State scientists in Alaska found more than 100 dead fish in Sherman Creek, downstream from the Kensington Mine, in August. Seven months later, Coeur Mining, the mine’s operator, and state authorities have not determined why the fish died off.
Lab testing on creek samples and mine effluent showed no evidence of pollution, according to a November letter from Coeur Mining. However, watershed ecologist Chris Sergeant hypothesized that contamination might have entered the creek prior to testing.
The sergeant emphasized the crucial need to regularly sample the water near mining operations. On August 8, mine workers used RocKracker, an explosive linked to toxicity in marine environments near Sherman Creek.
The following day, the fish, including Dolly Varden Char and pink salmon, were found. While Couers consultants acknowledged a potential link, they claimed water tests showed no harmful chemicals from the explosive.
Gene McCabe, director of Alaska’s water division, stated that pinpointing the cause remains challenging. Regulators have asked Coeur to propose monitoring improvements and alternative explanations if mine operations were not responsible.
Coeur’s spokeswoman, Rochelle Lindley, confirmed the company’s commitment to working with state agencies. A state pathologist ruled out infection as the cause, stating that dead fish below the mine’s treatment plant suggested water quality issues.
Regulators discovered hemorrhaging in several fish, indicating acute exposure to toxins. Despite this, Coeur’s sampling met Clean Water Act requirements, complicating the investigation. Coeur has since halted RockKracker’s use of adjusting monitoring protocols and created a blasting operations oversight position.
This news article was originally published by Alaska Beacon.
