|In addition to working in the pit,
we were very lucky to hitch a ride on the company huey
helicopter. The ride was pretty smooth, in spite of the high
altitude. Of course, the guys took the opportunity to tell us all
about the World War II plane wrecks that litter the area and the ghost
stories of some of the victims.
|There is a
story about a Dutch nurse who survived the crash for several days and
allegedly wrote a short journal as she died - she's said to haunt the
general mine area, especially in the underground portions. I
know much about ghosts and all, but it makes me wonder what she would
think, getting to watch the history of an unusual part of the world
unfold over the course of decades. She'd have watched the
doing the exploration to (re-) discover the deposit, the Papuans in
their daily lives and the war they fought over lands near the mine, and
of course the development of the mine itself. Will she watch the
mine slowly run out 100 or 200 years from now?
|The Grasberg deposit itself is
named after the big, grassy hill in which it occurs. The big
Grasberg hill sat right there, next to a small, high grade deposit
called Ertsberg that was the original interesting thing in the
area. It took some sharp geologists who sometimes had to pull
some fast ones to find the Grasberg deposit. It's a lesson to me
- you can be sitting right next to the world's largest copper-gold
deposit and not know it at all if you don't pay attention!
is no longer a hill, rather it's now one of the largest open pit mines
in the world. The engineering involved with digging such a hole,
separating the valuable minerals from the rock, and then transporting
the valuable stuff down to civilization is truly awesome.
|In the pit, trucks and loaders are
busy, drill rigs are drilling, and everyone is working hard. As
with any place in the world, there are folks in the general mine area
who slack off - but not in the Grasberg pit. I was impressed with
the very serious business of mining and good attention to safety.
boom stacker - a conver belt that makes piles of broken rock. I
don't really know much about what they're piling or why it's important
to do so, but Al made a big deal of it and maybe some of you mining
engineers will get a kick out of seeing a photo of the thing.
|Some of the geologic features in
the pit are truly remarkable. Stacie stands next to the Banded
Clay Zone in this photo - a deposit thought to have formed by shallow
circulation of groundwaters in a hot/warm spring environment.
stages of the geological event that formed the ore are characterized by
the formation of a banded quartz-magnetite rock. You can see that
the magnet sticks right to the wall of the pit. This rock
sometimes hosts high grade copper and gold ore.
|The late stages of the geological
event that formed the ore were particularly sulfur rich and deposited
native sulfur (yellow) in pyrite veins. I'm told that this can
lead to firey blasts in the pit when they're blowing up the explosives
to loosen the rock up.