WASHING ALLUVIAL GOLD.

WASHING ALLUVIAL GOLD.

A Simply-constructed Cradle.

DEAR "Martingale,"-Could you or any of the team supply me with some information concerning the construction of a cradle for washing gold out of alluvial dirt? The cradle we have in mind would be about three feet long, and that would be quite large enough. We would prefer one made of fiat iron rather than wood and would appreciate a sketch-plan if one is procurable.

CHASING THE WEIGHT, Narrikup.

Not being a mining man I had to refer your query to the Mines Department, who kindly supplied the particulars and the plan shown here.
The construction of one of these contrivances is quite simple. The body consists of a wooden box about 3 feet long by 18 inches by about 15 to 18 inches high, inside measurement.
The front part of the box is cut away as shown in the sketch attached, and an inclined apron board, B, extending the full width of the box is fixed on the inside. On the bottom of the box was nailed two rockers, D, being merely two curved pieces of wood (or steel if. preferred). The front rocker is slightly lower than the back one, in order to give an inclination towards the front. On the inside of the bottom of the box two or, three cleats, C, are fixed. ; A sieve or riddle box, ' A, is made 18 inches square, outside measurement and about 6 inches deep. The bottom of this
consists of ½ in. mesh screen. This fits into the top of the main box. The gravel is shovelled into the riddle ! box; the operator rocks the machine and pours on water. The dirt is carried through the screen and falls on to the apron, B, which is covered with blanketing or canvas. Some gold is caught on this. The dirt then passes from back to the front of the machine and the gold and heavy concentrates are caught in the cleats or riffles, C. Mercury is some- times placed behind the riffles to assist in collecting the gold.
To clean up, the" riddle is removed, blanket taken from apron and washed, and accumulation behind riffles scraped out.-"M,"



Western Mail
January 1938
http://newspapers.nla.gov.au/

The old apron gets people confused! They were removable for frequent cleaning, some had riffles some didn't, the canvas was far from water proof which helped the whole process.
Coarse gold if any, was always found in the apron, the bottom sluice would catch the fines.
Cheers.

a simple and wonderfull example of "form follows function". Nice post
Chimpy