The court ruled recently that Rise discharged arsenic, iron, and manganese into the creek from point sources, rejecting the company’s arguments that the metals occurred naturally or that the connection between the mine’s underground shafts and surface drains was too speculative to prove.
The Idaho-Maryland Mine, a subsurface gold operation in Nevada County, has been flooded with approximately 385 million gallons of water since it stopped operating in the 1950s. Water samples from the mine’s New Brunswick Shaft showed iron and manganese concentrations approximately five times greater than federal limits.
Downstream of the mine’s surface drains, water samples revealed arsenic levels more than double those upstream, with iron and manganese levels described as “markedly higher.”
Rise, which purchased the mine complex in 2017, argued that the pollutants were not “added” to the creek because they occurred naturally when water dissolved surrounding rock, or because the water was merely recirculated from the creek itself.
The court rejected the natural occurrence defense, citing Ninth Circuit precedent that the Clean Water Act does not require “human transformation” of materials for them to be considered pollutants.
“Water naturally laced with sulfur could be freely discharged into receiving water used for drinking water simply because the sulfur was not added to the discharged water,” the court wrote, quoting the Ninth Circuit, noting such a result would “improperly undermine the integrity of the CWA’s prohibitions.”
Rise also contended that plaintiff Community Environmental Advocates Foundation failed to prove the mine’s underground shafts were hydraulically connected to the surface drains discharging into the creek.
The court found the connection established by multiple technical reports, including one from Geocon Consultants that referenced waste discharge from the mine to surface water, and a U.S. Environmental Protection Agency-commissioned report stating groundwater drained through the East Eureka Shaft directly into Wolf Creek.
Rise’s experts offered declarations that the shaft locations were “not known with certainty” and that it was “more likely than not” the drains were not connected to the shafts. The court dismissed this as “speculation,” citing precedent that such “guesswork” cannot survive summary judgment.
The court also rejected Rise’s argument that the discharge was not a “point source” because the pollutants originated from the mine’s 73 miles of underground workings rather than a single pipe.
Mining activities that release pollutants from a “discernible conveyance” constitute point sources, the court noted, finding the Eureka and East Eureka Shafts to be such conveyances.
Rise applied for a discharge permit in November 2024, after receiving a Notice of Ongoing Violations from the plaintiff in September 2024. The court noted that while Rise had applied for a permit, it had not yet received one, and the application process did not excuse the ongoing violations.
The court granted the plaintiff’s motion for partial summary judgment on liability.
The court found that CEA member Ralph Silberstein established standing by showing he had refrained from fishing, swimming, and wading in Wolf Creek due to pollution concerns.
Silberstein, a resident of Grass Valley for nearly 30 years, had stopped consuming fish from the creek due to health risks associated with the mine’s pollution.