5 minute read
The challenges and opportunities of decarbonising the Bowen Basin
from BBMC Yearbook 2023
by bbminingclub
Steph Byrom, General Manager –Decarbonisation,Talisman Technical
For Queensland's coal sector, the revised Safeguard Mechanism is not just a policy shift; it's a paradigm shift. It delineates clear targets for emissions reduction with an overall 43% reduction across Safeguard facilities between now and 2030. Each operation requires a different reduction based on site-specific emissions intensity and the delta between this and the industry average emissions intensity. For most sites, it’s a daunting 25% to 50% reduction by 2030.
The Bowen Basin coal industry now has the unique opportunity to unlock fugitive gas emissions as a resource to drive both operational gains and tangible emissions reductions.
We are now entering a time where emissions intensity curves will impact the risk and opportunity of an operation alongside cost curves. This is a sink-or-swim moment for the coal sector, particularly for those high-quality but gassy metallurgical mines in the Bowen Basin. The big question for any mine owner or operator: how do we continue to extract value from our mines in a low-emissions future?
Underground coal mines: Safety and greenhouse gas management go hand in hand
Managing fugitive emissions from coal mine methane is well understood in underground coal mines as this has been primarily a matter of safety.
Concentrations of methane in the mine workings above the safety threshold are managed via pre- and post-drainage, coupled with flares. The remaining gas will report through to the vent stack as ventilation air methane (VAM) where the low concentrations make GHG management very difficult and expensive. VAM abatement technologies are available and starting to make headway in Australia.
While safety will always be paramount in mining operations, we stand before an untapped opportunity to marry this safety requirement with enhanced gas recovery for Safeguard compliance. The high-quality gas extracted from pre- and post-drainage is a resource that can provide opportunity through additional revenue via offtake, or operating cost reductions through power generation.
The Open-cut conundrum: Understanding equals opportunity
Open-cut coal mines present a different kind of challenge. Since the commencement of GHG reporting, the industry has applied a blanket approach in the form of an emissions factor provided by the Clean Energy Regulator to report fugitive emissions.
This method, while straightforward, overlooks the nuanced and varied nature of the gas emissions across different sites. Our role as consultants has evolved to unravel this complexity, helping operators understand the actual volume and potential value of their gas. This understanding is the first step toward leveraging it, not only for compliance but also for improved economic outcomes.
There are two ways of draining this gas ahead of mining. One is surface-to-in seam (SIS), where rigs drill through the overburden layers to the coal seams. This method harnesses directional drilling that can follow the coal seam horizontally. However, this method can be expensive and leaves steel casing in the ground which can be a safety hazard when mining progresses. The other method is horizontal drilling from a bench or a ramp in the pit. This method drills straight into the coal seam and can target multiple seams at once. It is approximately half the cost of SIS drilling and uses no steel in the process. Once the gas is recovered, it can be put to beneficial use. This can include, but is not limited to use as power generation to offset purchased grid power, conversion to compressed natural gas for use in haul trucks to displace diesel, conversion to ammonium nitrate for use in blasting, or sale to a third party.
Mapping the journey to compliance and beyond
We know there are ways to reduce emissions and create opportunities for each site, particularly when it comes to gas. However, each operation will have a different pathway. The journey starts with developing a base case to understand where each operation’s emissions are sourced. This requires meticulous data gathering to develop a detailed emissions profile for each site. Once we have established a clear picture of the current state, the path to reduction can be developed. It involves a careful assessment of both the immediate and long-term modifications required to align with the Safeguard Mechanism and beyond. Projects must be classified not just by their emissions reduction potential but also by their ease of operational integration and economic impact. This assessment must bring operations along the journey – without their buy-in, we reduce the likelihood of having a meaningful impact.
Navigating short, medium, and long-term horizons
Our strategic approach must consider the temporal realities of project implementation. Short-term initiatives will focus on optimising current processes and behaviours for immediate gains. Medium-term projects will involve more significant capital investments, integrating commercially available technologies that promise a reasonable return on investment.
Long-term strategies require a strong understanding of global and local climate change politics, anticipating future technological developments, and embedding flexibility into the planning and design of mining operations.
Prioritisation through economic lenses: The role of MAC curves
An essential tool in the decarbonisation arsenal is the Marginal Abatement Cost (MAC) curve. This economic model allows us to weigh the cost of the project against the potential emissions abated across the life of mine. Some projects will show clear cost savings; others may have costs that need to be justified by the scale of emissions reduction or the strategic advantage they may deliver. The MAC curve is not merely a theoretical exercise; it frames dialogue with stakeholders, aligns economic rationale with emissions reduction compliance, and guides the industry towards a sustainable and profitable future.
Boosting the Bowen Basin
As the Queensland coal mining industry contends with these new regulatory requirements, our mandate is clear - guiding our clients not just to meet compliance, but to lead the industry through decarbonisation. The strategies we devise, the technologies we champion, and the efficiencies we uncover will collectively define the industry's trajectory in the decades to come.