Prince George, B.C. – The provincial government has released information on the inspection history at the Mount Polley mine site.

According to the Ministry of Environment, following reports of a previous breach at the mine, Ministry of Energy and Mines officials investigated an incident on May 24, 2014, and determined this was not a breach but rather, the height of the tailings pond was above regulation. This occurred in a different area of the tailings pond than the Aug. 4th, 2014, dam failure.

At the time of the advisory, the distance between the water elevation and the crest of the dam (freeboard) was less than one meter. The tailings pond level returned to authorized levels and freeboard was approximately 2.4 meters when last measured. Mine records show that the operation was carrying out visual dam inspections and measuring freeboard at an acceptable frequency, including daily measurements following the incident.

On May 24, 2014 the ministry issued an advisory to Mount Polley Mining Corporation for exceedance of the height of effluent within the tailings impoundment. The effluent level returned to authorized levels commencing June 30, 2014.

Since the Mount Polley mine was permitted in 1995, the ministry says there have been 16 geotechnical inspections conducted by ministry geotechnical inspectors. One inspection was conducted each year from 1995-2001 and in 2006, 2008 and 2013. Two inspections were conducted in each of 2005, 2007 and 2012.

Here is a historical record of the number of all types of inspections (including geotechnical)

each year from 1999 to 2014:

• 1999 – 1

• 2000 – 4

• 2001 – 22 (care and maintenance started September 2001)

• 2002 – 4

• 2003 – 2

• 2004 – 5

• 2005 – 15 (mine re-opened March 2005)

• 2006 – 10

• 2007 – 10

• 2008 – 8

• 2009 – 9

• 2010 – 7

• 2011 – 4

• 2012 – 6

• 2013 – 15

• 2014 (to-date) – 8

Monitoring devices, called piezometers, designed to measure the pressure of water in the dam, did not show any changes in the water pressure before the dam breach. The last piezometer readings were taken on Aug. 2, 2014. The investigation will determine if the piezometers were located correctly.

Ministry of Energy and Mines inspectors continue their investigation of the tailings pond breach and are continuing with interviews of mine staff and a review of all applicable documentation on the mine site.  Ministry of Environment conservation officers are independently investigating the breach.

If employees, former employees or the public has any information that would be helpful to the investigation into the cause of the tailings pond breach, they are asked to call the Report all Poachers and Polluters (RAPP) line at 1 877 952-7277 or online at: www.env.gov.bc.ca/cos/rapp/form.htm