I would like to describe the modern day Banjo.
I hope my description of what a Banjo banker is can be understood. The banjo is what I use for prospecting and yes I only go for gold but if I come across a gem I will pick it up. I can shovel straight into the top hopper, which has the ability to wash most clays. I do not bend my back nor do I get wet hands and at times I can work in boots, with no need for gum boots. From the back of the top hopper to within 4 inches of the discharge end of the hopper runs a slick plate once the gold passes through the punch plate, it then falls and settles on the slick plate, water then moves the wash to the rear of the bottom hopper.
At this point it is meet with another deflection plate which places the wash into a tray designed and placed for that to happen. From the tray the wash then enters another slick area then meets the hydraulic jump which rolls back the cavitation {air bubbles} just in front of my riffle section. Then on through to the riffle section and out of the unit.
The advantages of the Banjo is the amount of material you can process, its ability to process most clays. Been portable with the ability to be moved within the working area. Been able to process the black sand without gold loss. Which all comes down to the amount of concentrate you have to clean up. It takes around 40 minutes to do a clean-up from start to stop. Is it not better to get 3 gram of gold from half a pan of concentrate. Rather than a 10 litre bucket full of concentrate.
How the idea of the Banjo Banker came about is unimportant but what I will say is the unit is the end result of the two pieces of equipment described below having been combined into one. The Banjo has used the slick idea from the Bush banjo and the retention style of the Wet Jigger. But todays Banjo is very different to the ones we first made which were used without any pumping required hence the name Banjo. Seeing as it was worked in the same manner as the bush banjo.
The Bush Banjo.
Back in 1936 I. Idriess wrote the below in his Book Prospecting For Gold. I now will quote a section from that book.
Dishing, Banjoing and Cradling. Chapter 3 page 16 through to page 18.
Having located payable ground, you procced to work it. Strip off the overburden with pick and shovel and throw it aside; but not on the ground you will want to work later. Overburden is the surface ground, in fact any ground which carries very little or no gold. You only want the very bottom, strip for a week, a month. How long depends on whether the storekeeper is pressing for your account. Then pick up the bottom and shovel it into a heap. Throw away any stones; there will be less to carry. If you are in Reef or specimen country, keep an eye on any iron or quartz stones you pick up from the bottom of the wash. There may be the odd specimen among the stones. If so, you can dolly them later and recover the gold, some forms of ironstone specimens are hard to distinguish; the gold is coated with a film of iron. As on a specimen field, some stones may carry a penny weight to twenty ounces of gold, you will soon learn to cast a practised eye on ironstone and quartz among the wash. specimen country is a term used for mineral country wherein reefs have shed numerous specimens down the gullies, creeks, valleys and flats. A specimen is a piece of stone, containing rich mineral, which has broken away from or been shed from a reef. Many alluvial fields carry specimens.
Cart, pack-horse, or wheelbarrow your accumulated wash-dirt to the nearest water hole. Not being running water the ordinary method of working is by Banjo or Cradle. A few hardened old-timers prefer to dish their dirt; but the process is very slow.
Banjoing is back breaking work. Still, in portions of Australia, particularly the far north, some men become remarkably proficient. A banjo is simply an open box, about 4 feet long. The head of the box may be 2 feet high, with the sides sloping to 6 inches. The width is 2 feet at the head, tapering to 18 inches at the end. This narrowing of the width is important. The bottom is covered by bagging. The tail of the box is open; but there is inserted a 2 inch ripple two pieces of board fastened across the tail to hold back the sands. The Banjo is placed, in a slightly sloping position, right against the edge of the water-hole. The digger throws a few shovelfuls of dirt well up into the head of the box. Then he steps into the water, grabs his prospecting dish, and throws a dish full of water into the tail of the box so that it rolls up to the dirt at the head and, partly dissolving it, comes back like a receding wave. This is met by another dish full of water and another and another until the dirt is reduced to the level of the ripple. There is then about an inch depth of heavy sands in the banjo. This is carefully scraped to the head of the banjo, a few more shovelfuls put in, and the procedure repeated. When all the dirt has been put through, the concentrates are put into the dish and washed.
There is a distinct knack in banjoing only acquired by practice. the idea is to keep the water striking the tail of the banjo so that, though the sludge runs out , the oncoming water carriers the heavier concentrates containing the gold back to the head of the box. The water can be used over and over again.
The Q.L.D Wet Jigger
Quote taken from the Department Of Mines, Sydney, N.S.W, A Guide Book For the use Of Prospectors in N.S.W. Fourth edition. 1933. Page 19
The Wet Jigger
The Wet Jigger is an efficient hand operated concentrating appliance used for the treating of alluvial material. It has been used for many years in Queensland and is rapidly coming into use in New South Wales. The Wet Jigger has many good points. It is easily made and is portable. Being well raised from the ground and self-discharging, there is little difficulty in disposing of tailings and hopperings. It is very easy to operate and has superior concentrating action to the cradle.
My Banjo
Now for the good news for our QLD members in regards to the new laws and such I am hoping to be able to present to those members a new way of sluicing that falls well within the state laws this should happen within the new year. But I will not make the same mistake as I did with the Banjo plans by the open display of them on the net. The plans of the idea will only be sent via pm. And I also will reserve the right as to whom I send them to.
