That was in 1996. Hennis didn't go back into the mine for five years. His second visit almost killed him.
A Harvard graduate in economics, Hennis purchased the Mogul by paying off its back taxes. It's one of a string of extensively worked mines in the famous Eureka District, which produced a fortune in gold a century ago. The Mogul had last been a going concern in 1965, but Hennis estimated that the mine still had four million tons of ore left in it.
"I never planned to operate the Mogul myself," he says now. "I wasn't that stupid. I wanted to put together the geologic information, prove up the reserves and have a responsible company come in and take it over."
Before his first foray into the mine, Hennis spent weeks clearing loose rock from the entrance by hand and shoring up timbers. His recon crew found a clear passage that extended several hundred feet into the mine, past a point where a modest flow of water came down the walls -- probably infiltration from a stream above. "The last 300 feet of the main drift was bone dry," Hennis recalls.
His second visit was prompted by an alarming call from state regulators, who informed him that the Mogul was discharging 165 gallons per minute of metals-laced water, making it one of the largest sources of mine pollution in the entire Upper Animas River watershed. Hennis was stunned: A rate of 165 GPM was more than five times the flow he'd found a few years earlier. In late summer 2001, accompanied by a state geologist, he went back to the mine to investigate.
They found a pile of loose rock and timber 35 feet inside the mine; a large pool of water was trapped behind it. Hennis checked the air quality, shoved a pipe through the debris to drain the pool, then returned an hour later, suited up in coveralls, with a headlamp and other equipment. While the state geologist was elsewhere, Hennis waded through thigh-deep sludge toward the pile, determined to clear it away.
He didn't bring his air-testing equipment with him this time. After the pipe had broken through the debris, the mine passage had filled with the atmosphere from the other side, which was rich in nitrogen and carbon dioxide but had little oxygen. After ninety seconds inside the Mogul, Hennis felt as if everything was going black around him.
"At first I thought I was just horribly out of shape," he says. "Then I realized I was in bad air and about to black out. If I'd gone down, it would have been into three feet of water and slime, with forty pounds of equipment on me."
Using his last reserves of strength, Hennis managed to make it back outside before he collapsed.
He waited a week for the bad air to clear out, then returned with candles and air monitors. This time he made it past the debris pile, then past the small flow of water he'd observed in 1996. The area that had been "bone dry" before was now a swamp of metal precipitates and water.
"It was like wading through molasses," he says. "Up ahead it sounded like Niagara Falls. I went in another 300 feet, and water was flowing from overhead, pouring down. We're talking about a torrent."
Where was the water coming from? Hennis had his suspicions, and his investigation plunged him into a long-running battle with neighboring mine owners, state health and mining officials, and the Environmental Protection Agency. The fight has cost him thousands of dollars in legal fees and his dream of reviving the Mogul.
At the heart of the dispute is a deal hammered out a decade ago between the Sunnyside Gold Corporation and the state's Water Quality Control Division (WQCD), part of the Colorado Department of Public Health and Environment, to settle a Denver court case. At one point the largest employer in San Juan County, Sunnyside stopped mining in 1991 and then spent millions cleaning up its site and treating the toxic water that flowed from its mine. The court settlement allowed the company to seal up the mine, installing bulkheads at the portals and flooding its workings, in exchange for undertaking other projects to improve water quality in the Animas basin.
Water discharges from several other mines in the area increased significantly after Sunnyside bulkheaded its mine. Various parties have advanced different theories about the reasons for the increased flow, and no one has ever established that Sunnyside's own mine pool is the culprit, possibly seeping into other mines through manmade connections or natural fissures. Still, in 2002, Sunnyside agreed to take on additional cleanup costs as part of its exit strategy, including paying for sealing off the Mogul. At the same time, the company was allowed to transfer its discharge permit to a smaller operator, which has struggled to meet its obligations to treat the remaining flow from the now-bulkheaded American Tunnel, one of the primary drainage points from the Sunnyside mine.