Emissions Reduction and Mine Affected Lands

Mining operations can have a permanent impact on the landscape. Mining frequently results in landscape impacts including open pits, mine rock piles, tailings storage facilities, and surface opening or adits for underground mining and mine shafts. When planning for closure, these features are often treated as liabilities, with efforts made to remove or eliminate them. For example, a common practice is to push mine rock piles into open pits in an effort to backfill the void when mining operations cease. At Okane, mine reclamation and rehabilitation go beyond return to previous ecological function. We look for opportunities in the mine affected landscape to determine the highest value future land use. In this context, we ask the question: 

“Can Mine Affected Lands Create Opportunities for Emissions Reduction?”

Gravitational Storage

Companies like Green Gravity are actively exploring this potential. Green Gravity leverages the vertical height of legacy mine shafts to create electricity by lowering heavy weights that turn a regenerative motor. Similar to the energy storage mechanism of pumped hydro, gravitational storage uses the gravitational potential energy of a mass moving between two heights. However, rather than water flowing between two reservoirs, Green Gravity requires much less space by using very dense materials. 

In this application, legacy mine shafts create an opportunity to move heavy weights vertically to capture and release the gravitational potential energy. This form of energy storage uses no processed chemicals, has no performance degradation, and does not require water. The system has a high Round Trip Efficiency, and the repurposing of legacy mining asset contributes to a circular economy while also lowering costs. The Green Gravity solution is highly modular, highly configurable, and suited to a range of operating locations.  

Yancoal Australia LTD (2022) and Green Gravity have executed a memorandum of understanding (MOU) to explore the potential for gravity energy storage at the Austar coal mine site. For more information about Green Gravity’s technology, please reach out via their website or email at info@greengravity.com. 

Figure 1: The Green Gravity Energy Storage System – The energy storage system is charged from renewables, where weights are stored at the surface, and then weights are lowered when energy is needed.  

Wind and Pumped Hydro

Other projects, like the Hünxe Windpark, are taking advantage of the unique landscape of mine affected lands (RAG Montan Immobilien GmbH, 2018). Wind turbines placed on top of legacy mine rock piles are taking advantage of the additional elevation to achieve a higher windspeed (Intergovernmental Forum, 2022). The Kidston Pumped Storage Hydro Project takes advantage of the different elevations of the Wises and Eldridge Pits from the legacy gold mine site to store and provide renewable energy on demand (Genex Power, 2023). Indemistu Australia Resources (Indemistu, 2019) are developing a pumped hydroelectric storage facility at the Muswellbrook Coal mine site. In all these cases, the mine affected landscape is treated as an opportunity, rather than a liability. 

Emission Reduction Targets

In 2021, members of the International Council on Mining and Metals (ICMM, 2023) set a goal of net zero scope 1 and scope 2 greenhouse gas (GHG) emission by 2050, with a commitment to developing meaningful short and medium-term targets to building the pathway to achieve this goal. The mining industry is under increasing pressure to take immediate actions on emissions reduction, while also continuing to supply the critical minerals required for the energy transition. As renewable energy options continue to decrease in costs, they become viable options for operating mines, creating an opportunity for more energy independence. Leveraging mine affected lands on operational sites could help create energy storage solutions for these renewable options.  

Okane’s Approach

To fully take advantage of the potential of mine affected lands, mining operations and surrounding communities need to consider land transition beyond the operating life of mine. When developing the closure vision for a site, Okane works closely with operators, impacted communities, regional economic planners, and Indigenous rightsholders to identify and evaluate returning land use alternatives. When developing mine closure plans, we consider the potential of mine affected lands to support emission reduction opportunities in conjunction with typical ecological restoration options. With this approach, we help companies manage and look beyond the potential liability of mine affected lands, to help them achieve the highest value returning land use.  

If you have any questions about our process for evaluating the potential of mine affected lands, or want to get in touch about a current project, don’t hesitate to reach out to us via our contact page, or by email at info@okaneconsultants.com. 

References

Genex Power. (2023, March 30). 250MW Kidston Pumped Storage Hydro Project. https://genexpower.com.au/250mw-kidston-pumped-storage-hydro-project/  

Green Gravity. (2022, March 17). Building the future of renewables using gravitational storage. https://greengravity.com/technology/  

Green Gravity. (2022). Using gravity to store energy [Online image]. Green Gravity: Our technology. https://greengravity.com/technology/  

Idemitsu Australia Resources (IAR). (2019, July 26). Muswellbrook chosen for Idemitsu Australia Resources major renewable energy study. https://www.idemitsu.com.au/renewables/  

Intergovernmental Forum on Mining, Minerals, Metals and Sustainable Development (IGF). (2022). Achieving a successful post-mining transition with renewable energy. https://www.igfmining.org/resource/achieving-a-successful-post-mining-transition-with-renewable-energy/  

International Council on Mining and Metals (ICMM). (2023). Environmental resilience: Climate change. https://www.icmm.com/en-gb/our-work/environmental-resilience/climate-change  

RAG Montan Immobilien GmbH. (2018, July 16). Hünxe wind farm opened. https://www.rag-montan-immobilien.de/aktuelles/detail/t2_news/windpark-huenxe-eroeffnet/  

Yancoal Australia LTD. (2022). Ambition: ESG Report 2022. https://www.yancoal.com.au/content/Document/230426_ESG%20Report_Design%20Format_FINAL.pdf