Day 9 (Thursday Sept. 14th)
Visit to Platinum mine & Transvaal Museum
This is Tim I'm actually writing this on Day 14 after our Braii/BBQ (see Day
14), while waiting for the next laundry cycle. This trip is getting long
enough so that when I stop to think back on what we've done and what I've
learned, it really takes awhile to mentally go through everything. That recall
has two phases for me at first just a couple images of particular places or
sensations, then the whole series of related images from that day. So far the
thing that sticks out in my mind first of all has been our tour of the
Rustenberg (Amplats) Platinum Mine.
Our day had been tightly planned by Amplats, so to reach Rustenberg by 8am we
woke up early at Pilanesberg to find that a wallet had been stolen and one of
the Venture's tires had been deflated. We called in the Bomb Squad, made some
phone calls, changed the tire, and left camp and turned north toward Botswana
instead of south toward Rustenberg!
A bit later we arrived in Rustenberg, where the public relations manager, who
had organized our day, had mercifully held things up for us our opening
reception was at the Mine Sports Club, which was polished and bronzed like the
Ritz Carlton! We were introduced to 'the noblest metal'over tea and crumpets,
and the company videos were followed by a presentation by the shaft geologist
and the head miner. Miners seem to be different from geologists here the
miners are engineers who design the blasting and excavating pattern, and the
geologists do a lot of pilot-hole drilling and assaying to figure out where the
best locations are for the miners to spend their resources. Despite this, the
mining industry and university geologists have a relation that seems to be a
lot closer than in the U.S. Several students we've met receive scholarships
from mining companies to pursue a B.S./M.S. in a certain avenue of research
that is of interest to the company, and in return the students are expected to
work for the mining company for a certain time after they receive their degree
like with the Armed Forces in America. On the up side, the students say that
it's nice to have the job security, but on the other hand their research
choices are more limited than ours.
After the videos and the talks we changed into the mine jump suits and
descended to the 14th level, about 500m underground. The temperature of the
Earth radiating from the rock there was about 85 degrees F, which they said was
much less than at the same depth in the gold mines in the Johannesburg area!
To prevent the mine from becoming too hot, the mine engineers have rigged up a
ventilation system that blew so hard in some of the bigger tunnels it was hard
to hear the guide.
Platinum and other platinum-group metals are extracted from three specific
layers, called reefs, each spanning a different level near the bottom of the
Bushveld complex, a magma intrusion that segregated into incredibly pure
layers as it cooled. The process by which it did this is unknown and very much
of interest to geochemists and petrologists since it is responsible for
concentrating the ordinary elements that are present in most igneous intrusions
in a rare, economical way. Each reef is between 50cm and 2 meters thick and is
basically continuous over an area stretching more than 300 kilometers east-west
and north-south! When the reefs come reasonably near the surface, on the
eastern and western edges of the Bushveld complex, mining companies (mostly
owned by Anglo-American) sink shafts and then simply try to follow the seam in
all directions, balancing the need for strong support and wide tunnels for
excavating material with the desire to essentially remove an entire
meter-thick layer of the Earth that is already buried inside the Earth!
Chromite is one of the most beautiful minerals I have ever seen. In the
massive form (reefs), it is actually called chromitite (to say that it is a
rock and not just a part of a rock anymore). The chromitite is jet black but
sparkles when light shines on it like a billion black diamonds. It breaks up
very easily into a powder, which blows off of the open-topped mine trucks as
they drive from the mines to the processing plants. As a result the highways
also sparkled in the sunlight as we drove it was very neat!
On our mine tour, we were led through the large (ventilation) wind-tunnels past
some of the smaller tunnels where electric trolleys receive the manually-loaded
chromitite ore and take it to elevator shafts. As we walked, the noise got
louder and the tunnel darker as we neared the active mining wall and wet
chromite dust filled the air. The sides and top of the tunnel were sparkling
black, and the floor was covered by 6 inches of black sludge. Very suddenly,
our mine guide disappeared up to the right near the top of the right wall of
the tunnel, and indicated for us to follow. In a matter of seconds, we were
crawling like spiders inside the 80cm-high chromitite seam which stretched as
far as you could see lengthwise and in depth!!!! Workers were operating
hydraulic drills mining out the ore an arm's length away the noise was so loud
you could not hear anything at all. The miners were absolutely covered with
the black jewels, and you could almost only tell they were there by the way the
lights on their helmets moved and illuminated isolated patches of the endless
crevasse. My heart just about rocketed through my eyeballs and it was a bit
more than could be easily comprehended, for a moment at first! We
spider-walked along the seam for about 50m before climbing down into another
tunnel that crossed that empty space inside the Earth like trenches must have
snaked across no-man's land 80 years ago. Workers just continued drilling as
we crawled by. The only thing holding up the top 400m of our planet from
settling 80 centimeters lower were stacks of wood wedged into the seam every
10m in each direction amazingly safe since Amplats had not had a collapse in
the last decade (I do not know whether they have ever had a collapse) and in
fact had gone more than a million shifts without an on-the-job injury on the
day of our tour. Each shift lasted 9 hours (5 hours on the wall), and we were
told workers did not even stop for bathroom breaks (they simply relieved
themselves). These platinum-miners are the highest-paid miners in South
Africa (around R3,000.00/month, which is about $6,000 a year here), putting then
solidly in the middle class. All in all, the mine overseers and supervisers we
ate lunch with afterwards really seemed very happy working for Amplats they
said it was much, much safer than working in gold mines, and had more community
feeling than any of the other mines in South Africa Amplats had really built
up a whole city around the mine, with a mine-sponsored school, hospital, and
heavy mine involvement in the local university and other community
structures. It was a little like being on a military base.
I will always thank my lucky stars I can work for a living with my mind and
not behind a hydraulic drill, and maybe in light of the seam-workers, Caltech
won't seem quite so stressful this year.
After a lunch of roast-suckling pig, smoked salmon, beef sandwiches (for
appetizers), lamb shanks, and banana-lemon-strawberry pudding for dessert, the
public relations manager offered to take our flat-tire Venture into town and
have a new tire put on!
We left the mine and drove to Pretoria, where Francis Thackeray, a
paleoanthropologist studying Australopithecus robustus (the most advanced
australopithecine) and Homo habilis (the first member of the Homo lineage) at
the caves near Johannesburg (see tomorrow's description). Thackeray brought us
into the Transvaal Museum (the South African natural history museum) and showed
us the early-man displays before taking us to the 'Broom Room' (named after the
famous paleoanthropologist Robert Broom) an air-tight vault in the basement
containing many of the original skulls and other hominid fossils!!!! He took
out the type-specimens for robustus and habilis, and showed us the famous
fossil Mrs. Ples which he and Joe are trying to date using paleomagnetics.
The upshot of his work is that he believes (and did a good job convincing us) that
Australopithecus robustus and Homo habilis are really the same species, divided
based on a few small differences in a small number of specimens which are
well-within natural variation in individual specimens of many extant species of
monkeys and other mammals. If this were true, it would really revolutionize
the way people think about human evolution the Australopithecus robustus has
been considered an evolutionary 'dead end', perhaps hunted to extinction by
Homo Habilis. It was fascinating stuff. We drove to Johannesburg and stayed
at the Day's Inn, down the street from McDonalds. Our inner austraolpithecines
were very hungry, but we resisted the temptation to do the easy thing and
instead went to a pasta and pizza bar that took two hours. It was good pasta,
though.
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