In environmental terms the after-treatment and subsequent utilization of worked-out opencast mining areas is of the greatest importance. One of the largest extractive industries in the world using the opencast method is that of sand and gravel. Ready Mixed Concrete Limited is the largest sand and gravel producer in the United Kingdom, and is pioneering new approaches to the problems of after-treatment.

Unlike other forms of development, mineral workings constitute a temporary use of land of comparatively short duration, yet often involving considerable areas. Therefore the planned after-treatment and after-use of the worked-out areas is of the utmost importance.

Dry gravel workings can either be filled with waste materials and restored to the original ground-level or the soils can be replaced, so that a new surface is created on the floor of the excavation. In both cases the new surfaces can be made available for agriculture, playing fields, or other forms of development. Flooded gravel workings can also be filled in a similar manner. However, the British Government is now anxious to retain many of these artificial lakes for water sports and other leisure purposes. If the new lake areas are to be made available for public leisure and recreation, then large sums of capital expenditure will be necessary. Leisure Sport Limited has been formed for the purpose of designing, building, and operating, centres of this kind.