Mount Polley Tailings Dam Failure: Lessons Learned for Professional Practice

June 9, 2022 — 10:30-11:45 a.m.

Just after midnight on Aug. 4, 2014, the Mount Polley tailings dam in British Columbia failed, releasing approximately 10 million cubic metres of stored water and 13 million cubic metres of saturated tailings to the receiving waters of Polley Lake, Hazeltine Creek, and Quesnel Lake. After assuring the safety of mine personnel and the downstream communities, the government of British Columbia responded by appointing an independent review panel (IRP) to assesses the failure. At the same time, the chief inspector of mines (CIM) initiated a comprehensive investigation into the mechanism of failure and the root causes of the failure.

The two investigations were held concurrently and although independent, they shared collected site investigation and laboratory test data. The IRP was led by Dr. Norbert Morgenstern of the University of Alberta, along with Dirk Van Zyl of the University of British Columbia and Steven Vick from the United States. The CIM team included ministry personnel with technical support from Klohn Crippen Berger and external specialists in forensic investigations and root-cause analysis.

In this session, Harvey McLeod, P.Eng., P.Geo., FEC, will share important lessons for professional engineers to learn from this event. These lessons include elements of:

  • professional reliance on other professionals as illustrated with an almost annual transition of the engineer of record (EOR) and engineering support staff
  • complacency with understanding the complexities of Quaternary geology and glacial processes as illustrated with “less-than-complete” site investigations
  • the importance of change management between consulting firms and between EORs
  • the weak governance processes the mine operator had in place leading up to the failure

The IRP and CIM investigations led to two major outcomes:

  • the B.C. Mining Code was revised to embed the principles of good governance and good design of tailings facilities into law
  • Engineers & Geoscientists British Columbia produced the Professional Practice Guidelines— Site Characterization for Dam Foundations in BC (2016)

Presented by

Harvey McLeod, P.Eng., P.Geo., FEC

Principal at Klohn Crippen Berger