141 
The following report has been made by Mr. Bayly on a large sample 
procured by Messis. Laidlaw and Skene: — 
Steatitic slate, dark coloured. 
Total weight of sample received, 14 lbs. 
The material was broken down and crushed to obtain a fair sample. 
This was analyzed, and a series of cyanide tests were made on it 
(No. 290). 
Assay value of bulk— 
oz. dwt. gr. 
Gold ... ... ... o i 23 per ton. 
Silver ... ... ... 00 11 per ton. 
Owing to the low value of the gold no amalgamation extraction was 
made. 
On attempting to- treat with cyanide in the ordinary manner it was 
found that owing to the extremely fine nature of the material it became 
quite impervious to solution. No percolation was possible. To render 
the test effective the sample was then thoroughly mixed with an equal 
weight of coarse quartz sand free from gold, and again treated with 
cyanide solution. Even with this assistance the solution would not pass 
through the vats, and it became necessary to use a reduced pressure or 
suction. The experiment was then carried on as usual, with the follow¬ 
ing results : — 
v Stength of cyanide solution, 0.24 %. 
Alkali required, 5 lbs. lime per ton. 
Time. 
Gold. 
Cyanide 
Consumed. 
hours. 
oz. 
dwt. gr. 
Extractions — 24 ... 
0 
0 22 
24 lbs. KC 
48 .. 
0 
0 17 
... 1.5 „ 
96 
0 
i 0 
. . • - 
0 
1 18.7 
= 97 % 
Assay of residues after experiment, o oz. o dwt. 4.3 gr. gold per ton. 
Cyanide consumed, 3.9 lbs. per ton. 
It will be seen that in 18 hours a payable extraction was obtained = 
o oz. 1 dwt. 15 gr. 
An extensive test as to the best methods of treatment would be neces¬ 
sary before advice could be given. This test, together with the second 
experiment (see below), serve to show that the gold present is amenable 
to treatment and is recoverable by cyanide. The residues after the ex¬ 
periment contained only 4.3 grains of gold per ton. 
A further sample was treated with cyanide and agitated by mechanical 
stirring for several hours. The solution was then filtered off through a 
vat-filter bed. 
Strength of cyanide solution 
Alkali required ... 
Assay of original ore 
Assay of residues 
0.24% 
5 lbs. per ton. 
o oz. 1 dwt. 23 grs. 
o oz. o dwt. 5 grs. 
Gold extracted ... 
Cyanide consumed 
12779. 
o oz. i dwt. 18 grs. = 90% 
3.35 lb. per ton ore. 
