Open-pit mining operations bear a degree of risk related to slope stability due to factors such as geology type, weather, seismic activity, and mining practices. Stability issues require a prompt response to continue operations, prevent further damage, and keep employees safe. In October 2021, record rainfall levels in Nevada caused a pit wall to fail at a client's open-pit hard-rock mine, forcing the closure of pit haul roads and two active mining areas. Our client turned to Barr for help to understand the situation and resuming production immediately by developing temporary, short-term controls as well as long-term plans to remediate the slide and prevent future failures.
Barr mobilized a team member who arrived at the site the next day for an initial assessment and worked with the client’s team to determine that saturation and increased pore-water pressure within a fault zone in the pit slope triggered the failure. We developed a monitoring approach and adjusted access to understand ongoing conditions while allowing mining to resume. While on site, we also developed a drilling investigation plan to evaluate potential risk for additional slope failures and inform the remediation design. Following execution of the drilling program with downhole televiewer surveys completed to obtain structural data in November 2021, Barr performed basic design analysis of the drilling and data to provide initial remediation design guidance by mid-December. Based on the findings, Barr worked with the client to implement a remediation plan with monitoring and a trigger action response plan (TARP) controls in place in January 2022.
Barr’s remediation plans were successfully implemented, and the facility returned to normal operations with its primary haul roads by early February 2022, less than four months after the slope failure. To learn more about Barr’s mining geotechnical services, contact our team.
About the authors
Russ Sheets has more than 15 years of experience using geological information to understand site conditions and make recommendations for mining projects. He has experience planning and executing investigations for new mine development, existing operations, and grounds failures. Russ has worked on projects from the pre-feasibility stage through mining, Additionally, Russ has implemented inspections and monitoring systems to understand soil and rock behavior.
Emily Rose has geotechnical engineering experience and a background in open-pit gold mining. Her services focus on large-scale slope stability, geotechnical monitoring instrumentation and deployment, slope stability analyses for highwall design, large-scale slope instability mitigation, development of ground-control management plans, characterization of rock and soil materials, preliminary site investigation, and shallow underground geotechnical stabilization. Emily specializes in providing geotechnical expertise and managing field investigations.