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| Western Mining History posted The mines of the Comstock Lode of Nevada were incredibly rich, but as they got deeper, both water and heat posed great difficulties that needed to be overcome. No expense was spared to drive the mines ever deeper. The ca. 1880 photo below shows the Cornish Pump that was installed at the Union Consolidated shaft. At the time it was the largest in the world and cost an astronomical $410,000 to install. Scientific American described the pump as having “a flywheel 36 feet in diameter, which, with its shaft alone, weighs 208,700 pounds. The high-pressure cylinder is 64 inches in diameter by 6 feet 9 inches stroke, and the low-pressure cylinder 100 inches in diameter by 8 feet 6 inches stroke.” More Comstock Lode photos: https://westernmininghistory.com/6126/comstock-lode-photos/ Chris Hills: Another contributor to the heat was the blasting of ore and the lack of good ventilation. Explosives generate tremendous temps that are easily transferred to adjacent rock. Without a way to dissipate it the heat stays put. This was true in the Homestake Mine at Lead, SD.PaulnLisa Sala: The new #4 shaft at the Lucky Friday Mine in North Idaho bottomed out at 8620' below the surface (actual depth). Rock temperatures were just shy of 150°F. Special high temperature resistant explosives had to be used due to the heat. Massive amounts of cooling was used to make the environment bearable for the miners. Ken Wesley: Could someone briefly explain why heat is associated with depth? Couldn’t possibly be because they were going deep enough to approach the earth’s molten center, right? Thanks. Western Mining History: Ken Wesley It's not just the core that is hot, most of the Earth's interior is hotter than the surface, it's just a matter of how deep you need to go to reach that heat. Nevada's "Basin and Range" topography is characterized by a relatively thin crust that is being uplifted by much hotter layers beneath, which is why there are so many hot springs in Nevada, and also the reason the mines get so hot at depth. It's more complicated than that, but that is a simple explanation. One part of a description of the heat deep in the Comstock mines in 1880: "Down where the men come from you must keep your hands off the pump column and the pipes, and if you pick up any iron tool you will at once put it down without being told to do so. Down there they handle things with gloves on, or wrap rags about the drills they are guiding and iron apparatus they are moving; and down there, too, you will learn to keep your mouth shut after you have drawn a few mouthfuls of hot air into your lungs." Steve Volk: Ken Wesley As alluded to the Comstock is an active hydrothermal zone. Lots of faulting that allows hot water in. Same process deposited the gold and silver. Lots of it! The mines had cooling rooms where ice was brought down to cool the miners. Read "The Bonanza King" by Gregory Crouch for an outstanding history of the Comstock Lode. Andrew Clayton: Here in Cornwall (uk) there are hot rocks, it's because the igneous granite is radioactive. Uranium has been mined here, and in some of the mines, the miners worked stripped to the waist. Scott Ole: I thought the Cornish mining pump in Iron Mtn. Michigan was the largest. Loren Maurina: Scott Ole you are correct. https://menomineemuseum.com/cornish-pump-museum Western Mining History posted The mines of the Comstock Lode of Nevada were incredibly rich, but as they got deeper, both water and heat posed great difficulties that needed to be overcome. No expense was spared to drive the mines ever deeper. The ca. 1880 photo below shows the Cornish Pump that was installed at the Union Consolidated shaft. At the time it was the largest in the world and cost an astronomical $410,000 to install. Scientific American described the pump as having “a flywheel 36 feet in diameter, which, with its shaft alone, weighs 208,700 pounds. The high-pressure cylinder is 64 inches in diameter by 6 feet 9 inches stroke, and the low-pressure cylinder 100 inches in diameter by 8 feet 6 inches stroke.” More Comstock Lode photos: https://westernmininghistory.com/6126/comstock-lode-photos/ |
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