Grasberg Mine Area

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 particularly sad 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 don't 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 geologists 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!
Grasberg 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.
This is the 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.
The early 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.

Back to Kurt Friehauf home page

On to People photos