Surface‑runoff and Sediment Control Facility Designs
Designed numerous surface‑runoff and sediment control facilities for surface and underground coal mines, active and inactive uranium mills, and hazardous-waste management operations. Facilities have included sedimentation ponds, diversion channels, riprapped channels, land reclamation, check dams, and culverts. State‑of‑the‑art models have been used to determine peak design flows and to aid in design of the structures. Design considerations have included selection of the appropriate design storm, avoidance of maximum permissible flow velocities, cost‑effective erosion control, and water-surface profile analyses. Served as a liaison between the clients and the appropriate regulatory agencies.
Uranium Mill Investigation, Southeastern Utah
Conducted an investigation at the site of an active uranium mill in southeastern Utah to determine appropriate remedial actions to prevent future groundwater contamination after a plume had developed due to seepage from tailings ponds. Performed surface geophysical investigations (electrical resistivity and very-low-frequency electromagnetic) to determine the extent of contamination, bedrock lithology, and the location of major groundwater-conducting fractures. Utilized water-level and quality data from over 140 previously existing and new monitor wells to aid in defining the extent of groundwater contamination. Conducted long-term pumping tests to determine the anisotropic nature of the groundwater hydraulic system. Modeled the fractured aquifer to determine the rate of contaminant migration and the effectiveness of the proposed remedial action. Designed a remedial-action plan consisting of hydrodynamic control of contaminant migration through the operation of several groundwater recovery wells and pumping this groundwater to evaporation ponds for disposal.
Abandoned Copper/Lead Smelter Investigation
Conducted groundwater, surface water, and soil investigations at the site of an abandoned copper/lead smelter in Utah which was being considered for addition to EPA’s National Priorities List. Installed multiple monitoring wells to assess groundwater hydraulic and quality conditions. Delineated and sampled areas of smelter wastes, including slag, calcine, baghouse dust, and miscellaneous waste which had accumulated during operation and demolition of the smelter. Data received from the laboratories were interpreted using geochemical and hydrologic models to determine the need for future remedial actions and the effectiveness of natural soils at attenuating the migration of inorganic contaminants from the waste sources. Developed a conceptual remedial-action plan together with work plans for remedial design. Information was also provided in support of the client’s pursuit of Innocent Purchaser Defense rules.
Stabilize a Steep-Slope Area Affected by a Coal Outcrop Fire
Designed methods to stabilize a steep-slope area of approximately 40,000 square feet that had been affected by a coal outcrop fire. The fire had originated in an adjacent abandoned underground coal mine and had resulted in denuding of the area and mass failure of several portions of the slope, including multiple rotational failure cracks with depths in excess of 25 feet and top widths in excess of 10 feet. The design consisted of creating a uniform slope in areas that had been subject to mass failure, installing gabions and anchoring the gabions to the slope using rock bolts, filling the gabions with road-base material and topsoil, and revegetating the area. Provided construction oversight and survey control during implementation of the project.
Dewatering Plan for Proposed Lead/Zinc/Silver Mine
Developed a conceptual dewatering plan for a proposed lead/zinc/silver mine that was projected to encounter significant quantities of hot saline groundwater. Previous dewatering operations in the region had pumped water to percolation ponds on an alluvial fan that was situated above a valley that relied on groundwater for irrigation of agricultural fields. Performed investigations to determine the potential of future dewatering operations to impact the valley’s groundwater resources. Reviewed data from local water-supply wells to determine whether or not past impacts had occurred. Evaluated alternatives for mine-water disposal and designed a monitoring program to assess future impacts. Served as a liaison between the mining company, regulatory agencies, and legal counsel.
Reclamation Plan for Abandoned Mine/Mill/Smelter Complex in Utah
Prepared a reclamation plan for an abandoned mine/mill/smelter complex in Utah. Collected soil, waste, and water samples to delineate acceptable topsoil and structural fill borrow materials and to determine requirements for isolation of waste materials. Prepared reclamation designs, giving consideration to regulatory obligations, demolition of structures, post-mining land uses, soil cover requirements, revegetation, and controlling runoff in a non-erosive manner. The reclamation plan also included plans for shaft and portal closure, backfilling and stabilization of disturbed slopes, reclamation of roads and pads, and general re-contouring of the area. Particular concern was paid to mitigating erosion that had occurred in the area since shutdown of mining operations and the beginning of reclamation. Project costs were also estimated.
Inactive Uranium Mill Tailings Piles in the western United States
Supervised data collection and analyses to evaluate the migration of inorganic and radioactive contaminants in surface and groundwater from several inactive uranium‑mill tailings piles in the western United States. Supervised drilling and monitoring‑well construction. Collected soil and water samples for quality analyses. Performed field tests to determine groundwater hydraulics. Analyzed all data to determine existing conditions and probable impacts of implementing proposed remedial actions. Prepared detailed reports for each site and associated sections of environmental assessments. Assisted in preparation of remedial-action plans.
Lixiviant Migration Study at a Texas Uranium Solution Mine
Evaluated the extent of lixiviant migration at a uranium solution mine in Texas. Developed cost estimates for restoration of groundwater quality at the site.