The East Pennine Coalfield is the most important of all british Coal's resources. Exploration and exploitation are closely related and studies of the coalfield's past history, present development and future potential are relevant to the whole coal industry in the UK. Historical recovery data are discussed and some of the geological features of the deposit that affect coal recovery are reviewed. Although the East Pennine Coalfield is at a mature stage of exploitation, with output from deep mines currently at about 54% of its peak level in the 1950s and 1960s, the resource has not yet been fully developed, even after major investments at Selby and Asfordby. Recent exploration results from the undeveloped eastern margin of the coalfield are briefly reviewed.