248 FANNING AND EDDINGFIELD. 
assays indicated about 80 per cent extraction, whereas the solu- 
tion assay showed an extraction of only 13.6 per cent. There- 
fore, the solution assay was used, and the assays of the tailings 
were discarded in all samples; except the last, where it was 
possible to filter the whole of the tailings and sample accurately 
after the usual washing and drying. In these last samples the 
tailings checked closely with the solution assays. 
As shown by Table XXIX, there is an extraction of 13.6 per 
cent in one hour, and this increases with time until in ninety- 
eight hours there is an extraction of 78.8 per cent with a cyanide 
consumption of 2.17 kilograms (4.8 pounds) per ton of ore. It 
is to be noted that after fifty hours the extraction shows no 
increase whatever, even though the time was continued up to 
ninety-eight hours. It is probable that the inefficient agitation 
had much to do with the relatively low extraction, and that 
further tests (not possible with us owing to lack of samples) 
with proper agitation would give an extraction equal to that 
obtained in similar tests on lot 1. 
TABLE XXXI.—Summary of cyanide tests. 
. 7 . Total 
Extraction by amalga- | Extraction by 
Product. Mesh. mation. cyanidation. ener 
Per cent. Per ct. |Hours.| Per ct. 
Original _-_____-_- Not amalgamated_-_____- 25.0 24) 25.0 
1 59.8 96.8 48 | 98.8 
Dore Ne: 1. eee about — — 
300 pesos per ton for the 
2 59.8 97.4 96] 99.1 
sample taken. 2 Wes eene 
through 150- 
Hea 3| Notamalgamated_| 79.9} 24] 79.9 
4 | Not amalgamated -_| 98.0 96} 98.0 
1 38.5 57.0 48 | 73.4 
Original through |__| ene 
60-mesh. 
2 38.5 82.3 96} 89.0 
1 41.6 95.4 
Greil coreue = 
Lot No. 2. Assays about SN 
110 pesos per ton. 2 41.6 96.5 
13.6 
1 | Not amalgamated -- 
92 per cent 
through 150- | 2 | Not amalgamated _- 
mesh. (REEF ee dene WM ry! | mer | = 
3 | Not amalgamated -- 5 
