 The Bradford Coalfield is isolated from the rest of the Manchester Coalfield ; its coal seams , laid down in the Carboniferous period , dip at an average of 1 in 3 towards the south and correspond more closely with those of the Oldham Coalfield . The Upper Coal Measures above the Worsley Four Foot mine horizon were worked at Bradford , where the Worsley Four Foot is known as the Parker mine . The Two Foot , Doctor , New , Yard , Bradford Four Foot , Three Quarters and Charlotte mines , above the Parker mine , are known as the Bradford Group ; the Charlotte mine is closest to the surface . The Openshaw mine , above the Charlotte , was worked for fireclay . Below the Bradford Group and the Parker mine are the Top , Middle and Deep mines , and 60 feet ( 18 m ) below them , the Roger mine . The Top , Middle and Deep mines correspond to the Major , Bland , and Ashton Great mines in the Oldham Coalfield . The Crombouke mine in the western coalfield corresponds to the Roger mine at Bradford Colliery . In total the workable seams contained 310 million long tons ( 347 million short tons ) of coal . 
