Seismic refraction profiling in opencast coal exploration

Annual production of opencast coal in the U.K. is currently about 15 million tonnes, the majority of it being obtained from sites worked under the supervision of the National Coal Board Opencast Executive. Approximately 1 million tonnes is worked from smalI, private, licensed mines, usually with total site reserves of less than 50000 tonnes. N.C.B. sites are worked by civil engineering companies, who tender for each new site on the basis of a detailed specification provided by the Opencast Executive.