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109. Reserves of the highest quality paper-filling china clay in the St. Austell Pdistrict laref festricted to one or two pits aanel 5accofdingly may be limited for economic reasons when opencast mining is carried below a certain depth. On this account it is important that research already under way should be encouraged in order to ascertain whether a method could be developed for beneficiating the medium and lower grades of china clay to replace the higher qualities if necessary. Close co-operation with the paper and pottery industries is also highly desirable in order to make the most of this valuable raw material by agreeing upon a scheme for standardisation of clay grades in keeping with the real mineralogical and chemical require- ments of the major users.
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110. In the Bodmin Moor and Dartmoor areas where the china clay deposits at present being worked are more isolated the difficulties of lateral expansion of pits is not present to the same degree.
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111. Both on Bodmin Moor and Dartmoor as well as St. Austell there are many pits situated in good china clay ground which are at present not being worked and are being maintained as reserves. In the Lee Moor area, on Dartmoor, the E.C.L.P. Co. has a lease over 2,000 acres of land which includes the famous Lee Moor Pit. They intend shortly to step up pro- duction from this ground to the rate of 100,000 tons a year. There is every indication on Bodmin Moor and on Dartmoor that ample reserves exist for 100 years at the present rate of production.
Summary
112. We accept generally the conclusion of the Working Party about reserves, and would draw particular attention to the recommendations made with a view to ensuring that the deposits can continue to be worked economically and efficiently. Although the actual deposits of china clay appear to be ample, there may well be an economic limit in depth to which the
pits can be carried unless measures are adopted at an early date to integrate production, mechanise operations to reduce costs, and to achieve a permanent solution of the problem of sand disposal, which is becoming urgent.
COPPER ORES*
113. During the early part of the 19th century over 50 per cent of the world's output of copper ores was contributed from mines in Cornwall and Devonshire, and from one or two other parts of the country, chiefly Anglesey, Cheshire and the Lake District. After 1860 the output from all sources steadily declined, mainly due to the discovery of larger deposits of copper ores in South America, Mexico and the U.S.A., and because the richer
of the ore bodies in this country were exhausted. The steady declits
output is well shown in Table IV on page 11.
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114. According to the statistics available the maximum output from Corn- wall was 185,000 tons in the year 1854, and the metal content of the ore was 14,100 tons. Generally speaking, the districts where copper ore was found correspond broadly to those also famous as tin producers, the chief district again being that of Carn Brea (para. 236). Other important copper producinggdistrictsfar6 Levant, Gwennap, St. AustelleCarado Tavistock (Devon Great Consols was at one time an important copper mine). In
* The information contained in this section is based largely on the "Special Reports on the Mineral Resources of Great Britain "-Memoirs of the Geological Survey.
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Anglesey the chief ofin was the famous Mona & Parys Mine which2ceased production many years ago, but from which a small production of pre- cipitated copper is still obtained. At one period (about 150 years ago) this mine was reputed to be the largest copper mine in the world. Cheshire the occurrences of copper ores were unusual in that they were replacements of sedimentary rocks and not lodes as in the other districts described. The chief locality was Alderley Edge.
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115. Several localities are known in the Lake District where copper has been worked, the most important mine being that of Coniston. Other districts where copper ores have been found and worked are Staffordshire (Ecton Mine being at one time a relatively large producer), Derbyshire, Shropshire, Yorkshire, Central and North Wales and the Isle of Man.
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116. After reviewing the evidence and records available, we came to the conclusion that a detailed examination of the resources of copper ores was hardly justified because on general grounds it seems most unlikely that any revival of copper ore production could take place which would be of national long-term importance. There is no doubt that all the richer known deposits of Cornwall, which was by far the most important copper producing district, have been exhausted, and there is no evidence that any substantial new deposits are likely to be discovered. It must also be remembered that at present the copper production of the world comes from relatively few but important mining districts in which most of the smelting facilities are concentrated. At the present time there are no facilities for smelting large tonnages of copper ore in Great Britain.
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FLUORSPAR
117. The mineral fluorspar, or fluorite (CaF), is found in economic quantities in veins or irregular replacement deposits in association with lead and zinc orés in parts of Derbyshire, the Northern Pennines (Weardale area, Co. Durham) and north-west Yorkshire. Up till about 1890 it was regarded only as a gangue mineral and was left in the mines by the old miners or discarded on the tip heaps as of no economic value. Nowadays, however, it is an essential mineral raw material in steel-making, and it also supplies the only economic source of the element fluorine in this country, the compounds of which are becoming increasingly important in the chemical industry. Fluorspar is also found in other mineralised areas of the country, e.g. Cornwall, North Wales and West Cumberland; there has been a small pro- duction from Cornwall in the past but generally deposits in these areas and elsewhere are unlikely to be of economic importance and can be disregarded for present purposes.
Production and Uses
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118. Present production comes from old lead mines re-opened for fluorspar, from veins in the lead mining areas containing mainly fluorspar, and (largely in Derbyshire and north-west Yorkshire) from dumps from old lead workings, In some cases in Derbyshire (e.g. High Rake) the waste material containing fluorspar resulting from the working of lead veins has been filled back into the mine workings so that it can only now be recovered by open-cast or undergroun@gmining 662
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