In the heart of North China’s Juye coalfield, a groundbreaking study led by Qi Liu from the China University of Mining and Technology is reshaping the way we think about mine water reinjection. Liu and his team have delved into the complexities of reinjecting high-TDS (total dissolved solids) mine water, offering a roadmap for safer, more efficient practices that could significantly impact the energy sector.
The study, published in *Meitian dizhi yu kantan* (translated to *Modern Geology and Exploration Technology*), focuses on the reinjection of mine water into deep aquifers, a process that has long been fraught with challenges. “The mine water in this region features elevated water inflow and high TDS, which leads to high water treatment costs,” explains Liu. By targeting the deep Ordovician limestone aquifer, the team identified a suitable reinjection target for minimally treated mine water, a finding that could drastically reduce treatment costs and improve operational efficiency.
Using advanced modeling software like the Groundwater Modeling System (GMS) and FLAC3D, the researchers simulated the long-term effects of reinjection. Their findings are striking: over a decade, reinjecting water through a single borehole at a rate of 200 cubic meters per hour resulted in a maximum groundwater level rise of just over 10 meters. However, when four boreholes were used with a combined reinjection rate of 800 cubic meters per hour, the groundwater level rose by nearly 26 meters. “The single-borehole reinjection could achieve an annual reinjection volume of up to 1.72 million cubic meters, suggesting considerable potential for groundwater storage and a huge cost advantage of water treatment,” Liu notes.
The study also highlights the potential risks associated with groundwater level rise, particularly the likelihood of water inrushes along faults. However, the team’s safety assessment system, which integrates regulatory guidelines and numerical simulations, provides a robust framework for mitigating these risks. “The safety assessment system established for deep-well mine water reinjection underscores that ensuring both water quality safety and mining safety is necessary for the implementation of a deep-well mine water reinjection technology,” Liu emphasizes.
The implications for the energy sector are profound. By optimizing reinjection practices, coal mines can reduce treatment costs, enhance water conservation, and ensure safer mining operations. This research not only offers immediate practical applications but also sets the stage for future developments in mine water management. As the energy sector continues to evolve, the insights from this study could pave the way for more sustainable and economically viable mining practices.
In an era where environmental and economic considerations are increasingly intertwined, Liu’s work serves as a beacon of innovation. It challenges the status quo and offers a glimpse into a future where technology and sustainability go hand in hand. As the energy sector grapples with the complexities of water management, this research provides a critical tool for navigating the challenges ahead.