A SUCCESSFUL EXPERIMENT.

Otago Witness, Issue 2240, 4 February 1897, Page 18

A SUCCESSFUL EXPERIMENT.

(Australian Mining Standard, Junuary 21.) The eminently successful result of the experiment made with 'the bromo-cyanide process by the South Star Company, Ballaraf, fully justifies and confirms all thab the Standard haa urged from time to time touching this general subject. To this no credit for any special degree of perspicacity attaches, seeing that ib only represents the working out of a self-evident proposition. The position taken up simply was that as good returns were obtained from slimes »nd tailings by chemical processes elsewhere, Australia was discounting its own resources by neglecting to take full advantaga of ,such methods. New Zealand had tound ib to be profitable, and bo also had Queensland ; but in the other colonies these examples had not been followed, except on the most limited scti'e. Now the matter has passed out of the realm of speculation, however well founded, and bus entered that of e'eaaonstrated faot. The brumo-cyanide procdes, by which the test has been made,, is tbo latest introduction, and was referred to in the Standard of November 12 last year as a highly recommended agent with which "Victorian mining men were then experimenting. The te*b was applied by the- Soubh Star Company, Ballarat, and the following is the report which the ohairman of the directors, Mr John A. Wilson, and the manager, Mr George Ruffle, have issued t j the shareholders, under date of the 13th inst. :—: — •'About four months ago your directors made the important discovery that your company was losiug aomethiug like 30 par cent, of the gold contained in the sbone, which was being carried away iv the tailings in the shape of fine gold. Th« loss on tbe 40,000 tons pub through th« battery is estimated to amount to about £24,000. Steps were at once ttken to devise some means by which this great loss could ba prevent a d, and as a similar state of affairs had existed* in South Africa prior to tbe introduction of the cyanide treatment there, it was decided fco obtain the fullest information regarding that process, with the view of ascertaining it' it couM be »ucce*Bfully applied to the South Star mine. Several test assays were then made, with highly satisfactory result*. Afc this stage Mr Svv&nson, the representative of tho Gold Ore Treatment Company, Limited, London (patentees of a newer process), arrived in Melbourne, and after several interviews with that gentleman it was agreed that a thorough trial should be msde with the bromo-cyanide system of treatment. A small test plant, capable of treating one ton per day, was erected on the mine without delay, and has been kept at work since 22 ad ult. The result of the bulk tests fully confirmed the several small trials previously m*de. The as3&y value ot the tailings was 3dwt 4gr per ton, and the bromo-cyanide treatment recovered 91 per cenb. of bhis, leaviog a residue of only 9 per cent., and it is anbicipated that even this result will ba improved upon as tha system become.s better iiuderstood. Iv any cssa shareholders cmi confidently look forward to getting an increase of about 3dwb per ton from the obone crushed, at a cos 1 ; of not more than 2s per ton. ,-Y.ou will bs gratified to learn thab most satisfactory arrangements hava be'-n made with the patentees for the right to use this process of treatment &t your miae. Your directors, claiming to be the first in these colonies to adopt the bromo-cyanide process iv a large and practical way, stipulated for very liberal terms, which thsv hare succeeded in obtaining. The Bucceis

which musb necessarily follow is deemed of such importance that your directors hava determined to lose no lime in advising tho shareholders as to what has been done in tho matter. Arrangements have now been mado and all contracts let for the ereofcion of a plans capable of treating 4000 tons per month, ami ib will be ready for work in from five to six weeks from data. In order to ensure tha besb results your directors have appointed Dr Storer, the eminent scientist, as contulting ohc-mist and engineer, under whose direction the whole of the bromo-cyanide works will fca carried on. The crushing plant will also be finished in about four weeks, and it is confidently anticipated that a sAving of from £700 to £800 per month in crushing ex* penses will the* be effected." The result above recorded — the recovery of the assay value to tho extent of 91 per cent. — is phenomsnaJ, anot splendidly testifies to the success of the bromocyanide process. If this could be relied upon in .ill cuaos (.hero would be no need to look farther for a satisfactory process of gold recovery. Bab as different constitutions are differeut'y affected by the sama drug", so the slimes of different ores respond differently bo the same treatment. Where one yields easily the other proves refractory, and more readily responds to the cyanide or chlorination proce3s. Still, by whatever system the immense sccumulations of tailings to be found in the colony — notably at Ballarat, B'rtdigo, ttnd Pleasant Creek — can be made to give up their gold contents, great advantage must be gained. What has hitherto been regarded as a waste product will be turned into a source of profit, work will be found for hands now idle, and the increase in the gold output will benefit the whole colony. The success of the South. Star Company should therefore mark an epoch in the mining history of Australia as that from which oyaniding in all its forms became a large and profitable province of the industry.