Goopaut..— Notes on Quartz Crushing at the Thames Gold-fields. 179 
inch at the bottom ; this enables the quicksilver and amalgam to be scooped up 
readily when cleaning up. It is usual to keep two ripples nearly as full of 
quicksilver as they will hold, and, when the lower one is too full, a part of the 
quicksilver is lifted from it and put back into the battery box. The length 
of the tables is about ten feet, and they are as wide as the front of the battery 
box. The blanket strakes below the silver tables are about 20 feet long; 
they are so arranged that a part of them may be washed from time to time 
without stopping the flow of water from the rest, or allowing it to go on the 
part from which the blanket had been removed. Instead of blanket, baize 
and coarse plush have been used with advantage. Shaking tables were not 
tried excepting at one battery. They proved very serviceable, but the wear 
and tear was great, and, as the miners were not willing to pay an extra 
price for its use, it was discontinued. 
The blanket tailings or blanketings, as they are otherwise called, consist 
mostly of iron pyrites and other sulphides, combined with quartz, and 
contain a fair proportion of gold and some quicksilver and amalgam that 
had escaped over the silver tables. These tailings are treated in berdans 
with extra quicksilver and ground up. The berdans now in use at the 
Thames, I think, exceed in size, those in use in any other gold-fields ; they 
are generally five fect in diameter, and I have seen one six feet. At one 
time a couple of rotating balls were considered sufficient for the amount of 
crushing required ; now, the general practice is to have a loose ball as well 
as a stationary one attached to a chain, and it is called a drag ball ; this 
drag does more work than a loose ball, but takes more power than should 
be used in grinding, for the drag grinds the bowl as much as the tailings. 
I am convinced that grinding and amalgamation can be better accom- 
plished in pans, such as Wheeler’s or Hepburn’s, than in berdans. Pan 
treatment, however, has the same fault as berdan treatment; in both cases 
the same material is continually re-ground, thus a deal of labour is lost, 
and quicksilver is used while grinding. This system accounts for the great 
waste of quicksilver at the Thames, and if quicksilver is lost, gold is lost 
also. 
This battering and grinding of quicksilver and amalgam seem to me to 
be the chief fault of crushing at the Thames. It is the basis of the system 
there, and I fear will not be stopped for some time. How many thousands 
of pounds worth of gold has been carried away with sickened quicksilver, 
it will be impossible to calculate ; but I am convinced a great proportion 
of it could have been saved. 
Having pointed out the chief errors of quartz-crushing, I shall, on a 
future occasion, shew how they may be avoided. 
