The Nez Perce Tribe issued a 60 day Notice-of-Intent on Wednesday to sue Canadian mining junior Midas Gold Corp.’s Idaho subsidiary, under the United States’ Clean Water Act. The tribe alleges that Midas has been illegally discharging arsenic and other pollutants into the waters of the company’s Stibnite Gold project, which is located on the tribe’s treaty lands in central Idaho.

In a press release responding to the notice on Thursday, Midas denied these claims, stating that “Midas Gold did not cause the current water quality issues at the site. Midas Gold has never conducted any mining operations at site and therefore has no control or responsibility for any pollutant discharges.”