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Captain Jack Mill (Left Hand Canyon, Boulder County)

This site is one of the "Superfund" hazardous waste sites in Colorado. A site qualifies for the National Priorities List (NPL or Superfund list) when the U.S. Environmental Protection Agency (EPA) determines there is a release or threatened release of hazardous substances that may endanger public health, welfare or the environment. In Colorado, the lead agency for Superfund remediation may be either the EPA or the Colorado Department of Public Health and Environment (the state health department).




The Captain Jack Superfund site is located at the headwaters of the Lefthand Creek Watershed in a narrow valley about 1.5 miles south of Ward in Boulder County, Colorado.




Mining for gold and silver began in this region in 1861 and continued intermittently untiil 1992.  Camp Frances, near Ward, was started in the early 1890s.  It was here that the Big Five Mining Group managed several mines, including the Adit, Ni-Wot, Columbia and Dew Drop.  The combined ores came down to the Camp by way of the adit tunnel.  Processing was carried out in the Dew Drip Mill or the larger Big Five Mill - locate on the side of the gulch below the Camp.  The Colorado and Northwestern Railroad was built through the Big Five/Camp Frances area to the town of Ward to service the mining area.


The histories of the Big Five Mine, located about 500 feet upstream from the mill, and the Captain Jack Mine (also known as the Black Jack Mine) are uncertain. The Black Jack Mine operated intermittently as an underground mine following its patent approval in 1917.  The Big Five Mine operated without a permit, so there is no way to track its official history through conventional paper trails.  It is unknown how long it originally operated before it was shut down.  The Big Five Mine consists of an adit (tunnel), a large waste rock pile and a settling pond.  The Mill Works area includes several lagoons previously used for settling tailings from the mill.  The lower portal consists of the Black Jack adit and the contents of a shed.  Other mine wases include waste material in Lefthand Creek and waste rock from the mine tunnels.


 The EPA added the Captain Jack site ot the National Priorities LIst (NPL) on September 29, 2003.



Samples indicate the presence of elevated concentrations of lead, arsenic, thallium, zinc, manganese, copper, magnesium, cadmium, aluminum, calcium and iron.  Site contaminants of highest concern are lead, arsenic and thallium.




Lefthand Creek is one of the sources used by Lefthand Water District to supply drinking water to approximately 15,000 water users.  Elevated levels of metals and other contaminants have been found in surface water and sediment samples from Lefthand Creek and its tributaries and from wetlands fronting along the creek.  Groundwater samples from two nearby wells show elevated levels of metals.  Uncovered tailings, ore concentrates and surface soil contaminants could pose a threat of dust emissions, especially to the nearby residences.  In addition to human exposures, the elevated metal concentrations in sediments and water entering Lefthand Creek affect aquatic life.


The selected remedy for cleaning up the Captain Jack Mill Superfund site has two components, as it controls both surface and subsurface contamination sources.


To control subsurface contamiantion, the remedy (Alternative 3B in the Remedial Investigation / Feasibility Study) includes an installed bulkhead, mine pool mitigation and long-term monitoring.  The concrete bulkhead will plug the draining mine adit, impounding the mine water.  The mine pool environment will have reduced oxygen levels, which, coupled with an injected caustic chemical, will increase the pH of the water to a neutral condition. The monitoring system will allow assessment of the effectiveness of the remedy and determine if additional action is needed. Remedy design should be completed in Spring 2013. 


Under the selected surface remedy (Alternative 2C), all site material containing the contaminants of concern in concentrations above the remedial action levels was excavated and placed in two onsite consolidation cells. Remedy construction was completed in November 2012.


Status Update pdf file   January 2014

Status Update pdf file   January 2013

Status Update pdf file   October 2010

EPA Lefthand Water Revitalization Project pdf file   


Mary Boardman, State Project Manager




Jeannine Natterman, State Community Involvement Coordinator


(888) 569-1831 ext. 3303 outside the Denver metro area



Joy Jenkins, EPA Remedial Project Manager




John Dalton, EPA Community Involvement Coordinator


(800) 227-8917 ext. 6633 outside the Denver metro area 

Mark Williams, Boulder County Health Project Manager