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The Great Battery of Kimberley

by ChrisCook Fri Oct 5th, 2007 at 09:06:01 AM EST

Just following on from an interesting post by Nomad last night re the awesome scale of gold mines in South Africa, they have diamonds too, of course.

The Great Hole of Kimberley

is interesting.

The Big Hole is an amazing sight, the largest hand-dug excavation in the world, it is 215 meters deep, with a circumference of approximately 1.6 Km (1 Mile). In the end 22.5 million tons of earth had been removed by muscle power!

The water is about 40m deep apparently, and the water surface is about 175m below ground level.

My thoughts turned to Dinorwig

The simple idea is to install a reservoir/ pool at ground level - drop a few pipes down the side of the Hole and stick Dinorwig-style turbines on the way and then pump water up using off-peak/ spare power (if any!)while pouring it back down again at peak times.

Using this method they could install wind turbines, connect them to the Great Battery Of Kimberley and get better rates for production than they would otherwise do.

But then, they probably use all the energy they can produce anyway...

The big problem with that is how wet and windy is that region?  One of the reasons why Dinorwig works, is it is in one of the most wet areas of Europe. if the surrounding area is too hot and dry then evaporation would make this plan untenable.

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Fri Oct 5th, 2007 at 09:17:44 AM EST

But the higher pool - or pools - of water needn't be at ground level, and they could be cisterns, shaded or semi-shaded and so on, maybe set into the sides of the upper crater, or whatever.

Equally, it needn't be a "mega" project to start with.

As for wind resource and solar resource in the area, I have no idea either.

It's just the idea of a f..k off big hole as a battery that I like!

Me, I'd just chuck the idea at a few engineering schools as a competition.

The "best" solution gets the ET prize...

"The future is already here -- it's just not very evenly distributed" William Gibson

by ChrisCook (cojockathotmaildotcom) on Fri Oct 5th, 2007 at 09:56:57 AM EST
[ Parent ]
is a city that's possibly going to die.

The moment underground diamond mining operation stop (and they have since ~2005 or nearby that date), any groundwater pumping to keep the mines operational will cease. On a sociological note, the main economic engine of Kimberley and reason of its existence in the first place (diamond mining) has stopped. Kimberley is not Johannesburg which has turned into the financial capital of SA - already in 2001 I found it a depressing place.

But now notice that they built the city on the very edge of the "Groot Gat".

While groundwater is now reported at 175 meters below ground level, in the horror scenario that was outlined during the 2001 visit, water tables will rise higher after pumping halts, and very likely contribute to destabilise the structural integrity of the pit. All open mine pits slump in the end. Kimberley's Great Hole is no different. I genuinely hope they've performed some integrity studies by now or, if not, are at least continue pumping... (And how sustainable is that?!)

Just to complicate the engineering challenge...

Re wind and rain - Kimberley is situated slap-bang in the Karoo - which has semi-desert conditions. Plenty of sun around (as large chunks of SA have), and an annual average of 410 mm precipitation. There is water in the pit practically year-round, although I don't know if there are numbers on annual fluctuation of water table change.

by Nomad on Fri Oct 5th, 2007 at 11:28:31 AM EST

But I'm only looking here at the Kimberley "Big Hole" (not any other mine) which ceased operations about 100 years ago, and has since part-filled with water, under which is a combination of collapsed mine, and material chucked into the hole.

It looks pretty stable now, and as far as I know, it's full of water year around, which as it's 180 metres down, and relatively shady, would not be surprising.

Frankly, in engineering terms, the concept is pretty trivial. It's not like you're hollowing out a mountain, as at Dinorwic.

That's the point.

But if there's no need, current or future for energy storage in the vicinity, then the idea would never even be a starter.

"The future is already here -- it's just not very evenly distributed" William Gibson

by ChrisCook (cojockathotmaildotcom) on Fri Oct 5th, 2007 at 12:26:20 PM EST
[ Parent ]

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