Osmiridium Mining in Tasmania

Sun (Auckland), Volume 1, Issue 110, 30 July 1927, Page 24

Osmiridium Mining in Tasmania

HSMIRIDIUM, one of the world’s rarest metals, formerly despised, is now worth many times . its weight in gold. A native alloy, akin to platinum, it consists mostly of iridium and osmium, with smaller percentages of rhodium, rutherium and palladium; it is white in colour, very heavy, and somewhat resembles steel filings. In only one place is it obtained in a “free” or alluvial state, and that place is Tasmania. Osmiridium is used in the manufacture of acid-resisting dishes, basins and crucibles, and in the production of bars for standard weights and measures. It is also used in electrolytic work, photography and for enamelling by jewellers. Surgical needles and jeweller’s drills are also made to a limited extent from this metal, and on account of its high melting point it is often employed for the preparation of the filaments of incandescent lamps. Osmic acid and osmic chloride, both highly poisonous gases, are derived front osmium and have been extensively used in warfare. But osmiridium itself is used almost exclusively for the tipping of gokl-nibbed fountain pens, and so fatno suitable substance has been found to take its place. In the early days, says P. Ormsby Lennon in “The World To-day,” Tasmanian prospectors operating in the north-west of the island, found a rich belt of country which yielded a variety of mineral substances of more or less commercial value. Prospectors for gold found, in panning off, an unknown metal of tin-white colour, which weighed much more than gold itself. It was regarded as a nuisance, as it was found difficult to separate from gold, and because a penalty of 7s 6d an ounce was imposed by the Mint for its non-removal. It is related by old miners how they filled oatmeal bags or pickle bottles with this apparently useless and irritating metal, and how they either gave it away as a curio, or else, finding it useless lumber. pitched it out of their camps. Little did they think what a fortune was in their grasp. In some localities it was so abundant and persistent that steps were taken to have it scientifically identified. It eventually transpired that this metal was osmiridium. At first, the price obtained was only 25s an ounce, but in 1910 it rose to £4 10s. From that time its value yearly increased until, in 1921, it reached the surprising price of £42 10s an ounce. The known Tasmanian fields soon were depleted, and it was not until'

1925 that a new one was discovered by a party of prospectors in the wild and almost unknown Adam’s River district lying out to the west of the island. The Adam’s River field is situated about 30 miles from Fitzgerald, the little timber-milling outpost at the Derwent Valley railhead. The route there lay through dense forests and swamps, and over high mountains. It was only possible to take packhorses out part of the way in the beginning, as the country was so rough and scrubby that they could not get through to the field. Intending diggers, therefore, had to “hump their swags” for the rest of the way. As these frequently weighed between 75 and 1001 b, the rest of the journey was slow and arduous work. There was no made track beyond a sort of pad, which had been beaten down by the first rushers, and owing to the heavy traffic over this it was knee-deep and often waist-deep in mud. In addition, it was littered with the fallen trunks of huge trees—sometimes eight or 10 feet high—and a man cumbered w*ith a heavy “swag” found it no easy matter to scale these. The rush took place in the middle of the Antipodean winter, and was the worst that had been experienced for many years. The early rushers had to cross the treacherous Florentine River by means of a narrow myrtle log and a handwire stretched from bank to bank. This log was often three feet under water, and the wonder is that men were not swept off it by the rapid current and drowned. But there were no fatalities. Many of the rushers were unable to reach the field and had to turn back to civilisation. Numbers of men were quite unused to the ways of the bush, not even having a rudimentary

knowledge of the art of camping out, and, in consequence, suffered great hardships. It was a common sight to see would-be diggers lying by the side of the track overcome by exhaustion. Some of them had to be carried in again.

Owing- to the difficulties of transport, the price of provisions on the field was higher than has been known on any other Australian mining field. A 41b loaf of bread cost Gs 6d, while a 251 b bag of flour cost nearly £4. One miner purchased £3 worth of potatoes and onions at the railhead, and the freight of these to the field cost him over £25. As is usual in such rushes, the sly-groggers were well to the fore, and in the height of the boom days they obtained as much as £lO for a bottle of rum, which was mainly composed of methylated spirits. At the height of the boom the place was strongly reminiscent of a Wild Western mining camp in the “movies.” Everybody “packed a gun.” From occasional wild rumours that filtered through to Hobart—the picturesque capital of Tasmania—one was led to believe that Adam’s River was the haunt of professional “bad men.” As a result, nobody ever thought of venturing out to the field without a revolver and a large supply of ammunition. At one time it was not possible to purchase a weapon in Hobart. Although there were no large fortunes made on the field, several men cleared quite comfortable sums. Quite a few miners found over 10 ounces of metal a day for periods extending over months. At the beginning of the rush the price for osmiridium was nearly £33 per ounce, and handsomely repaid miners with good claims. Many claims returned their possessors anything from £4O to £2OO a week, but, on the other hand, hundreds of men could not obtain enough to provide them with a liv ing. The Adam’s River field is rapidly on the decline, and production has fallen off considerably. The country in which it lies is in ail exceedingly rich mineral belt, and as the area is gradually opened up, it is highly probable that further important discoveries of commercial metals will be found. The Commonwealth of Australia has recently sanctioned an annual grant to the Tasmanian Government with the object of opening up this great terra incognita, which, in a few years to come, will most likely prove to be of great Empire importance. Hitherto all development has been dependent on individual effort.