...It was just (click here)
such a case of bad luck that happened in the Sunnyside mine at Silverton,Colorado’s mining disaster. The mine had worked its way under Lake Emma and the miners complained about the safety of the situation.
Mining engineers are not geologists.
The complaints were researched by the mining engineers and it was determined that the mine was well within the margin of safety. At a depth of 90 feet below the lake, the margin of safety was well within the limits. With the safety concerns addressed the mining company managers decided to go forward with removing the last pillar under the lake. This pillar was so rich in gold, a 4” seam of bright shiny gold ran the entire length of the pillar.
This pillar was the last structure remaining between safety and disaster. Now, someone is going to tell me the miners were wrong and the owners were right. Sure. And, of course, the pillar of rock was worthless, too.
This is where the bad luck comes in. The lake bottom sediment had filled and concealed a crevice that came out at the gold laden pillar underground. When the pillar was removed the miners discovered a “soft pocket” of was made of glacial rock flour. Glacial rock flour is just what it sounds like; rocks that have been ground by glaciers into flour.
Now. GLACIERS from the ice aqe dominated this area and created geological deposits. This instability is a very real issue. Engineers are not the folks to evaluate geological formations. The geology was known and one might ask, how did the lake get there in the first place. Well, could it be because the glaciers ground the land into pulverized sediment and the glacier was melting and retreating and a 'watershed' developed from glacier weight and erosion. Hm. Sounds interesting. Basically, this region of Colorado had gold. But, it also had unstable geological structure.
It was worked a little to find its limits. It ended up being about twenty feet long and four feet wide, but more scary was that the top could not be found and this spooked the miners, who refused to re-enter the area. The new plan was to drain the lake the following summer so the gold ore could be retrieved. This was sort of the calm of good luck before the outpouring of bad luck. Sometime after the last workers clocked out on Saturday, the flour plug gave way to the force of water above it. This deluge of water filled the mine and emptied through the lower mine portals completely emptying the lake in only a couple of hours. The lake covered a couple of acres of land. Rocks, glacier till, and flour plugged every nook and cranny of all the mine workings with natural clay-like cement.
