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Rico Argentine Mine

 
Site Contact:
Craig Myers
On-Scene Coordinator

(myers.craig@epa.gov)

Site Location:
Rico, CO 81332
 response.epa.gov/RicoArgentineMine

The Rico Argentine Mine Site includes the historical water treatment settling ponds and associated waste, and it includes historic mine working associated with the St. Louis Tunnel. The Site is adjacent to the Dolores River and extends into Telescope Mountain and its related mine workings. The St. Louis Tunnel Adit and settling ponds are located on the eastern edge of Dolores County approximately ½ mile north of the town of Rico. The adit discharge is approximately 1.5 to 3 cfs (or 600 to 1300 gpm) seasonally, and has been the subject of several versions of pilot and demonstration water treatment systems since 2011. This discharge represented over 50% of the zinc load on the Delores River prior to 2011.  

Prior to construction of the various versions of water treatment systems, the settling ponds area was on the eastern bank of the Dolores River and occupies about 80 acres along the flood plain. The settling ponds contained metals precipitate sludge that has remained onsite since water treatment operations stopped around 1996. 

Construction of a full scale wetlands based treatment system, the Expanded Constructed Wetlands Treatment System, or ECWTS, began in 2024. This system has been designed to remove substantial amounts of suspended and dissolved metals from the adit discharge water to improve the health of the Delores River.  


St Louis Tunnel Ponds - view south towards Rico St Louis Ponds - tracer dye from Argentine Shaft injection St. Louis Tunne Adit portal and mine water discharge from the adit. St Louis Tunnel - discharge from adit, portal in backbround with abandoned WTP. Argentine/Blaine mine property - tailings impoundment (right) Pond 18 lime/metals precip sludge removal Drying Cell - Pond 18 solids Blaine Adit - coffer dam Mine water pool behind the Blaine adit coffer dam at 350 inby. Rock fall debris at the Humbolt crosscut before mine pool was pumped from the Blaine adit. (400 ft inby) EPA contractors and pump system and manifold at the Blaine adit coffer dam used to remove the pooled water and pump base flow. rock debris fall from raise above the Humbolt crosscut 400 feet in the Blaine adit - following pumping. Section Dredge on one of the settling ponds removing lime treatment-precipitation solids Close up view of the bioreactor media that is being placed in the vertical flow treatment cell of the Enhanced Demonstration scale system. Construction of the Enhanced Demonstration Wetland - biochemical treatment system Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm. The right side of the photo is the demonstration wetlands bioreactor cell. The central/right component is the enhanced demonstration wetlands settling basin, the central/ left is the manganese removal basin, and the left edge is the bioreactor cell. Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm. The right side of this photo is the edge of the manganese removal cell in the enhanced demonstration wetlands, the central cell is the bioreactor cell of the enhanced demonstration wetlands, the far left is emptied pond 15. Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm. The distant right corner is a pile of materials to be placed in the repository once ready to receive material. The central portion of the photo is the western berm of the repository for treatment solids, and the left is the interior of the repository receiving a layer of gravel over a fabric liner layer. Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm. This photo is the repository area receiving a layer of gravel over a fabric liner layer. Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm.the right side of the photo is the northern end of the repository area the left portion of the photo is the historic lime treatment plant which is now utilized for housing the telemetry system and addition of treatment agents. Water Treatment and Repository Area Overview Photo. Taken from the Northwest corner of the repository berm. The right side of the photo is the influent to the water treatment systems from the mine discharge. The central area is the settling basins and beyond that the horizontal wetland portion of the demonstration wetlands area, the left side of the photo is the demonstration wetlands bio reactor cell. Water Treatment Flow Photo. The right water flows from the right side of the photo into the demonstration and enhanced demonstration wetlands though the valve in the center of the photo or into the historic treatment ponds on the left side of the photos. Water Treatment Flow Photo. Water flows from the mine discharge into a channel flowing under the access road through the culverts shown in the center of the photo. Water Treatment Flow Photo. A portion of the mine pool water is siphoned through a monitoring well into this pipe system and into the historic treatment ponds. This photo is the flowrate monitor for the flow of this wetlands bypass. Water Treatment Flow Photo. A portion of the mine pool water is siphoned through a monitoring well into this pipe system and into the historic treatment ponds. This photo is the flowrate 145.9 GPM for the flow of this bypass. Enhanced Demonstration Wetlands System. This is the settling basin located at the beginning of the treatment train. Note it is covered in black, plastic spheres to offer cold temperature protection. Enhanced Demonstration Wetlands System. Looking south from the settling basin towards the manganese removal basin. Enhanced Demonstration Wetlands System. Manganese removal basin, note the black media in the manganese removal basin is a high surface area plastic to aid in treatment. Enhanced Demonstration Wetlands System. Bioreactor cell located after the manganese removal basin and before the aeration cascade. Enhanced Demonstration Wetlands. South of Pond 15 (Pond 15 is on the right side of the photo) is the aeration cascade located at the end of the treatment train for the enhanced demonstration wetlands. In the right forefront of the picture is overflow water drainage for Pond 15. Enhanced Demonstration Wetlands. Lower end of the aeration cascade, contains plastic material with surfaces designed to increase aeration. Historic Treatment Ponds. Pond 15 from the southwest corner. Mine Pool Pumping System. Drilling location for horizontal wells at the eastern edge of the historic lead repository north of the historic treatment plant. Note the Drill bit, located next to the pipe section, on the pallet, it is missing it drilling shoe and is awaiting correction to continue drilling. Demonstration Wetlands - Effluent from Wetlands and Wetlands Bypass Demonstration Wetlands - Settling Basin for the Bio Reactor Wetlands Demonstration Wetlands - Bio Reactor Cell for Bio Reactor Wetlands, note the black plastic media covering the cell to provide solar warmth to the cell. Demonstration Wetlands - Aeration Cascade after the Bio Reactor Cell Demonstration Wetlands - Horizontal Flow Wetlands - Settling Basin. Note the Black plastic media on the surface, this provides solar thermal protection for the settling basin. Demonstration Wetlands - Horizontal Flow Wetlands - Surface Flow Wetlands. This cell has different grasses planted and are growing well. Demonstration Wetlands - Horizontal Wetlands - Subsurface Flow Wetland. Note the various plant life growing on the surface, the more dominate grass types have taken hold and are thriving. Demonstration Wetlands - Horizontal Wetlands - Aeration Channel (left) and Rock Drain (right). The aeration channel has high surface area rocks and electronic bubblers. The Rock Drain assists with metals removal. Demonstration Wetlands - Effluent South of the Enhanced Demonstration Wetlands Repository - Constructing run on controls on the western side of the repository. Repository - Run on controls directing water away from the repository. Saint Louis Tunnel Adit - The Adit is collapsed, note the pipeline that exits the adit, this extends into a portion of the tunnel in front of additional blockages. The Pipeline is currently used to siphon water from the tunnel which then bypasses the wetlands systems. Adit Control - Water Siphoned form the adit is discharged into the treatment train here, south of the wetlands systems and mine effluent bypass.
For additional information, visit the Pollution/Situation Report (Pol/Sitreps) section.