316 
PROCEEDINGS OF SECTION B. 
(11) Moderately fine crushing is as necessary as it is for 
ama] gamation. 
(111) The roasting should be done in reverberatory furnaces ; 
oxidation of the sulphur should be complete ; and with 
heavy sulphuretted ores the salt should be added only 
after most of the sulphur has been driven off. 
(1v) 
The ore should be leached in shallow charges, and the 
solution passed through continuously and rapidly. Time 
is a factor of importance all through the process. 
(v) If possible (and the writer believes it is possible), the 
use of wood vats and tanks should be avoided. 
In this 
climate it seems almost impossible to keep such large 
wooden vessels tight, even for a few hours of emptiness. 
Table I. 
: ‘ Mill Ex i calculated 
é Material Assay value ERED ces after-— 
Vat. preatecl of Roasted 
Ore per ton. | 
Hypo. | Extra. Hypo. Extra. 
OZ. per cent. | per cent. | per cent. | per cent. 
A Tailings is. 18°75 U8 73°9 265 65:0 
B Tailings ... 19°60 71:0 75:0 58°1 68°4 
C Tailings ... 20°90 74:4 80°7 32°1 47°5 
D One serene: 71°85 86°36 87°96 85°95 83°53 
E Ore we sess dss 68°25 84°25 SOests) |) chasavone SY) 
F K, reroasted atl) 81:08 83°36 86°06 90:2 
G Flue Dust G28) |||  acdaonode 81°15 82-2 84:29 
Ee a sOrem eae ie 73.00 80°35 88:43 86°58 85°39 
J Ore? tee 71:50 74°69 90°42 80°84 56°00 
K Ore) i iieeeee 85°90 84°25 87°84 53°26 89:00 
L Ornensoccayecs 68°25 84°47 86°89 43°08 85°06 
M Flue Dust 78:05 76°62 US IY) = || sooncosce 79°12 
Table II.—Value of Precipitates. 
Silver Gold 
Lot. aco) (oz. per ton). (oz. per ton). Remarks 
1 1104955 2,432 2225 Wash-water and weak solution. 
2 12°3 8,550 5°25 Regular sulphides. 
3 6:0 4,100 4°6 0. 
4 W287) 907 0°8 Wash-water. 
5 57 12,025 | 12°8 From ordinary solution only. 
6 5°5 6,305 | 4:45 | Regular, 
U 7°85 122919) i 15:0 Same as No. 5. 
8 3°85 HOP) | bye | Regular. 
9 8:1 2,631 | 2°22 Regular and wash-water pre- 
| cipitates mixed. 
10 oul 2,273 | 2:0 do. do. 
