Minnesota Mine Shaft Tracer Data, Lion Creek Watershed near Empire, Colorado, July-November, 2017

On July 26, 2017, a solution containing approximately 200 kilograms of dissolved sodium bromide was added to the the flooded underground shaft of the Minnesota Mine, near Empire, Colorado. This addition was conducted as part of an effort to determine the degree to which the mine shaft is hydrologically connected to a series of downgradient seeps and springs. These seeps and springs discharge from the hillside and enter Lion Creek, an acidic, metal-rich stream that lies immediately to the west of the Minnesota Mine. A water quality sonde and pressure transducer deployed within the shaft recorded temperature, specific conductance, and stage before, during, and after the addition. The downgradient seeps and springs were also monitored [...]