Client: Rio Tinto
Location: Cibola County, New Mexico, USA
Challenge. Develop and implement reclamation plan to allow transfer of mill site to the U.S. Department of Energy for long-term monitoring and closure of mine in accordance with state regulations and requirements
Solution. To close the L-Bar mill and tailings site, INTERA prepared the reclamation and closure plan, bid specifications, and construction contract documents, and provided construction and quality control oversight for reclamation activities that included: constructing lined evaporation cells, an enhanced evaporation system, and a radon barrier; transferring residual tailings liquid to the evaporation cells; moving waste tailings ore, salts, and windblown radium 226 to the former tailings pond area; decontaminating, demolishing, and burying the mill facility in place; re-sloping the tailings dam and the barrier surface to minimize surface erosion and protect against infiltration; and re-vegetating the reclaimed area. We developed a compliance strategy for groundwater using alternate concentration levels and alternative abatement standards in conjunction with monitoring. After gaining regulatory approval, the L-Bar mill site was transferred to the U.S. Department of Energy for long-term custody. To support closure of the JJ No. 1 mine site, INTERA provided engineering and construction oversight for the reclamation and closure of 11 vent shafts. We designed and implemented an award-winning “hardscaping” method, resulting in vent shaft closures that are more consistent with the landscape, reduce the disturbance and carbon footprint required to obtain borrow material, and create wildlife habitats for small mammals, reptiles, and avifauna. This innovative closure method accelerated the completion of one of the first uranium mine closures in the State of New Mexico.