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Poutsch Freezing Process in Shaft-sinking. This process is one of the greatest feats of mining engineering of the present age. The great difficulty that mining engineers have to contend with in sinking shafts through quicksand is entirely overcome. No iron cylinders are actually necessary. The shaft can be sunk in the ordinary manner, and either lined with strong timber or with brick or cement; that is wherever pipes can be driven down. Within the last three years two shafts were sunk at Huntly, in the Auckland District, through from 60ft. to 80ft. of quicksand, which had large logs of timber in it. Cast-iron cylinders were used in sinking, but even with these there was a difficulty in carrying these down plumb. When the logs of timber were met with, one side of the cylinder would rest upon the timber, and when this occurred the shaft would go out of being plumb. The freezing process renders shaft-sinking in any soft material containing water now comparatively easy. It was adopted by Mr. Pcetsch in sinking some shaft in connection with the Belgian coal-mines. 4\fter-

Ore. Locality. Gold present by Assay. Gold extracted by Process. Gold in llefuse. Percentage obtained. Sheba tailings Mixed lot ... De Kaap tailings Reliance Reef quartz Bendigo quartz Day Dawn quartz, No. 1 No. 2 No. 3 Concentrated tailings Swazieland quartz ... City and Suburban ... Crown Ore... Transvaal Dwt. 48 24 331 11 1,789 130 22J 11 22 17 2501 76 884 30i 7i 84 17* 915 105 9* 28 40 107 164 42 2 54 19* 48 4,430 25 30 65| 28 4 14 14 143 14 118 1941 20* 38! 34{ 64" 138J lO" 17 21* 55 14 4 Dwt. 46 231 32|11 1,760 127 22 11 21 16 2411 71 779 28 6* 8* 14 834 96J 8* 23| 35f 102i 132 36 2 491 17* 43 4,200 22i 27 64 25 3f 13| 131 134 12 91f 184i 18| 36i 321 61 1321 9 19 21f 55 Hf 8* Dwt. 2 1 1 96 97 97 100 98 97 99 100 95-1-94 96 94 88 92 87 97 81 91 92 90 85 90 96 80* 86 100 91 89 90 95 90 90 97 90 94 98 95 93£ 86 78 95 90 95 94 95 95-1-90" 100 100 97 84 93f it • • • Victoria... Queensland trace *22 3 trace „ ... ... it „ ... ... South Africa Transvaal New Zealand (Silver) Transvaal 1 ■H 100 2 1 Transvaal Gold Exp. Co. „ tailings Mount Shamrock tailings „ ore (a) „ (b) Caledonian Extended „ tailings ... Mariner's Lode Ravenswood ore Golden Egg quartz ... Dick's Luck ore Glasdyre ore Loando Mine Bethango ore Cumberland tailings... Arsenical pyrites Concentrates Concentrated tailings Venus Mine Concentrated river sand Westward Ho Mine ... Lochaber Syndicated, No. 1 ... „ . „ No. 2 ... Astyra Mines Gipsy Queen Reef Per Mr. Jones New Organos (arsenical pyrites) Great Eastern Extended Devala Moyar Rio Grande Do Sul ... Indian Gold Mine Company ... Tinnamary Mines (a) Per Mr. Irvine Per Mr. Stranger Stafford Mine Queensland // • • ■ a ' •' New Zealand Queensland a • • • Transvaal South Africa Wales Dakota, U.S.A. ... Queensland Tasmania Wales ... Morgan Mine,Wales New Zealand Assam ... Queensland Nova Scotia trace 8i ::; 81 1 4i 4* 4 *32 5 nil 6* 2 *210" 2i 2| 2} * * 10 2 3 10 2 2 2 8 4 i ¥ trace i 4 2 2 Turkey ... Transvaal Spain Colombia, S.A. New Zealand India Brazil India French Guiana West Coast of Africa Anstralia U.S.A Monroe Edwin Bray concentrates Westward Ho Mine ... South Africa Queensland Dutch Guiana Ore trace * Three-fourth: of this gold can be obtained by a seco: id chlorinatioi