Hydrogeologic Support for the Mt. Hope Mine EIS

M&A conducted investigations to support an EIS for mining one of the world’s largest molybdenum deposits. In addition to drilling, testing and monitoring, we developed a numerical model to project pit inflows and post-closure pit-lake development. Our modeling results, which supported a geochemical characterization, were coupled with a regional model to project the impacts of the proposed mining operations.


The proposed Mt. Hope project — a primary development interest of General Moly — targets a 1.3 billion pound molybdenum reserve. Because the project is located on BLM land, an EIS is required to predict the regional effects of the proposed mining operations.


Environmental Impact Studies

  • Characterized the fractured-rock hydrogeology of the planned pit area
  • Designed and implemented a well drilling / testing program to obtain the data needed to characterize hydrologic conditions in the fractured-rock aquifer
  • Led hydraulic testing activities near the proposed mine facilities and open pit
  • Designed and implemented a groundwater monitoring program for the proposed mine area
  • Established a data collection and transfer system to facilitate rapid analysis by the EIS team
  • Prepared a comprehensive report that met the rigorous requirements of EIS approval process
  • Provided technical support services during the regulatory review process

Groundwater Modeling

M&A developed a 3D groundwater flow model for the fractured rock aquifer and used it to…

  • Identify pit-dewatering requirements
  • Predict groundwater level changes during and after mining operations
  • Create a water balance for the post-closure pit lake
  • Assess whether the future pit lake would remain a passive hydraulic sink
  • Develop sector-specific pit-radius inflows, characterized by rock type, to support a geochemical pit-lake analysis by a partner consultant

We coupled this local model with a regional model (developed by a partner consultant) to project the impact of the proposed mining operations on groundwater conditions in Diamond Valley.