Energy management
Coal seam methane, followed by electricity and diesel, are the dominant contributors to Coal & Allied's emission profile.
Addressing coal seam methane requires adoption of new technologies, such as those used in the coal seam methane trial being conducted in collaboration with university researchers at Mount Thorley Warkworth.
Coal & Allied's energy management objective is to improve energy use at our operations, projects and in the supply chain, and to embed efficiency processes into our systems.
Our energy management programme is designed to address, understand, prioritise and reduce our energy use. A major project is currently being implemented to meter electricity and fuel use of all equipment and facilities consuming at least 10 per cent of our energy.
In 2008, Coal & Allied's energy management programme avoided reported emissions of 38,000 tonnes of CO2 equivalents. The following programmes helped achieve these results:
-
Coal & Allied sites saved more than 7200 tonnes of CO2 by using two per cent biodiesel sourced from a by-product feedstock
-
More than 7000 tonnes of CO2 emissions were avoided due to dragline productivity improvements at Hunter Valley Operations
-
Across the Coal & Allied businesses improved trucking efficiency saved significant amounts of diesel through a project called payload optimisation. This initiative saved more than 12,000 tonnes of CO2 which equates to more than 4.5 million litres of diesel
-
Installing more efficient engines in heavy mining equipment allowed Rio Tinto Coal Australia to lower the amount of fuel consumed by its equipment. This work has had the added benefit of increasing the life and reliability of the equipment. At Hunter Valley Operations this work delivered efficiency savings equating to 1600 tonnes of CO2
-
More than 5000 tonnes of CO2 were saved at Hunter Valley Operations by optimising the coal processing plants. This work includes changing old pumps with out with high efficiency variable speed drives and consolidating our processing plants
-
By recycling waste oil and using it in explosives, Hunter Valley Operations saved more than 194,000 litres of diesel, equivalent to about 500 tonnes of CO2
- Installing timers and daylight sensors on lighting plants at our sites avoided producing more than 400 tonnes of CO2.
Energy use
In 2008 we set voluntary targets for the amount of energy used to produce a tonne of product coal. For Coal & Allied the target was 0.013 gigajoules (GJ) per tonne of equivalent material.
Overall our businesses delivered energy use results close to target, with Coal & Allied operations using 0.014 GJ per tonne of equivalent material moved.
Our operations are designed to efficiently remove large volumes of dirt to reach the coal. The amount of material we move is the major influence on the energy we use and the emissions we produce.
Factors influencing material movements not anticipated when we set our 2008 targets affected energy use at our New South Wales sites. These factors included a significant increase in semi-soft coking coal production (37 per cent higher than in 2007) that requires additional processing, substantially reduced in-pit coal inventories, and a five per cent increase in overall coal production compared to 2007.
Greenhouse gas emissions
We set voluntary targets in 2008 for the amount of greenhouse gas emissions produced in our process. The Coal & Allied greenhouse target was 1.41 kg CO2-e (excluding methane) per tonne of equivalent material moved.
Our Coal & Allied operations produced 1.53 kg CO2-e per tonne of equivalent material moved, which exceeded our target. These results were affected by factors not anticipated at the time of setting the target, including a significant increase in semi-soft coking coal production (37 per cent higher than 2007) that required additional processing, substantially reduced in-pit coal inventories and a five per cent increase in production compared to 2007.
