Black clouds form a mountain in the sky, dump a magnitude of water, and leave Butte overwhelmed by unexpected flooding and contamination heading westward down Silver Bow Creek.
That might sound like science fiction, but to Dave Williams, a Bureau of Land Management geologist, it’s not. He says that kind of storm could hit southwest Montana this spring or next year or years from now. If such a storm does occur in Butte or Anaconda, he says the consequences could be dire for the Superfund cleanup.
Williams has been talking at public meetings this winter about climate change and how it could affect Butte’s remediation. Williams says climate change isn’t just a scary futuristic apocalypse our grandchildren will face. Climate change is here, and it’s now, Williams says.
“I can’t say it’s an issue next year or the year after, but it’s going to happen sooner or later,” Williams said recently. “It could happen next week or five years from now, but statistically, it’s going to happen.”
Williams says that what matters most for mines – and mine reclamation – are more frequent droughts.
“A warmer atmosphere holds more water,” Williams said. “That’s when we have precipitation events.”
Williams says that in 2011, clouds gathered to form a tropical-storm amount of moisture far from the tropics. The squall came to eastern Montana.
It hit in the Fort Belknap Indian Reservation area, dropping 11 inches of rain over a day and a half. It caused extensive damage at Zortman-Landusky, an abandoned Pegasus Gold mine near the reservation.
Wayne Jepson, Department of Environmental Quality hydrologist, said a normal annual amount of rain in that part of the state is 18 inches. The storm that brought 14 inches in 10 days was estimated to be a 500-year storm.
“It affected all of eastern Montana with landslides and unstable ground,” Jepson said.
The cost to repair to Zortman-Landusky was around $500,000, Williams said. Because the agencies did the cleanup work with public funds, the repair work was done “on the cheap,” he said. The costs could’ve been higher.
Trees fell, rain sliced deep red gorges into the hills, roads and culverts disappeared as they were washed out by the torrent, and the whole valley was silenced by water.
Jepson said a reclaimed waste rock dump – one that had been stabilized and revegetated – became saturated, collapsed, and “the lower toe of it” slid half a mile down the gulch below it.
“It was flooding like we’ve never seen before,” Jepson said.
Though not as severe, a shock of rain has already hit close to home.
Anaconda faced an unexpected gully-washer that sent nearly an inch of rain in about 20 minutes over Stuckey Ridge in July 2017. Within less than 30 minutes, one storm caused $660,000 worth of damage to Old Works Golf Course.
The Jack Nicklaus-designed course had to close eight holes. About 18-to-24 inches of sludge landed on the greens. Rocks the size of bowling balls tumbled down the hill and bounded where golf balls should have been landing.
Parts of Stuckey Ridge have been reclaimed, but not all of it, and the unreclaimed section sent contaminated debris. Atlantic Richfield Company stepped in and footed the bill, which included lost green fees to Old Works — damaging to a course already struggling to stay afloat.
Loren Burmeister, Atlantic Richfield Company liability business manager, said the problem wasn’t solely caused by the event itself but by debris buildup.
But a situation of this order is exactly what Williams is warning about. With parts of Butte and Anaconda still not fully remediated, there are vulnerable areas where big storms could cause a heap of trouble.
The Environmental Protection Agency says that it considers climate change in its review process that happens every five years.
Williams says that in Butte, drainages on the Butte Hill that have not yet been fully remediated will be the most at risk to such a storm.
While national leadership in Washington D.C. continues to debate whether climate change exists or is worth worrying about, industry began bracing for the impacts of climate change long ago. Similarly, Atlantic Richfield has not waited around to factor climate change into the Superfund remedy.
Josh Bryson, operation project manager for Atlantic Richfield, said the company designs with crazy-making storms in mind.
Bryson and Burmeister say engineered controls have been put in place to capture sediment that might wash down during a super storm.
Bryson says a 100-year storm would send sediment into a basin and that “99 percent” of all storms, including the really bad ones, would send sediment into those concrete sinks.
Even so, Bryson said there is some vulnerability.
Williams says that where grass and other vegetation has already taken hold over mine waste, such as the hill rising above Uptown, is not likely to fail. At least not any time soon. The long established grass roots should withstand the potential for potent erosion.
But over time, drought is expected to be the norm. Down the road, a more long-term worry is never-ending dry conditions.
With increasingly less snow and shortened winters, plants, including those used to reclaim mine waste, become increasingly stressed and might not be able to adapt to limited moisture, Williams said.
“Drought will severely impact the effectiveness of the covers we’re building,” Williams said.
EPA says that no matter what, human health would be protected.
“If an unexpected or unprecedented event should occur at any Superfund site, EPA response authorities would address any impacts to human health and threats to the environment,” Chris Wardell, EPA community involvement coordinator at Region 8, said by email.
DEQ says it has also planned for climate change during the lower portion of Silver Bow Creek.
The agency took out waste far enough back from the creek for a 100-year flood. That should keep creek water from encountering new waste, DEQ said.
DEQ cleaned up the lower portion of Silver Bow Creek with money provided by Atlantic Richfield through a settlement and is still doing touch-up work in some spots.
But Williams says that when it comes to extreme weather, there’s no way to avoid sending metals into the waterways.
“Ultimately it would dilute, but with the situation in Butte, there’s no way to avoid loading metals into the creek and moving it down the drainage,” Williams said.
Bryson said that if metals wash downstream to deposit on banks, Atlantic Richfield would evaluate the condition of the stream and “work with the agencies to determine responsibility and figure out who is responsible for the mitigation, whether it’s lower Silver Bow Creek or downstream of that.”
Mark Thompson, Montana Resources’ vice president of environmental affairs, says the mine also factors in for scary-making squalls.
If all the slopes around the pit failed and fell back to as flat as they could go, the sediment that would crash into the pit’s water would add six months of normal rise to the toxic lake, Thompson said.
Thompson said the mine keeps a close eye on those slopes.
“We have a network of monitoring that can predict failure pretty accurately,” he said.
As for Yankee Doodle Tailings Pond, the place where MR’s waste lands behind an earthen dam reaching around 700 feet upward, Thompson said the 2015 Legislature passed a bill that, among other things, mandates by law that mines in Montana have to address global warming in design of tailings ponds.
“In our design, we looked at the worst flood event,” Thompson said.
The engineers factored in the possibility of an excess of rain plus snow pack melting and both Moulton Reservoirs north of the pond failing all at once.
Thompson says such a ferocious landslide of water and melted snow would create 20,000 acre feet of water, or the equivalent of nearly 20 inches of rain.
“We can stow that without over topping,” he said.
If a bad storm unleashes on the home of hard rock mining, DEQ says the agencies would decide on the course of action and who would pay for what.
Williams said that a catastrophic storm, whenever it does gobsmack Butte and Anaconda, will do all kinds of damage. The possibility of heavy metals that remain deposited from the more than 100 years of mining and smelting damage washing downstream could actually be the least of either town’s troubles.
“From the standpoint of those of us who work in mine site reclamation, it’s a big deal,” Williams said of climate change’s effects. “But in terms of the larger issues, like infrastructure, it’s just one of the pieces.”