Journey to the Center of the Earth: Mponeng

My friend and colleague, Professor Ernst Breet at North-West University in Potchefstroom, South Africa, arranged for a very special trip to the Mponeng Mine for us recently. Mponeng (which means “Look at Me” in the local African language) is the world’s deepest gold mine. After a brief induction, we each donned coveralls, boots, eye and ear protection, a hard hat with a miner’s lamp, and a self-rescue breathing apparatus, and then took an unbelievably fast elevator down through the main shaft almost 4000m (about 2 ½ miles for you metrically challenged people, like me…).

The environment in the mine is a hot 31°C with very high humidity, but we only got to experience those “mild” conditions thanks to a sophisticated cooling system. The rock face way down there is 60°C and the “air” temperature would be a deadly 55°C without cooling. Ice is made for the cooling with huge fridge plants that use vacuum conditions to reduce the boiling point of water to 0°C. Water vapor is released, and ice is scraped from the top of the ultra cold water and sent down the mine to a dam for to provide chill for fans.

After a long, long walk, we eventually got to an area where workers were mining by cutting away gold-bearing rock with compressed air hammers. This rock is loaded into trams, taken to the main shaft area, and lifted to the top with elevators, where gold is eventually separated from the bulk rock for further processing.

I was amazed at the working conditions in the mine: the heat and humidity, the noise, and the claustrophobic working spaces in the gold-bearing materials area. This combined with the huge infrastructure and technology to support the effort, as well as the numbers of workers (several thousand), made the fact that the mine only produces 10g gold per ton of rock quite shocking.

As usual, and if you stuck around this long, you might say eventually, there is a link to gas chromatography in this blog. Restek provides gold-plated inlet seals for Agilent split/splitless injectors, and I’m appreciating those much more after my journey to the center of the earth: Mponeng! Mike Goss and I recently invented what we call a “flip seal”, which allows two uses for a gold inlet seal, something that seems very timely now.  Hmmm... I wonder if any of the gold came from Mponeng.

Flip Seal Dual Vespel Ring Inlet Seals

Enjoy the pictures of my trip to Mponeng!

Entrance to Mponeng Mine, the World's Deepest Gold Mine (near Potchefstroom).

The Main Shaft for Mponeng Mine. The cables are attached to the elevator that takes you down, down, down...

 

Randall, one of the Chief Mining Engineers for AngloGold Ashanti, operators of Mponeng, tells us how it's done at 4K underground.

Working at the bottom in the gold-bearing area. Can't be claustrophobic and make it a full day here!

The Gold! Not much, huh?

Jack and Ernst in Mponeng

Back up top where they make the ice to cool the mine.