Ore movement is typically the single largest energy-using activity for an open pit iron ore mine, with haulage alone accounting for about 30% of a site’s total energy consumption. Other vehicles and mobile equipment used for ore extraction, stockpiling, and loading can account for another 25% to 30%.

The most commonly used fuel for haulage is diesel and with the decrease in diesel fuel rebates, operating costs have increased significantly. These costs are set to continue rising in 2014 when transport is included in the carbon pricing mechanism – potentially making ore movement off-site more expensive, whether by truck or rail.

Mapping diesel fuel use both onsite (mine fleet) and off site (ore transport) highlights levels of diesel fuel consumption and wastage. This can assist mine operators in identifying potential fuel reduction opportunities to reduce operating costs, optimise operating efficiency, and meet internal and external drivers in sustainability.

The first step in mapping your diesel use is to recognise consumption levels by equipment type e.g. heavy mobile equipment such as excavators, drill rigs, loaders, haul trucks, dozers and graders; medium-size equipment such as service trucks; on-site light vehicles; and off-site transport such as road trains or locomotives. Categorising the equipment by activity and type will help determine the fuel used on-site and off-site.

Off-site ore transport is usually operated by a third party who may pass-through the equivalent carbon cost increase to the mine operator, unless contracted otherwise. It is important that an operator communicates to all transport contractors, their desire to reduce operating costs through improved fuel use. Working together with the contractor by assisting them to assess their fuel consumption may potentially result in fuel reduction.

Once the fuel use has been categorised, it is possible to see where the largest fuel use has occurred and therefore where the greatest savings opportunities may lie. The next step will then be to consider the other parameters of vehicle and equipment use, some which will be within the control of the miner to change (e.g. idling times) and others which the miner may be able to influence (e.g. driver training) or may not be able to influence (e.g. distance from mine to port).

Those iron ore miners who participate in the Energy Efficiency Opportunities (EEO) program can use the EEO assessment framework as reference for change and report the energy saving projects as part of their organisation’s assessment requirements. Either way, whether liable under the EEO or not, improving fuel use will reduce operating costs. And with around 20 per cent of operating costs being from energy use, a 5% decrease can make a big difference to the bottom line.

Miners in Australia have been trialling and implementing a number of fuel reduction activities.

These include fuel additives for fleets; reducing the number of stops required by the haul trucks; using dynamic real time dispatch system to optimise haul truck movements and reduce idling times; trialling an auxiliary battery on haul trucks for operating the cab’s air-conditioner during idle times, allowing the engine to be turned off; and improving haul truck management e.g. engine management, driver training, maintenance tracking, load management, and tyre pressure management.

Other leading practice fuel reduction activities include using lighter weight and more fuel efficient vehicles and equipment; implementing in-pit equipment maintenance; using electric driven mobile equipment and locomotives with regenerative breaking; replacing truck haulage with conveyor systems from the mine face to the plant, combined with in-pit crushing to reduce ore size; and optimising digging schedule to reduce the number of shovels required at any given time.

Trials of each of the above fuel reduction activities have been shown to reduce diesel consumption by up to 5%. Using cleaner fuel alternatives and improving fuel efficiency of the mine fleet and ore transport options reduces operating costs, improves air quality, and reduces the miner’s carbon liability.

For more information on achieving energy cost savings in mining operations, contact Kate van Namen on (08) 9213 7421 or via email at kvannamen@golder.com.au.