Waste Rock and Heap Leach Cover System Performance Evaluation
Location
Peru
Client
Minera Barrick Misquichilca Pierina
Project Description
GSA designed and monitored store and release cover systems to reduce net percolation and oxygen ingress into closed waste facilities in an area with extreme seasonal precipitation (>1000 mm in six months). In-situ and laboratory hydraulic characterization of waste rock, heap leach and potential cover materials were used to help design two multi-layer cover system test plots to assess net infiltration, surface water runoff and erosion. Instrumentation consisted of multiple cover performance monitoring systems and surface water flow monitoring to perform a complete water balance. Monitoring was performed for 3.5 years with a final field investigation to determine rooting and how clay liner permeability changed over time. Unsaturated flow models were developed and calibrated with the monitoring data to predict long-term cover system performance and evaluate different cover system alternatives.
Project Highlights
- Design of multi-layer cover system test panels
- Design and implementation of automated cover system performance monitoring and surface water runoff monitoring systems
- In-situ and laboratory hydraulic characterization of cover and waste rock material
- Monitoring system data collection and maintenance
- Develop and calibrate unsaturated flow models with the test panel data to predict long-term cover system performance