See a few comments about the “Gold Cube” so thought I would tell its history and how it came about to be. Well its concept came from New Zealand, More specifically Tauranga Bay. Westport NZ. Yep good ole NZ.
Some years back now, when I moved to Westport, I got interested in black sand beach gold long before I got into dredging. I actually lived at Tauranga Bay which is 17 K from Westport. I had a mate out at Charleston by the name of Val Currie, actually Valentine, but he went as Val. Once I got over calling him a girls name, we turned into real good mates. Van ran and owned the Tourist Gold Mine at Charleston. It has a water wheel and fluming, and ran a set of four stampers, that crushed cemented black sand deposits quite a way in from the existing coast line. The mine was actively worked full time by his grandfather in the late 1800s early 19th century. Val was born and raised in Charleston and he to developed an interest in black sand gold mining, after all it was in his DNA. When he had grown up and Buller was starting to get a bit of tourist activity, Val being the entrepreneur he is, decided to resurrect the old stamper and develop a tourist mine, that also supplied him with a cash income via gold produced and sold. . The area had been pretty well worked over by his Grandad, mainly by tunneling and a few open faces. So he put up new fluming and did a lot of work, and eventually he had an operating 18th century Stamper Battery, complete with tables and copper plates, that all worked. In the summer his water supply had to be rationed. So he only turned on the wheel when he had tourists going through, gave it a couple of turns, the stampers went up and down a few times and the tourists were happy. Then it was water off… In the winter with much more water he could run the battery as a working mine and produce gold. His grandfather had mined out the richer leads, but there was plenty of lower grade ground on the claim that still produced reasonable gold. Often Val and and I would go into many of the tunnels and sample the support pillars left behind, to support the roof. Man it sure was rich ground the old boys had. The cave weta"s didn’t worry us, and trust me there were plenty clinging to the roof. Eventually Val open casted some of the tunnels, but retained plenty for their historical value. And of course to let the tourists have a nosey in. No PC Health and Safety crap in those days. .
Val taught me all he knew aout black sand gold mining, he was a wealth of knowledge. Testing black sand with a gold pan is next to useless, And the D shovel method is the way to go. You take a sample with the shovel, then with plenty of water you wave the shovel in a circular motion, whilst at the same time going back and forwards. In a matter of no time you are left with the heaviest minerals which are zircon and garnet and the gold. You are then able to actually count the tiny fly shit specs of gold and get an idea of the grade of the ground. If there are to many tio count, you are onto real good ground.
I studied the tables closely and how they were designed. Charleston was actually first discoverd for it black sand gold deposits on the current Nine Mile beach. This was worked by Shetlanders who came out from the Shetland Islands late 18th Century. They used what are called beach boxes to catch the black sand gold. They were lined with copper plates that mercury was run over and rubbed gently in, the mercury sticks to the copper, the black sand was run over the plates and the gold was caught by the mercury. Becoming amalgam. After a time the mercury becomes what is termed “Sickened” to cure that each day prior to mining a well versed miner used to piss on the plates. For some unknown reason, piss used to vitalise the plates and they were ready to do their work abd catch gold. Maybe it was the nitrates in human urine. A good chemist would know. Anyway it works. I guess it was stumbled on accidentally. I can visulise some miner turning up in the morning to work his tables, with a stinkin hangover after a night on the grog. Bladder full, so takes a piss on his plates and holly hell, it helps his plates catch more gold. Thats why black sand goldminers drank lots of grog. They need to pee a lot eh. Thats a true story. Even Val adopted the practice, but was unable to ever get his missus to squat on the plates.
Of course eventually the mercury was so full of gold it couldnt hold any more. That was when the amalgam was scrapped of, and retorted to obtain the gold. The copper plates were then re-applied with fresh mercury and ready to do their work again.
Now what made this system work was called Boil Boxes, I will attach a diagram to assist as to how they work. The boxes are placed.along the tables. There is a slat in them. The water containing the black sand and gold, goes along the table, it then has to run underneath the slat and comes out the other side. Now as the table is set at an angle and there is some back pressure the waterr trys to climb to its former level, but it cant and it collapses. And continues on its journey to the end of the sluice or table, going through several Boil boxes as it does so. Now this raising of the water, in effect creates a column, that is slightly higher than the table it is going to spill on. In effect you have created a gravitational column.and gravitational Columns sort specific minerals into an assemblage due to their individual density and weight. So simply put this causes, the lighter material to climb to the top of the column and the heavy ones are retained at the bottom of the column. As it moves forward, the gold being the heaviest and being at the bottom hits the mats or mercury first and is captured. Thats why the majority of the gold in any system is captured just after the riffles or Boil Boxes. By the time it gets to the end of the plate, it is all jumbled up again. So through another boil box it goes and the process is repeated. Etc etc.Clear as mud hope eh. Right that will do for now. Its not far off my beer time, and my plates have sickened somewhat so I need to make up a good strong brew for them in the morning. Speights works pretty well, but Ranfurly Draught works pretty good to and is cheaper.
To Be Continued. . , .