1.1.1 Incident Category

Time-Critical Removal Action 

1.1.2 Site Description

The Bullion King Mine is located in San Juan County, at 12,400 feet near the headwaters of Porphyry Gulch.  The site is 11 miles from the town of Silverton and is located 2 miles west of US Hwy 550 up a steep, rough, and extremely narrow four wheel drive road.  The general vicinity is characterized by steep talus slopes, vegetated alpine tundra, lakes, and abandoned mine features.  

The Bullion King Mine waste lies immediately adjacent to the headwaters of Porphyry Gulch.  The stream’s geomorphology varies from cascade to drop pool. The stream courses over exposed glaciated bedrock for most of its short (ca. 1 mile) length.   The stream runs year round but winter flow is reduced to a trickle. 

The primary hydrologic source on the Bullion King Mine property is snowmelt.  Snow remains on the site from October to July (on average snow years).  Additional hydrologic sources include snowmelt run-on from areas located topographically above the site, via overland sheet flow.  The waste dump is barren, devoid of vegetation or exposed native soils, and exhibits large rills and gullies from water flowing on the site.  Snowmelt and precipitation leach through the mine waste and discharge out the toe into Porphyry Gulch throughout the spring and summer months, with the largest flows in the late spring/early summer.

1.1.2.1 Location

The coordinates of the Bullion King Mine are 107° 44' 32" West and 37° 53' 19" North.

1.1.2.2 Description of Threat

The Bullion King mine site contains a waste rock pile that continually erodes during spring runoff and storm events and leaches metals into the creek. The Animas River Stakeholders Group (ARSG) completed a report which identified the Bullion King Mine as one of the most significant source of metals loading to Mineral Creek during high flow conditions. 

Water quality samples taken in the 1990s at Porphyry Gulch’s confluence with Mineral Creek indicated metals and acidity met water quality Table Value Standards (TVS).  However the Mineral Creek sample site M07 approximately ¼ mile below M06 always vastly exceeded TVS during other times.  It was only after further characterization of the mine wastes, including volume estimates, observations, and leach testing that it became apparent that large loads of metals are carried down the steep and mostly inaccessible Porphyry Gulch during and after storm events and during spring run-off.  

1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results

The Bullion King mine portal is collapsed and has acid mine drainage emanating from the collapse feature.  The acid mine drainage flows over and to the side of the approximately one-half acre, 15,000 cubic yard waste pile.

The Porphyry Gulch stream segment (COSJAF08 WQCD segment) is listed as impaired for not meeting the applicable aluminum, zinc, copper, lead, manganese, iron, cadmium and pH standards. The classified use that is not protected is aquatic life. 

The Bullion King has been characterized and evaluated by the ARSG Remediation Feasibility Work Group to determine its feasibility and priority for remediation.  Since all higher priority mine waste projects have been completed, the Bullion King has become the highest remaining priority project for remediation in the Mineral Creek basin.  Total Maximum Daily Load (TMDL’s) for manganese, aluminum, lead, cadmium, copper, iron  and zinc have been adopted and this project will help facilitate implementation and attainment of the TMDL.  

2.1.1 Narrative

2.1.2 Response Actions to Date
Starting in the fall of 2015, the Colorado Division of Reclamation and Mine Safety (DRMS) conducted this work under a joint action memorandum using funds from the state abandoned mine restoration program, EPA 319 grant funds, and private non-profit funds from ARSG.

DRMS regraded and capped the waste pile such that it would shed water and prevent interaction between precipitation and mine waste material. They also diverted/rerouted the mine drainage around the waste rock pile as part of this effort to further reduce surface water infiltration into the pile. During the removal, as is the case in many mine sites, DRMS encountered more waste rock than designed for. This caused a portion of the repository to be too steep for the chosen capping method, and the cap material slipped just before winter.

DRMS and the OSC re-evaluated the remedy, and elected to re-mobilize after snow melt in the summer of 2016 to repair the cap. A small portion of the lower cap liner was removed and the waste rock amended with portland cement to both stabilize the material and to leave a rough surface for a rocky soil vegetative cap to be installed. The cap was installed and all disturbed areas re-vegetated by late September 2016. 

2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)

This is a state lead action, with DRMS acting under OSC direction. No extramural CERCLA funds were used for this response.

2.2.1 Anticipated Activities

None.

2.2.1.1 Planned Response Activities

None.

2.2.1.2 Next Steps

None.

2.2.2 Issues

None.

2.5.1 Safety Officer

N/A

2.5.2 Liaison Officer

N/A

2.5.3 Information Officer

N/A

3.1 Unified Command

N/A

3.2 Cooperating Agencies

EPA and DRMS

None. All personnel have demobilized from the Site.

6.1 Internet location of additional information/report

 www.epaosc.org/BullionKingMine

6.2 Reporting Schedule

None. This is the Final POLREP for this Site.

www.epaosc.org/BullionKingMine