CAB129-36 — Page 38

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CHAPTER III

Page 39.

·Page 39 of 662 MINERAL RESOURCES (ENGLAND AND WALES)

ANHYDRITE

45. The most important source of supply of this anhydrous calcium sul- phate mineral at the present time is the Teeside area in N.E. England where the Billingham mine of I.C.I., Ltd., is probably the largest single producer of anhydrite in the world. There the mineral occurs alone, but in the Eden Valley in Cumberland and Westmorland, the only other place where anhydrite is being worked, and elsewhere in the U.K., anhydrite is found in conjunction with gypsum, the hydrated form of calcium sulphate (para. 141).

1

Production

JARE

46. Anhydrite production was commenced in 1926-27 when the Billing- ham mine was opened. In the course of the War, output was doubled from about 400,000 tons to 800,000 tons per annum, the main increase and indeed three-quarters of the total production coming from that one mine. Currently the production exceeds 900,000 tons per annum.

History and Uses

-

47. Anhydrite had little known commercial value prior to the develop- ment in Germany before the 1914-18 War of the Haber-Bosch method of fixing atmospheric nitrogen as ammonia and the double decomposition pro- cess for making ammonium sulphate by the action of carbonated ammonia liquor on finely-ground anhydrite (or gypsum) whereby calcium carbonate was precipitated and ammonium sulphate recovered from solution by evapora- tion. This process was developed as part of the German synthetic ammonia industry.

KALONGA

48. Parallel research had shown that the mineral could also be used for the manufacture of cement with the recovery of sulphur in the kiln gases for sulphuric acid manufacture, but the large pyrites reserves in Germany obviated any serious need for its furtherance.

49. These processes were made use of by I.C.I. Ltd. when borings put down in 1926 for water at Billingham proved the presence of over 150 ft. of anhydrite in 5 main bands at depths between 650 and 950 ft. The synthetic ammonia plant on the site provided abundant quantities of ammonia and carbon dioxide for the ammonium sulphate reaction and coke supplies were also on hand nearby for the production of cement and the recovery of sulphuric acid.

50. The second World War accentuated the importance of making both sulphuric acid and ammonium sulphate from anhydrite owing to the diffi- culties in obtaining supplies of foreign pyrites, and led to the anhydrite present in the gypsum mines of the Eden Valley also being extracted for ammonium sulphate manufacture at a Government factory erected at Prud- hoe-on-Tyne. This plant, as well as that at Billingham, has since been maintained at full production owing to the world shortage of nitrogenous fertilisers.

51.

♦ smal ampunt of anhydrite is used in making plaststof 662

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Billingham

(Durham)

TABLE V

Page 40RODUCTION OF ANHYDRIPage 40 of 662*

MOCUMIM GINAWA (tons) Gází

Cocklakes (Cumberland)

Birks Head (Westmorland)

Total

1939

401,276

1940

446,697

1941

558,703

1942

585,302

1943

$670,526

1944m0.

7685,116

1945

...

699,565

90,646

5,842

796,053

1946

~848,004

96,601

360

944,965

1947 1948

828,021

91,439

365

919,825

n.a.

n.a.

n.a.

911,814

n.a. not available

Resources...al gand-cline Desiq vidgul sta mysl llar sum sit.

eta di bue videns.EX DURHAM AND N.E: YORKSHIRESTE DAG 29 cued

52. In the Teeside area, as has already been stated, there is at least a total thickness of 150 ft of anhydrite in 5 principal bands, 3 or 4 of which appear to be solid mineral without marl or rock-salt intercalations. The area of country underlain by the mineral is not precisely known, but I.C.I. Ltd. within the confines of their own holding at Billingham, estimate they have 70-75 million tons of extractable mineral in a single bed assuming a 56 per cent. recovery from an average seam thickness of 15 ft.

A

53. It is clear, therefore, that as the anhydrite continues in this and other beds eastwards to the coast at Hartlepool and southwards over the Tees estuary, an area which, as far as the Cleveland Hills alone, is roughly 50 sq. miles, the total quantity of mineral present must exceed that figure many times (the mineral runs about 3,500 tons/acre ft., or roughly 24 million tons/sq. ml. ft.);

CUMBERLAND-WESTMORLAND

54. In the Eden Valley, near Carlisle (see also paras. 151-2), no detailed estimate of the quantity of anhydrite present has as yet been made but we are informed that a survey would undoubtedly show“ of tons".

many millions

55. A large reserve of anhydrite is also likely to be present near St. Bees in West Cumberland, where, however, it is mixed with gypsum.

OTHER AREAS

56. We are advised by the firms concerned that the reserves of anhydrite in the other main areas where gypsum is being mined (Nottinghamshire, Sussex, etc.) are both small and impure, and, therefore, of little or no importance. Anhydrite (with gypsum) has also been recorded in bore-holes in the Furness district of Lancashire.

Summary

57. Resources of anhydrite in the Billingham area are likely to be at least 75 million tons. Further large resources exist south of the River Tees. Many millions of tons of anhydrite are also known to be present in the Eden Valley in Cumberland and Westmorland and also in West Cumber- land. It is clear that the resources are sufficient to meet requirements on present day standards for many years.