How eleven gold miners are going green
Gold miners are embarking on a number of initiatives to shift their operations to renewables, said the World Gold Council.
Earlier this month the council released a report on gold’s greenhouse gas (GHGs) emissions profile and climate change impacts. Miners run energy-intensive operations, but many are taking steps to move to less reliance on fossil fuels. BHP Billiton, the world's biggest miner, highlighted steps its taking to reduce green house gases in its annual report and even tied executive compensation to meeting environmental targets (paywall).
Some examples from the World Gold Council's climate report are excerpted below:
Agnico Eagle is currently working with a coalition of Inuit representatives and businesses to look at alternative energy sources in Nunavut. At present the region is totally reliant on diesel fuel for energy. The long-term goal of the coalition is to build hydroelectric transmission and fibreoptic infrastructure to deliver a cleaner, more sustainable energy across the region and for the benefit of future generations. A similar initiative in Mexico is poised to bring a steady supply of electrical power to the La India mine, while also benefiting local communities and families.
Barrick Gold, recognising that adapting to climate risks is an opportunity, – to reduce energy usage, maximise renewables and make significant cost savings – has implemented a number of key changes at its mines, including:
- Enabling 64% of the energy requirements at the Kibali mine in the DRC to be met by three hydropower stations
- Introducing solar power to the Loulo-Gounkoto complex
- Introducing sensors to the Kibali and Loulo-Gounkoto properties to automatically switch off lighting and ventilation when no workers or machinery are present
- Using waste heat recovery systems to achieve higher efficiencies from the natural gas fired generators at the Nevada site and at the Pueblo Viejo off-site power plant
- A commitment to setting a science-based greenhouse gas emissions reduction target in 2019.
Centerra, at its Mount Milligan mine in British Columbia, Canada, has recently entered into a partnership with local electricity company, BC Hydro, aimed at delivering more energy efficient methods. BC Hydro will fund research into energy-related solutions and delivery mechanisms, such as variable speed motors for milling operations.
Of immediate practical impact, Centerra has also implemented a ‘no idling policy’ for on-site vehicles. This policy is becoming recognised good practice at gold mine sites. It ensures unnecessary fuel consumption is eliminated – and when one considers a single 797F haul truck consumes 50 litres of diesel an hour when idling, the significance becomes obvious.
Eldorado has been improving energy efficiency at its Kisladag site in Turkey, upgrading its fleet of mining equipment to use electric power. This has resulted in a significant decrease in diesel costs and an increase in energy efficiency (with an estimated 26% reduction in loading energy consumption per tonne of rock moved).
IAMGOLD’s hybrid 15MW solar-diesel plant at its Essakana mine in Burkina Faso has proved a great success. The largest solar plant in sub-Saharan Africa, it was expected to contribute to a reduction in the mine’s fuel consumption of approximately six million litres per year, reducing its annual CO2e emissions by nearly 18,500 tonnes. As of 31 December, 2018, with only seven months of service, it was exceeding expectations and targets, saving approximately 3.9 million litres of fuel and reducing CO2e emissions by approximately 12,000 tonnes.
Kinross reported that the energy efficiency projects it implemented in 2018, such as the mine road redesign at the Tasiast mine in Mauritania (which reduced the length of hauls and lowered diesel fuel use), resulted in an annual reduction of 10,000 tonnes of CO2.
Kirkland Lake Gold’s Macassa Mine in Canada first introduced electric trucks and scoops underground in 2012. Currently, Macassa has 24 electric scoops and 8 electric haul trucks, resulting in 80% of the production being handled by battery electric vehicles. This significant commitment to battery equipment reduces greenhouse gas emissions at Macassa by approximately 2,400t CO2e/year compared to if the mine used only diesel equipment. Macassa has achieved some of the lowest carbon intensity rates in the industry, approximately 50kg of CO2-e per ounce of gold.
In addition to lower emissions, battery-powered equipment offers Macassa many other benefits, including improved economics (lower operating and ventilation costs), as well as better, cleaner and quieter working conditions. With the success at Macassa, Kirkland Lake Gold is now looking to introduce battery mobile equipment at other sites, both in Canada and Australia.
Newcrest announced a new Climate Change Policy in 2019 and several associated measures to mitigate climate-related challenges, including a GHG emissions intensity target of 30% reduction by 2030 and the introduction of internal shadow carbon prices of US$25 and US$50 per tonne of CO2e in jurisdictions where there is no formal carbon pricing regime.
The company is assessing options to use renewable power generation and low emission technologies, which will reduce its GHG emissions intensity, while improving productivity. Innovative mine design also has the potential to reduce energy demand at site, and other initiatives to reduce emissions include:
- Coarse ore flotation, which allows grind size to be coarser, reducing power usage • Autoclave partial oxidation, which reduces oxygen and power needs
- Opportunities for liquid natural gas to replace heavy fuel oil
- Oxygen storage bullet to reduce oxygen venting and save power
- Ore sorting to reduce the amount of material to grinding circuit, which lowers power
- Geothermal upgrades to increase geothermal production.
Newmont Goldcorp has set a public target to reduce its GHG emissions intensity by 16.5% by 202045 and has implemented a range of initiatives, as part of an integrated global energy and climate strategy (and the company’s Full Potential continuous improvement programme) aimed at delivering on this commitment. It is also assessing science-based targets and potential transition pathways to 2030.
In our previous report we described the company’s Tanami power project in Australia, which was nearing completion. The plant has since been successfully commissioned, providing the mine with a reliable energy source while lowering associated costs and carbon emissions by 20%.
In Ghana, Newmont Goldcorp has installed a 120-kilowatt (kW) solar plant that will power the Akyem mine camp and mess hall during daylight hours. It has a 25-year asset life and is re-deployable, so it can be disassembled and moved to another location at closure. Initial data show considerable cost, environmental and social benefits. Over five months, the plant produced more than 75,000 kWh of solar energy, resulting in an emissions reduction of more than 32,000 kg of CO2e. The plan is expected to produce energy at half the cost of grid power.
In Argentina, over 20% of the electricity supply at Cerro Negro now comes from renewable energy produced by a third-party wind farm. During the first eight months of the project approximately 12,000 tonnes of CO2e was saved, which is an 18.5% reduction in emissions intensity (kg CO2e/tonne moved). Over the next decade, the percentage consumption of clean energy at Cerro Negro will gradually increase to 38,000 MWh/year, meaning that 35% of electricity used at the site will come from renewable energy.
Pretivm Gold are reducing their diesel consumption at the Brucejack mine in Canada via construction of a transmission line to connect the site to the provincial hydro-based power grid.
Beyond our membership, other gold mining companies are also making substantial progress in implementing energy transition strategies. Use of solar PV technology has been rapidly making an impact.
B2Gold has installed a 7MW solar plant at its Otjikoto mine in Namibia. Prior to this, the mine obtained all its energy requirements from heavy fuel oil (HFO) diesel generators. Both B2Gold and the local government perceive the solar plant as delivering positive economic, environmental and social impacts that are likely to outlive the life of the mine. B2Gold has also initiated the construction of a 30MW solar power plant at its Fekola mine in Mali, expecting to substantially reduce operating costs and greenhouse gas emissions.
Gold Fields continues to develop an onsite 40MW PV array at its South Deep site in South Africa, using a long-term power purchase agreement with a renewable developer, to provide nearly 20% of its electricity needs.
Gold Fields also recently commissioned a gas (16MW)/ solar(4MW)/wind(18MW) and battery (13MW/4MWhr) micro-grid at its Agnew Gold Mine in Western Australia. The micro-grid can provide up to 54% of the mines’ electricity needs, abating some 40,000 tonnes of CO2eq per annum. And at its Granny Smith Mines, also in Western Australia, Gold Fields has started construction of 7MW with a 2MW/1MWHr battery unit, expected to abate some 9,500 tonnes of CO2-eq per annum.