The broken rock in the open pit is segregated into ore and waste based on the assay of rock cuttings sourced from the blasthole production drills.
This assay analysis determines the sulphide copper percentage and gold grams per tonne for material within the vicinity of each blasthole.
The forecasted metal prices and metallurgical recovery is used to calculate copper equivalent percentage.
A forecast of mining and treatment costs establishes the mining cutoff grade and hence the material to be trucked to the plant for processing.
The plant uses three stage crushing, and conventional rod and ball mills with a flotation and dewatering circuit to produce a copper /gold concentrate.
When the mine is up-and-running, it mine moves 80,000-90,000 tonnes of material per day, the mill has a capacity to process 17,800 to 22,000 tonnes per day (tpd) of ore depending on hardness. Mount Polley concentrates are trucked to facilities at the Port of Vancouver and then shipped to overseas smelters.
At Mount Polley, we look for individuals to
join our workforce who display a variety of skills and training levels.
We have a training department that will train
workers from other industries.
Our key goal is to source workers locally. The
furthest away workers are usually recruited from is Quesnel or Williams Lake.
Several of Mount Polley’s staff are from Big Lake, Horsefly, and Likely, and
live near the mine.
Staffing Numbers at Mount Polley
When Mount Polley is in full operation, we have
as many as 370 staff working on rotation at the mine, most often in four crews.
Shifts are typically a 12-hour day shift and
12-hour night shift; four crews; seven days on, seven days off.
Additionally, we have about 50 support staff including administrators, supervisors, warehouse workers, engineers, geologists, assayers, technical personnel, and human resource staff.
Imperial congratulations to Dr. ‘Lyn Anglin on being named a
recipient of the Canadian Institute of Mining, Metallurgy and Petroleum’s (CIM)
Distinguished Lecturer award. The CIM Awards
honour the mining industry’s “finest for
their outstanding contributions in various fields. Their achievements and
dedication are what make Canada’s global mineral industry a force to be
Due to her extensive experience in
geoscience research and engagement with the public, Dr. Anglin was hired
as Imperial’s Chief Scientific Officer in 2014 to assist with the response to
the Mount Polley tailings spill.
During ‘Lyn’s tenure, she provided technical advice to the Company’s
spill response team, and liaised with First Nations, local communities,
government regulators and industry associations regarding the spill response
and progress on remediation.
The area around Likely has a long and fascinating
history of placer mining. Placer mining refers to mining materials (mostly
gold) deposited in ancient stream beds that are still largely unconsolidated (i.e.
relatively loose materials).
Some of the earliest gold discoveries in the area were made in 1859, one in the Horsefly River, and one in the Dancing Bill Gulch. The latter became known as the China Pit and then the Bullion Pit, and is located just downstream of Likely on the west side of the Quesnel River. The Bullion Pit is now a local historic site with a public walking trail.
Placer gold was also discovered near the mouth of
Keithley Creek on the Cariboo River about 12 km upstream from Quesnel Forks in
July 1860. Other significant discoveries were subsequently made just 4 km south
of Likely on Cedar Creek, and in Quesnel River itself.
In 1897, the Golden River Canal Co. decided to build a dam across the Quesnel River at the outlet from Quesnel Lake in order to block the river and be able to work the gravels from the bottom of the river. The tent town that developed on the site was known as ‘Quesnel Dam’. In 1920, the dam was dynamited and the remnants of the dam can be seen just north of the Likely Bridge in Likely. After the removal of the dam, the residents decided to rename the town ‘Likely’ after a local prospector, John Likely.
The Bullion Pit ulimately became a very significant gold producer in the area. BC Minfile report number 093A 025 states that “In 1897, the Consolidated Hydraulic Mining Company commenced full scale operations and between 1898 and 1902, the company processed 5,912,700 cubic metres of mixed materials, recovering 1,402,316 grams of gold at a recoverable grade of 0.132 grams per tonne gold… Estimations indicate that a total of 200 million tonnes of material were removed by hydraulic methods and 5.463 million grams (175,644 ounces) of gold were produced.” Indications are that much of this material was discharged directly into the Quesnel River.
The shortage of water in the early 1900s led the operators of the Bullion Pit to construct a number of water control and diversion works on local streams and lakes to gather water for the hydraulic operations at the pit. Photos from the BC archives, including ones featured in the TV program “Gold Trails and Ghost Towns – The Bullion Pit episode”, document weirs and diversion ditches built on Polley Lake and Hazeltine Creek and other creeks in the area.
This Facebook page gives regular updates on the areas in BC that were part of the mine’s early gold mining history.
Many placer mines continue to operate in the area around Likely, including near Quesnel Forks. Quesnel Forks is a restored ghost town located 12 km outside of Likely with a rich mining history and is also worth a visit. It is situated at the point where Cariboo River meets the Quesnel River, and features a beautiful campground and a number of restored and partially restored old buildings.
Mount Polley takes water quality very seriously. Extensive monitoring is evidencing the effectiveness of the remediation and site water management programs undertaken by Mount Polley.
How is water quality monitored in Polley and Quesnel Lakes to ensure proper environmental monitoring is being carried out?
Mount Polley follows the BC-ENV approved Comprehensive Environmental Monitoring Plan. The results for all our monitoring sites are published in the publicly available Annual Environmental and Reclamation Reports.
Polley Lake water met all BC Water Quality Guidelines for aquatic life parameters in 2019 with the exception of phosphorus, which was elevated even prior to mining. As Polley Lake is immediately adjacent to the mine site, this indicates the mine is doing a very good job of capturing and controlling run-off.
A number of sites are monitored in Quesnel Lake, and in 2019 there were no exceedances of acute BC Water Quality Guidelines.
At one monitoring site in Quesnel Lake, there was one minor copper exceedance of chronic BC Water Quality Guidelines in 2019, but as copper is also naturally occurring in the native soils and sediments around Quesnel Lake, and there are a number of creeks that empty into the lake near this sample site, it is difficult to know if this exceedance was natural or related to the mine.
We often get asked if we continue to discharge into Polley Lake or Quesnel Lake?
The mine discharges mine site water, that meets strict permit limits, through diffusers at depth into Quesnel Lake. This water is the only substance the mine is discharging to Quesnel Lake. The mine does not discharge water into Polley Lake.
Mount Polley discharges only mine site water that meets strict Environmental Management Act (EMA) permit guidelines.
treated by a water treatment plant, when needed to meet permit requirements, before being released into Quesnel Lake. The water going into the treatment plant (influent) is monitored on an ongoing basis, and the treated water leaving the plant (effluent) is sampled regularly for analysis. Not all water at Mount Polley requires treatment to meet EMA permit water quality guidelines before discharge, and in the past, water that was simply stored in Springer Pit was found suitable for passive discharge.
The lake water quality is also routinely monitored and sampled regularly as part of the mine’s Comprehensive Environmental Monitoring Plan.
Continued monitoring data confirm that remediation efforts are effective.
Currently, there are no indications in the monitoring data that the water discharged from Mount Polley is having any negative effects on Quesnel Lake water quality or aquatic life.
If you are interested in looking at water quality data collected on surface water in the area around the Mount Polley mine, in addition to data in the mine’s annual reports, results are available through the BC Government Surface Water Monitoring Sites Interactive Map.
The remediation effort at Mount Polley is ongoing; however, we are very proud of the major milestones that have been completed to-date.
Repair of lower Edney Creek, re-establishment of link to Quesnel Lake and installation of new fish habitat for spawners from Quesnel Lake, completed in spring 2015, with evidence of successful spawning by Interior Coho, Kokanee and Sockeye Salmon.
Completion of construction of a new Hazeltine Creek channel in May 2015, to control erosion and provide base for remediation of the creek itself and the creek valley.
Ongoing planting of native trees and shrubs in the riparian and upland areas along the creek, now totally more than 600,000 trees and shrubs planted.
Installation of over 6 kilometres of new fish spawning and rearing habitat in upper to middle Hazeltine Creek. Evidence of successful 2018 and 2019 Rainbow trout spawning in upper Hazeltine Creek.
Clean-up and repair of 400 metres of Quesnel Lake shoreline, including placement of new fish spawning gravels.
Re-establishment of wetlands in the Polley Flats area adjacent to the repaired TSF.
We hope that you and your family are staying safe and following the preventative measures and actions you can take to stay healthy and prevent the spread of COVID-19.
We are doing our part during COVID-19. Imperial Metals Mount Polley mine has donated two boxes of N95 masks and four boxes of surgical gloves to the Williams Lake Hospital.
Newcrest-Imperial Metals Red Chris mine is providing additional medical support in Iskut, Dease Lake and Telegraph Creek, and is working with the Tahltan Nation to support the provision of basic groceries to the Iskut, Dease Lake and Telegraph Creek communities. In addition, Newcrest will help source health and sanitary supplies pending availability and lead times.
There has been recent speculation about whether or not Mount
Polley is dumping waste into Quesnel Lake. In short, the answer is no. Current treatment of water at Mount Polley,
including the dilution zone at depth in Quesnel Lake, ensures water released
into Quesnel Lake is in line with BC and Canadian water quality standards.
Mount Polley discharges only treated mine site water that meets strict
Environmental Management Act (EMA) permit guidelines.
All mine site water is collected and is
treated by a Veolia ACTIFLO™ water treatment plant before it is released into
Quesnel Lake. (see veoliawatertech.com
for more information on their treatment systems and how they work.) The water
going into the WTP (influent) is monitored on an ongoing basis (measurements of
turbidity every 15 seconds) and the treated water leaving the plant (effluent)
is sampled regularly for analysis. The lake water quality is also routinely
monitored and sampled regularly as part of the mine’s Comprehensive
Environmental Monitoring Plan.
The following are facts that explore, in more detail, the
discharge from Mount Polley into Quesnel Lake. We hope this information provides
factual clarity about Mount Polley’s approved activities.
Is Mount Polley’s discharge having negative effects on Quesnel Lake?
are no indications in the monitoring data that the Mount Polley discharge is
having any negative effects on Quesnel Lake water quality. If you are
interested in looking at some of the water quality data that has been collected
on surface water in the area around the Mount Polley Mine, the results are
available through the BC
Government Surface Water Monitoring Sites Interactive Map
Is the water in Quesnel Lake contaminated? Is it safe to drink?
At this time, there are
no indications of contamination of Quesnel Lake water from the Mount Polley
spill. The mine, and the Ministry of Environment and Environment Canada,
continue to monitor Quesnel Lake. With the exception of natural causes, the
lake does not exceed environmental guidelines for any of the constituents of
concern that are found in the Mount Polley tailings.
As early as August 12, 2014, BC’s Interior Health
Authority (IHA) rescinded all water use restrictions from Quesnel Lake
(including for “drinking water, personal use, fishing, swimming and
recreational purposes”), except for the immediate impact zone where
Hazeltine Creek entered Quesnel Lake. The IHA notice also stated that “Interior
Health has no reason to believe that this water was ever exposed to unsafe
levels of contaminants from the mine breach. As a result, flushing and testing
of individual water supply systems is not considered necessary.”
All water use
restrictions were fully rescinded July 13, 2015. (Note: IHA always
advises that surface water be treated for pathogens prior to use/consumption.)
How much is the mine discharging into Quesnel Lake?
Management Act permit annual average authorized discharge rate is 29,000 cubic
meters per day. The actual discharge rate depends upon the rainfall experienced
at site which varies from year to year. In 2019, the annual average discharge
rate has been 14,883 cubic meters per day, significantly less than the mine’s
Did you know that over the past six
years, over 39 community meetings have been organized and hosted by Mount
Polley management and environmental staff?
Mount Polley is committed to the
environment and to ensuring the community is kept up to date on remediation
Over 24 meetings have been held in
Likely, the community in closest proximity to the Mount Polley mine. Meetings
have also been held in the communities of Quesnel, Horsefly, Big Lake and
These meetings provide an opportunity
for local residents to learn about the activities and progress of the
remediation work and research programs being conducted, and the opportunity to
engage and ask questions.
There is still work being done to
complete the rebuilding of fish habitat in Hazeltine Creek. The rebuilding and
revegetating of the lower part of the creek will be the last part of the
remediation work to be done.
Guest speakers have included
consultants and representatives from provincial Ministries who help educate the
local community about environmental remediation.
Furthermore Mount Polley has
established The Mount Polley Mine Public Liaison Committee (PLC).The PLC is
comprised of representatives from the local communities of Likely, Big Lake,
Horsefly and Williams Lake, local First Nations, government ministries,
consultants and mine staff.
Meetings are held on a quarterly basis,
with the purpose to share information about activities at the mine site with
the PLC members, who are there as representatives of their communities. The
agenda for each meeting includes updates on mine operations, environmental
monitoring, and remediation. There is also a roundtable discussion at each
meeting for all participants to pose questions and discuss any community
Extensive remediation work in the areas affected by the 2014 breach at Mount Polley has been achieved during the past five years.
Over $70 million dollars has been spent on clean-up work, including environmental impact and risk assessment studies, and remediation and monitoring of areas impacted by the spill.
Throughout 2019, the environmental department collected 1,115 water and soil samples. 336 surface water, 234 lake samples, 104 contact water, 77 groundwater, 181 seep, and 153 soil/other samples.
The construction on Hazeltine Creek concluded at the beginning of October and will re-commence at Lower Hazeltine in the Spring of 2020. The flow of Hazeltine Creek was monitored monthly.
There are 3 on-site environmental technicians to do the water sampling, environmental monitoring, inspections including reporting, database, spreadsheet data entry, communication, and coordinating meetings/tours.
Even though environmental monitoring slows down in the winter months, the environmental staff remain busy in the office with reporting, data entry, database management, scheduling, meetings, shoveling snow and general cleaning duties.
We continue to work hard to exemplify the highest site remediation standards and look forward to updating you as our work continues.