Future Of The West Coast The Gold Industry—And Its Consequences

Press, Volume C, Issue 29709, 30 December 1961, Page 8

Future Of The West Coast The Gold Industry—And Its Consequences

[SpeeUHp wrtttn for "The FrsssT bp ARTHUK UTSH] m 'J’HE West Coast has wonderful attractions for visitors, and the tourist industry is one that can grow without destroying the country that supports it I wish we eould have said that of the gold industry of the past, by which much good land was ruined without need, surface sou being washed into the depths of the ponds where dredges operated, and buried under stones. At almost trivial expense, the water carrying the soil to waste could have been pumped up on top of the stones that were left behind the dredges. Conversion of stony wastes to useful land is one of the problems left to be solved locally.

It Is nearly a century since the first gold rush to the West Coast, but there are people who believe that there may till be more gold left than has yet been taken out. I am one of them. The problem is how to recover the gold economically. The Supplementary Report on the West Coast does not mention gold. The earlier Report does mention it, but without new ideas, and with some foolish impatience with the National Parks Act. Without that, and similar protection of natural assets, the future of the West Coast would be dim indeed. In the course of ages, glaciers and rivers have cut great valleys into mountains, bringing out immense quantities of stone, and also gold. In some places, natural pro. cesses left the coarser sizes of gold in river beds and river terraces, from where it was recovered by panning the gravel and sand. But glaciers grind rock to dust like the finest flour, and gold would be ground to dust in the same way. The finer the the gold, the more readily it travels in running water, and it is likely that where the early prospectors recovered much gold by panning, large amounts would have been washed downsream to river

estuaries, where the gold and the silt eould settle out in still water. (Von Haast. pages 104-5 and 254 describes the goldbearing areas of the West Coast and Otago.) Quartz Mining At Walhl In quartz mining at Waihl, you could not see any gold at all in the quartz, altogether there was more than £5 worth in each ton. The quartz was crushed to sand, which went over copper sheets amalgamated with mercury; this picked up some of the gold. The sand was then crushed to “slime” in a ball mill containing flints from Iceland. The flow through this mill was led to tall vats containing a solution of potassium cyanide. The slime was agitated in this solution for about three days, by a flow of compressed air introduced at the centre of the conical base of the vat. The slime that had taken so much effort to produce, was then separated and dumped, but the solution, containing gold and silver, was taken to “zinc boxes" where it was precipiated as a black sludge. This was retorted and melted gold and silver bullion cast into heavy ingots. These contained a greater weight of silver, but much greater value in gold.

West Coast gold recovery, in the early days, went as far as washing only. Any gold too fine to be seen was lost Mote recent gold dredging uses two stages of recovery, including the mercury amalgam method. But the final stage, using cyanide could not be accommodated on a dredge. "Tailings” In various places, ‘‘tailings” left by early methods at gold recovery, have yielded valuable returns by the use of cyanide. The greatest "tailings dump" if one may so term it, (that I know of) is the immense deposit about Okarito lagoon, and reaching far inshore to the head of the estuary. But it was only in the last century that any gold has been taken upstream: before that, the river must have carried down all sizes of gold that it eould transport. The total amount of gold in the estuary is doubtless immense, but the total amount of sand and gravel is so much more immense that one cannot say without adequate testing what results might be obtained by excavating to rock bottom and processing that material that has been dumped by the river during many thousands of years. The gold would be likely to be unevenly distributed, some parts of the deposit rich, and others non-payable or even barren. There, however is the great buried treasure which may bring disappointment or immense wealth to the West Coast. Surveys And Bores There is a case for surveys, bores with continuous sampling, investigation, research, planning on a large scale. Such investigation should be amply justified. The quickest and most certain large-scale industry for the West Coast, in my opinion would be the tourist industry, but with other highly important prospects for major industries: the possibility of new electrochemical industries: the possibility of investigation favouring gold recovery by modern methods from the Okarito estuary, and possibly from other places where rivers have buried gold near the sea. The preservation and controlled use of native forests in perpetuity is also more important than many people have yet realised. Few places can grow New Zealand timber so well, but radiata can be grown almost anywhere, and is not in the same class. The tourist Industry badly needs good roads completed as soon as possible, particularlv the Paringa-Haast link to Wanaka. The whole of the West Coast needs much more extensive and better air services. The more that new Industries can be developed and owned by West Coast people, the more will the West Coast profit by them. (Concluded.)