Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!

1 - 20 of 20 Posts

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #1 ·
The Premier Diamond Mine, located in the town of Cullinan a few kilometres east of Pretoria, is often simply called the Cullinan Mine. The place is named after Sir Thomas Cullinan, the original mine owner. It’s about an hour and a half’s ride from Johannesburg. This mine produces about 1,000,000 carats of diamonds annually which is not a particularly high yield. 1 carat = 200 mg. Therefore 1M carats = 200kg. Approximately 80% of the output comprises industrial diamonds, with the remaining 20% being gem quality diamonds. It employs just 1,200 people. The mine was sold to Petra Diamonds last year by De Beers.

However, this single mine has produced over 25% of all the 400+ carat diamonds ever found. Probably its most famous stone is the Cullinan Diamond (over 3,100 carats) which was mined in 1905. The major diamonds cut from this stone are part of the British Crown Jewels with the ‘Star of Africa’ topping the royal sceptre & the ‘Lesser Star of Africa’ adorning the imperial state crown.

Star of Africa (530 carats)



The mine has produced other notable diamonds over the years such as the Golden Jubilee and the Millennium Star.

More recently a rare blue diamond of just 7.03 carats from the Premier Mine smashed the all time price per carat record when the buyer paid over $ 9.4 Million for it only last month. The new owner named it the ‘Star of Josephine’.


When I lived in England my parents took me, as a young boy of 6 or 7, to visit the Tower of London. I well remember the Beefeaters, the ravens, the torture chambers & the Crown Jewels. Apart from the occasional state function, the Crown Jewels are permanently on display at the museum in the Tower. Well, having seen these magnificent diamonds as a kid I thought that now would be a good time to go on a tour of the mine where the Cullinan Diamond was found.
 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #2 ·
This report is more about the destination rather than the trip itself. I set off last Saturday morning and travelled across the monotonous veld which this time of year is brown & featureless, being in the middle of our dry season.



There was some early morning mist around and it was pretty cold



It soon brightened up & warmed up. I’ve noticed that in some literature Cullinan is still described as a village, but it has definitely grown in to a small town over the years



It has pleasant tree lined streets which will be lined with parked motorcycles the following morning, the place having become a favourite destination for the Sunday breakfast run.


 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #3 ·
It’s a very laid back town & it’s a pleasure just to stroll around



A new housing development advertisement. ZAR 980,000 = approx. $ 120,000.



Much of the architectural style is original or pseudo Edwardian. Cafes and gift shops abound.
 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #4 ·
All mines are ugly IMO & even diamond mines are no exception. A view of Premier from a distance



The mine surface tour starts with a 10 minute video and is a guided walking tour.

Diamonds are formed at a depth of 120 to 200 km below the earth’s surface and they are 100% carbon. The right combination of temperature, pressure & chemistry can lead to carbon atoms bonding and crystallising in to diamonds.

If diamonds are found in river beds & estuaries the type of mining process is called alluvial. Inland mining requires kimberlite pipes to bring the diamonds to the surface, usually by means of a volcano.

Mine entrance



The winder room (sorry the pic is out of focus) showing a ‘Ward Leonard’ type winder manufactured in the UK over 50 years ago & still in full service



 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #5 ·
The winder moves the ore-carrying skips up and down the mineshaft via the headgear



Spare skips ready to be installed when needed



The original pit (where the Cullinan Diamond was found)



The mine ventilation installation in the background gives an idea of scale


 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #6 ·
All the mining is underground nowadays. The workings are down to 800 metres below the surface and there are 700 km of shafts & tunnels!

There is a museum at the mine. Obviously all the next few pics are of glass replica stones.

The rough Cullinan- about the size of a clenched fist



The same basic stone with the nine cut diamonds that form part of the Crown Jewels






A statue of Sir T. Cullinan is situated outside the shop


 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #7 ·
Inside the shop



Many diamonds were on display and for sale. The price is in the region of $ 600 per carat. The diamonds on display had Cullinan’s trademark, the Cullinan Star Cut.

This, in my view, is one of the most informative websites available to anyone wishing to buy diamonds: About Diamond Cuts.

The tour was over. I found it very interesting & there are zero restrictions on photography! The cost was ZAR 60 = US $ 8.

Outside the mine there are static exhibits of some weird & wonderful examples of old mining machinery.







 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #8 ·
On the outskirts of the town is a cemetery and memorial for the 300 or so prisoners of war who died at the military prison camp during WWII. This prison, Zonderwater, housed in excess of 60,000 Italian POW’s from 1941 to 1947 who had been taken prisoner during the North Africa campaign (el Alamein and so on) & during the smaller Albanian & East Africa campaigns. Upon release around 20,000 former POW’s applied to stay here, with the rest returning to Europe.



I duly departed and took a slight detour through Pretoria, our capital. The city centre is situated in a bowl surrounded by hills. These pics were taken from outside the Union Buildings, the country’s houses of parliament (for 6 months of the year only, because parliament transfers to Cape Town for the other half of the year). The gardens are manicured and open to the public.








 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #9 ·




This is a replica of the National Monument that stands in the war cemetery in Delville Wood, France, commemorating those who fell during the Great War



It was a pleasant and rather different way to spend a Saturday.

In my next ride report I hope to show a possible reason as to why there are multiple diamond, gold, platinum & chromium mines in this part of the world!

Till then :),

DaveB.



 

·
Premium Member
2004 Daytona 955i, 2018 Indian Roadmaster, 1980 CB650C in resto
Joined
·
17,801 Posts
I love your reports, Dave; keep 'em coming!


That's one &$%* big hole in the ground.
 

·
Registered
Joined
·
1,687 Posts
Nice one Dave!

Great photos and educational too!!

Well done.



V.
 

·
Registered
Joined
·
23 Posts
Nice one, Dave.

That bought back lots of memories... I worked as an engineer for Anglo-American / De Beers head office in Johannesburg between '88 and '98 and visited Premier Mine on many occasions, along with the other big diamond mines at Finsch, near Kimberley, Venetia up near Messina, Orapa, Letlakhane and Jwaneng in Botswana and Oranjemund in Namibia. Premier was always my favourite, I think, as it was in far more civilised surroundings than the others and didn't require a flight and an overnight stay to visit, although going to Oranjemund was always nice; you don't get to the seaside too often living in Jo'burg... and the beaches are HUGE in Namibia! :D

As big holes in the ground go, Premier's the fourth biggest in the world... Orapa in Botswana is quite a bit bigger; but also a horrible, dusty, sweaty place to work, with temperatures around 44C in the summer.:eek:

Yes, Cullinan definitely my favourite diamond mine...

Compared to other mining in RSA the diamond mines are quite shallow... the gold mines already went down to 3500m when I was there, and we were looking at projects down to 3800m. I believe there are now plans to go down to 4300m. Some interesting facts (if you like this kind of thing?) the cages travelled at 16 m/s (58 km/h, 36 mph) so to get down to 2300m took about 2.5 minutes. Below 2300m you transfer to another (underground) winder, as it was impossible to go deeper in a single drop. The reason for that is that the weight of the steel rope is such that it cannot support itself with adequate safety factors. A bigger rope doesn't help, as the weight goes up proportional to the breaking force, and the stresses remain about constant. Trying to get round this limitation was one of my pet projects.

Ah well, enough rambling...
 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #16 ·
Howzit Strumpet08. I referred to my next planned trip. This will involve travel past the two deepest mines, AngloGold Ashanti's Mponeng & Tau Tona mines. There are conflicting reports on the web but it looks like they are both beyond the 3,800m depth now. Anyway, they will not be the focus of my trip; they just happen to be along the way... :)

DaveB.
 

·
Premium Member
2004 Daytona 955i, 2018 Indian Roadmaster, 1980 CB650C in resto
Joined
·
17,801 Posts
The reason for that is that the weight of the steel rope is such that it cannot support itself with adequate safety factors. A bigger rope doesn't help, as the weight goes up proportional to the breaking force, and the stresses remain about constant. Trying to get round this limitation was one of my pet projects.
Two words; carbon nanotubes.


Sure, there are deeper mines, but do any of them have this kind of visual impact? I've been about a km underground, but this is far more impressive from the surface:

 

·
Registered
Joined
·
2,437 Posts
Discussion Starter · #20 · (Edited)
1 - 20 of 20 Posts
Top