As the copper resource is developed, mining begins by extracting ore closest to the surface. As these resources are removed, equipment must mine ore from an increasing depth. Deeper pits result in longer, uphill hauls for trucks to deliver ore to the mill for processing — increasing diesel consumption, which results in greater energy consumption and GHG emissions.
In addition, to enhance project economics, higher grade ore is commonly processed early in the mine life, followed by lower grade ore. For example, Teck’s Highland Valley Copper Operations were processing ore with a copper grade of 0.47% in 1988; this had declined to a grade of 0.30% in 2012. Decreasing ore grades mean that greater amounts of material must be moved and processed to achieve the same quantity of final product.
This combination of increased haul distances and decreasing ore grades increases energy consumption and GHG emissions required to produce each tonne of product over the life of a mine.
WHAT IS TECK DOING?
While an operation’s energy profile will typically demonstrate increased energy consumption over time, the aim is to minimise the impact of increasing energy consumption and GHG emissions. Energy goals focus on pursuing projects that enhance energy efficiency and thereby reduce GHG emissions at any stage in a mine’s life. This can be in the form of harnessing alternative energy sources such as wind.
In the future, it is likely that new resource development projects will be in even more remote locations, perhaps with lower grade material that is more challenging to extract and process. These factors all suggest that mining is likely to become even more energy intensive. This will make it challenging to reduce energy intensity and the associated GHG emissions. With this understanding in mind, Teck is developing goals around the design of new projects to ensure that it is continually evaluating best practices for future operations.