Goopaut.—Notes on Quartz Crushing at the Thames Gold-fields. 177 
process. This title will distinguish it from processes used on other fields. 
It is accomplished thus—the quartz, as it comes from the mine, is shovelled 
from time to time into a stamper box, in which usually work five stampers, 
of about eight ewts. each, at about seventy (70) strokes a minute. Water 
is conducted into the box to the amount of about eight (8) gallons per 
stamp per minute. The quantity of water varies aceording to the material 
operated upon, whether it be mullocky or not. A small quantity of quick- 
silver is poured into the box, to amalgamate the gold with which it may 
come in contact. In front of the box there is a perforated iron grating, 
through which the pulverised quartz, when fine enough, is forced by the 
impact of water caused by the continuous fall of the stamps. The constant 
outflow of crushed quartz and water from the stamp boxes is received on a 
table, having on it grooves or ripples, containing quicksilver and a large 
extent of amalgamated copper plates smoothly nailed on. This may be 
called the silver table; it catches a large proportion of the free or amalga- 
mated gold which escapes from the battery. The flow then passes over 
blanket tables, which arrest mechanically all the heavier particles. The 
blankets are frequently washed in tanks, to remove the rich deposit on 
them. The blanket tailings thus produced are treated in large berdans 
with quicksilver, one berdan being allowed for five stamps. By this means 
a fair proportion of extra gold is extracted fromthem. Settling pits are pro- 
vided beyond the blanket tables, so that, if deemed advisable, the tailings are 
saved for after treatment, or for sale to those who make it their special 
business to manipulate tailings. ‘The entire battery is cleaned up at the 
end of each crushing, or once a week, if the crushing be continuous. All 
the amalgam from the stamp boxes, from the silver tables, and berdans are 
carefully cleaned and retorted in cast iron retorts, to separate the gold from 
the quicksilver. The spongy gold is then taken out, and sent to the bank 
for melting. Such is the usual process resorted to for private or public 
erushings ; and the object of this paper is to criticise the modus operandi ; to 
point out what I consider its errors, and to suggest a method of working 
which is likely to prove more profitable. 
The engine-power required will vary according to circumstances, such 
as weight of stamps, size and number of berdans, and the amount of water 
required to be pumped. If each stamp be not heavier than eight ewts., 
and there is a berdan of five feet in diameter to five stamps, and water is 
required to be raised, say 20 feet, for battery purposes, one and a half 
horse-power to each stamp will be about the required power. I have 
known engines working beyond that, but it was not considered profitable, 
as the speed became variable, and a larger proportion of coal was consumed 
in comparison to the steam-power obtained. x 
