73

a—3

When he first started this process of treatment he used to have a much greater depth of pulverised material in the vats; but he found that this did not leach satisfactorily, owing to the quantity of slimes, and therefore reduced the depth of sand to 20in., which, he states, gives good results. The solution, after being used, is pumped up into the tank and made up again to the required strength. It is tested by evaporating a small quantity of the solution, say 10oz., in an evaporating dish, and finding the quantity of potassium-cyanide it contains, and then an extra quantity of crude cyanide is added to bring it up to the required strength. There is no getting away from the fact that there is a certain loss of cyanagon due to its decomposition by the oxygen in the air, and probably this decomposition is greatest when the liquor is trickling out of the pipe which leads from the bottom of the vat to the tanks containing the zinc-shavings ; and in treating any ores having an acid composition they would tend to decompose the cyanagon and liberate hydrocyanic acid. This process is only yet in its infancy, and no doubt will be considerably improved on yet as regards the method of application. The cost of the crude cyanide is about Is. 6d. per pound.

Statement showing the Results of Working the Mines in the Ohinemuri and Waiorongomai Districts for the Year ended 31st March, 1893: —

11—C. 3.

Averi Nam' of Mon ploy age ber f For Owners. For Tj ibuters. Tailing! treated. I em'ed. « Locality and Name of Mine. Area. Value of Ore sold. a 9 3 do £ 5b a in r. o r, A H Quartz Gold crushed, obtained. Quartz crushed. Gold obtained. Quantity. Gold obtained. A. It. P. Tons. Oz. dwt. Tons. Oz. Tons. Oz. dwt. (hinemuri County— Maratoto—Maratoto Karangahake—• Ivanhoe and Truro Woodstock.. Crown Talisman Earl of Glasgow Diamond Imperial Sundry Claims Owharoa—Smile of Fortune Waitokauri—Jubilee Waitekauri North —Golden Cross Komata—Komata Gold-mining Company Waihi— Waihi Silverton 18 2 10 42 0 0 30 0 0 110 0 0 30 0 0 27 0 20 9 3 12 10 2 14 2 10 112 2 3 2 1 2 10 8 6 50 4 83 220 110 .394 5 4 3 6 480 140 2 2,000 138 0 467 0 45 0 28 0 27 0 15 0 26 4 168 0 102 0 29 0 115 109 576oz.; 5s. per oz. 51 tons ; £40 per ton 3,266 oz.; £2 per oz. 5J tons ; £33 per ton, 12 3 2 103 0 15 26 0 20 60 0 0 8 130 68 6,680 oz.; £5,632. 422 0 0 83 0 38 150 12 18,279 800 500* 0 29,681oz. 10 dwt.; £48,809 Is Id. Totals .. 991 1 17 373 22,526 11,545 0 245 177 'iako County— Waiorongomai—New Find Newshams 31 0 36 5 0 0 16 3 4 853 480 540 0 280 0 186 60 1,650 297 14 Totals 36 0 3G 19 1,333 820 0; 186 60 1,650 297 14