The Sydney Morning Herald (NSW : 1842 - 1954)(about) |
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Saturday 18 March 1905
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OUR INDUSTRIES.
COPPER MINING.
XX.
Doubt and uncertainty surround the cir-
cumstances attending the earlier discoveries of copper in this State. It is believed that copper was the first metal discovered and mined in New South Wales, and that this took place as far back as 1844. Records show
that in 1845 copper lodes were worked at
Copper Hill, near Molong, and at Pool's Creek, near Canowindra. Two years late copper-mining was carried on near Rockley. Writing to Earl Grey, Secretary of State for the Colonies, Governor Sir Charles Fitzroy, on March 1, 1849, advocated the making of a geological survey of the colony, stating that "copper mines are already in operation in the neighbourhood of Yass and Molong, near Wellington Valley." In 1851 the Rev. W. B. Clarke discovered copper in the Marulan district, and in the following year found cop- per and lead ore at Quidong, in the Snowy River district. Since then copper has been found in greater or smaller quantities in 60 different portions of the State, and is being worked more or less actively in about 20 localities.
The most successful copper mine is the Great Cobar copper mine. The aboriginal name "Cobar," or "Copar," means "Raddle" (earthy iron oxide), and it was from the oxidised outcrop of the lode, now yielding magnificent returns of copper, that the aboriginals obtained the coloured pigments with which they ornamented their bodies when holding corroborees. Two stories are told as to how the discovery was made by white men. One is that in 1869 Thomas Hart- man and Campbell, whilst boring for water in the locality, camped at the well formed by
the natives scooping out from the outcrop the soft, ochrous material which they used on their bodies. Hartman and Campbell were attracted by the rusty sediment at the bottom of the hole, also the blue and green stains around its sides. Raking aside the ashes of a camp fire near by, Hartman discovered beads of metallic copper, which he showed in Bourke. It was then surmised that the copper was melted out of ore that had pro- duced the blue and green stains on the side of the hole. The other story is that the two men broke off some of the ore, and whilst on their way to work showed it to a Cornish woman named Mrs. Kruge, who identified the stones as being copper ore.
Hartman and Campbell at once returned to Cobar, and on October 6, 1870, secured a mineral conditional purchase lease of 40 acres, which embraced the outcrop in which the native well was situated.
After Hartman and Campbell had been a short time at work on the outcropping lode, Mr. Russell Barton—intimately connected for many years with the subsequent develop- ment of the copper industry—chanced to visit the locality. Being acquainted with copper mining in South Australia, he at once, pur- chased an interest in the venture. Rich ore was sent by team to Bourke, and carried thence by steamer to the Port Adelaide Smelting Works. In this way 2000 tons of ore were sold at a profit. In January, 1876, the Cobar and Southern Cobar Copper-mining Companies were amalgamated, and became the Great Cobar Copper-mining Company of to-day.
As one copper mine is like another in re- gard to the method of working adopted—the same remark applies to gold mines—it is only, necessary to describe the manner in which the ore is won in the Great Cobar Copper mine in order to indicate how the work is done in other copper and gold mines. There is the one marked difference, however, viz.. that whilst the copper ore is sent to fur- naces to be smelted, in the case of gold mines the reef material is crushed in batteries, thence passed over quicksilver wells and cop- per plates to catch the free gold by amal- gamation, whilst the pyrites are caught on blankets and in "ties," and afterwards roast- ed, so as to enable the gold to be taken up by quicksilver. The men are now working at 800ft on the eastern branch of the lode. It varies in width from 50ft to 70ft, and is taken out bodily in a series of stopes that go as high as 50ft. As this immense cavern pro- gresses forward, it is filled in behind with mullock, so as to prevent the works collaps- ing. The ore is sent to the surface, where it is first roasted in 3000 to 4000 ton heaps, after which the partially calcined stone is mixed with fluxes obtained from the syndi-
cate's gold mine at the Peaks, five miles away, put into the blast furnace, and the copper, silver, and gold contents brought down to a matte containing from 35 to 40 per cent. of copper. This matte is sent to Lithgow to be treated for the production of practically pure copper. This process will, however, be dealt with in a separate article relating solely to the ore-smelting industry of the State.
Coming to other copper discoveries, we find that the Nymagee copper mine, purchased in 1880 by the Cobar Mining Syndicate, has had a checkered career. It was first opened up in 1880. At 700ft the main shaft is on a lode of massive sulphides 30ft wide, and averag- ing about 2 per cent of copper. The mine was originally worked by a company which paid £94,000 in dividends between 1883 and 1889. In 1893, owing to the bursting of the copper boom, followed by the low price of copper, operations ceased. As already stated, the mine was purchased in 1896 by the Cobar Mining Syndicate, which first started with a blast furnace, and afterwards adopted the pyritic system of smelting. Nymagee copper is of good quality, contains a small proportion of silver, but no gold.
The same two men who discovered the Co-
bar copper lode found the Girilambone de- posit on the Western railway line. They
started work on it in 1880. The mine was clos- ed, down from 1885 to 1893, also during 1895 and 1896, when it was floated into the com- pany that now works the lode. The oxidised ores—blue and green carbonate, and red oxide—went down to 200ft. Though the depo- sit is of considerable width—as much as 40ft —the copper ores, both in the oxidised and sul- phide regions, are mixed with quartz, hence the necessity for extensive concentration un- der conditions that lead to a considerable loss of copper contents. Owing to the silicious nature of the lode, pyritic smelting is not practicable. Reverberatory furnaces are, therefore, used. A large reduction plant is at work, and the copper is of extremely good quality, the assay value being 99.95 per cent.
or almost pure copper.
Like the Girilambone deposit, that being worked by the New Mount Hope Company, 120 miles south-east from the Nyngan rail- way station, consists chiefly of impregnation and segregations, hence it requires concen- tration before smelting. The lode was discov- ered in 1878, and in 1881 was floated as the New Mount Hope Copper Mining Company, The oxidised zone reaches to 270ft, where the ore consists of earthy blue and green carbon- ates, red oxide of copper, with grey sulphide. The sulphide ore is of high grade, but as the ores were wanting in iron sulphides, it was ne- cessary to bring iron ore from Mount Allen, 11 miles distant, for fluxing purposes. A consid- erable quantity was obtained, but as the ore was found to contain a large percentage of gold, the Mount Allen iron ore was subse- quently worked for that metal.
A remarkable deposit is that which has been worked with varying degrees of success by the Lake George Mines, Limited. The mine was first opened in 1882, when the outcropping lode, composed of auriferous gossans, was worked for gold. Two years later it was found that the gossany formation was lying on top of a large low-grade copper lode. In 1885 a blast furnace was started. The lodes were at first worked by two companies, but in 1894 they were amalgamated, and subsequently re- formed under the title of the Lake George Mines, Limited.
An interesting copper mine is known as the Gulf Creek (Limited). It is situated 10 miles from Cobbadah. Opened somewhere about 11890, two ore bodies of remarkable, richness were discovered. They consist essentially of massive iron pyrites, permeated by copper glance of an impalpable character, so that the whole material has a black appearance. It is stated that at one time rapid decomposition of the ore was in progress. So much heat was evolved that in some of the stopes the min- ers could scarcely handle the ore. The Gulf
Creek deposits are said to bear a considerable resemblance, both in the mode of their oc- currence and composition of the ore, to those of Rio Tinto, in Spain. But whilst the ore from the Gulf Creek mine averaged 14 per cent. down to 148ft, in the Rio Tinto the deposit yields but 2½ per cent. of copper.
In conclusion, it is only necessary to con- trast the facilities now afforded to the cop- per mines for securing cheap railway car- riage of fuel (wood or coke) and fluxes, with the great disabilities that existed in the pre- railway days, to see at a glance that the copper mining industry of to-day stands in a
far better position of proving remunerative with a low-grade ore than was the case in the early days of the industry, when the rich zone of copper carbonates was available. Be- fore the railway system of the State was ex- tended west, copper mining was carried out under heart-breaking disabilities, due to scarcity of water and fuel, but more espe- cially in consequence of the long distances over which the copper had to be carted to the nearest railway station. The cost of carting ore in the old days was as high as £42 a ton. To-day it is not more than £3. Only a rich mine could pay in the pre-rail- way days. When the copper corner, en- gineered by the Societe des Metaux, ran the price of the article up to £60 a ton, then it was possible to reap rich dividends out of the Cobar copper mine with a lode aver- aging 7 per cent. of copper, but when the boom burst, and copper came down to £36 a ton, it was impossible to work the lode at a profit. Moreover, the methods adopted in the early days were most unscientific, and, therefore, wasteful of the metal sought to be won. To-day, by the aid of scientific me- thods, assisted by cheap railway freights, 2½ per cent. ores are made to pay where 7 per cent. meant failure in the past.