GO 
minerals; and at the more complete plants the amount is less—probably from 2dwt. 
to 3dwt. per ton. Still, when an attempt is made to estimate the gold value of the 
tailings of such a district as Sandhurst, the figures become very large. Since 1860, 
some five or six millions of tons of quartz have been crushed, and if 4dwt. or 5dwt. per 
ton have been left in the quartz this would give a value of £5,000,000 worth of gold 
on or about the surface of Sandhurst, which, with our present appliances, cannot be 
profitably extracted. Where gold is locked up in mineral matter heavier than quartz 
there is a good field for those who are introducing scientific ore-dressing machinery, 
and they will at the same time collect any free gold and the quartz grains which 
contain sufficient gold to materially affect their weight. It is more than twenty years 
since my late colleague, Professor Ulrich, now of the University of Otago, tried to 
introduce into Victoria scientific ore-dressing machinery. Since that time hardly a 
year has passed without some one following his example. Yet, strange as it may 
seem, up to the present time a good ore-dressing plant does not exist in Victoria. I 
do not mean to say that there are not good plants, doing all that is required of them; 
but where refractory or complex ores occur there is a great waste of very rich material, 
and plenty of room for the introduction of true ore-dressing machinery, and it should 
pay handsome profits.” 
On this subject, the following letter and enclosure have been received by the 
Department from Mr. R. Murray Smith, the Agent-General for this colony 7 in London, 
viz.:— 
8 Victoria Chambers, Victoria-street, Westminster, S.W., 13th June. 1884. 
Sir, 
I have the honour to enclose for your information copy of a letter which I have received from 
Mr. Herbert Robson, B. Sc., on the subject of the extraction of gold from pyrites in the colony of Victoria 
by the process of levigation. 
I have the honour to be, Sir, 
Your most obedient servant, 
(Signed) ROBT. MURRAY SMITH. 
The Honorable the Minister of Mines, Melbourne. 
[Enclosure .] 
312 Rice lane, Walton, Liverpool, 7th June, 1884. 
Sir, 
I venture to trouble you with a few lines, having seen a statement in the Times about the extraction 
of gold from pyrites in Victoria. 
The gold in pyrites being free could, I think, bo profitably extracted by levigating the pyrites, 
previously very finely ground. 
Ihero is no reason why pig-iron and sulphuric acid should not bo made from the pyrites afterwards. 
1 he grinding and levigating of the pyrites, being purely mechanical processes, requiring neither 
chemicals nor skilled labour,‘could, I venture to express a belief, be done very remuneratively. 
With many apologies for trespassing on your valuable time, 
I beg to remain, &c., 
(Signed) HERBERT ROBSON, B. Sc. Lond. (Honors). 
R. Murray Smith, Esq., Agent-General for Victoria. 
Tlie letter and enclosure were referred to Mr. Newbery, who reported as 
follows:— 
Tlio gold enclosed in tho pyrites is in extremely minute grains. Tlie cost of grinding is great 
when carried far enough to liberate the gold, and in tho operation the gold is flattened and still further 
divided, so that it is easily carried away with the pyrites slime. 
At Walhalla, Mr. Henry Rosales ground the pyrites to an impalpable slime, and it then required 
treatment in the most perfect amalgamators to extract the gold. The slowness of tho process has pre¬ 
vented its adoption. 
.At tho Yarraville pyrites works the ground ore was silk dressed, but the loss, owing to gold 
u floating,” was very great. 
Very little of our pyrites is of any value for the manufacture of sulphuric acid, as, for the most 
part, it is arsenical. 
Amongst the many appliances designed to extract gold from its ores, which 
have from time to time been before tlie mining public, a recent invention by Mr. 
Rowland Jordan deserves special mention. Writing of this invention, Iron (November 
7th) says, “It accomplishes the extraction of tlie gold from the most refractory mineral 
combination without the application of fire or water, and it effects its object at a very 
moderate working expenditure per ton of ore. The ingenious process embodies four 
novel principles or conditions of treatment. In the first place, the ore is reduced and 
