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Measurement of barometric efficiency (BE) from open monitoring wells or loading efficiency (LE) from formation pore pressures provides valuable information about the hydraulic properties and confinement of a formation. Drained compressibility ( α) can be calculated from LE (or BE) in confined and semi-confined formations and used to calculate specific storage ( S ). S and α are important for predicting the effects of groundwater extraction and therefore for sustainable extraction management. However, in low hydraulic conductivity ( K) formations or large diameter monitoring wells, time lags caused by well storage may be so long that BE cannot be properly assessed in open monitoring wells in confined or unconfined settings. This study demonstrates the use of packers to reduce monitoring-well time lags and enable reliable assessments of LE. In one example from a confined, high- K formation, estimates of BE in the open monitoring well were in good agreement with shut-in LE estimates. In a second example, from a low- K confining clay layer, BE could not be adequately assessed in the open monitoring well due to time lag. Sealing the monitoring well with a packer reduced the time lag sufficiently that a reliable assessment of LE could be made from a 24-day monitoring period. The shut-in response confirmed confined conditions at the well screen and provided confidence in the assessment of hydraulic parameters. A short (time-lag-dependent) period of high-frequency shut-in monitoring can therefore enhance understanding of hydrogeological systems and potentially provide hydraulic parameters to improve conceptual/numerical groundwater models. [ABSTRACT FROM AUTHOR]

Understanding when and why groundwater recharge occurs is of fundamental importance for the sustainable use of this essential freshwater resource for humans and ecosystems. However, accurately capturing this component of the water balance is widely acknowledged to be a major challenge. Direct physical measurement identifying when groundwater recharge is occurring is possible by utilizing a sensor network of hydrological loggers deployed in underground spaces located in the vadose zone. Through measurements of water percolating into these spaces from above, we can record the potential groundwater recharge process in action. By using automated sensors, it is possible to precisely determine when recharge occurs (which event, month, or season, and for which climate condition). Combined with daily rainfall data, it is possible to quantify the 'rainfall recharge threshold', the amount of rainfall needed to generate groundwater recharge, and its temporal and spatial variability. Australia's National Groundwater Recharge Observing System (NGROS) provides the first dedicated sensor network for observing groundwater recharge at an event-scale across a wide range of geologies, environments, and climate types representing a wide range of Australian hydroclimates. Utilizing tunnels, mines, caves, and other subsurface spaces located in the vadose zone, the sensors effectively record 'deep drainage', water that can move beyond the shallow subsurface and root zone to generate groundwater recharge. The NGROS has the temporal resolution to capture individual recharge events, with multiple sensors deployed at each site to constrain the heterogeneity of recharge between different flow paths, and to quantify (including uncertainty bounds) rainfall recharge thresholds. Established in 2022, the network is described here together with examples of data being generated. [ABSTRACT FROM AUTHOR]

At mine sites in a stressed watershed, groundwater dominated licensed water take, and water-use productivity was dependent on site practices and constraints. Solutions for mining and water in this context include: (1) state-based water governance within a national framework; (2) information tools, including mine site water-reporting frameworks; (3) site water sharing and salt trading; and (4) technologies and leading practices. While water reporting has improved, evaluating the significance of hydrological changes over the long-term remains a challenge, particularly for groundwater and saline discharges to rivers. [ABSTRACT FROM AUTHOR]

The off-axis integrated cavity output spectrometry (ICOS) method to analyse porewater isotopic composition has been successfully applied over the last decade in groundwater studies. This paper applies the off-axis ICOS method to analyse the porewater isotopic composition, attempts to use the isotopic shift in groundwater values along with simple geochemical mixing model to define the groundwater processes in the Sydney Basin, Australia. Complementary data included geophysical, hydrogeological, geochemical, and mineralogical investigations. Porewater from core samples were analysed for δ 18 O and δ 2 H from various sedimentary units in the Basin and compared to endpoint water members. Stable δ 18 O and δ 2 H values of porewaters in the Basin (− 9.5 to 2.8‰ for δ 18 O and − 41.9 to 7.9‰ for δ 2 H) covered a relatively narrow range in values. The variability in water isotopes reflects the variability of the input signal, which is the synoptic variability in isotopic composition of rainfall, and to a minor extent the subsequent evaporation. The porosity, bulk density and mineralogy data demonstrate the heterogeneity that adds the complexity to variations in the isotope profile with depth. The source of chloride in the sedimentary sequence was related to rock–water and cement/matrix–water interaction rather than to evaporation. The heterogeneous character of the sedimentary rock strata was supported by a change in pore pressures between units, density and variability in rock geochemical analyses obtained by using X-ray fluorescence (XRF) and X-ray power diffraction analyses. This research identified distinct hydrogeological zones in the Basin that were not previously defined by classic hydrogeological investigations. Isotopic signature of porewaters along the detailed vertical profile in combination with mineralogical, geochemical, geophysical and hydrogeological methods can provide useful information on groundwater movement in deep sedimentary environments. The findings of the study are valuable in management of sensitive ecosystems and potable resources above mining areas. [ABSTRACT FROM AUTHOR]

Quantifying the retardation (Rd) of reactive solutes as they migrate through low-permeability clay-rich media is difficult, thus motivating this study to assess the viability of combining centrifuge modeling and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) techniques. An influent solution containing Cl-, trace metals, and lanthanide species flowed at 1.0 mL·h-1 through an undisturbed clay-rich core sample (33 mm diameter × 50 mm long) mounted in a UFA Beckman centrifuge operating at 3000 rpm (N factor = 876g). During the 87 day experiment, the hydraulic conductivity of the core was 3.4 × 10-10 m·s-1. Effluent breakthrough data indicate the Rd of TI to be 10; incomplete breakthrough (non-steady-state) data for 145Nd and 171Yb suggest Rd values of ⪢75 and ⪢85, respectively. At the completion of the transport experiment, longitudinal sections of the core solid were analyzed for 145Nd and 171Yb using a Cetac laser ablation system coupled with an ICP-MS. The longitudinal core sections yielded Rd values of >10 000 for 145Nd and 171Yb. This study demonstrates coupling these techniques can provide Rd values for a wide range of reactive solutes with relatively rapid testing of small-scale, low hydraulic conductivity core samples. [ABSTRACT FROM AUTHOR]

Fossil fuel powered energy generation is highly water intensive and competes with other end users for water. An assessment of the water footprint of energy systems is thus an important consideration for planning decisions that balance demand with reliable supply of both energy and water, cost-effective technologies, and the imperatives of climate change. A comprehensive study is lacking in the Australian context where fossil fuels currently dominate energy supply and freshwater can be a scarce resource, though water-energy footprint studies are available elsewhere. Therefore, for the first time, this study has attempted to track the freshwater footprint of fossil fuel production and subsequent electricity generation in the National Electricity Market (NEM) region of Australia. Water withdrawal and consumption intensity factors, mostly Australian values, were used to calculate the water withdrawal and consumption volumes at spatial scales of thermoelectric power plants, catchments and states within the NEM. The vulnerability of energy production in the region to water stress on a catchment level was also analysed, though limited by available data. The results showed that coal accounted for more than 85% of the total freshwater withdrawal and consumption associated with fossil fuel energy production. Thermoelectric power generation dominated water withdrawal volumes, while water consumption was dominated by primary fuel production. A considerable amount of consumed water (256 GL/year) was found to be exported as virtual water, mainly associated with coal. It was also revealed that at least six of the twenty seven catchments in the NEM region were experiencing medium to high water stress, with competition between multiple water users for available freshwater, particularly during dry periods. This study provides insights on commonly overlooked aspects of 'water for energy' in Australia that provides a basis for ongoing assessments and planning. Image 1 • Comprehensive assessment of freshwater footprint of fossil fuel energy sector in NEM, Australia. • We analysed water stress due to primary fuel production and electricity generation at catchment scale. • Coal accounted for major share of energy related water footprint. • High competition for water in major energy production catchments and thus creating high water stress. • Study indicates need for integrated water and energy planning. [ABSTRACT FROM AUTHOR]

The hydraulic conductivity of jointed rocks is one of the main input parameters to predict water inflow to engineering structures that are located in the jointed rocks. Quantification of this parameter is also vital to simulate the water flow within rock aquifers. The hydraulic conductivity of jointed rocks is controlled by the geometrical characteristics of the existing joint network inside the rock mass. This paper presents an analytical method to estimate hydraulic conductivity, which considers the rock joints as a finite circular-shaped plane inside the joint network. The concept of intersection probability of each joint set with a virtual cylinder is used to estimate the number of joints inside the objective volume. This novel method provides a tool to calculate the hydraulic conductivity tensor based on the geometrical properties of pre-existing rock joints. Comparing the results of this method with long-established methods, at a site in Fanay-Augeres Mine (France), shows that the proposed method has very high accuracy in predicting the hydraulic conductivity tensor. Additionally, its formulations can be used to conduct sensitivity analysis on the calculated hydraulic conductivity. [ABSTRACT FROM AUTHOR]

Biochar is a product of the thermal treatment of sustainably sourced organics or waste biomass, which enhances nutrient availability and exchangeable cations after soil application. Biochar feedstock is one of the primary factors influencing the availability of exchangeable cations in biochar and soil-biochar mix. However, this influence is not satisfactorily understood due to contrasting data among literature for the cation exchange capacity (CEC) and the lack of standard analysis methods for CEC of biochar and soil-biochar mixtures. Therefore, this research was conducted to assess cation exchange in contrasting soil-biochar mixes, where CEC is measured as (1) the sum of base cations (Na+, K+, Mg 2+, and Ca2+) displaced by ammonium acetate (CEC-BC) and (2) NH 4 + displaced by potassium chloride (CEC-NH 4 +). For the first time, we have evaluated CEC-BC and CEC-NH 4 + in 21 different biochar samples using a modified method. We then used 12 representative biochars with 3 soil types (2% w/w biochar) and provided insights on relative changes in CEC-BC and individual base cations. Some previous studies have indicated a relationship between CEC and surface area and a degree of additivity in the resulting CEC of soil-biochar mixes. However, our study demonstrates an absence of these correlations and a lack of additivity in the representative biochar products. We found that biochar prepared from mixed garden wastes can increase K+ or Ca2+ in loamy or sandy soils and mitigate potential soil sodicity problems in loamy soils. However, a clayey soil may or may not need biochar for the specific purpose of increasing exchangeable cations. Our results revealed that biochar prepared from hardwood or mixed garden waste can retain NH 4 + and deliver it to soil acting as a sink and source for soil nutrients. [Display omitted] • Presence of exchangeable cations in biochar is primarily influenced by feedstock type. • Exchangeable K+ was increased by more than 400% in sandy loam soil after application of 2% w/w biochar. • Hardwood or cellulosic biomass derived biochar increases the cation exchange capacity of clayey soils. • Biochar can help mitigate potential soil sodicity by reducing exchangeable Na+ in loamy soils. • Biochar can store significant NH 4 +, suggesting potential use as a slow-release fertilizer. [ABSTRACT FROM AUTHOR]

Groundwater extraction is increasing rapidly in many areas of the world, causing serious impacts such as falling water tables, ground surface subsidence, water quality degradation, and reduction of stream baseflow on which many ecosystems depend. Methods for understanding and predicting the impacts of groundwater extraction generally lack detailed spatial and temporal knowledge of the subsurface hydrogeomechanical properties. This review provides a comprehensive understanding of Earth and atmospheric tides and their impact on subsurface pore pressure. First, we evaluate the global occurrence of Earth and atmospheric tides. Then, we illustrate their impact on the groundwater response and connect this with the theory of poroelasticity, which underpins quantitative analyses. Finally, we review methods that utilize these impacts to characterize groundwater systems and to quantify their hydrogeomechanical properties. We conclude by highlighting their potential as passive and low‐cost investigation techniques and by outlining the research and developments required to progress and make analyses readily available. Thus, hydrogeomechanical properties of subsurface systems could be obtained at unprecedented spatial and temporal resolution, adding additional value to commonly acquired groundwater and atmospheric pressure data. Key Points: Earth and atmospheric tides occur globally, are predictable or observable, and induce groundwater oscillations under semiconfined conditionsTides, in combination with poroelastic theory, enable groundwater system characterization and hydrogeomechanical property quantificationAnalyzing groundwater responses to Earth and atmospheric tides is an underutilized passive technique to quantify subsurface properties [ABSTRACT FROM AUTHOR]

Cemented paste backfill (CPB)/rock interface shear resistance results in a spatiotemporal stress reduction in CPB and thus affects the mechanical stability of CPB structure in underground excavations. To study the stress distribution in CPB structure, an integrated model consisting of a cohesive zone model for CPB/rock interface behavior and a multiphysics model for hydrating CPB behavior is developed. The predictability of the proposed model is validated against measurements from laboratory tests and field studies. Thereafter, the validated model is used to investigate the influence of curing time, stope geometry, and field backfilling operation on the spatiotemporal stress development in CPB structure. It has been found that the CPB/rock interface loading is able to reduce the stress levels in CPB by up to 75%, and taking advantage of this phenomenon can significantly reduce the operation cost. Moreover, there exists a critical stope width that governs the extent of stress reduction in CPB. In addition, continuous mining activity in the secondary stope exerts limited impact on the stress redistribution in the primary backfill body. These findings provide practical guidance for the safe design of a CPB structure as well as a more strategic mining plan for the adjacent ore body. [ABSTRACT FROM AUTHOR]

Roughness on rock joints produces a variable aperture across the joints and increases the flow path length. These conditions should be taken into account for a good approximation from cubic law. In this paper, the concept of local true aperture and tortuosity is applied to assumed joints where surfaces are matched to each other and correspond with standard Joint Roughness Coefficient (JRC) profiles. Furthermore, the hydraulic behaviour of JRC profiles is studied by a new laboratory experiment setup. The analytical approach provides new insights into the effects of roughness on hydraulic properties of rock joints. The results indicate that for a constant mechanical aperture, both the minimum local aperture and hydraulic aperture decrease with increasing JRC. Furthermore, tortuosity and standard deviation of local true aperture increase with JRC increment. The trend obtained between different parameters and JRC shows an obvious fluctuation for JRC lower than 10. On one hand, the results of this study along with a critical review of previous studies demonstrate that JRC profiles cannot present a precise roughness increment when JRC is less than 10. A new laboratory setup was designed to study the flow behaviour of JRC profiles. The results obtained from laboratory experiments under linear flow conditions validate the accuracy of the applied analytical method. [ABSTRACT FROM PUBLISHER]

Specific storage (SS) has considerable predictive importance in the modelling of groundwater systems, yet little is known about its statistical distribution and dependency on other hydrogeological characteristics. This study provides a comprehensive overview and compiles 430 values of SS from 183 individual studies, along with complementary hydrogeological information such as estimation methods, lithology, porosity, and formation compressibility. Further evaluation of different approaches to determine and utilize SS values for numerical groundwater modelling, along with the scale and source of uncertainty of different measurement methods, was carried out. Overall, SS values range across six orders of magnitude (from 3.2 × 10–9 to 6 × 10–3 m–1) with a geometric mean of 1.1 × 10–5 m–1 and the majority (> 67%) of values are in the order of 10–5 and 10–6 m–1. High SS values of ~10–4 m–1 were reported for glacial till and sandy lithologies, particularly for shallow and thin strata where leakage may obscure the estimation of SS. A parallel assessment of 45 transient regional-scale groundwater models reveals a disconnect between findings of this study and the way SS is treated in practice, and that there is a lack of foundational SS data to conduct quantitative uncertainty analysis. This study provides the first probability density functions of SS for a variety of lithology types based on the field and laboratory tests collated from the literature. Log transformed SS values follow a Gaussian/normal distribution which can be applied to evaluate uncertainties of modelling results and therefore enhance confidence in the groundwater models that support decision making. [ABSTRACT FROM AUTHOR]

Underground mining operations have the potential to alter groundwater systems and facilitate hydraulic connections between surface water and groundwater. The nature and degree of these interactions need to be evaluated to identify mining risks to surrounding water resources and to predict potential operational effects and environmental impacts, such as hydraulic stress on local surface waters. Environmental water tracers (EWTs) are commonly used to study such interactions in mine water and hydrogeological studies. However, the opportunities presented by EWTs could be more widely utilised to benefit the mining industry and the environment. Some of the challenges faced include the lack of practical frameworks, the need for more examples of EWTs applications in mining, and the possibility of complex interpretation of tracer results. This paper reviews previous studies that have applied EWTs in groundwater systems within or near mine sites, mostly from Australia, China, and India. The EWTs used in these studies include water quality parameters, major ions, stable isotopes, radioisotopes, and dissolved gases. The opportunities of applying multiple EWTs to identify water sources, mixing, and determine recharge rates and groundwater residence times are discussed. Limitations of different EWTs in terms of their capabilities, reliability, cost of analysis, effort, and processing times are reviewed. Steps for selecting suitable EWTs for specific mine hydrogeology assessments should be commensurate with the risks. Finally, this paper provides an overview of suitable EWTs that will be a useful contribution to appropriate water resource management decisions around mines. [ABSTRACT FROM AUTHOR]

This article reports the first application of coupled total organic carbon cavity ring-down spectroscopy (TOC-CRDS) for the analysis of the δC signature of dissolved organic carbon (DOC) in freshwater samples. DOC represents a major, dynamic component of the global carbon cycle. The export of DOC from soils into rivers and groundwaters may be highly climate sensitive, and much of this export may occur in ephemeral fluxes. Thus, a robust, simple and inexpensive method for the continuous determination of DOC concentration and quality is urgently needed. We detail recent advances made in the analysis of the δC signature of DOC using a TOC-CRDS system optimised for the analysis of DOC with natural abundances greater than 2.5 mg L with no sample pre-concentration required and sample volumes of 40 mL. Precision between replicated samples was comparable to conventional analysis by gas-source isotope ratio mass spectrometry, yielding δC values with standard deviations of ± 0.5 ‰ for DOC concentrations higher than 1.5 mg L. The utility of this technique for the analysis of DOC in samples with a broad range of compositions and concentrations (2.5-25 mg L DOC) is demonstrated. Since DOC δC can be measured continuously, ca. 45 min per measurement, this method enables the online monitoring of DOC in river water, water intakes and treated waters, allowing changes in DOC fluxes to be monitored in real time. [ABSTRACT FROM AUTHOR]

Accurate and frequent measurement of mine water quality is essential for timely management and regulatory requirements. At mines, traditional water sample collection practices are sometimes unsafe or impractical due to accessibility challenges. Unmanned aerial vehicle (UAV)-based remote water sampling has benefits in accessing small, shallow and isolated waterbodies in hazardous environments. In this study, an integrated electromechanical pneumatic system was developed to provide an effective, efficient and safer means to acquire mine water samples using UAVs. The system was tested to collect and analyse ponded water from a tailings storage facility to measure pH, electrical conductivity and dissolved oxygen. [ABSTRACT FROM AUTHOR]

One of the largest challenges for groundwater management is reliable modelling of semi-confined and confined aquifer systems with variable degrees of vertical connectivity. There is often a lack of sufficient hydraulic and hydromechanical data for each strata in a complex aquifer system to enable robust and reliable numerical modelling. Currently, data are often spatially and temporally sparse due to the extensive labour and setup costs of aquifer pump test techniques, and whether aquifers are semi-confined or confined is poorly quantified. The analysis of Earth and atmospheric tides in standard monitoring bores (pressure gauged) offers significant utility to provide a preferential alternative to long term pump tests in confined aquifers. These novel techniques also enable unprecedented monitoring of changes of the degree of confinement of aquifers and variations in hydromechanical properties over time. We provide a synthesis of the current understanding and utilization of Earth and atmospheric tidal analysis of groundwater level data for characterization of subsurface systems. We also highlight uncertainties in techniques that are being developed, to encourage discussion and further research. [ABSTRACT FROM AUTHOR]

Biochar products that hold and release water within a stable carbonised porous structure provide many opportunities for climate mitigation and a range of applications such as for soil amendments. Biochar that are produced from various organic feedstocks by pyrolysis can provide multiple co-benefits to soil including improving soil health and productivity, pH buffering, contaminant control, nutrient storage, and release, however, there are also risks for biochar application in soils. This study evaluated fundamental biochar properties that influence Water Holding Capacity (WHC) of biochar products and provides recommendations for testing and optimising biochar products prior to soil applications. A total of 21 biochar samples (locally sourced, commercially available, and standard biochars) were characterised for particle properties, salinity, pH and ash content, porosity, and surface area (with N 2 as adsorbate), surface SEM imaging, and several water testing methods. Biochar products with mixed particle size, irregular shapes, and hydrophilic properties were able to rapidly store relatively large volumes of water (up to 400% wt.). In contrast, relatively less water (as low as 78% wt.) was taken up by small-sized biochar products with smooth surfaces, along with hydrophobic biochars that were identified by the water drop penetration test (rather than contact angle test). Water was stored mostly in interpore spaces (between biochar particles) although intra-pore spaces (meso-pore and micropore scale) were also significant for some biochars. The type of organic feedstock did not appear to directly affect water holding, although further work is needed to evaluate mesopore scale processes and pyrolytic conditions that could influence the biochemical and hydrological behaviour of biochar. Biochars with high salinity, and carbon structures that are not alkaline pose potential risks when used as soil amendments. [Display omitted] • Optimisation of biochar surface structure will also enhance WHC. • Increase in meso-porosity increases WHC and decreases hydrophobicity. • Considering inter-particle porosity is critical for biochar WHC. • Surface angularity and roughness of biochar enhances its WHC. • Modified methods for key biochar characterisations for soil application are provided. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking (SCC) of cable bolts in underground mines is a universal issue with limited cost effective solutions at present. Understanding the SCC mechanism of cable bolt failure is crucial in maintaining effective ground support and hence increasing the safety and productivity of underground mines. However, to date, no practical laboratory system has been developed to replicate the SCC mechanism which occurs in underground mines. In this study, based on the chemical properties of mine water, an acidified solution containing sulphide is synthesized. The solution is exposed to the wire strands from cable bolt in the laboratory to model service failure. It is shown that the applied stress intensity and time to failure have an inverse power law relationship in wires of cable bolts. Similar features are observed in both laboratory-failed specimens and the service-failed cable bolts under macroscopic and microscopic examinations, demonstrating the ability of the proposed framework to simulate failure of cable bolt subjected to SCC in the laboratory. Furthermore, the impact of stress intensity and hydrogen concentration on SCC are examined and a cohesive failure mechanism on the cable bolt SCC crack initiation, growth and catastrophic failure are presented. The proposed framework can be applied to the reinforcement materials for improved understanding of the SCC mechanism in underground mines and tunnels. [ABSTRACT FROM AUTHOR]

Coal-seam gas production requires groundwater extraction from coal-bearing formations to reduce the hydraulic pressure and improve gas recovery. In layered sedimentary basins, the coalbeds are often separated from freshwater aquifers by low-permeability aquitards. However, hydraulic connection between the coalbed and aquifers is possible due to the heterogeneity in the aquitard such as the existence of conductive faults or sandy channel deposits. For coal-seam gas extraction operations, it is desirable to identify areas in a basin where the probability of hydraulic connection between the coalbed and aquifers is low in order to avoid unnecessary loss of groundwater from aquifers and gas production problems. A connection indicator, the groundwater age indictor (GAI), is proposed, to quantify the degree of hydraulic connection. The spatial distribution of GAI can indicate the optimum positions for gas/water extraction in the coalbed. Depressurizing the coalbed at locations with a low GAI would result in little or no interaction with the aquifer when compared to the other positions. The concept of GAI is validated on synthetic cases and is then applied to the north Galilee Basin, Australia, to assess the degree of hydraulic connection between the Aramac Coal Measure and the water-bearing formations in the Great Artesian Basin, which are separated by an aquitard, the Betts Creek Beds. It is found that the GAI is higher in the western part of the basin, indicating a higher risk to depressurization of the coalbed in this region due to the strong hydraulic connection between the coalbed and the overlying aquifer. [ABSTRACT FROM AUTHOR]

• Mineral reactions were observed during water injection into carbonate core samples. • The core samples did not contain any clay minerals. • The mineral reactions dissolved intergranular cement dislodging the rock grains. • The mineral reactions dissolved the grain's surface, releasing silicate fines. • Redistribution of dislodged fines and migration of silicate fines caused clogging. Water injection into an aquifer is generally motivated by one of three objectives: disposal, managed aquifer recharge (MAR), or aquifer storage and recovery (ASR). Any of these would be undermined if an injection well were to become clogged. This paper investigates whether mineral reactions can cause mobilization of fines and rock grains, and if so, how this would affect clogging. Injection experiments are performed on Edwards Brown (dolomite) and Indiana limestone core samples. X-ray Powder Diffraction analysis of the rocks shows that no clays are present. Filtered-deaired deionized water and pure salts are used to prepare the injection fluids. The core samples are subjected to four sequential injections of fluids: at salinities 44,580 mg/L (referred to as "seawater"), 14,860 mg/L, 7,430 mg/L, and 0 mg/L (deionized water). These salinities are selected to represent disposal, and less saline fluids to represent MAR and ASR projects. Pressure difference is recorded across the core sample at each stage and is used to calculate permeability. The effluent samples are collected to characterize produced fines and elements. The increase in the pH of the effluent samples suggest mineral reactions, which is supported by an increase in the concentration of chemical elements in the effluent samples. Scanning Electron Microscopy (SEM) images show pore enlargement due to dissolution and depict pore blockage due to fines migration, grains redistribution, and mineral precipitation. Mineral reactions dissolved the grain's surface and intergranular cement, releasing silicate fines and rock grains, which in turn reduce the permeability of the rock by 68 % to 99.9 %. [ABSTRACT FROM AUTHOR]

This study explores the extent and quality of localised mining water-related disclosures from the Australian state of New South Wales (NSW). The data set provides an atypical opportunity to study voluntary and mandatory environmental reporting, as mining companies often produce their own voluntary sustainability reports, yet some mandatory reporting is also required due to NSW development consent conditions. In order to assess the extensiveness of mandatory reporting, development consent reporting requirements are compared to a selection of voluntary water reporting indicators. Most indicators were taken from the Global Reporting Initiative (GRI) and Water Accounting Framework for the Minerals Industry (WAFMI), but the authors also included additional indicators derived from community water-related discussions. It is found that most of the information required by the indicators is also required by the consent conditions. In particular, information relevant to four GRI indicators is reported within either annual reviews or environmental management plans. Consent conditions are discretionary, however, and older consent conditions may not require such reports to be made publicly available through the internet. Additionally, a content analysis is conducted of available mandatory and voluntary reports from four mining operations. The voluntary reports were found to provide site-level information that was either as good as that found within the annual reviews, or of lesser quality, but in no instance better. Further, no voluntary report stated definitively whether operations impacted on water sources. Nor was there any reporting on water storage capacity or the quality of water after recycling or reuse. Finally, Dryzek's ‘discursive democracy’ theoretical framework on the quality of a deliberation system is used to analyse the extent to which NSW legal and administrative processes are designed to facilitate deliberation by catchment residents. Theoretically, the system is well designed, as important information is made publicly available and community consultation is a mandatory part of the process. However, the system is not without flaws and could be improved by providing better access to information. [ABSTRACT FROM AUTHOR]