1. National Coal Board, Recovery of Reserves, NCB Mining Department 1978 p4
2. National Coal Board Publication;NCB,1975
3. Whitworth K R ‘Induced Changes in Permeability of Coal Measures Strata as an Indicator of the Mechanics of Rock Deformation above a Longwall Coal Face’ Symposium on Strata Mechanics, University of Newcastle upon Tyne, 5–7 April 1982, pp 18–24
4. Singh MM and Kendorski FS (1981) ‘Strata Disturbance Prediction for Mining Beneath Surface Water and Waste Impoundments’ Proc 1st Conf. on Ground Control in Mining, West Virginia University, Morgantown, USA, USA WV, July 1981, pp 76–89, (1981).
5. Whittaker, BN, Singh RN and Neate CJ ‘Effects of Longwall Mining on Ground Permeability and Subsurface Drainage’ Mine Drainage Proc. of the 1st International Mine Drainage Symposium Denver, Colorado, May 1979, pp 161–183