It looks like the most adventurous thing in the world. That dark opening in the hillside attracts, tempts, excites. What wonderful treasures are waiting to be discovered inside? What artifacts could remain in this time capsule, mute testimony to an era when gray-haired men moved tons of rock in search of their dreams? Such is the poetic appeal of the romance novel that it might lead you to lose your senses and walk into an old mine. Thousands of these small openings are scattered throughout the country. Although most common in the historically “hard rock” western mining states, they can also be found in the former lead and copper districts of the Midwest. In reality, multiple dangers lurk beyond the pale ring of light filtering through the mouth of the tunnel.
While exploring a field area for a thesis project, I spent six weeks camping and hiking in the West Elk Mountains in the Colorado Rockies. My days were spent hiking the flanks of a majestic 13,000-foot peak, chosen because of tantalizing reports of silver mining activity around 1900. During my walks, I came across several old mining workings. Some were simply short tunnels dug into the hillside, designed to test for the presence of silver, copper, and lead ores that might be distributed within the porphyry intrusive contact zone that defined the mountain peak. Other works, although small, were relatively more sophisticated and had rail tracks stretching from the walkways to the progressively spreading pile of fine waste rock. I explored each of them, sometimes crawling over mounds of rocks that had fallen from the roof or ribs, or widening a hole and sliding through the mound of washed earth to get to the floor of the sinkhole.
This really was the height of madness, as he was alone in the desert and had no idea of the potential dangers. I currently work in the field of ground control engineering and have first-hand knowledge of numerous fatalities that have occurred in active mines when rock fell from the roof without warning. I have also become more familiar with the extensive engineering design work and variety of support systems required to develop and maintain a mine opening. “Old-timers” have often had luck developing small openings in hard rock, but modern mining engineering indicates that time is not conducive to stability.
A more insidious danger is represented by the lack of breathable air. In sealed underground openings, the air may have become “stale” by not circulating outside. In modern mines, personnel are dedicated to designing and maintaining the ventilation systems that circulate fresh air throughout the mine. Some gases displace oxygen, but they are colorless and odorless and do not warn of danger until the person suddenly realizes that they have been holding their breath for several minutes. This is a condition known to miners as “black damp” that can cause unconsciousness or death. While working in Bolivia, I entered more than a dozen small mines in a district that had been developed initially by the Spanish, or perhaps even the Inca, and later by a Polish mining engineer in the early 20th century. The more modern operation had closed in the 1980s when the underground part of the mine was abandoned as unprofitable, but a small open pit was developed intersecting some of the old workings. As a geologist working to unravel the geological history of this area, I went into the mine to document the relationships between the intrusive phases. As I concentrated intently on the last face of the mine, trying to decide if the rock was rhyodacite or dacite, I suddenly felt a warm, tingling, numb sensation in my nose and lips. Panicking, I exhaled what little air was left in my lungs and held my breath, while at the same time turning and running back down the tunnel. Strange and ghastly shapes of tarps and rotten wood danced in the shadows cast by my flashlight. I had little hope of running the nearly 1,000 feet to the mouth of the mine, but as gray specks floated before my eyes, I decided to keep my legs pumping to at least get out of what might just be a pocket of stale air. Then I saw a strip of light where the floor of the open shaft intersected the tunnel. Fresh air! I ran to the cut and gulped in the mountain air. Although the air smelled of decomposing sulfides, at least the threat of black moisture was gone, so my panic subsided enough to allow me to walk quickly out of the mine.
Crawling into an old mine, where no miner or engineer has assessed the condition for decades, is something I would now consider sheer stupidity. No shiny trinket or rusty artifact is worth it. Take a picture of that beckoning hole and then leave it alone. Remember that the “veterans” have already removed the stone and dropped it on the ground for you. Treat yourself to a bit of azurite, malachite, chalcopyrite, or pyrite from the dump if you need a souvenir, but stay out of that mine!