El Sauzal Closure

El Sauzal Closure

Water management was a significant challenge at the El Sauzal mine given the site’s steep topography and flashy rainfall history. ERC was retained to develop a diversion and water management plan for the mine’s closure. Site and historic regional precipitation records were evaluated to define the magnitude of rainfall expected at various frequencies. A risk assessment was completed to consider flow frequency and facility sizing. Based on this analysis the mine selected the 100-year storm event for design. ERC’s design included over six kilometers of channel. Design also included sediment ponds, energy dissipation structures, stilling basins and rundowns. Due to the varied flows, slopes and ground conditions a number of types of channel armoring were required with armoring including vegetation, bedrock, concrete and geowebs.

Project Categories:
mining

Haile Gold Mine – South Carolina

Haile Gold Mine – South Carolina

Gold was first discovered in Lancaster County, South Carolina in the 1820s. In 2007 Romarco Minerals acquired the property and began the process of planning, designing and permitting a modern mine at this historic location. ERC provided water resource and environmental consulting services through feasibility, permitting and final design. Environmental work included baseline wetland delineations, habitat functional assessments and impact assessments. Water resource work included climate evaluations, hydrologic and hydraulic assessments, water balance modeling, water supply assessments, spillway design and erosion control. ERC was particularly instrumental throughout the permitting process given our technical and regulatory expertise. We worked with the Corps and their third-party contractor during the EIS process and helped secure permitting which has led to operations of what will become the largest gold mine in the eastern US.

Project Categories:
mining

Minera Panama – Panama

Minera Panama

With its location in the rainforest and in an environment that receives nearly 5 meters of annual rainfall, water management is one of the critical technical challenges for Minera Panama. ERC was brought into the project due to its experience characterizing and developing water management plans for mines in locations with extreme climatic conditions. Our first task was to establish estimates of design rainfall events and associated runoff for short-term and extended wet cycle conditions. Our next challenge was water diversion. The main local river, the Rio Botija, ran right through the initial mining target and needed to be diverted around the planned pit. ERC’s design included a risk based assessment of tradeoffs between design storms and allowable pit flooding. The ultimate design required lining to minimize seepage and related instability adjacent to the pit wall for the 2 kilometer channel. Finally ERC developed an operational water balance model for mine personnel use in managing pit sumps and surface water dewatering systems.

Project Categories:
mining

Newmont Nevada Operations

Newmont Nevada Operations

ERC has provided water resource and environmental services to Newmont Mining Corporation at their eight Nevada sites. At all locations, accurate quantification of water requirements and needed storage capacity is paramount to efficient and safe operations. Climatological conditions have been quantified to allow the mines to understand both short-term and multi-month and year weather conditions that can impact water management. Probabilistic water balance modeling has been completed to predict operational variability at tailings storage facilities, heap leaches and operations that have multiple interlinked facilities. ERC’s stochastic models have been used for project planning, permitting, design and closure scenarios. We have been involved in overall water management of facilities including estimates of fresh water requirements and design of diversion channels and sediment control measures. ERC has also provided ecological planning and design services for heap cover/closure design, revegetation planning and landscape-based closure reclamation.

Project Categories:
mining