Advancing Together With Barrick Gold

Environment Hemlo Mine reduces emissions by 24 percent, captures Canadian industry award

Optimizing the mine's underground ventilation system drives down energy consumption and greenhouse gas emissions

Barrick's Hemlo mine has been recognized by Canada's Department of Natural Resources for its innovative energy conservation program. The northern Ontario-based mine received a Canadian Industry Program for Energy Conservation (CIPEC) Leadership Award for implementing a project that reduced greenhouse gas emissions by 24 percent and lowered energy consumption by 10 percent between 2013 and 2015. The award was presented at a ceremony Tuesday in Niagara Falls, Ontario, hosted by CIPEC through Natural Resources Canada and the Excellence in Manufacturing Consortium.

"Congratulations to Barrick Gold Corporation on their CIPEC Leadership Award," says Kim Rudd, Parliamentary Secretary to the Minister of Natural Resources. "Their vision for responsible mining and use of new technologies to improve energy efficiency are cutting-edge. I commend them on their extraordinary Hemlo mine that is helping to drive down energy consumption, cost and emissions."

Hemlo was able to drive down energy consumption and greenhouse gas emissions by optimizing its underground ventilation system, says Andrew Baumen, the mine's General Manager. The multi-year project involved implementing ventilation on demand in select areas of the underground and creating a new full-time position at the mine to manage fans that were not connected to the ventilation-on-demand system. In addition, the Hemlo team tapped into the geothermal properties of the mine to help manage air temperature in the underground.

"It was a huge project for us that required a cross-functional team effort, so we are extremely proud that our employees are receiving this recognition," Baumen says.


An early example of Best-in-Class

Ventilation is a critical feature of underground mines. It provides the fresh air that allows miners to work safely and comfortably more than a kilometer below surface in the case of the Hemlo mine. However, ventilation is also costly. It is the largest energy expense at Hemlo at more than C$5 million annually. It's also the mine's biggest energy user.

With the gains made by Hemlo, however, energy required for ventilation has fallen sharply in recent years. Energy consumption as measured by ventilation per tonne of ore fell from 96.7 kilowatt hours per tonne (kWh/tonne) in 2013 to 86.1 kWh/tonne in 2015—an 11 percent reduction. Consumption is expected to drop to 73.2 kWh/tonne by the end of 2016, a 24 percent reduction relative to 2013.

In addition to the ventilation project, Hemlo has a comprehensive energy management program that follows a continuous improvement approach. The mine's overall energy costs, which encompass electricity, diesel fuel, propane, and the use of explosives, among other things, fell from C$31 million in 2014 to C$26 million in 2015—an 18 percent decrease.

"Hemlo's performance and creativity in driving down their energy consumption, emissions and costs over some very tough years in the gold mining industry is inspiring," says Richard Williams, Barrick's Chief Operating Officer. "This is a leading example of the type of work we are carrying out across the organization through our Best-in-Class program and the team at Hemlo should be proud."

Barrick's Best-in-Class program is a strategic initiative aimed at driving a culture of business improvement and operational excellence across the business. Improving energy efficiency is a key area in which Barrick is striving for Best-in-Class performance—and an area in which Hemlo has a long track record of success. The mine's first energy management project dates back to 1992. It was designed to capture waste heat at the mine and use it to preheat cold air entering the mine during winter. The project paid for itself within two years and continues today.

By 2011, energy costs were rising again at Hemlo. To address the issue, Hemlo created an energy management program with the objectives of reducing energy consumption, improving efficiencies and lowering costs. An energy champion was appointed and a cross-functional energy management committee was formed to develop and implement the program. One priority area was ventilation.


Ventilation on demand

Historically, the large network of auxiliary fans in the Hemlo underground have operated 22 hours a day, seven days a week, 365 days a year. Each fan runs at anywhere from 50 to 200 horsepower. In addition, the mine's main exhaust fan and two intake systems operate at a combined 3,500 horsepower. That's nearly double the horsepower of the world's fastest supercars, except Hemlo's machines run year-round.

After reviewing costs and energy consumed by Hemlo's ventilation system, the energy management team realized the status quo could not continue. One solution was to install a ventilation-on-demand system that encompassed the entire underground. This would allow operators to automatically close any of the mine's several hundred fans in any area of the mine when ventilation was not required. However, this option was not realistic given cost constraints. So a compromise was struck: ventilation on demand would be implemented in strategic areas of the mine to maximize efficiency and reduce costs.

Fans not converted to ventilation on demand are now managed by an individual hired specifically to oversee this segment of the ventilation system. These fans are now turned off when ventilation is not required instead of running 22 hours a day, generating significant cost savings.


Harnessing the elements

During winter, temperatures can sink as low as -40 Celsius at Hemlo, and remain below zero more than five months of the year. As a result, propane is needed to heat the fresh air funneled underground by the mine's intake fans.

In 2015, Jason Leclair, Hemlo's Senior Ventilation Technician, had an innovative idea to reduce heating costs: take advantage of the mine's naturally-occurring geothermal properties. This opportunity became practical when the neighboring David Bell underground mine closed in 2014. Hemlo is located adjacent to David Bell, allowing the Hemlo ventilation team to draw fresh air via tunnels, or stopes, in the David Bell section that connect to the surface. Because of the frigid climate, the stopes contain ice build-up and the fresh air that circulates through them is very cold. However, as this air descends through the stopes and into the Hemlo underground, it warms due to the mine's geothermal properties. This reduces heating requirements in the winter, saving the mine up to 30 percent annually in propane costs.

During summer, the effect is reversed: the stopes, known as ice stopes because they contain ice year round, cool the warm summer air in the underground providing a more comfortable working environment.


Benchmarking

As part of the energy management changes, the Hemlo team developed in-house tools to track energy savings and emissions. For example, one tool tracks the on-off status of different fans and is compared against real time metering data. This helps operators improve efficiency by determining whether fans are operated on the most optimal schedules. Another program tracks the impact of the ice stopes on monthly and cumulative energy savings.

While the energy efficiency initiatives have translated into substantial cost savings for Hemlo, Baumen says the program's positive impact on the environment is equally important.

"Yes, this is about operating more efficiently and managing costs, but it's also about environmental stewardship and minimizing our environmental footprint," he says. "It's the sort of initiative that makes our people proud of where they work; I know I'm proud of my team and the way we all pulled together to make this happen."