AUSTRALIAN OPAL AND OPAL MINING.

Star (Christchurch), Issue 7203, 14 September 1901, Page 1

AUSTRALIAN OPAL AND OPAL MINING.

Considerable quantities of opal are found in Queensland! and New South Waleii (writes John Plummer). In tiEe latter Stat« the commoner kinds are: found im many, localities, espeoudly in the aeagihotirlKiwi of Orange, but they possess little or utt commercial value. Precious or noble opal is obtained principally at Whit© Cliffs, ia the day western country, about 780 m2e*» from Sydney and 65 miles from Walcannia.. Th& latter townsihip is about 100 miles front Br-oksn H331, and the whole country is saaxi to be rich in minerals, but the deficient water supply seriously retards the efforts of prospectors. According, t<> Mx'E. P. Pitti man, in ih&s work on ? The Mineral Ref sources of New ,Soir&.\W*les," the prrif ! (so^opakHof-Wfiatff-iGKI&r-as S» *h* casf of many other i valuable • mineral depoart^ were discovered by accident.' In 1889 q> hunter, while tracking a wioundfid kanga* roo, picked up a piece of fihe hriEmtttiyw coloured mineral on the surface. After tibql find had been reported a careful 6earch of the locality was made, with the result thai several more pieces were discovered. Pros* pecting trendies were then excavated', anil the gem was found in ratu. Since thatl time mining operations ihave been carafe^ on continuously, dihough sometimes undesr great difficulties,. a 9/ 4n tnsne of drought $he locality is very \ badly provided witihi water. Opal mining tolas, however, nwy be* come A SETTLED INDUSTRY,, and a tlhiriviTig townsfcip has been estab* lished at White Cliffs. The area mtihiui Which the mineral has been found in iiha district ia about fifteen males long by about two miles wild*. Prospecting for precious opal is a d«« cidedly hazardous business, because, as 4 rule, there are no indications ■whatever on tie surface of t(he occurrence of the mineral below. It is only in. very rare instances tfoat an outcrop of the gem can be weny and the usual procedure te ti> dig a trench or p3t in such a position 'as fonteyinay die* tate, and trust to luck. Fortunately, sink-" ing is easy, as the rock is of a soft nature, and, in a fair number of instances, th« opal (has been met witib at a very short di** tanco from the surface, tihougk <a large ma-t jority of the pits are" unsuccessful. Fo? several years the belief existed amongst th« miners that it was useless to prospect tin precious opal at a greater depth tihonf twelve feet from the surface; but of lat« the incorrectness of this view <has been proved, and the stones -have been discover* ed at a deptih of nearly fifty feet. Accord* ing to an authority quoted by Mr Pittmatt there is a wonderful variety of opal found on the field, and the prices paid locally} run from zero to £25 per ounce, the ounotf being the unit of purchasing en the rough* It is rarely that tihe price paid'exceeds £29 per ounce. In valuing opal a good- many; points ihave to be taken into accounts Needless to say, colour is tihe first, reel fire, or red in combination wUSh yellow* blue, and green being the best. Blue bj| itself is quite valueless, and green opal it not of great value, unless the odtour is verjj vivM and tihe pattern good. That th* colour should be true is a vital point. How* ever good it may be, if it rams Sn. streakt or patches, alternating with colourless oi inferior quality that is untrue, it is of conw paratively small value. . PATTERN IS AN IMPORTANT FACTOR *T in the value, the various kinds being dta« » t-jnguished respectively as "pinfbe," when the° grain, if it may so be called, is very small; '"harlequin," when tQue colour is all in small squares, the more regular the bertn ter; and "flashfire," or "flash opal" whetf the colour stows as a single flash, or isl very large pattern. Many valuable opals have been found. from time to time, one, weighing about four and a half ounces, being sold 1 by the) finder for £100. Of course in London ifl would bring a considerably "higher price., Another opal, weighing nine ounces, was accidentally broken in two, the pieces weighing seven and two ounces respectively, and was valued locally at £700. Tlhd value of the opal obtained since the dda» covery of the deposits in 1889 to the end of 1899 is estimated at £376,599, but mudhj of the opal obtained is not officially rfti ported.