Thursday, January 11, 2018

Cripple Creek & Victor Gold Mine

I love my Mother Earth. And I have always seen an open pit mine as an abomination. And yet, I have willingly moved next door to one.  (click on pictures to enlarge - the photos do not capture the immense size of the equipment being used or the pits being dug!)

Cripple Creek & Victor Gold Mine seen from the sky.
The towns of Cripple Creek and Victor are marked.
Someone once said that until mankind quits devouring minerals like they were candy, mining and open pit mines will be necessary. A very true statement.

Gold was discovered in a gulch outside of Cripple Creek in 1890. Within five years the town had grown to 8,000 people. The neighboring town of Victor was founded in 1894 . By 1901, at the peak of production, there were 500 mines in the District and $77 million in gold had been taken from the ground. 

Gold production continued until it tapered off in the 1920's, with a brief resurgence in the 1930's. World War II saw a halt to all gold production. In 1995 , a new process of gold leaching was developed and extraction began again at the Cripple Creek & Victor Gold Mine. But this time the ore wasn't coming out of shafts, it was being mined in an open pit. 

I am not going to give a lot of details about the early days of gold mining here in the District. That is a story for another series of posts. What I am going to write about is the modern day mining which is currently taking place just over the hill. The current owner of the Cripple Creek & Victor Gold Mine is Newmont Mining Corporation, a world wide mining company.

Pit located on northeast section of mining area. This pit is now used for rock disposal.
An open pit mine is just what it sounds like. A great big hole in the ground that keeps getting bigger because of the rocks (minerals/ore) that are being taken out of the hole. Blasting (with explosives) is done which loosens the rock near or just below the surface of the ground. Large heavy equipment then takes out the loose rock to be processed. This process of blasting and hauling rock is repeated over and over until the ore is all extracted. Roads are built around the sides of the pit to allow the heavy trucks to drive down to the bottom.

This hillside is being stripped down to bare ground and will soon look like the photo below.

The gold found here is not in the form of a nugget or dust. It is found mixed in with other minerals and must be separated from these other components via a leaching process. The ore bearing rock is sent to a crusher then on to a mill for processing. Once the rocks have been milled down to a more manageable size,  they are then taken to a leach pit where the precious minerals are extracted. A diluted Potassium Cyanide solution is sprayed on the crushed gold bearing ore in the leach pit. The cyanide trickles down through the rocks, binding with the gold and silver. At the bottom of the pit are carbon filters which trap the cyanide/gold mixture. 

Leaching area
Once the gold and other precious minerals are trapped in the carbon, it is then sent to another processing station where the gold, silver and other minerals are separated from the carbon and smelted down into bell shaped forms called dores. These dores are then sent to a refinery in Switzerland so the gold, silver and other minerals can be separated.

The rock which has no mineral value is loaded back on to dump trucks and taken to a part of the pit which has already been mined. There the rock is dumped and the mountain begins to take shape once again.

Disposal pit with roads running around the sides.
Dump trucks can be seen bringing rocks to be dumped.

Dump truck bed now being used for a viewing platform near the disposal pit
We frequently follow tankers carrying potassium cyanide up the mountain road to Cripple Creek. Never see the gold shipment leaving the mine though. Wonder who's riding shotgun on that stagecoach?

On Monday, I will write about the new exploration going on at the mine and its impact on the local community. I'll also write about the community involvement of Newmont and the most important part of the mining process - reclamation.

Mountainside near disposal pit that has been reconstructed.


FreeDragon said...

When I saw the first photo of this post I thought of a distorted skull.

Debra She Who Seeks said...

Open pit mining is a scar on the landscape, no doubt about it. But it's also much safer for workers than underground mining.

the dogs' mother said...

Very interesting report!