HOT CREEK MINE, A FAULTY PLAN?

If they started mining near Hot Creek, in the fault-laced Long Valley Caldera, could it trigger a major earthquake? What would happen to the water?

Questions like that brought a crowd to Mammoth Brewing Wednesday night, where local scientists laid out what a proposed mining project near Hot Creek could mean for the Eastern Sierra’s water, wildlife and geology.

The event was organized by Emily Markstein, co-founder and campaign organizer of No Hot Creek Mine, a coalition opposing renewed exploratory drilling plans by Canadian company KORE Mining near Hot Creek. Markstein said the goal was to help residents understand what is at stake if mining activity moves forward.

“This is an opportunity for those of us who care about this place … to make a difference and do something,” Markstein said.

KORE’s latest proposal appears to revive its 2021 exploratory drilling plan: 12 drill pads across roughly 1,848 acres of mineral claims in the Long Valley area. Under the earlier proposal, each pad would host up to three core borings for rock sampling, with drilling expected to last about a week per location.

That earlier project was approved by the U.S. Forest Service through a pair of categorical exclusions, allowing the agency to bypass the fuller environmental review normally required under the National Environmental Policy Act. Environmental groups, including Friends of the Inyo, challenged the approval in court, and in May 2024, the Ninth Circuit struck it down.

Now, with a new proposal back before federal officials, opposition has quickly reassembled.

Wednesday’s event featured three scientists speaking about the mine’s potential impacts on pollution, aquatic ecology and geology.

Water, faults and mining risk

The night’s centerpiece talk came from geologist and hydrogeologist Geoff Beckner, who has spent most of the last four decades working in environmental geology and groundwater contamination.

Beckner focused on the geology of the Long Valley Caldera and the potential impacts of exploratory drilling and eventual mining near Hot Creek. While he said mining has a place in some areas, Beckner argued Hot Creek is not one of them because of its proximity to groundwater, surface water and a pressurized geothermal system.

He described the Hot Creek area as geologically young, faulted and hydrologically complex, with groundwater flowing west to east through the caldera and hot water rising to the surface at Hot Creek. The proposed mining target, he said, lies along the Hilton Creek Fault, which also serves as a conduit for mineralized fluids.

Beckner said drilling and mining could disrupt groundwater recharge, alter subsurface geothermal flow and introduce contaminants into the watershed. 

He pointed in particular to the possibility of acid drainage and heavy metals mobilizing into groundwater and surface water if mining advances beyond exploration.

“Nobody has assessed the true risk for this,” Beckner said, arguing that regulators and the mining company need to move beyond simply identifying threats and instead quantify the probability and consequences of those threats through a full risk assessment.

Beckner also criticized the prospect of cyanide open pit mining in such a sensitive setting, saying liners and containment systems are never failproof and that contamination, once released, is difficult to reverse. 

“This is an industrial facility,” he said. “This is not a Sheraton resort. They’re doing nasty things out there.”

To be clear, the proposal currently at hand is for exploratory drilling, not a cyanide open pit mine. But opponents fear that if drilling confirms an economically viable deposit, KORE could sell the project to a company prepared to pursue a full-scale cyanide heap leach operation.

Pollution doesn’t stay put

Environmental toxicologist Aleksandra Karapetrova widened the lens.

Karapetrova, who recently completed a Ph.D. in environmental toxicology at UC Riverside, presented research on microplastics in the Sierra snowpack and used it to make a broader point about how pollution moves through mountain systems.

Her work sampled snow on both sides of the Sierra Nevada, including in the Mammoth area, to measure how microplastics are deposited from the atmosphere. She found that even remote snowfields contain plastic particles carried in by storms, with higher concentrations near more developed areas such as ski resorts.

The lesson for Hot Creek, she said, is that contaminants released into the environment do not stay neatly contained. They move through air, snow, runoff and groundwater, entering larger pollution cycles that are often hard to reverse once they begin.

Fish, food webs and the watershed below

The ecological case against contamination came from Emily Martin, a Ph.D. student and summer researcher at the Sierra Nevada Aquatic Research Laboratory, who studies alpine lake food webs and how fish stocking, climate change and water quality shifts affect those systems.

Martin described Sierra lakes as “sentinels of change,” arguing that what happens on the landscape eventually shows up in the water. Those lakes, she said, support fisheries, wildlife habitat, recreation and clean drinking water, while feeding a larger watershed that includes streams, meadows, groundwater systems and Hot Creek itself.

Hot Creek, Martin noted, is especially unusual because it draws from both Sierra snowmelt and geothermal springs in the Long Valley Caldera, creating conditions that support its well-known trout fishery.

But healthy fisheries, she said, depend on more than fish alone. Much of her talk centered on zooplankton, microscopic organisms that graze on algae and form a crucial link in lake food webs. Changes to those communities can ripple upward to fish and water quality.

Martin also discussed the legacy of trout stocking in formerly fishless alpine lakes, which created popular recreational fisheries but also reshaped Sierra ecosystems. Trout prey heavily on native zooplankton and amphibians, she said, sometimes shifting lakes toward murkier, more algae-rich conditions.

She pointed to a photo of a lake choked with stringy algae, joking that the result looked “a little more Indiana-y” than the clear alpine water most Sierra visitors are used to.

Climate change is compounding those pressures. Earlier snowmelt, warmer lake temperatures and increasingly erratic precipitation are already changing lake conditions across the Sierra, Martin said, making long-term monitoring more important as scientists and land managers try to understand how those changes affect both aquatic ecosystems and the fisheries that depend on them.

By the end of the evening, all three researchers had made it clear that even exploratory industrial activity can carry consequences far beyond a drill pad in a landscape like Hot Creek.