Emergency Release and Fish Kill Occurred
What to know:
In October 2018, Left Hand Creek landowners reported a fish kill up to 10 miles downstream of the Captain Jack Mine. The fish kill was a result of a standard practice emergency mine pool release conducted by the EPA and CDPHE in September 2018. Prior to the release, the bulkhead flow-through valve was shut, and inner mine pool level was rising much faster than anticipated. The excess water needed to be released. Water quality data from the mine pool indicated acceptable conditions to release without treatment. Though unknown at the time, these data were not representative of the entire mine pool water column. Concerning water levels in the inner mine pool combined with apparently acceptable water quality led to an emergency release of mine water into Left Hand Creek. In reality, the mine pool water was highly acidic and laden with toxic metals that caused a fishkill. After this event, a temporary treatment facility was installed to treat the excess mine pool discharge. Sub-surface remediation activities were then halted in order to revise the remedy techniques.
Mining Begins in the Ward DistrictMining activity began in 1861 following the discovery of gold...
Water Quality Issues ReportedWater quality issues were likely occurring since mining began in...
Captain Jack Mill ConstructionApproximately 12 mines were operated in the headwaters area of...
Captain Jack Mine ClosureAfter nearly a century of activity under multiple owners at...
EPA Superfund Designation of Captain JackBy 2003, Captain Jack Mill was listed on the EPA’s...
Record of Decision IssuedIn 2008, Captain Jack Mill Superfund site completed a final...
Surface Remediation CompletedThe surface remediation occurred from 2011 to 2013. This work...
Sub-Surface Remediation BeganThe Subsurface Remediation began in late 2015. This work aims...
Emergency Release and Fish Kill OccurredIn October 2018, Left Hand Creek landowners reported a fish...
Sub-Surface Remediation ContinuedAfter the emergency release and resulting fish kill, the sub-surface...