by Jim Richards
I heard a snap and the boulder came at me in an instant. It hit the water with an almighty splash and I reeled back just far enough for the boulder to miss my foot as it hit the bottom where I had been standing.
The sling had slipped through its holding clamps and broken loose. It could have been a nasty scenario and the near miss shook me up a bit. We were so isolated I shuddered to think what could have happened if my foot had been caught underwater by the boulder. I would have hoped for it not to rain, I suppose.
I avoided finding myself under any more boulders after that, and we put a double clamp on the sling. A diver a week was dying in Guyana. I didn’t want to be that week’s statistic.
Charlie had got a shock too. The freed cable had whiplashed back at him and was luckily stopped by a tree, or it could have taken his head off. We put a thick, wet hessian sack on top of the cable from then on; known as a dead man, it would absorb the energy in case of another break.
As our boulder moves unfolded, we quickly got into a mess. The discard area was full and the travel route for the remaining boulders was blocked. We were starting to double- or triple-handle certain boulders, which was wasted effort.
I got out some paper and planned the moves. It was like a game of underwater chess, thinking ten moves ahead. I had been the best in my school at chess, which had counted for nothing at the rugby-mad Brecon, so it was satisfying to be finally using that previously unappreciated ability.
Next morning we began the moves. The rocks were about a third lighter underwater due to buoyancy, which helped a lot. But once you pulled the boulders out of the water they became a lot heavier and harder to handle.
We proceeded well and in two days had cleared the entire area and opened up a decent amount of gravel that had underlain the boulders. It looked like good diamond gravel too; indurated and poorly sorted.
I started dredging and, as usual, to test this new material while diving, I scooped up a handful of fine gravel and held it in the palm of my hand. Then, simulating the action of the gold pan, I winnowed away the lighter material, leaving the heavies to be observed in my palm. So far I had never seen any gold. But as I tested this lead, I looked at my hand and could not believe my eyes. There was a half-inch tail of gold in my palm, which meant it was very rich dirt. I was on the gold.
We washed up that afternoon, starting out with the diamond sieves.
Coarse sieve: nothing.
Medium sieve: two diamonds; clear, colourless stones, each one over a carat.
Fine sieve: numerous smaller stones, mostly of good clarity and colour.
We were elated, and when we went to wash the batea it was yellow with fine, floury gold. We were having to pan very carefully to ensure we didn’t lose any.
This was more like it.
By the end of the day, we had found about 7 carats of first-rate diamonds and over an ounce of gold. In today’s money these would be worth around $5,000. An outstanding day: I had recouped many of my costs in this one short session.
The next morning we had an excellent opportunity to test how the sluice box had been performing by re-treating the tailings from the rich gravels mined the day before. Sluice box recovery was of critical importance. A 30 per cent recovery (recovering 30 per cent of the gold and diamonds from the material treated, with the other 70 per cent being lost over the end of the sluice box) would be a disaster. A 60 per cent recovery was poor. An 80 to 90 per cent recovery was good, and was my target.
Up until now, I had been checking the sluice box recoveries by separately washing the material from the top and bottom halves of the sluice box. We always found nearly all of the gold and diamonds in the top half of the box, which was a good sign; now I could do a better check.
The tailings (material that dropped off the end of the sluice box) were easy to re-treat as they were already correctly sized for the dredge and, after only half an hour, we had them all sucked up. We washed up and indeed did find about 10 per cent by weight of the diamonds we had discovered the day before. Thus our recovery was probably about 80 to 90 per cent.
I was also pleased that this re-treatment only found smaller stones and very fine gold, which proved we were capturing the bigger diamonds and the coarser gold first time around. Recovery of the ultra-fine floury gold was probably only around 40 per cent and was always going to be a problem with such a short sluice box. There wasn’t much I could do about that, so I didn’t worry about it.
Next we went back over the gravel concentrate (the material retained by the sluice box) that we had sieved and discarded the day before. In the exhilaration of a good find, you can get a bit sloppy. Sure enough, upon resieving we recovered another 10 per cent by weight of diamonds.
I was a bit surprised and concerned by this, as I had figured we were being most assiduous in our picking. Offsetting this problem, the diamonds from this second pass were the smaller stones of poorer quality and colour (such as brown) that were more easily missed and worth considerably less.
One stone of a decent size (0.75 carat) was totally covered in red iron oxide, which is why we hadn’t seen it. When I scraped off the iron, there was a perfect, colourless diamond inside.
We were starting to do well, but I was now suffering from persistent ear infections due to the constant diving; I had been doing about seven hours in the water every day for six weeks. Like most Guyanese, Charlie couldn’t swim, far less dive, so it was all on me. My ill-fitting wetsuit was taking its toll and my ears had been wet for so long that the earwax had lost its waterproofing capacity and bacteria had taken hold.
It was time to take a break. We were nearly out of food, fuel and just about everything else anyway. As a bonus, Sarah was due to arrive in Guyana the following week on her youth charity trip. So it was a good time to stop and, despite my dalliance in Georgetown, I was looking forward to seeing her.
Before we packed up, we had to do a final separation of the gold. Every day of mining, we poured the black sand and gold concentrates from the batea into a large jar that contained mercury (locally known as quicksilver or silver).
Alluvial gold miners the world over face the same problem of trying to separate the fine gold from the other heavy minerals (black sands). The finer the gold, the harder it is to separate, and when the gold is as fine as flour much of it can be lost. To counter this, mercury is used to assist in catching and separating the fine gold.
Mercury is the only metal that is a liquid at room temperature. It reacts with gold to form a soft, heavy, silvery coloured amalgam (mixture).
I recovered my amalgam by washing away the black sands (which do not react with the mercury) in the batea, leaving the heavier bead of amalgam at the bottom of the pan. This was a danger point for dredge owners, as enterprising panners could try and steal gold by pressing the amalgam under overgrown fingernails, to be retrieved later.
I pressed the amalgam into a small iron mould. At this stage, in order to ‘burn off the silver’, as the Guyanese would say, they would place this mould onto the camp cooking fire, and the mercury would burn off, leaving the pure gold.
This was near suicidal, as mercury is highly toxic. For every gram of gold produced, 2 grams of mercury were getting burned off, and many of the miners in Guyana had strokes or tremors in their forties (the ones who lived that long), presumably caused by mercury exposure. They were not just poisoning the environment, but each other.
I took a more cautious approach and made a rough retort from a long glass bottle and a jam jar (tins would react with the mercury), which allowed the recycling of the mercury and the protection of ourselves and the environment.
After retorting off the mercury we were left with a 3-ounce slug of gold (worth around $3,600 at today’s prices): enough to pay for the flights, fuel and food.
More encouragingly, we had about 10 carats of diamonds: good stones, too. I was paying Charlie 5 per cent of whatever we found, and Cyrilda got 10 per cent as a royalty for letting us work her claim. For six weeks’ work I wasn’
t getting rich, but I had turned a modest profit. It was an encouraging start.
We packed up all the gear and stored it at Colin’s camp for safekeeping. Cyrilda had a plane coming in that afternoon and we were eager to be on our way back to Georgetown.
Back in town, Cyrilda and I agreed on the stones she could keep as her royalty and I took the gold to be sold at the local buyer. He took the slug and put it under a blowtorch to ensure all the mercury was gone – some miners would try to bolster the gold weight by only half burning off the mercury, or even by placing lead inside the gold.
I got my money for the gold, gave Charlie his share, and had some dollars in my pocket, plus 90 per cent of the diamonds.
I knew a lot of the expats in Georgetown. Somewhere along the line, they’d started calling me ‘Jungle Jim’, and a number were most interested in my mining operation. Several of these were also keen to buy a few diamonds. I found this to be a lucrative line of sale, as I could sell the stones to the expats for twice what a local buyer would pay me. This helped my bottom line considerably.
A couple of days later, Sarah flew in. She was no longer working at Disney World and was now based back in the UK. It was lovely to be with her again. I was hoping to get her up to Ekereku, and we sorted out some dates when she would be free from her charity obligations.
We spent that evening at Palm Court. It was wonderful to catch up on her news and find out what was going on back in Britain. This was 1991, and communications were difficult out of Guyana. Even international phone calls had to be pre-booked days in advance with the telephone exchange.
Sarah and I spent a couple of days together and had fun touring around the sights. The zoo filled me with mixed emotions, with its extensive collection of native animals that included a number of jaguars. The management were trying, but the place was run on a shoestring. This was the kind of sponsorship opportunity a foreign mining company these days might pick up as part of a wider conservation and education initiative. Back then there were no takers – the thought would not have even occurred to the wealthier local miners.
Most of the travel around Georgetown involved the local minibuses and endless chatter among complete strangers. One topic was always popular. Guyanese people talk about the colour of their children the same way British people talk about the weather. The races were so mixed up and the lineage often so doubtful that this speculative theme provided endless entertainment. One popular theory to help the country overcome its simmering racial tensions was for everyone to just procreate with each other until they were all the same colour. There was plenty of trying.
Sarah then returned to Georgetown, to go and build something at a leper colony.
I threw myself into preparing for the next trip. Once more in town, among the hardware stores, I had to control myself. All of the spare parts and odds and ends I had needed, I could finally buy. I had to be careful though, and not spend all of my hard-won and modest profit.
My favourite shop in town was Rafferties, in Charlotte Street, a blacksmith’s that fabricated mining equipment. They did a great job making some of the items I needed, and at a fair price too.
I was fortunate to have a reasonable place to stay in Georgetown, as housing and services there were basic. Guyana, in the Amerindian language, means ‘Land of Many Waters’ and the locals treated their plumbing accordingly. Mains water was only on for a couple of hours each day, so people just kept their taps on with buckets underneath to ensure they could wash at night. This just exacerbated the problem. You also had to boil all drinking and cooking water or you caught dysentery. Likewise the electricity supply was intermittent. For cooking, people used bottled gas if they could afford it, or more commonly kerosene stoves, which led to some horrific burn accidents.
After two weeks, Charlie and I were ready to go mining again. I was well rested and my ears appeared to be healthy.
We only needed half a plane this time and Cyrilda used the other half, which helped cut costs. We flew into Ekereku, headed back to the falls and got stuck into it.
We fell into the old routine, but struggled to find much. After two weeks of almost nothing I was tempted to once again target a boulder field: higher reward, higher risk.
We started working on an area I had been eyeing off greedily. It was a difficult place to operate, as the boulders were jammed into a gap about 3 metres wide between two rock bars that jutted out into the river.
There was also nowhere to put the boulders, so as we worked we piled them up high on top of each other, forming an underwater ravine. Remembering my earlier close call, I carefully chocked each boulder with rough wooden wedges. It was nerve-racking when you were diving with the precarious boulders high above you; if a chock gave away you could be horribly trapped. The demise of Cyrilda’s diver earlier in the year was always at the back of my mind.
Even so, the area was becoming richer as we moved towards the bank, and I was happy with what we were finding, despite the slow progress.
The following day, Sarah flew into Ekereku on one of Cyrilda’s flights. She was in for four days and the whole mining experience was transformed into enormous fun by having her around to share it with. As an added bonus she could also scuba dive, so I got another diver to help out: talented girl. We continued dredging on the line of boulders.
A couple of days later, after an early start to the diving, I groped forward with my hand under the boulder train ahead and I felt the bedrock disappear. This was encouraging. Any hole in the bedrock had great potential – above all for potholes, which could hold mineral bonanzas.
Eagerly we moved the boulders out of the way with the winch and continued dredging. This was getting easier as we could now dump the boulders into the areas we had already worked, so the ravine problem was mitigated. The gravel looked really good: dark, indurated and full of black sand – the best I had seen.
The hole I had spotted got bigger, and then I felt another one. After some more boulder removal, we had uncovered two circular openings about 70 centimetres in diameter in the riverbed: potential potholes.
Potholes form in the bottom of rivers. They start off as zones of weakness that are preferentially worn by the action of water and entrained rocks. This weakened area continues to erode until it is large enough to hold small pebbles; this material then swirls around the bottom of the hole, powered by the water current. This pebble circulation accelerates the erosion and further deepens the pothole. The sand created by attrition of the bedrock and pebbles gets flushed out of the hole. New pebbles drop in to replace the eroded ones and the process continues indefinitely, deepening the pothole as it goes.
During this erosion phase, the pothole is described as active. It can be active for many thousands of years, and for all this time gold and diamonds will be dropping into the hole from the river. Because the gold and diamonds are heavier than the quartz sand, they don’t get flushed out, and this causes a gradual build-up of these minerals in the pothole. Diamonds are further concentrated by being extremely hard and resistant to abrasion.
The longer the pothole is active, the higher the diamond and gold concentrations may become. This can give rise to some immense bonanzas, or ‘jewellers’ boxes’ as they are sometimes known. Some of these potholes on the Orange and Vaal rivers in South Africa have delivered diamonds worth tens of millions of dollars.
The build-up of gold and diamonds in the pothole will continue until river conditions change or the pothole is no longer active. By this time, the pothole may be completely or partially filled with rich ore. The bonanza will finally be preserved when the pothole is sealed by boulders, emplaced during a flood.
However, more often these changing river conditions will either flush out the pothole or totally erode it, thus destroying the prize. And most potholes do not even concentrate the gold and diamonds in the first place, as they are continually flushed out.
Only a small proportion of potholes will concentrate and retain the bonanza grades of gold and diamonds – maybe 1 to
5 per cent of the potholes, depending on the river. These were the prizes we were after; they did not get flushed out and they did not get eroded, they formed in just the right part of the river to collect and retain gold and diamond bonanzas: the Goldilocks zone.
I directed the intake nozzle and started sucking at the gravel on the nearest circular feature. It was perfect-looking material and appeared to have been there for a long time. As the gravel was sucked away, a pristine circular pothole about half a metre in diameter opened up. Impatiently I dredged away at the material within the pothole, throwing out the oversize cobbles as I went.
I surfaced and turned down the engine to look at the riffles in the sluice box.
My heart started pounding. ‘Look, Sarah, gold! See it?’
‘Yes, I see it. That’s incredible. What are you working?’
‘Potholes; two of them, I think, and they look bloody perfect. Both of you, just make sure the sluice doesn’t get bogged up or flushed out, and I’ll clean out the first hole,’ I said, and put the mouthpiece back on.
I got the thumbs up from Sarah and Charlie and I ducked under. I was soaring with adrenalin. We were on it.
After about an hour’s dredging I was about 1.5 metres down into the pothole and the gravel still looked excellent. It was getting harder and harder to work in the tiny space. I was headfirst fully inside the vertical pothole, with the 4-inch suction hose, and there was literally no room to move. I didn’t care; nothing was going to stop me cleaning out this hole. I shifted my arm a bit and, without warning, I was stuck, solid.
I tried to move left, then right; I was wedged in tight by the hose. With rising panic I started to struggle, but this just packed me in tighter. It suddenly felt as if I was getting no air. I sucked and sucked on my mouthpiece. The panic rose further.
I had to get a grip on myself. If I continued panicking, I would die. With all the will I could muster to keep on top of my gut-wrenching fear, I stopped moving. I controlled my breathing and kept it to an absolute minimum, allowing the air to build up in the reserve tank. It was the panic that had compromised my already limited airflow.