C.-2.

43

Parcels Nos. 258 and 259, picked stone containing quartz, iron-pyrite, blende, and ruby silver. Parcel No. 261, slag from cyanide bullion from Waiorongomai. This slag contained too much copper to permit the evanidal ion of the residue. I'areel No. 262/l", X. D, three samples from Mount Zeehan, Thames. 262/1: Net weight, 2,293 Ib. of quartz with blende, galena, pyrile, and chalcopyrite. The ore was crushed and concentrated. Although fine gold was intermittently seen on the Wilfiey table practically no amalgamation took place on the plates on account of the heavily mineralized nature of the ore. The values of the various products were as below : —

The weight of concentrate saved was 12'25 per cent. About 60 per cent, of the gold, silver, and lead values arc in the concentrate. Parcel No. 262 X. —Net weight, 567 lb. of very heavily mineralized ore, chiefly galena, blende, pyrite, and chalcopyrite. The values of the products obtained after crushing were as under : —

The weight of concentrate saved was 43'7 per cent. It contained 75 per cent, of the original bullion and lead values. The high value of the slime was due to fine mineral, which could, however, be decreased by the use of a slime-table. Parcel No. 262/1). —Net weight, 1,390 Ib., consisting of mullocky quartz with the usual sulphide minerals. This parcel was crushed through a 25-mesh screen and concentrated and graded as in previous parcels.

The concentrate was 13'7 per cent, of the original, and contained 60 per cent, of total bullion values and only 30 per cent, of the lead. The low lead-extraction was due to the intimate mixture of galena with the quartz, and renders the further subdivision of the ore necessary. The sands from the three parcels aggregated 2,5711b., carrying 9 dwt. gold and 2 oz. of silver per ton. After treatment for four days with o'3-pcr-cent. solution of cyanide, 50 per cent, of the silver and 55 per cent, of the gold were extracted. After three more days' treatment the total silver-extraction was 55 per cent, and gold 61 per cent. The low extraction was due to the presence of sulphides in the sands. Gyanidation, of Slimes. —The slimes were agitated in a B.M. tank with air for forty-eight hours. Original assay of slimes: 16 dwt. gold, 4 oz. 6 dwt, silver, per ton, valued at £3 12s. 6d. per ton. The residue assayed 2 dwt. gold, 10 dwt. silver, per ton, giving an extraction of 87 per cent, of gold and 89 per cent, of the silver. Cyanide-consumption was 2 lb. per ton. Gyanidation of Concentrates. —loo lb. were slimed and agitated with o'4 per cent, cyanide. Original assay, 3 oz. 2 dwt. gold and 13 oz. silver per ton. After three days' agitation the residue assayed 5 dwt, gold and 10 oz. 5 dwt. silver per ton. This shows an extraction of 92 per cent. of the gold and only 20 per cent, of the silver. A stronger solution for a greater time results in a higher silver-extraction. Cyanide-consumption, 17 lb. per ton.

Sample. Gold, per Ton. Silver, per Ton. Value per Ton for Gold and Silver. Lead, por Cent. Zinc, per Cent. Copper, por Cent. Original Sand .. Concentrate Slime .. Overflow Oz. dwt. 1 6 0 9 6 15 0 9 J 0 7| Oz. dwt. 4 0 1 2 19 10 3 0 2 0 £ s. d. 5 12 0 1 18 1 28 19 0 2 4 0 1 14 0 2-40 0-68 8-97 0-77 0-38 2-82 1-14 13-38 2-62 1-97 0-76 0-19 3-61 0-38 0-37

Sample. Gold, per Ton. Silver, por Ton. Value per Ton for Gold and Silver-. Lead, per Cent. Zinc, per Cent. Copper, por Cent. Original Sand Concentrate Slime .. Oz. dwt. 4 10 1 7 7 18 1 15 Oz. dwt. 17 10 6 12 27 18 10 10 £ s. d. 19 15 0 (i 1 2 34 7 9 8 I 0 13-25 2-50 22-20 10-60 1648 10-20 22-13 12-71 2-78 1-47 4-93 2-31

Sample. Gold, per Ton. Silver, per Ton. Value por Ton for Gold and Silver. Lead, por Cent. Zinc, per Cent. Copper, per Cent. Original Sand Oz. dwt. 0 14 0 7 3 2 0 5 Oz. dwt. 3 10 2 2 13 0 1 14 £ s. d. 3 3 0 1 12 2 13 14 0 1 3 5 3-18 1-93 6-75 2-12 4-43 2-21 14-94 2-49 0-50 0-20 3-24 0-10 Concentrate Slime ..