UNKNOWN

Greymouth Evening Star, Volume XXXI, 16 February 1901, Page 4

UNKNOWN

(Mining Eecord.)

Now ‘.l.a. several dredges have got to work on the West Coast some indication is being given of the extent to which the now industry is likely to succeed there. So far the returns have not been so steady as from Otago claims. We are disposed to think that this will be characteristic of Coast claims. The rivers there do not cut through huge alluvial deposits throughout almost their entire length, as does the Molyneux and most of our gold bearing streams. Probably the Hokitika Kiver is the one that most resembles the Molyneux in this respect. Both the Buffer and the Grey are gorge rivers, whose bottoms are not so even as the clay beds that characterise the Molyneaux. The chances, therefore, are that the returns will fluctuate more. There is no doubt, however, that the West Coast is highly auriferous country, and the gold in many places is very heavy and easily saved. It is only natural to suppose that this heavy class of gold will not be so generally distributed as the bran like gold of the Molyneux. While this is so it. is also true that there is no place in the Colony, except perhaps Orepuki, which has had so much experience in treating fine gold as the West Coast at Charleston and its neighbourhood. There is, therefore, a new problem for gold dredgers'there to solve. Not only is the gold over large districts very fine, but it is also heavily charged with black sand. How to save the fine gold upon tables which the black sand takes possession of is the difficulty. Some of the dredges use quicksilver for the purpose. But the means adopted must in the first place be mainly mechanical in their nature with the object of concentrating the gold so that the concentrates should be worth 5 to 7dwts to the ton. It will then be possible to treat them chemically with a good show of profit. The attention of dredging engineers is now being given to the best mechanical means of saving this fine gold and of keeping the tables clear of black sand. As is pointed out by Mr. J. P. Smith in hia article in the Mines report last year the breadth of the concentrating table is more important than its length. And it must be to the spread of the tables and their pitch and the quantity of water used upon them that attention must be directed to get the best results. At present no at'empt has made to suit the quantity of water to the amount of solid matter being treated. But with the attention now being devoted to th’s subject it will not be long before ihe conditions of tne West Coast will evolve a typo of dredge suitable for its own circumstances.