WAITEKAURI.

Auckland Star, Volume XXXIII, Issue 165, 14 July 1902, Page 2

WAITEKAURI.

The Waitekauri Company's battery is to be closed down for a time owing to the fact that the ore now coming to hand is not of a payable quality. In order to develop the mine, driving will be continued at the various SLUICING CLAIM. Towards the end of last year Mr Malcolm Fleming was sent 'to the West Coast by a party of Auckland "■entlemen to report upon dredging claims. He recommended sluicing, m preference to dredging, whereupon an extensive sluicing claim was taken up by the Nine Mile Creek Sluicing Company, Mr Fleming being placed in charge. Sluicing began a few days ago, and yesterday Mr Fleming wiredthat everything is in splendid order, and although they are only sluicing over burden and old. tailings at the present time, there is a good show of gold on the tables, and the prospects are good. DEEP BORING. In January, 1899, a bore hole was started on the Turf Club's property, Johannesburg, but was stopped on October Ist of the same year, owing to the war. On the 14th 'Of July, 1901, boring-, was resumed. This drill hole struck the main reef at a depth of 4800 f- The rods were left in the. hole for the 20 months while the war was going on. The weight of the rods which carried out this operation was about 1G tons. The hole was sunk in ten months and a half, inclusive of stoppages, but exclusive of the time work hat} to be abandoned during the war. It is considered the new strike at Turffontein not only gives proof of undoubted permanency to the gold industry of the Itand, but also doubles the computations which have been made with regard to the ultimate value of the whole formation. This should give food for reflection to mining investors as to what might not be the outcome of putting down deep bores, say, on Thames and Coromandel "foreshores, and aljo as to how many thousands of pounds would, have been saved in the last. 30 if boring was done first ho ascertain if the indications below were such as warranted sinking shafts. SMELTING PYRITIC ORES. The question of successfully dealing with sulphide ores is one of great importance, especially as the working in most mines seems to get into Tefractory ore as they go downwards. Mr W. F. Koch, in a paper read recently before the Engineers' Society of Pennsylvania, claimed that instead, of being a deleterious ingredient, sulphur may often be a positive advantage, ■if the older methods, of treating such ores are abandoned and the gold is obtained by pyritic smelting- In this case the sulphur, instead .of being wasted by roasting it off, serves as. fuel, replacing an equivalent quantity of coke. The ores charged into the furnace are quartz ores, lime ores, quartz and lime ores, quartz and aluminous ores, all containing gold in varying , amounts and a small percentage of copper. Mixed with these are the pyritic ores, ringing from pyrites to pyrites with quartz, quartz witi pyrites, lime and pyrites, and quartz,' lime, alumina, and pyrites, Which form a fairly representative list of refractory g-old ores. TJhe furnace used is a simple water-jacketed blast' furnace, having , provision for collecting the waste heat, which is utilised for warming the blast. This blast should be just powerful enough to get a hot; zone right at the tuyeres, a greater supply of air being a disadvantage, since there is- then atendency to set up reactions in the descending column of ore and fuel. For similar reasons the height of ore above the tuyeres should not be too great. The charge consists of a mixture in the. following proportions of ores, such as those already mentioned: l > y,rites,vls per cent.; quartz ores, 45 per cent, (these usually contain lime and pyrites): lime ores, 2,0 per cent.; low grade matte, 10 per cent.; slag. 5 per cent.; coke, f> to 3 per cent.; and from 1 to 2 per cent- at charcoal, which costs at the furnace in question about half the price Of coke. The charge of fuel added is thus about 5 per cent. of the total. "Whilst the furnace is at work slag is run oft' continuously, whilst the matte which contains all the gold, silver, and copper in the original charge is tapped out from the bottom of the furnace as required. When the copper contents of such matte amount to 45 per cent, it is "standard," and can be sold to the large copper refiners, who will extract from it the gold and silver. It! this standard is not reached the matte is passed again through the furnace till it is enriched.to the necessary, degree , . The slag; contains only traces df gold and silver and is thrown' away. A complete plant, capable of treating 40 tons of ore per day, and .yielding ?, to 4 tons of standard matte, costs, it is stated, but a couple of thousand pounds, and stamp mills are not required, since it is unnecessary to pulverisp the ores before passing them into the furnace.