Tert-amyl methyl ether (TAME) is used as a gasoline fuel additive for octane improvement and air emissions reduction. The aqueous solubility and apparent low relative biodegradation rate of TAME has led to groundwater impacts due to accidental releases of gasoline containing TAME at motor fuel retail sites. This study has investigated the natural attenuation of TAME based on field-measured groundwater data at 14 globally distributed fuel retail sites with historical releases of gasoline. Using a multiple lines of evidence approach, the research evaluated TAME degradation through historical monitoring data, geochemical analysis, and compound-specific isotope analysis (CSIA). First-order TAME attenuation rates ( k point ) were calculated from decreasing concentration trends over time in 43 individual monitoring wells, having a mean and standard deviation of 0.0018 ± 0.0013 day −1 , and a median rate of 0.0016 day −1 (first-order half-life = 1.2 years), comparable to similarly estimated rates for methyl tert-butyl ether, a more widely studied ether oxygenate. Shifts in CSIA measurements at five sites indicated that biodegradation was the dominant attenuation mechanism at one site, a secondary factor at three, and was inconclusive at one site. The study also measured stable carbon and hydrogen isotopes in TAME and its intermediate metabolite, tert-amyl alcohol, providing new insights into degradation pathways. Results showed that attenuation is influenced by site-specific hydrogeological conditions, with hydrogeologically simpler aquifers yielding clearer biodegradation signals, and aerobic conditions resulting in more rapid biodegradation. The findings support the viability of monitored natural attenuation as a remediation strategy for TAME-impacted sites. The study recommends further research to refine isotope enrichment factors under varying redox conditions. Overall, this work enhances understanding of TAME behaviour in groundwater and demonstrates the utility of CSIA in distinguishing between physical and biological attenuation processes.

Real-time prediction of rock slope stability in active mines remains a critical challenge due to complex geology, dynamic mining stress, and environmental factors. The Pulang Copper Mine, with its complex structural setting and ongoing subsidence, requires advanced monitoring to mitigate failure risk. This study aimed to develop and validate an IoT-driven Enhanced Transformer model for real-time prediction of the Factor of Safety (FoS) and stability classification, integrating numerical simulation, IoT data streaming, and deep learning to improve early-warning capability. A FLAC3D simulation replicated two years of mining (730 daily steps) at six strategic monitoring points, generating time-series data for displacement, velocity, acceleration, and FoS. An IoT framework streamed this data with <5-second latency. An Enhanced Transformer architecture with multi-head self-attention, multi-task learning ( λ =0.5), and advanced feature engineering was trained on the sequences. The Enhanced Transformer achieved superior performance, with testing R² ranging from 0.416 (Station 5, characterized by complex transitional kinematics) to 0.991 (Station 4). Testing MAE ranged [0.003596 (Station 2)–0.019071 (Station 5)], a reduction of up to 88% compared to the Standard Transformer. For four-class stability classification, the model attained a mean test accuracy of 0.993, with critical-class recall reaching 1.0—guaranteeing zero missed alarms for life-threatening critical and unstable conditions, the paramount objective for early-warning systems. The proposed IoT-Enhanced Transformer model provides a highly accurate, real-time solution for slope stability prediction, significantly outperforming conventional models.

Distinguishing between fault breccia and volcanic breccia is critical in tectonically active regions, because their mechanical and hydraulic properties differ substantially and directly affect the stability of large engineering structures. This study aims to identify the origin and characterize the engineering geological properties of breccias at a proposed power plant site within the Philippine Mobile Belt, where active faulting and volcanism exist. To achieve this, an integrated investigation was conducted, including detailed geological mapping, thin-section analysis, electrical resistivity surveys, drilling investigations, and in-situ/laboratory tests. The results reveal that breccias are spatially associated with linear geomorphological features and subsurface low-resistivity zones, exhibit jigsaw textures and rotated clasts in drill cores and thin sections, lack diagnostic volcanic textures, and show very low mechanical strength compared with surrounding greenschist host rock. These observations collectively indicate that the breccias are fault-derived and form part of a fault damage zone, rather than being volcanic in origin. From an engineering perspective, clay-rich fault breccia has important implications for slope movement, differential settlement, and groundwater control in large infrastructure projects. The integrated multi-method approach adopted in this study provides a robust framework for distinguishing fault breccia in complex tectonic settings such as the Philippine Mobile Belt.

Cornwall's history as one of the richest metal-mining regions in the world has left a legacy of hundreds of kilometres of abandoned mine workings containing millions of cubic metres of water. Despite the growing development of mine-water heat schemes in former coal-mining areas in the UK, the potential geothermal resource within the flooded mines in Cornwall has yet to be fully recognized. The utilization of this resource presents a few challenges that are different from those met when extracting heat from former coal mines, but it presents readily accessible opportunities for producing sustainable low-carbon heating, cooling and thermal storage. There are recorded to be 154 mines in Cornwall that are over 200 m deep. Recent studies have identified the temperature and volumetric resource that may be available in some of the deep mines, together with examples of four mines that show distinctly different types of hydrogeological systems. This has demonstrated the potential and the importance of thoroughly understanding the hydrodynamics of the shafts and underground workings, and how these can be best utilized as a low-enthalpy heat resource.

Argillaceous slate exhibits distinct disintegration characteristics during the interaction between water and rock. To investigate the disintegration of argillaceous slate, its macroscopic disintegration characteristics were examined through disintegration resistance tests. The mineral types and contents of the rock samples were determined using X-ray diffraction, while microstructural evolution during disintegration was analyzed via scanning electron microscopy. Nuclear magnetic resonance was employed to explore the mesoscopic mechanisms of argillaceous slate disintegration. A nonlinear dynamic equation was formulated based on nonlinear dynamics theory to quantitatively characterize the disintegration process of argillaceous slates under water-rock interaction. The results indicate that: 1) The disintegration process of argillaceous slate exhibits staged characteristics, with crack development categorized into three distinct stages. 2) During disintegration, the microstructure of argillaceous slate transitions to a more porous and loose state, as evidenced by the detachment of local flakes from the sample, the accumulation of flakes on the surface, and the formation of numerous pores. As the duration of water immersion increases, the internal pore radius of the argillaceous slate expands, leading to a continuous increase in the proportion of larger-sized pores. 3) The micro-scale fracture surface area of argillaceous slate increases with prolonged soaking time and shows a negative correlation with the anti-disintegration index. 4) Predictions derived from the nonlinear kinetic equation align well with the experimental data, demonstrating the equation's effectiveness in modeling the disintegration of argillaceous slates under the nonlinear quantification of water-rock interactions. The research results can provide a reference for the research and treatment of soft rock disintegration.

Decarbonising heat in combination with energy storage can be a key component on the way to achieving net zero. Hundreds of thousands of flooded, post-closure coal mine shafts are estimated to exist based on relevant mining authority databases across industrialised countries and we are proposing they should be considered an unused asset for large scale thermal energy storage. These numerous, pre-existing structures are often situated close to high population density areas and surrounded by insulating bedrock. There have been no completed Mine Shaft Thermal Energy Storage (MSTES) pilot studies to-date; as a result, its feasibility and performance as a heat storage system for district heating networks remains untested. The objective of this study is to conduct a CFD simulation of heat storage in a flooded Scottish mine shaft with a vertical closed loop heating system suspended in the top 50 m of the mine shaft to gain a better understanding of: temperature distribution in the shaft and surrounding environment, as well as any buoyancy-induced mixing with deeper mine shaft water below the heating system. The presented simulations focus on the heating phase of an MSTES operation over 10 days. In this scenario an unstratified shaft, selected for a MSTES pilot study, is heated from a small closed loop pipe with varying temperatures and heat transfer coefficients from the pipe to the water. The result provide assurance that a pilot test at the site can be delivered safely, and opens the possibility of future full-commercial scale projects.

The paper explores how urban construction activities on steep slopes in hilly or mountainous regions—where land scarcity drives development—exacerbate landslide risks. Landslides frequently occur near construction sites, yet these human influences are often excluded from landslide mechanism analyses. The study posits that such events are not coincidental but result from construction-driven disruptions to hillslope hydrogeology and groundwater systems. Activities like coastal land reclamation, excavations, and deep foundation works significantly alter subsurface water flow, raising groundwater levels—a critical yet underappreciated factor in slope stability assessments. Through case studies in Hong Kong, the paper demonstrates how construction modifies hydrogeological conditions in slopes with confined groundwater, typically found in igneous rock formations. These slopes feature permeable fracture zones between shallow, weathered, clay-rich soil layers and deeper bedrock. Construction activities disrupt these systems, destabilizing slopes by increasing pore-water pressure. For instance, excavations can intercept aquifers, while deep foundations may obstruct natural drainage, both elevating landslide susceptibility. The findings stress the need to integrate human-induced hydrogeological changes into slope stability evaluations and urban planning. This approach emphasizes proactive consideration of construction impacts on subsurface water regimes and is critical for mitigating landslide risks in densely populated mountainous regions.

Climate warming has significantly altered hydrological processes in the Yangtze River source region (YRSR), leading to various hydrological and ecological challenges. This study examines the spatiotemporal evolution of terrestrial water storage (TWS) and groundwater storage (GWS) using GRACE satellite gravity data, GLDAS hydrological model data, and meteorological data. The results indicate an overall increase in TWS, with groundwater storage rising in the western region (west of Qumalai) since 2007, while declining in the eastern region. GWS shows little seasonal variation. The rapid temperature rise in the western part is identified as the primary driver of these changes.

In former coal-mining regions, mine water geothermal heat (MWGH) offers a low-carbon means of delivering space heating and hot water in towns and other built-up areas. A large-scale roll-out of MWGH over the coming decades could be a viable option for public policy, as part of a wider strategy to reduce reliance on natural gas for heating homes and other buildings. This paper considers how the operation of MWGH could have an impact on the available geothermal resource in the longer term. Using a simple one-dimensional model of the geothermal system, we define and solve the transient heat conduction problem relating to the period following the start of heat abstraction at the mine level. The results of this analysis indicate that intensive abstraction of heat from mine levels can lead to significant cooling of the adjacent rock strata within a relatively short time-frame. To give an indication, 5°C of cooling over ten years is quite possible. The solution to the transient heat flow problem also indicates the existence of a direct causal relationship between the intensity of heat abstraction and the rate of rock-cooling. This relationship can be used to guide the design of new MWGH schemes, by identifying (and excluding) areas of the design space that would result in unacceptably high rates of cooling. We present chart-based tools and heuristics for use by designers, and also discuss how these insights might inform regulation regarding the exploitation of subsurface geothermal resources.