Odds ‘n’ Sods Part II: Sinking shafts in South Africa–hot, dangerous, and exhilarating

Earth scientists are a well-educated bunch, although we don’t always come across as clever when we’re five beers into our cups. Most geologists — other than self-taught prospectors — have some form of university degree. Many of my colleagues were so enamored with the University study-drink-drink-more-study-repeat routine that they did what I did, and went back to university to earn a master’s degree or doctorate on top of their undergraduate degrees. Clever bunch, geologists. But eventually, assuming you have no wish to be an academic geologist or a waiter, reality bites and some sort of salaried earth science career is needed to fund the pub breaks.

In June 1984, much to my surprise, I graduated with a decent degree. A few months later I was poking forlornly around the City of London, knocking on doors and handing out a naively-bad resume to any mining company that would take it. I got my break when Anglo American interviewed me minutes after I walked into their head office looking for anyone from HR to talk to. A month later I was on a plane to Jo’burg to start a three-year contract as a mine geologist in the deep-level gold mines in what was then the Western Transvaal (now Gauteng province). After two days in the city signing paperwork, I was shipped off to the small mining town of Orkney, where I was billeted in the single mineworkers hostel and unceremoniously thrown into the deep end as a shaft geologist on Vaal Reefs 5 Shaft (see part one of this story for more).

It’s hard to describe the former scale of the underground gold mines in the Witwatersrand basin. They were, quite simply, huge. Many have closed since my time; they ran out of ore or, partly due to their extreme depth, they became uneconomic to operate when the gold price fell off a cliff in the 1990s.

When I arrived in November 1984, Vaal Reefs had nine separate shafts going down at least 7,000 feet (2,134 metres) each, producing about 2.5 million ounces of gold per year. I ended up with the senior geological responsibility for No. 2 Shaft which produced 250,000 oz. of gold a year, 10% of the total mine production. The mine employed about 45,000 people, many of them migrant workers drawn from across southern Africa, with 20,000 or so working underground every shift.

Surrounding Vaal Reefs were three other large mines — Stilftontein, Buffelsfontein, and Hartebeestfontein— all similar in scale. Sadly, accidents were common, with about one death per thousand employees a year, and on occasion they could be truly disastrous. In May 1995, long after I’d left South Africa, a lift accident at No. 2 shaft killed 104 miners when the cage dropped 500m down the shaft.

Mine planning meetings were held in Afrikaans, a version of Dutch; no allowance was made for me, the English geologist, because of the fractious history between the English and Afrikaners. Luckily I spoke reasonable German so the Afrikaans wasn’t too hard to pick up. Underground we spoke Fanakolo, a pidgin of various Southern African tribal languages with some Afrikaans and English thrown in to the mix (I still have my English-Fanakalo dictionary.) I went underground up to 4 times a week depending on the needs of the miners, assiduously avoiding certain areas of the mine which I considered too dangerous because of regular seismic activity.

Ralph Rushton’s dictionary. Photo by Ralph Rushton.

My job as mine geologist was to supervise all geological aspects of the underground operations. Working closely with the surveyors, we mapped the advancing access tunnels, sampled the mine faces where the ore was extracted (although this was mainly done by the surveying teams), and interpreted the data so the miners were always “on” the ore body, or at least knew where their tunnels were relative to the ore. We also had drilling machines working for us, exploring ahead of the active faces to see if there were faults or folds, or pockets of pressurised water that might cause complications.

This is all routine stuff that most geologists can do in their sleep with adequate training. In South Africa, it was complicated by the depth of the mines. I never worked shallower than about 5,700 feet (1,737 metres) below surface, and spent most shifts around 6,000-8,000 feet (1,829-2,438 metres) down. The deepest I went was on a long-wall mapping training course at 11,500 feet (3,505 metres) below surface in the Carletonville mines between Vaal Reefs and Jo’burg.

With depth comes the natural geothermal heat from the rocks. The rock temperatures in the deepest newly-blasted faces could exceed 40 degrees Celsius. Well-ventilated tunnels might be in the high 20s, but poorly ventilated “ends”, ones that had sat for weeks not advancing, became fiercely hot and could get up into the mid-40s with high humidity. Oftentimes, you wouldn’t actually know how hot an end was until you got to the face of the tunnel to start work in the sauna-like heat. We took drinking water down in frozen two-litre bottles, which melted away merrily while we worked.

But vertical shaft sinking was by far the nastiest work environment I’ve ever experienced. It’s the digging of the vertical hole — thousands of feet deep — that serves as the main access to an underground mine. It’s the absolute sharpest, pointiest end of mining, with no room for error if things go wrong.

I spent about six months intermittently on-call as a shaft sinking geologist on a new, deep-level gold mine that was under construction near Klerksdorp. Vaal Reefs 10 shaft was a twin-shaft system —one for men and materials and cold air going down, the other for ore hoppers and warm air coming back out. The shaft was already about 3,000 feet (914 metres) down, headed for a final depth of 8,000-or-so feet, and my job was to be available to map the rocks whenever there was a long-enough break in the blasting schedule to allow me down, which happened every 45 vertical feet (14 metres) or so. “Available” meant any time, night or day. When the phone rang, the Master Shaft Sinker would be on the line telling you to be there in an hour, ready to go. I’d turn up in my little blue VW beetle (God I hated that car, but that’s a different story), get changed and hurry over to the shaft clutching my note book, ruler, spray paint and pen.

The No. 8 shaft at Vaal Reefs circa 2007. Photo by Ralph Rushton.

You climb into a 5-6 feet (1.5-1.8 metre) deep metal bucket called a kibble, and down you go, with whatever material or crap happens to be going down to the team at the bottom. To come out, you get in the kibble with whatever’s coming out. I once stood neck-deep in a kibble filled with five feet of greasy, cold, drill water (try pumping water 3,000 or 4,000 feet vertically … not easy, hence the need for large buckets during development.) Other times you’d be perched on the lip of the bucket with your feet on a couple of tonnes of rubble being hauled up out of the hole.

Going down a sinking shaft for the first time is a very strange experience. You drop through the safety trap door at the top, which is there to stop stuff falling down and killing people. The door closes behind you, and everything goes pitch black. The kibble didn’t run on side rails so there was no sound or feeling of motion. If the shaft bottom is deep enough, it’s totally silent until you’re a few hundred feet above the work platform and the drills. Then, in a sci-fi moment, you start to see the floodlights, and hear the unbelievable cacophony of noise made by the drilling and the cementing crews who are lining the shaft with steel and reinforced concrete lining.

The bottom of a 3,000 foot deep, 30-foot (9 metre) wide vertical hole, with eight rock drills going, is a hostile place. For a start, it’s cold. All the compressed air used in the rock drills is venting and decompressing, dragging the temperature down. Then there’s the noise: Imagine eight big rock drills in the front room of your house and you’ll sort of get the idea but not really. Sound wouldn’t bounce back from dry wall like it does from solid rock. I still suffer from slight hearing loss in my right ear, which I ascribe to being a 23-year-old idiot geologist who didn’t wear earplugs.

And lastly, there’s the constant rain of debris from the six-level working platform above you, where the steel work and concreting takes place. Gobs of partly set concrete, wood, bits of rock, the odd tool … it all falls to the bottom, so you’d better have your hard hat on and don’t stand too close to the shaft wall.

My work took 20-30 minutes to finish. You orient yourself to due north – the Master Sinker always knows where north is— and mark off every meter around the shaft with paint, like the numbers on a clock face. Then draw a circle in your note book, mark off the same numbers on it, and draw in the geological features relative to those numbers. Easy.

But take too long and drillers would get impatient and drop the drill rig (called a jumbo) down from the platform, and start drilling the next blasting round. Time is money in shaft sinking— the mine needs to start producing ore as soon as possible to recoup the huge capital outlay needed to build it, and everyone gets paid production bonuses to keep things moving. Geologists stop stuff from happening so we can do our work, which isn’t popular.

Once the drill jumbo is down and the drills are fired up, you’re stuck at the bottom of the shaft until they’ve finished a full round. The jumbo is essentially a mechanical octopus with a drill on the end of each leg that completes gradually smaller concentric circles of holes, each around four meters (13 feet) deep. At Vaal Reefs, a full blasting pattern took about three to four hours to complete. So if I took too long and missed the last kibble out before the jumbo dropped, I was stuck there, standing up for four hours, cold and deaf, with 20-30 guys and eight drills. A total nightmare, which happened a couple of times over the six months I was on call.

But on balance, I had it relatively easy. A colleague once told me his experience of working at Western Deep levels, which was heading down to a final depth of 14,500 feet (4,420 metres) below surface — two and a half miles— with two vertical shafts and an inclined adit to finish. He was mapping the second vertical shaft down at about 11,000 feet (3,353 metres). They’d begun to cut a mining level so he had a side tunnel to map. Stepping back into the shaft from the side tunnel, something landed a few feet in front of him. Surprised by it, he looked up and noticed the drillers all standing completely still as other objects landed around the shaft bottom. Somebody had accidentally let some steel H beams drop down the shaft and after falling 3,000 feet, bouncing off the sides of the shaft as they fell, they’d turned into steel lumps and had blown through the working platform like cannon balls. The drillers know there’s nowhere to run when something falls down the shaft, so their instinct is to stand still; they either get hit or they don’t. Luckily nobody was hurt.

As I said, nasty and hostile — that’s shaft sinking — but I’ll never regret doing it.

–Ralph Rushton is a geologist and has worked at mines and exploration projects around the world including stints in South Africa, Turkey, Bulgaria, Yemen, Iran and Pakistan. He is currently the president of Aftermath Silver (TSXV: AAG; US-OTC: AAGFF), a silver development company with projects in Chile and Peru. In his spare time, he writes about mining and exploration for his popular blog, urbancrows.com. He graduated with a geology degree from Portsmouth Polytechnic in the U.K., and completed a masters degree in geology at the University of Alberta researching the source of the placer gold in the Klondike.