporated the takes , or coal reserves , of Moston and Ashton Moss Collieries into the redeveloped Bradford Colliery . Moston was closed , but the shafts of Ashton Moss were retained for winding men and equipment . 
