The term 'conservation' has been interpreted in many different ways. When applied to a single resource, for example water or soil, it is easy to understand; but when applied more generally to the environment or countryside it is more difficult. For the conservation of one resource often competes with the conservation of another. Two ideas seem to be important in any definition: the maintenance of potential and the element of social choice. A possible definition is the following: 'the attempt to match the use of the land and of resources at any one time with the needs and aspirations of society at that time while, as far as possible, retaining their potential unimpaired for future generations'. The choice to exploit minerals seems to depend largely on economic considerations, although it would be possible and certainly desirable to concentrate more on the conservation of minerals (gaining the greatest human benefit per unit of mineral used), as, for example, by recycling or voluntary economy. Conservation of minerals is not generally adopted, however, until the resource becomes scarce or in times of national emergency. Countryside conservation, in contrast, concerns interests which in themselves may be mutually conflicting: the needs of traditional rural occupations; the demands for space of an urban and industrial society; and aspects of the national heritage. A simple antithesis between mineral exploitation and countryside conservation is therefore hardly possible because the considerations governing each of them are so different and because they are only two of the many interests concerned in the use of rural land. In Britian there is relatively little danger of causing irreversible damage to soil, water or air. Skills are available to undo damage done and there appears to be the political will to use these skills. The danger rather is of damage to aspects of 'heritage', due not to the total scale of mining activity but to the location of workings where other features of value can be irrevocably damaged. Conflict can be reduced by preparing strategic plans for each resource which identify areas of particular significance. The value of this approach is illustrated by the Nature Conservation Review of the Nature Conservancy and the work of the Water Resources Board in planning water resources. The work on sand and gravel and on limestone illustrate what can be done with certain minerals. The case of non-ferrous metals is obviously more difficult but general indications of location and importance should be possible. Aspects of the national heritage can be grouped under five heads associated with: rural ways of life; beauty; nature and genetic resources; evidence of history culture and architecture; wilderness. National assessments are urgently required for landscape value and wilderness - both notoriously difficult to evaluate. Although such strategic assessments can reduce potential conflict, their effectiveness is greatly reduced because at present there is imperfect correspondence between value and the degree of statutory protection. A crucial measure in determining what this should be is how irreversible would be the change or irrevocable the loss. Conservation is concerned with gaining the greatest sustained use per unit of resource; economics, with return on capital invested. The two often conflict. There is a need to explore more deeply and critically the intellectual and philosophical basis of decisions about the use of resources.