While visiting home I decided to go out and visit Kennecott Copper - the world's largest open pit mine (in fact, the world's largest man-made structure). Anybody who is from Salt Lake City easily recognizes the huge man-made mountains of overburden visible against the natural Oquirrh Mountains, but it is still difficult to believe that such a hole hides behind it.
Although my dad engineered for Kennecott for many years, I had not been out to see the pit since I was a kid. It was as impressive as I remember it.
On the way up I caught a photo of the Wasatch Mountains (the bigger
mountains on the other side of the valley) from a large
Started in 1906, an entire mountain has literally been inverted to yield
a stupendous gash in the Oquirrh's which is 2.5 miles across and 3/4 of a
mile down. Here's a picture of this monstrosity:
Apparently the Sears Tower would only reach about halfway up this hole.
Furthermore, each one of those trucks is literally the size of a HOUSE! They
have a 255 ton capacity (kicks the HELL out of your 3/4 ton pickup, eh?)!!!
If you don't
believe me then here is a truck tire to prove it (my brother Trent is over
6 feet tall).
Notice the pretty mountain tops in the background - this site is both wonderful
The light wasn't quite right, but here you can see the bottom. The shovels
down there are about the size of my apartment complex! Completely electric, each
bucket has a 98 TON capacity. They dig in ore which
has been loosened by explosives (I recall hearing those explosions daily across
the valley as a kid).
Ore was once taken out of the mine to the concentrator on carts like
this (through a railroad tunnel in the mountain):
and rocks were hauled up in baskets like this.
But nowadays ore is devoured by a huge crusher and sent 5 MILES along
a conveyer belt (through the defunct railroad tunnel) towards the concentrator
outside of the mine. The crusher is BARELY visible in this picture about
halfway up the side of the mine.
I wish that I had taken a photo of the concentrator because I recall fondly the memory of seeing the lights on that giant conveyer belt from across the valley snake its way through the mountains and into a GIGANTIC warehouse where it is pulverized and flotation-concentrated.
Although the ore is quite poor (only 0.6% copper), the process is so efficient that Kennecott has produced FAR MORE wealth than the famous Comstock Lode, Klondike and California gold rushes combined. The concentrator creates a mush of water/ore which is 28% metal, which is then pipelined 17 miles completely across the Oquirrh Mountains to the modern smelter near the Great Salt Lake.
It is here that the ore is dried and melted many times, taking the rich metals from below and discarding the slag which accumulates on top of the molten mass. The operation is really unbelievable. Finally the 98% rich copper is enriched further to 99.9% by an anodic electrolytic process.
Keep in mind that the mine also produces a considerable amount of gold, silver, and molybdenum. I wouldn't mind sneaking into that smelter for a little Merry Christmas!!!
Consider this juxtaposition of beautiful snowy mountaintop and road-sized
terraces snaking down to the bottom of the pit
It seems that about half my life has been spent listening to my uncle (who is in some position of authority at the smelter) complain about this/that idiot. I even seem to recall (although I might be dreaming it) an accident where somebody poured a house-sized keg of molten copper all over the floor of the smelter, ruining much of the newly-modernized $880 million complex. I can definitely recall when my dad estimated the tower for the smelter - the tallest stack in the world. They had to custom order the largest crane EVER MADE to build that beast, and now the stack sits as a testament rising nearly halfway up the adjacent mountain!
On the way out I attempted to catch a photo of the venerable Mt. Timpanogos
jutting from the valley floor.