Many mining professionals in the room would have heard about increasing efforts in the industry to cut the “carbon footprint” of individual mines. But most still would have been taken aback by David Prior’s assertion that a single mine haul truck is dumping about 5000 cubic metres of CO2 a day into the atmosphere – “roughly the volume of two Olympic swimming pools per day per truck”.
Addressing an audience in Perth, Western Australia, at the 2022 AusIMM Open Pit Operators Conference, the 30-year industry veteran and current commercial manager with Hexagon Mining used the example of a Caterpillar 793, 230-tonne payload truck burning about 150 litres of diesel per hour in his illustration of how technology can be used now at most sites to reduce scope 1 greenhouse gas emissions.
The technology being increasingly ubiquitous fleet management systems using vehicle sensors, computing analytics and automated vehicle dispatching. The systems have been around in mining for 40 years. However, Prior said today’s sophisticated FMS could generally be having a far bigger impact on operational efficiency, and hence fuel and other inputs, than many systems were.
“It’s a pretty simple relationship between diesel usage and CO2,” Prior said at the AusIMM conference.
“It’s a linear relationship using a conversion factor. If we know how much fuel we’re burning we know how much CO2 we’re producing.”
The Caterpillar 793, a popular truck in bigger mines, burned fuel equating to circa-500kg of CO2 per hour of operation.
“If you convert that to a volume it equates to 278 cubic metres per hour or around 5000 cubic metres per day, per truck, of CO2,” Prior said.
Industry studies showed haul trucks and loading equipment contributed about 80% of a mine’s site-based emissions, with mine site diesel use estimated to account for a staggering 14% of Australia’s total scope 1 emissions. The country’s Clean Energy Regulator also counts six mining companies among Australia’s top-20 greenhouse gas emitters.
The AusIMM conference heard repeatedly that environmental, social and governance (ESG) issues were more frequently cited as major risks to miners’ social license to operate, investor retention and even new talent recruitment.
“The cost of capital can be up to 25% more expensive for a mining company with a poor ESG rating,” Prior said.
However, the “reality is we’ll be operating diesel-powered equipment in mobile fleets in open pits for a number of years still”, he said, based on the current development trajectory of alternatives.
The key theme of his presentation was that available technology could have a major impact on average mine efficiency long before “green” trucks replace the current standard yellow, orange and white ones. And he suggested FMS development in the hands of companies such as Hexagon was moving much faster to deliver new capabilities.
“Current [systems] have pretty basic fuel management capabilities [and] no future predictive modelling of fuel consumption levels, etc,” he said.
“In the future we should see a FMS that’s capable of predicting the fuel burn of each vehicle based on key inputs [such as] payload, speed, rolling resistance and so forth … and once we have that robust predictive model the FMS can proactively manage fuel consumption, again by taking into account and perhaps manipulating truck speed and haul route, etc.
“A predictive model of truck fuel consumption combined with the existing dynamic truck assignment algorithms opens up several opportunities for reducing truck fuel usage. The FMS is already forecasting future truck idling events such as queues at the shovel or the dump. By combining this with a model of fuel consumption ahead of the truck, the FMS could advise or even intervene with factors such as truck speed or route. In the simplest scenario the FMS knows there is a queue of trucks ahead at the shovel and advises the operator to intelligently slow down to save fuel. Intelligently meaning understanding which sections of the road will have the greatest impact on fuel burn based on previous runs … [and] still arriving at the shovel to avoid queue time, or getting there too late.
“The FMS will be a key to managing truck emissions as we transition away from diesel engines.”