Environmental and Engineering Reclamation Services
Black Cloud Mine, Leadville, Colorado
EA provides environmental and engineering reclamation services for Resurrection Mining Company’s (RMC) Black Cloud Mine, located in Lake County, Colorado near the town of Leadville. Reclamation of the legacy lead-zinc mine site is conducted under a CERCLA Consent Decree, as administered by the Colorado Division of Reclamation, Mining and Safety (CDRMS). Major reclaimed features included a 20-acre milling/processing site and the associated 40-acre tailings impoundment, as well as numerous appurtenant satellite mine sites. EA’s reclamation engineering services include mine tailings and waste rock management (including acid-generating material), water management (tailings area surface, seepage collection and treatment, and non-contact diversion), and contractor procurement and construction oversight. Additionally, EA provides environmental assessment, remedial design, and reclamation design consisting of building demolition, removal of chemicals and waste, hauling and placement of waste rock on to the tailings, regrading of the tailings, placement of growth media, revegetation, and design and installation of diversion channels. This ongoing project was awarded the 2015 Excellence in Hard Rock Reclamation Award from the Colorado Mined Land Reclamation Board.
Tailings Dam Raise and Reclamation Plan
Umetco Minerals Corporation, Hot Springs, Arkansas
EA designed and supervised construction of an embankment raise of the 125-foot-high tailings dam and developed a reclamation plan to be implemented during continued operation of the tailings impoundment. The raise and reclamation work improved the existing drainage system and overall stability of the impoundment. The project included subsurface investigation and piezometer installation, flood routing and spillway design, seepage analyses and blanket design, cover design, stability analyses, liquefaction analyses, and construction oversight.
Comprehensive Reclamation and Closure Plan
EA designed reclamation plans for an above-grade uranium tailings impoundment, a below-grade tailings impoundment, evaporation ponds, and mined pits. EA staff performed site-wide hydrology, characterization of the groundwater and geochemistry, risk assessment for clean-up of radiological contaminants, seepage analyses, stability analyses, and radon attenuation analyses. The reclamation plans were approved by the U.S. Nuclear Regulatory Commission.
Abandoned Uranium Mine Reclamation
EA was the lead consultant for development of the removal action related to historic uranium mining activities on land currently under the control of Babbitt Ranches near Cameron, Arizona. The site consists of abandoned mining units within two sections of land that were under an Agreement and Order on Consent (AOC) for Interim Removal Action. The scope of work included development of a Health and Safety Plan, Quality Assurance Project Plan, Field Sampling Plan, Data Management Plan, Quality Management Plan, Background Determination and Gamma Scanning Plan, and Removal Site Evaluation report, all of which have been approved by the U.S. EPA. Review entities included U.S. EPA Region IX, Arizona Department of Environmental Quality (ADEQ), Arizona State Lands, Bureau of Reclamation, and the Navajo Nation. EA and their team have worked directly with the EPA and other agencies through the review and comment process to obtain approved work plans.
Heap Leach Pad Drain Down and Rinse
EA completed unsaturated flow modeling and geochemical analyses for the drain down and rinse of a heap leach pad for final closure at the Yanacocha Mine. The project consisted of modeling the projected discharge rate from the pad during and after closure. The geochemical properties of the discharge solution from the heap leach pad during and after the proposed progressive closure were also modeled to determine the projected duration of longterm monitoring and potential water treatment requirements.
Reclamation Site Services and Water Management
EA staff provide services for the Idarado Mining Company, a subsidiary of Newmont, at their facilities in Telluride and Ouray, Colorado. Services provided by EA staff have included collection and disposal of tailings from impacted sites, stream stabilization, maintenance facility design, activities associated with preservation of the historic Pandora Mill building, and water management for the historic Bridal Veil Power System. Water management activities for the Bridal Veil hydroelectric system include Engineering, Procurement, and Construction Management (EPCM) services for rehabilitation and maintenance of nearly four miles of historic pipelines supplying water to the Bridal Veil Powerhouse. The facility, operated under a FERC permit exemption, provides electricity to the Town of Telluride and the San Miguel Power Association. EA provides project management and engineering services for rehabilitation, replacement, and maintenance of the pipelines that supply water to the powerhouse, including dam safety programs for the two high-mountain storage reservoirs that supply water to the project. EA’s project managers coordinate with Newmont, Telluride, San Miguel County and FERC managers, and Colorado Dam Safety officials to ensure the safe and efficient operation of the system.
Reclamation of a Mill Site Building
Idarado, Telluride, Colorado
EA staff have worked on reclamation of the Pandora Mill building and site for Idarado Mining Company, a subsidiary of Newmont. EA staff provided asbestos surveying and abatement oversight of the mill. EA staff coordinated interested parties, including the Colorado Division of Reclamation, Mining and Safety (CDRMS), the History Colorado Administration, the Town of Telluride, San Miguel County, and other local entities, to develop a plan to preserve the Pandora Mill. As part of this project, EA staff organized and directed stakeholder meetings, worked with CDRMS to develop reclamation amendment options, determined viable clean-up levels for the mill, obtained cost estimates for the clean-up, and presented viable options to state and local government officials. We worked closely with Newmont leadership, their internal and external counsel, site managers, and regulators to effectively keep the project moving forward. As a result of our involvement with this site over many years, we correspondingly have a good understanding of multi-jurisdictional regulatory boundaries that affect the site. We are also aware of the intricacies of working on a site in the near proximity to residential, recreational, and tourist areas.
Landslide Investigation, Hams Fork Spoils
EA performed a forensic investigation for a landslide that occurred during construction of a haul road to move coal mine spoils. The investigation included a review of geologic reports and mapping for the site and region, a site visit to observe the landslide, subsurface investigation and laboratory testing, groundwater monitoring, seismic, slope stability, and infiltration analyses, and preparation of a report with conclusions and recommendations regarding the causes of the landslide and slide mitigation.