Reclamation and Closure

EA considers not only the technical issues, but also the business, economic, regulatory, political, social, and legal dynamics of a project. We work with private and public sector clients to resolve legacy mine site issues. EA has worked through the CERCLA process on several large-scale mining Superfund sites, representing the interests of both the Potentially Responsible Parties (PRPs) and the responsible public agency. EA provides support for Clean Water Act (CWA), NPDES, NEPA, RECRA, and EPA RI/FS needs.  We have also engaged in abandoned mine land reclamation, voluntary clean-ups, legacy uranium mining/milling sites, and large-scale surveys of state lands for agency planning and liability purposes. EA also provides third party review of closure and reclamation plans.

Heap Leach Pad Closure

EA’s engineers and scientists complete investigations and analyses to predict heap leach pad drain-out and water chemistry during and post closure. We use saturated flow models and unsaturated flow models to optimize closure cover design.

Tailings Impoundment Closure

EA designs take into account tailings dewatering and consolidation, seepage analyses, and control, and infiltration analyses. We use state of the art unsaturated and saturated flow models to predict cover infiltration and drain down. When needed we use finite element models to predict long term tailings consolidation.

Groundwater

Our hydrogeologic and water quality staff is experienced in contaminant fate and reactive transport modeling, development of groundwater remediation alternatives, and water resource modeling.

ARD Mitigation

Our geochemists work with clients to develop operational waste rock handling plans, water management plans, water treatment requirements, and closure mitigation plans to mitigate Acid Rock Drainage (ARD) issues.

Geochemistry

EA provides geochemical expertise for mine permitting, operations, and closure. This support includes source term development, design of static and kinetic AGP tests, pit lake modeling, fate and transport studies and modeling, modeling for discharge permitting, and forensic assessments. We employ a variety of geochemical and reactive transport models to simulate the complex geochemical environments present at mine sites.

Infiltration Analysis, Cover and Liner Design

EA performs detailed cover design analyses for tailings impoundments, waste rock piles, and other mine features, as well as developed closure options to protect human health and the environment. Our designs have included the used of GCL, HDPE, and compacted clay liner and cover systems. EA staff use unsaturated flow models to design the cover systems for mine closure systems.

Stability and Erosion Control

EA completes stability and erosion analyses for mine facilities including tailings impoundments, waste rock piles, and pit slopes. EA staff are skilled in the collection of geotechnical data in the field via geotechnical drilling, test pits, and CPT. Our design team uses the site data to develop stable landforms that meet the long term needs of the local communities, regulatory agencies, and our clients. EA is currently working with existing clients to apply the principles presented in the Global Industry Standard on Tailings Management to their tailings impoundments.

Reclamation & Closure Services:

Engineering & Design
  • Site civil design
  • Structural design
  • Dam design, storage and delivery
  • Dam safety review, decommissioning
  • Hydraulics and hydrology
  • Geotechnical design
  • Geologic analyses, geologic hazards
  • Hydrogeology, geochemistry
  • Forensic studies, litigation support
  • Feasibility analyses, costing
  • Construction management
Mining Closure
Process, Instrumentation, Controls
  • Water treatment design
  • Instrumentation, controls, and PLC
  • Electrical design, arc flash
  • Mechanical design
Environmental Monitoring & Compliance
  • Permitting, compliance
  • SPCC and SWPPP plans
  • Remedial investigations and site characterization
  • Groundwater remediation
  • Feasibility studies
  • Stormwater management
  • Health & safety
Construction Material Testing
  • Field engineering
  • Soil, concrete, asphalt testing
  • Quality assurance/quality control
  • Geotechnical laboratory testing

 

 

EA team members have prepared reclamation plans, cost estimates, construction specifications, and engineering designs for more than 60 mine sites worldwide.