|South Terras Mine|
|Parts of the structures were actually built of uranium ore!|
|Here are the remains of the cement settling pond. This was used in the extraction of radium.|
CORNWALL'S PREMIER URANIUM AND RADIUM MINE
(Presidential Address by Courtenay V. Smale, November 1992)
Journal of the Royal Institution of Cornwall Vol. 1 1993
Copyright - The Royal Institution of Cornwall
This paper is based on the Address given on 28th November 1992 and is drawn from extensive research into a unique, albeit small, mining and mineral processing venture in the history of Cornish mining.
Set in the period of irreversible and massive decline in Cornish tin mining, it followed the peak periods of copper and tin production in the 1840's and 1870's respectively.
Just prior to the commencement of the twentieth century the number of operating tin mines had dwindled from hundreds a quarter century earlier to less than ten, due to the competition from cheaply won foreign tin. The mini-revival of tin mining in Cornwall in the 1960's was accompanied by public interest and curiosity into the County's underground metalliferous mining past. That same period saw numerous publications on the subject, but few addressed the operations of individual mines in detail. This situation was catalytic in providing the incentive for me to embark on an in-depth study of a single mineSouth Terras..
The active life of South Terras spanned six decades, roughly divided equally between iron, uranium, and radium production from 1870 to 1930.
South Terras is located around Tolgarrick Mill, one mile south west of the village of St. Stephen in the Parish of St. Stephen in Brannel. The mining sett lay in the valley of the River Fal, the river forming the western boundary of the property.
The country rock consists of killas in the form of grey and brown slate of the Lower Devonian Meadfoot Group with greenstone and elvan dyke intrusions. The metamorphic aureole around the southern boundary of the St. Austell granite outcrop is not readily discernible but is believed to run about a half a mile north of the South Terras workings. R. Symons 1871 map of the Terras Mining District shows the general trend for mineral lodes of the area to course E.S.E. By contrast the uranium lode of late stage low temperature origin cross-courses 10° west of north and carries minerals of nickel, cobalt, arsenic, bismuth, silver and uranium.
The iron deposit at South Terras, exploited in the mine's early working, is regarded as a metamorphic one in greenstone rather than a true lode. The ore near the surface is in the form of ochre, being underlain by magnetite.
The primary ore of uranium worked at South Terras was uraninite or pitchblende, a variable oxide of uranium. A secondary zone of mineral enrichment occurred in the upper levels of the mine characterised by torbernite and autunite, hydrated phosphates of copper/uranium and calcium/uranium respectively. These two minerals provided the wealth of the uranium production phase of South Terras. The primary mineralisation phase at South Terras is considered to have occurred approximately 225 million years
ago, followed by remobilisation and partial loss of radiogenic lead as recent as 60 million years ago. Of academic interest, two extremely rare nickel arsenates, xanthiosite and aerugite, were discovered at South Terras from dump material by Arthur Kingsbury of the Department of Mineralogy, University Museum, Oxford. He submitted them to the British Museum (Natural History) in 1959 and they were later confirmed to match those discovered in Johanngeorgenstadt, Saxony in 1858. The occurrences of these two minerals at South Terras were a first for Britain.
The west side of the lane leading to Tolgarrick Farm was the site of early exploitation of the iron deposit. Old workings are referred to on a plan and section of the mine produced by James Henderson of Truro in 1874, and consist of an opencast pit in the outcrop of the deposit. By 1874 new workings, also in the form of a pit, had been taken down to their economic limit, and a transition to underground mining enabled the orebody to be further worked. Power to the site was provided by flat rods from a water wheel which also drove a set of stamps in the valley, a short way upstream on the feat serving Tolgarrick Mill. The plan also shows development of the iron deposit in a north westerly direction to a point where it intersected a tin lode near South Adit Shaft.
Production in those early days was modest indeed, output returns in the late 1870's indicating an annual tonnage of iron ore of at best a few hundred tons. Mineral statistics for the period give the value per ton as ten shillings. Despite the operation bearing the name South Terras Tin Mining Company Limited from 1872 to 1888 the returns of tin ore from the mine are so small as to be irrelevant. A significant name associated with the early workings was James Harris-James, the Managing Director of the mine from the early 1870's to 1889 when the Uranium Mines Limited acquired the mining rights. The famous German chemist Martin Heinrich Klaproth (1743-1817), first Professor of Chemistry in Berlin from 1810, discovered the element uranium in 1789 one hundred years before it was seriously exploited at South Terras. Klaproth noted the element in pitchblende or uraninite, the chief ore of the metal, and named it after Uranus, the seventh planet in the solar system. The planet had been discovered in 1781, just eight years earlier by William Herschel.
Public mention of the discovery of uranium at South Terras was made in the summer of 1889 by the Mining Journal. It reported that about four years earlier a lode was cut which produced an unusual apple-green mineral. At first it was regarded as a low grade copper ore of little value, but on analysis was found to be rich in uranium. Doors were at once fitted to the edit for security and the green mineral, torbernite, became known locally as "Green Jim" by way of familiar reference to Mr. Harris-James. Over 40 tons of uranium ore had already been sold from South Terras, raised from the lode which was from four to five feet wide carrying a mineralised leader averaging two to six inches in width. The uranium ore in the lode wandered from the centre to the hanging wall and the foot wall and occasionally drifted into the killas. The claim that this lode was unique was justified, inasmuch that although uranium, like gold, is widely distributed throughout Cornwall, this marked the first and only occurrence where uranium was the main metal. At all other mines in the County from which uranium was raised and sold, it was secondary to the production of either tin or copper, and confined to small portions of the metalliferous vein. At South Terras the uranium lode was over 250 fathoms in length with near unbroken uranium mineralisation.
The main uses for uranium at that time were in the ceramics and glass industries. The yellow sesqui-oxide was used to impart gold and greenish tints to glass while the protoxide was favoured in the production of black porcelain. These were to be the markets for the mine's products throughout the uranium phase of its life, attention to be turned later to the extraction of radium.
Other unusual uses of uranium claimed in the 1880's were in photography as a substitute for the chloride of gold, in electroplating as a substitute for gold, and in electrical installations.
Some parts of the lode assayed 30 percent uranium and with a market price of £2400 per ton for the metal it is understandable that the operation at South Terras was to receive more than a little publicity in the years to come.
The South Terras Tin Mining Company had been finally wound up in November 1888 and this paved the way for a new company to be formed to work the uranium lode.
The Uranium Mines Limited, registered in October 1889 with a nominal capital of £120,000, issued an elaborate prospectus inviting applications from the public for shares in the Company, formed to acquire mining rights and work certain deposits in St. Stephen in Brannel parish.
Mining rights had been granted for twenty-one years from 25th December 1887 and along with a number of mining reports, plan, sections and panoramic view of the mine, the prospectus was sympathetically commented upon by the Mining Journal.
On the closing day for share applications the Mining Journal carried a letter to The Star submitted by A.J. Leese the Secretary (pro tem) of The Uranium Mines Limited answering certain questions asked by that journal. One comment was "You are correctly informed that three or four years ago the property was known as the South Terras Mine, and that it has been managed by Mr. J. Harris-James, whose management, however, ends with the sale to the company. Any strictures you may pass upon that gentleman, therefore, whether deserved or undeserved do not apply to or affect this company." - an ignominious departure of the former Managing Director of the mine.
In January 1890 Captain W.R. Thomas reported that 33 persons were employed on the mine and that the new shaft had been linked with the edit level, timbered, and preparations made to continue sinking. By March the shaft was 5 fathoms below edit and the engineers' report recommended the introduction of compressed air and rock drills to replace hand labour.
In September 1890 the directors of the company issued a circular to shareholders, informing them that crushing machinery, winding gear, and compressed air for rock drilling had been installed. The main shaft had reached 35 fathoms depth, and crosscutting and development along the 10 fathom level continued.
A laboratory for the manufacture of the oxide of uranium in London was under supervision of Mr Benedict Kitto, a well-known figure in Cornish mining circles.
A statement of produce sold by the Company from April 1890 to June 1891 shows that uranium was being sold in the form of ore and as uranium oxide. The ore price varied from £20 to £100 per ton according to its grade, the oxide commanded a regular price of 13s 6d per pound. The main customer for both forms of uranium product was Bettmann & Kupfer, London agent for a German company.
Sadly, the Uranium Mines Ltd was voluntarily wound up with a view to reconstruction on 28th July 1891, it being reported at an extraordinary general meeting that the mine had a large quantity of ore but lacked the chemical plant to treat it. The Chairman expressed the hope that when the capital came in a larger plant could be installed to execute their orders.
The Mining Journal carried a terse note under the heading 'Mining in Cornwall and Devon' in October 1892 stating that Captain W.R. Thomas had accepted a position as Manager of some gold mines in Nova Scotia and that his departure was equivalent to a formal pronouncement of failure at the Uranium Mines. Work did however continue at the mine on a reduced scale with no more than eleven employees until 1899.
A new player in the field, the Minerals Research Syndicate Limited registered on the 4th August 1899 with a nominal capital of £6,000, acquired The Uranium Mines. Within a few months the number of employees increased threefold and the mine produced increasing tonnages of ore, but of lower grade, for the ensuing three years. The statement for landlord's royalty 1901 - 1902 showed Bettmann & Kupfer as the sole purchasers of ore which over this period was shipped in barrels or casks varying in weight from seven to twelve hundredweight. Royalty payable to the Boconnoc Estate was based on one twenty-fourth of the sales value.
During the period from 5th September 1903 to 4th February 1905 the property was in the hands of a receiver and operations were practically suspended. Consequently no ore was sold in this period and the property was sold by public auction by order of the Court in 1904. Once again South Terras failed through lack of capital.
In the interim between the working of South Terras by the Minerals Research Syndicate and the British Metalliferous Mines the Cornish Guardian ran a series of articles in January 1904 on the discovery of radium and its importance for the future of South Terras.
Reporters and correspondents had great difficulty in comprehending and communicating the properties of radium, struggling with hyperbole in attempts to convey its power. A choice example in the 15th January edition read:
"The three great salient features of radium are its enormous energy, heat and light. So prodigious is the velocity of the electrons which radium emits, that if the total energy of one gramme were converted into weight-raising power, it would be able to raise the whole of the British Navy to the top of Ben Nevis."
James Harris-James was once again to become associated with plans for the reopening of South Terras, making optimistic claims for the mine's future. More realistic and considered comment however provided the content of the final article on 29th January, concentrating on the lack of capital, lack of pumping and raising machinery, and lack of underground development. Throughout much of the life of South Terras Mine it was customary to confine underground working to the drier summer months, sufficient ore being raised to provide all year round processing on surface. The reason for this was twofold; the uranium lode lay underneath the River Fal making the underground workings abnormally wet even at shallow depth, and the limited pumping capacity installed.
British Metalliferous Mines Limited succeeded the Minerals Research Syndicate as operators of South Terras in 1905 on a 21 year lease from 1900. Production of ore in 1905 was derived from waste tips only, underground mining being resumed in the following year. Barrels or casks were now replaced by two hundredweight bags. Assays of uranium ranged from 3 to 31 percent.
Whilst Bettman & Kupfer continued to be the main customer for the German market, an important customer trading as the Kingsway Syndicate appeared from November 1906. A contract for the supply of 7 1/2 grammes of pure radium bromide valued at £30,000 for use in the new Radium Institute was agreed, the pitchblende from which the radium was to be extracted to be secured from South Terras. In 1911 the mining setts including South Terras were sold for £3,100 to an undisclosed buyer.
The discovery of radium and demonstration of its remarkable and peculiar properties is credited to Marie Sklodowska Curie after four years of tenacious research, with the assistance of her husband, Professor Pierre Curie. Radium bromide was separated by the Curies in 1898 but it was not until 1911 that radium itself was isolated.
Rontgen rays had been discovered in 1895, followed a year later by Henri Becquerel's discovery of radioactivity in uranium salts whilst studying fluorescence of those salts. The rays emitted were later to be known as gamma rays. This research, coupled with Becquerel's encouragement, induced Marie Curie to follow up sources of radioactive emissions.
The Curies tested many minerals, rocks, metals, etc., and found that none of them were so strong in radioactivity as pitchblende. In observing that pitchblende was more radioactive than uranium metal, she suspected that there could be another element of greater radioactivity in pitchblende.
Ore for testing came from the Joachimsthal Mines in Bohemia, the main uranium producing area in the world. The Austrian Government agreed to present a ton of residue to the "Two French Lunatics" to enable them to further their research. Marie Curie was to obtain 1/10 grain of radium salt from 2 tons of residues after painstaking laboratory experiments.
The turning of attention from uranium to radium at South Terras for the remainder of its working life provided the press, including the mining journals, and the local public an opportunity to engage in the most bizarre correspondence and dialogue. Colourful in language and entertaining to a high degree it frequently lacked hard useful fact, permitting romanticism to have its head.
Perhaps the most interesting period in the life of South Terras began with the registration of the Societe Industrielle du Radium Limited on 16th November 1912, with a capital of £200,000. A new lease was negotiated for 21 years to March 1934 and a subsidiary company, Societe Francaise du Radium, set up to treat the ore from South Terras in France. The parent company's board comprised four French and four English directors. The share prospectus contained numerous reports on sampling at South Terras, including one from the laboratory of Madame Curie on the radioactivity of the water in the mine, dump material, and specimens from the deep levels of the mine before it was submerged.
Professor Jacques Danne, Director of the Laboratory for Testing of Radioactive Substances at Gif, France estimated that the dumps on the mine contained at least 9.7 milligrams of radium as bromide. A laboratory was to be set up at the mine under the supervision of Monsieur Malandrin, analyst at the Gif Radioactive Laboratory. Ore was to be shipped to France where at the rate of 5 tons per day, 5 milligrams of radium bromide valued at £16 per milligram were to be extracted.
At this juncture the hitherto supportive mining magazine editorials vented their disgust at what they considered to be a sham and ridiculed the prospectuses of both the Societe Industrielle du Radium and the neighbouring Radium Ore Mines. Under the title 'The Radium Hunters' in the February 1913 issue of the Mining Magazine an attack was launched on the South Terras flotation which included the following remarks:
When high science is mixed with low finance the result is confusion...
A little learning is made to leaven a large mass of pretentious ignorance...
However, it appears to be admirably adapted to a pseudo-scientific exploitation of old mines and new simpletons, as is illustrated by the South Terras flotation...
Among the sponsors of the scheme are four Frenchmen, of whom it may be presumed in all kindness that their knowledge of business is inversely proportional to their scientific attainments. Among the English directors is the usual histrionic nobleman whose part it is to shed a phosphorescent lustre on the title page of a prospectus.
The outbreak of war in 1914 caused operations at South Terras to be suspended.
In October 1921 the Mining World carried a short note on the prospects of Cornwall
having a spa, a rather tongue-in-cheek comment under the sub-heading:
- Grampound Road as a Health Resort
It is true that Grampound Road is undeveloped; that neither the enterprising builder nor his confrere, the jerry-builder, has yet invaded its precincts; that it has no orchestra to emit the "concord of sweet sounds"; that it has no pump room, and, as Sam Weller would say, "no nuffin" - but perhaps to seekers after health it may be more important to know that Grampound Road has an almost unlimited supply of radio-water, and in this respect may at no distant date become a rival even to Bath. True also, Grampound Road has no Beau Brummel, or a promenade upon which he may do a modification of the Piccadilly crawl, and no Beau Nash to exhibit the latest conceits in tailoring; but, at least, it must be credited with having given birth to the famous novelists, Silas and Joseph Hocking, whose imaginative proclivities were no doubt fired, and whose delicate
fancies were stimulated by the radio-waters, of which in infancy they may, with more or less discretion, have imbibed copious draughts.
A resumption of working after the Great War saw the installation of a new extraction plant completed in 1922. Initially this was to treat some 200 tons of ore containing an estimated 2500 milligrams of radium. By August 1922 pumping and mining operations had recommenced and the extraction plant was performing satisfactorily. This was the first plant of its kind to be erected and operated in Cornwall for the extraction of radium salts. The sandy residues, of low radioactivity, were sold on the Continent as a valuable manure. Apparently their value was not appreciated in this country! The ore to the plant was originally dry-crushed and graded in preparation for chemical reduction, but a change to wet crushing was developed to improve recovery and speed of treatment.
The Mining Magazine reported in September 1924 that amalgamation of South Terras Mine with Tolgarrick Mine had been concluded by their respective owners, with the aim of increasing their activities in radium products.
In March 1925 the Boconnoc Estate initiated action which was to lead to the downfall of the Societe Industrielle du Radium. As landlord, the Estate had long been dissatisfied with the company's failure to comply with many of the clauses in the lease. These breaches included no check assays and the sale of all results abroad leading the landlord to be suspicious that he was not receiving his just dues. The mine had worked the old dumps and remnant ore, not a shilling being spent underground. In instructing solicitors to act, the landlord's agent F.J.H. Somerset wrote that the company was a hopeless crew to deal with.
The final company to try its hand with South Terras was the British & General Radium Corporation Limited, registered on 1st February 1928, taking a concession from the previous lessee. Despite the company name it was described in the July 1928 edition of the Mining Magazine as a German Syndicate and was headed by Dr. I. Strauss a Swiss director. A laboratory was established in Trevarthian Road, St. Austell and the mine unwatered to the 40 fathom level below edit by January 1929.
Stope fillings from the mine were removed and treated, yielding on average 100 milligrams of radium bromide per month upon which dues of 1/48 were paid.
Two months later the company approached the landlord with a view to negotiating a new lease to 1950 at £150 dead rent per annum. The Estate countered with a demand for £500 per annum rent plus a £1,000 deposit.
In June 1929 mining engineer F.C. Cann submitted a commissioned report on South Terras Mine to the Banco Espanol del Rio de la Plata who had taken a financial interest in the operation. Cann's comments and recommendations included deepening the mine, extending the existing levels, more stope sampling and opening up the ground. This was precisely what was advocated in a report in the Cornish Guardian 25 years earlier.
The mine closed for the last time in March 1930 and for the next seven years protracted negotiations continued to seek common ground in creating a new lease. The landlord, however, had experienced too many breaches of conditions to bow from his position and in 1937 successfully obtained a Court order for the repossession of the mine. To partially defray outstanding rents a forced sale of the machinery on the mine was held. Notwithstanding an attempt to negotiate the use of South Terras as a spa in 1937, the removal of dump material for use at Trebelzue airfield in the Second World War, and test drilling for uranium by H.M. Geological Survey in 1952 the mine has remained closed.
Unquestionably the most important person involved in the production of radium concentrates at South Terras was Dr. Marcel Leon Pochon. Born at Versailles of Swiss parents in 1889, he studied at the School of Industrial Physics & Chemistry in the Rue Llomond, Paris and graduated in 1906/7.
In 1912 he left Paris to work with Jacques Danne at South Terras, returning to superintend the extraction of radium at the mine in 1920. The narrow-lode shallow underground operations at South Terras presented no unusual mining engineering challenges but the expertise demanded on surface in the extraction and concentration of radium was of paramount importance.
Pochon lived in a bungalow a few yards from South Shaft at which the uranium lode outcropped. An unfortunate occurrence in November 1930 prompted him to write posthaste to the Boconnoc Estate Office thus:
South Terras Mine 20th November 1930
Dear Mr Skentelbery
I have to inform you that a serious collapse of ground happened at the Mine during the night near the South Dump.
Apparently the first Southern Stope at the 10 fm level went down carrying down with it the adit level & all ground to surface above.
My potatoes patch in my garden has gone down & the path leading from the road to the bungalow is undermined.
The full width of the lode is exposed & huge loose rocks are hanging on the hanging wall of the lode & the hole may go right to the bottom of the 10 fm level.
The whole thing can only be made safe by refilling, but it will take several hundred of tons to do it by taking in it the dump material.
The tenant farmer, Mr Rowse, is using the field for his horse & cattle and the repair will have to be done.
As I do not know who is now responsible for the Mine, I am notifying Mr Parkes & I am afraid the Estate will have to take the matter in hand & get in touch with the Company.
In 1932 Pochon left for Canada where he set up a pilot plant at Port Hope for treatment of ore from the Great Bear Lake operated by the Eldorado Gold Mining Company. The following year saw him produce the first 100 milligrams of radium in Canada and he became recognised as an international authority on processing pitchblende.
He died at Port Hope in April 1958 and was the last chemist in America who had worked with Madame Curie.
The South Terras saga was one which deserved better than its undignified demise. It was a series of under-funded attempts at exploiting two of the most expensive elements mined in their day.
It is estimated that ore having an unsuspected radium value of £450,000 was shipped to the Continent over a 20 year period before radium was discovered. How different the fortunes of South Terras may have been had the discovery of radium taken place twenty years earlier or, alternatively, the working of the uranium lode commenced twenty years later?