27
:
119. Output from all sources is at present (1948-49) around 55,000-60,000 tons per annum, and according to the British Fluorspar Producers Associa- tion will areas5 to 64,000 tons, estimated as follows Page 53 of 662.
Grade
(CaF2 content)
up to 75 per cent.
75/80 per cent.
80/85 per cent.
90/95 per cent.
over 95 per cent. "Flotated "*
:
bruge olan edi Tons of 20 stum aldr
per annum.
19,250 mibe to zinone alge:
8,500
22,000
2,800
oof Isido.adT
ગમ ( ૨૨ ફે
2,000 collage [azo92, 201 9,000 (increasing to 14,000 d
“
GE AS50 svad 2915 tons during 1949)! Spar up to 85 per cent. grade usually contains up to 10 p
cent. silica, and is sold mainly as a flux for metallurgical purposes, chiefly to steel works. Higher grades of spar are used in the non-ferrous and ceramic industries, but the bulk of the "flotated "* spar, which is over 95 per cent grade and contains a minimum amount of silica("acid-grade spar ") is sold for chemical purposes, chiefly for the manufacture of hydrofluoric acid bed
120. The bulk of the acid grade spar at
spar at present comes from Derbyshire, 75 per cent. of it from Glebe Mine, Eyam; the remainder is obtained by hand-picking pure lump spar. It is understood, however, that sources of supply of acid grade spar will shortly be available in Weardale where flotation plants are now in course of construction. About 85 per cent. of production of metallurgical spar comes from Derbyshire and the remainder from Durham. Production from north-west Yorkshire is small (about 500 tons p.a.).
Reserves
two new
id anog) ni epo regrow in angenant squat guillon
121. Several years' supply of fluorspar still remain in many of the deposits at present being worked and also, according to existing information, elsewhere in the mineralised districts. There are, however, many difficulties both technical and otherwise, preventing precise estimates being made. Also the mines are relatively small and often meagrely equipped and the operating companies have not usually made a practice of endeavouring to prove reserves of mineral far ahead of existing workings,
D
Ano pa bas
122. Another important consideration is the difficulty of deciding at what level of working costs and selling prices a particular mineral deposit of average or low grade will become economic to work. From the national point of view, however, such depósits clearly have a potential value and their future importance will be enhanced as new and improved processes of mineral recovery become available. mon. vinhas run acimense ste doble de
{
123. The estimates of reserves given below have been drawn up in con- junction with H.M. Geological Survey; they are based on figures supplied to us by individual members of the British Fluorspar Producers Association, and from data obtained as the result of a re-survey of the producing areas by the Geological Survey during the last few years. The classification of the reserves, by reason of the diverse nature of the information available, of the occurrences themselves, and of the standards used by individual producers, has been difficult, and in most cases represents a compromise, with the balance weighted if anything on the conservative side. Generally the state of development of the mines does not permit a useful distinction being made between "proved” and “probable" reserves, so these categories have been combined. The estimates cover all the important occurrences known in England and Wales, reduced to a basis of 100 per cent. purity CaF, content, *This isPaaten 58 sensed by fluorspar producers to sign geospa Concentrated by the flotation process.
28
*
B
TUE
to overcome extreme variations in grade. In practice, the tonnage of sale- able produen vill beolarger according to the grade to which the mineral is dressed... This will be offset by the losses of CaF, content which will occur in the course of
of the course of mining and dressing arising from (a) the grade of mineral mined, (b) character of mineral and nature of impurities, (c) mode of occurrence and mining method used, (d) nature and efficiency of concentration plant, (e) degree of concentration classification and dressing required. Using present day standards the recovery would be from 50-75 per cent., say 60 per cent. on average. This figure will certainly be improved upon in future as steps are being taken to improve dressing facilities but it would be unwise to assume a maximum recovery exceeding 75 per cent.
PUIDUS Tifne birov doidy to ou 124. When we come to estimate the number of years working represented by the reserves, two additional factors must be considered first, changes which might occur in the rate of consumption of fluorspar in this country, and second, changes which might arise if an export market, now of negligible proportions, were re-developed by the industry. In the first case it might be reasonable for present purposes to assume an increase of 10 per cent. over the next 10-15 years. It is not possible to estimate the effect of exports, although undoubtedly steps should be taken in the national interest to recover markets abroad, especially in the U.S.A.. which, twenty years ago amounted to several thousand tons per annum.
o Costanzo ognel pedto sne staɗff zinove jo svusmuis vuloofflue ovong lon STABLE XI✨ daid a noiselnorge to Budmale Wivesbou edi ab ad liv FLUORSPAR RESERVES Gbru wingroine steving ot .barcob lliw v(tons in terms of 100 per cent. CaF2) Beedi to Smoosho 20:1 915 qungco aint ni Proved and to Possible and qe vlisen 25mm Bells lo qu flod ssd Probablebror Speculative Robivilam Squal to Durham |__(piston mormolque no VEDNO 180 500
Mines $125,000 539,000 564,0001
Jadig betonix qsh 0 {Dumps *90*0.box.prsjem 17,500 Yorkshire
Dumps Derbyshire or bi notiei aixo ed
FusMines to broke of 110,000
Dumps
125,250 Teisung a mi moderneppe [277,750
Total
d to 100,000 $117,500ÕBUT Bernsly vligions.jos stom og of orad
15,000
15,000 folleggsongs to a od 05
170,000 280,000
hiz 235,000
360,250
etaula
30
so1,059,000 1,336,750
| 30
Jaskemm 16 meritzozeɔ to sodmur
..
125. The figures in Table XI have been consolidated into totals for Durham, Yorkshire and Derbyshire, but those for each county were based on separate estimates made for the two categories of reserves, proved and probable ....,“ possible and speculative for each of the following sources of supply:
dar akal duck sidansqmoo visit tous shoilib oo niisa nyt valeabai
Sedling.
CoNenthead (Firestone Dump)
Dumps Durham
Stotfieldburn Rotherhope (Middle Level). pubom e broke don blue Stanhopeburn.:8 opt to quBoltsburn 0 sirupi ola Hope Level:t vansioffls froindool adı % Jaufą *Groverake.
Yorkshire.
road Terin
Mines
*Park Burn-Cammock Eals.
ubung oberg-gids to
*Black Dene. groenco et wit realu ei at CT
Hunstanworthi anulansilage aros Himno soubert einsia memez boailous
Greenhow.. Grassington.
Derbyshire (small properties omitted)
Masson. wind or bora Glebe, od nele blow neurotipa od ni benar
bon footpwllator to
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