Challenge. To identify, develop, and permit a 4,000-gpm (252 L/s) water supply and to manage the environmental permitting process for a proposed mine and mill in a region where freshwater resources are both scarce and the focus of public and regulatory concern.
Solution. INTERA led a program of exploratory drilling, aquifer testing, and groundwater flow modeling, to demonstrate that the deep, non-potable Capitan aquifer can sustain the proposed pumping rate of 4,000-gpm (252 L/s) for the 50-year life of the mine. We designed and drilled two production wells, each approximately 5,387-ft (1,642-m) deep, and characterized aquifer properties by conducting a 7-day, constant-rate pumping test. Water produced from testing was stored in a 7M gallon (26M L) storage pond engineered, constructed, and reclaimed by INTERA. As required by the federal Environmental Impact Statement (EIS) process, a groundwater model was developed to evaluate the impacts of proposed pumping on the Pecos River, a connected stream subject to an Interstate Compact Agreement for water deliveries between the states of New Mexico and Texas. The model results showed minimal impacts from pumping to the Pecos River and government approvals of the model were delivered without delay to the 28-month EIS process. In support of the Owner’s disclosure requirements, INTERA contributed to the NI 43-101-compliant Preliminary Economic Assessment, Pre-Feasibility Study, and Feasibility Study by authoring the water availability and environmental permitting sections. Environmental permitting responsibilities included managing the EIS contractor, securing the air quality permit for construction, and managing specialty environmental surveys. Additional details on the project can be found here.