Mine Inflow Research Articles

Study on the water-richness law and zoning assessment of mine water-bearing aquifers based on sedimentary characteristics

To study and prevent the water hazards of deep coal mines roof in the Inner Mongolia–Shaanxi (IM–S) mining area, it is essential to correctly evaluate the water-richness distributions of water-bearing aquifers in roof. This paper puts forward a sediment control method for water-richness law and zoning in the roof aquifers of deep Jurassic coals. To determine the vertical distance of direct water-bearing aquifers, the height of fractured water-conducting zone was detected by an underground network parallel electrical method. The plane and lateral spatial distribution patterns of the water-bearing aquifers and the control of the water-richness distribution was analyzed with the sediment control method. An evaluation system that consisted of four indicators, i.e., sedimentary environmental impact index, interlayer ratio of sandstone and mudstone, sandstone thickness, geophysical water-richness anomaly index was constructed. Furthermore, an Analytic Hierarchy Process (AHP) was introduced to establish the comprehensive zoning map. Finally, through the example analysis of Muduchaideng coal mine, the zoning evaluation results of water-richness were verified by the mine inflow. The findings of this study provide scientific guidance for prevention and control of mine water hazards in the IM–S mining area.

Mine inflow prediction model based on unbiased Grey-Markov theory and its application

Mine inflow prediction model based on unbiased Grey-Markov theory and its application

Discussion on Some Topical Issues of Water Prevention and Control in Coal Mines

Effective prevention and control of water hazards in China’s coal mines require that several key issues be addressed. The key issues discussed in this paper are the complex and variable water inrush types in mines, uncertainties in calculation of mine inflow, and the primary mechanism of water hazards resulting from mining-induced bedding separation. Challenges encountered in reinforcement and grouting of the seam roof and floor are also discussed, as well as the risks posed by mine closure. We suggest research areas to better predict and understand the impacts of these issues and propose a direction for improvement of coal mine water control.

Thermal groundwaters of the UK: geochemical indications of flow, vulnerability and possible threat to the shallow hydrosphere

Three types of thermal groundwater are known from the UK: warm springs (≤45°C), mine inflows (≤50°C) and deep basin waters (≤80°C). The warm springs depend on Carboniferous Limestone conveying water to sufficient depth (600–3000 m) to acquire a significantly higher temperature. The springs have residence times of a few thousand years, but also contain ≤5% modern groundwater. Their water quality is little threat to the environment; the main danger to the springs is construction activity near the emergences. Mine inflows significantly >20°C are known only from Cornish granite. High dissolved 4 He has been interpreted as indicating long residence of the thermal component, but there is also modern water in the system, leading to uncertainty in the mean age. Unpredictable fracturing could hinder development of this resource, while the seawater-like salinity, combined with the presence of toxic metals, would require treatment or re-injection of the spent water to protect the near-surface environment. Mesozoic sedimentary basin brines reach temperatures >60°C, suitable for district heating. This resource is large and effectively invulnerable. However, these waters are generally more saline than seawater and, while disposal of spent brine could take place into the sea under favourable conditions, re-injection would be necessary for inland sites.

Stable isotope systematics and geochemical signatures constraining groundwater hydraulics in the mining environment of the Korba Coalfield, Central India

The present study explores the use of stable isotopes and major ion chemistry of various water sources such as mine water, groundwater, river water, and rainwater to identify the dominant hydrogeochemical process that controls the water quality in the active opencast coal mining area of the Korba Coalfield, India. Different hydrochemical models have revealed that the study area is mostly characterized by two facies alongside a dominance by ion exchange: i.e., a slightly mineralized Ca2+–Mg2+–Cl− and a meteorically derived Ca2+–HCO3− fresh water facies. In the isotope bivariate plot, the samples plot to the right of the LMWL and slopes observed in pre (4.94) and post-monsoon (5.85) seasons are not as steep as the LMWL (7.95) and this warrants the suggestion that meteoric water is the major source that replenishes the dynamic groundwater resource in the study area after being subjected to evaporation. The negative d-excess values (< 0) and enrichment of the δ18O ratio observed at some locations suggests a non-equilibrium process and a “mechanism of mixing”. A noteworthy fact is that isotopically river water is in tandem with the mine water samples for both seasons and testifies to a hydraulic connectivity between Hasdeo River water and mine water through a major fault. It is substantiated by mine inflows assessed by the sump test for Kusmunda and Gevra, which is two times higher than the predicted values by Darcy’s law. The wide variation in the isotopic composition is attributed to different vapor sources viz., southwest monsoon (SW) that originates in the Arabian Sea and locally driven air moisture from surface water bodies.

Groundwater Source Discrimination and Proportion Determination of Mine Inflow Using Ion Analyses: A Case Study from the Longmen Coal Mine, Henan Province, China

Complex hydrogeological conditions in China’s coal mines have contributed to frequent mine water disasters. A simple and effective method to determine water inflow sources and paths is therefore essential. The Longmen Mine, located in Henan Province, in central China was used as a case study. A Piper diagram and cluster analysis were used to screen the characteristic values of 18 water samples from potential aquifers. A comprehensive fuzzy evaluation of the groundwater ions was carried out to determine the main source of the total mine inflow. Then, based on conservation of ionic masses, a matrix function was established to calculate the groundwater recharge composition. Finally, using measured water inflows for the Cambrian limestone aquifer, the calculated and observed results were compared. The results showed that the Carboniferous Taiyuan Formation limestone aquifer (the L7 limestone aquifer) accounts for 60.8% of the total mine inflow, while the Cambrian limestone and roof sandstone aquifers account for 34.8 and 4.4% of the inflow, respectively. The normal mine inflow totals about 19,200 m3/day, of which 6,840 m3/day is from the Cambrian limestone aquifer. This agrees well with the calculated value of 6,720 m3/day. Thus, the method is feasible and reliable.

Predicting Open Pit Mine Inflow and Recovery Depth in the Durvuljin soum, Zavkhan Province, Mongolia

Increasingly, mine issues and water resources are being managed on a watershed basis, while addressing problems at the local mine scale. A good example of this developed when empirical and analytical modelling of the potential inflow to an open pit mine in the Durvuljin soum, a region in northwest Mongolia, indicated that inflow would be on the order of 0.3 to 10.5 L/s. In this study, the radius of influence due to open pit mining was estimated to be between 0.6 and 3 km. Based on simulated drawdown contours and transient pit inflow figures that captured the impact of mining and groundwater inflow rate variations over a period of time, it appeared that advanced dewatering will not be required at this mine, unless currently unknown major fractured structures are intercepted. In-pit basal sumps and pumps should be sufficient to remove water from the mine floor. However, an assessment of the final pit level is also crucial to planning the post-mining surface and groundwater quality/eco-system and mitigation requirements during recovery. Our post-mining water table recovery estimate indicated that inflow will exceed evaporation and that a shallow lake will likely form. While such solutions, which do not rely on complex numerical models nor excessive input data, are not appropriate for all hydrogeologic situations, they are relevant to the conditions encountered at most mine sites.

Discharged water from mines shows alteration in its physical properties and may be acidic depending upon the concentration of heavy metals and sulphate ions, which pose hazardous effects on groundwater and ecosystem. This paper deals with the characterisa

Discharged water from mines shows alteration in its physical properties and may be acidic depending upon the concentration of heavy metals and sulphate ions, which pose hazardous effects on groundwater and ecosystem. This paper deals with the characterisation of water being affected by coal mining in the Basharat area of Punjab. Total eleven samples were collected from different water sources including groundwater, mine outflows, mine inflows and surface water in the vicinity of Hassan Kishor Coal Mine. All samples except that of groundwater showed higher turbidity, lower pH values and higher total solid contents. Higher concentration of iron and copper in all samples indicate higher acid mine drainage (AMD). Relatively larger concentration of calcium in groundwater as compared to its presence in other samples demonstrates quashing effect of overlying limestone to the AMD.

Field experiment on coalmine heat disaster governance using cold source from surface water

Regarding the lack of cold source for underground cooling systems from either mine inflow or return air, field experiments were taken in a high temperature deep coal mine with abundant cold source from surface water. Taking Sanhejian coal mine as an example, this paper introduced the technology scheme of heat disaster governance using surface water cold source. The paper presents the basics of this field experiment at the beginning, following by the design and site layout of the cooling system including the analysis and calculation of cold source. Numerical calculation method is also applied based on the operation parameters to simulate the influence to the surface river ecosystem. The results suggest that the temperature of surface water shall be lower than 34°C after heat exchange, and when more cooling capacities are needed in the future, increasing the water flow is more favorable than increasing the cooling range of water, which is better for the ecological environment protection.

Prediction of Mine Inrush Water Based on BP Neural Network Method

Based on predictions of the mine inflow of water and the complexity of influential factors, a method of BP neural network is put forward for mine inrush water prediction in this paper. We chose proper impact factors and establish non-linear artificial neural network prediction model after analyzed the impact factors of mine water inflow in Shandong Heiwang iron, and also made one prediction with normal mine water inflow during the iron mining operation. It turned out that the result can match with the actual prediction data, which make it possible to predict the mine water inflow with the prediction of Artificial Neural Network.

Hydro-geological Conditions and Mine Inflow Water Forecast of the Western Long Beach in Junggar Coalfield

Gushing water is harmful to underground coal mine safety. Jungar coalfield is the major coal base in the Chinese Midwest, and coal-bearing strata are mainly Shanxi Formation and Taiyuan Formation. Coal seams can be mined in the western long beach are 3#, 5#, 6#, 9#. This paper analyzed regional geological conditions, hydro-geological conditions in the western Long Beach of Jungar coalfield, and water-filled factors, predicted mine water discharge, based on the prediction, and proposed prevention and treatment measures of coal mine water.

Water Source Determination of Mine Inflow Based on Non-Linear Method and Hydrochemical Characteristics

Nonlinear methods can be used to identify inrush water rapidly. Yet to identify the mixture water must be combined with water chemistry analysis. Take 9 levels inrush water in Tangshan Mine as an example, according to routine water test data, nonlinear methods, including gray correlation analysis, stepwise distinguishing, neural network, were used to determine water supply quickly, and the results were compared. On the basis, the indicators of piper three-line graph, SI, PCO2 determine the composition of the mixed water and supply channels. The results showed that the main recharge sources of 9th levels inrush water are alluvial and Ordovician limestone water, and infiltrating surface water. Possible ways to supply water are the tectonic fracture, gob, leakage shaft, closed adverse drilling.

Behaviour Characteristics of Pressure Bump of Deep Mining in Kailuan Coal Mine and Micro Seismic Monitoring Technology

Pressure bump is a serious disaster to threat coal mine production safety. The roof and floor strata in Kailuan coal mine are made of sandstone and mudstone with relatively poor rigidity. Most of mines have been into the deep mining stage over one thousand meters. High-stress becomes the key factor induced pressure bump. In this paper, according to coal mining strata, fault development, mine inflow and other geological factors, based on fracturing parameters of mine rock and wall rock in the pilot mines (Qianjiaying Mine, Tangshan Coal Mine), boundary conditions of the occurrence of pressure bump is tested by numerical simulation using RFPA software. It discusses the mechanism and laws of pressure bump under high stress in the deep mining. Mining face and roadway are taken real-time monitoring, using micro seismic monitoring system (MMS). The location and level of micro seismic events within the coal formation caused by breakdown could achieve precise position. Spatial distribution and characteristics of coal and rock bursting could be identified. The stability of coal and rock could be monitored real-time and analyzed. Pressure bump could be predicted and prevented effectively.

Reliable Mine Water Technology

Mine planning, permitting and operation require reliable water technology in all its aspects: water inflow, water use, water disposal and discharge, and water impact. Mine water evaluations are relied upon by mining companies, mine regulators and the public to determine whether the mine is technically feasible, optimally designed, financially sound, socially acceptable, and environmentally benign. Review of the water management performance of mines world-wide indicates that the results obtained from mine water evaluations are frequently unreliable. The magnitude of error is often significant, and the direction of the error is usually to underestimate mine inflow, water usage, water contamination, water discharge, and/or environmental impacts. Examples of mine water evaluations where the results have proven to be unreliable were used to formulate and illustrate a set of general principles that should be applied to every mine water evaluation to ensure that the results reflect the full range of possible outcomes, with that range centered on the most likely outcome. Mine water evaluations performed using these principles can be demonstrably reliable, credible to all of the mine stakeholders, and improve the profitability, public acceptance, and environmental protection of mining projects.

R/S Analysis and its Application in the Forecast of Mine Inflows

Abstract In this paper, the status quo and modeling principles of R/S analysis of non-linear theory are introduced and reviewed. Given the hydro-geological conditions of the Wutongzhuang coal mine, Hurst exponents of mine inflow for the main shaft, ventilating shaft and auxiliary shaft were obtained using R/S analysis, which are 0.772 0, 0.824 7 and 0.905 1 respectively. Since all of the three Hurst exponents are larger than 0.5, it can be concluded that the trend of mine inflow are a long-term as well as persistent problem. Based on the level of duration, the shafts can be listed in decreasing order as the auxiliary shaft, the ventilation shaft and the main shaft, which appears identical with the actual situation of the mine inflow. With R/S analysis, a new method for long-term forecasting of mine inflows is provided.

Uranium and its decay products in samples contaminated with uranium mine and mill waste

The routine determination of the activity concentrations of uranium isotopes ( 238 U, 235 U and 234 U), thorium isotopes ( 232 Th, 230 Th and 228 Th), 231 Pa, 226 Ra, 210 Pb and 210 Po in the environment is one of the most important tasks in uranium mining areas. Natural radionuclides contribute negligibly to the external radiation dose, but in the case of ingestion or inhalation can represent a very serious hazard. The objective of this study was to determine the activities of uranium and its decay products 230 Th, 231 Pa, 226 Ra, 210 Pb and 210 Po in sediments and water below sources of contamination (uranium mine, disposal sites and individual inflows) using gamma and alpha spectrometry, beta counting, the liquid scintillation technique and radiochemical neutron activation analysis.

Improving a regional model using reduced complexity and parameter estimation.

The availability of powerful desktop computers and graphical user interfaces for ground water flow models makes possible the construction of ever more complex models. A proposed copper-zinc sulfide mine in northern Wisconsin offers a unique case in which the same hydrologic system has been modeled using a variety of techniques covering a wide range of sophistication and complexity. Early in the permitting process, simple numerical models were used to evaluate the necessary amount of water to be pumped from the mine, reductions in streamflow, and the drawdowns in the regional aquifer. More complex models have subsequently been used in an attempt to refine the predictions. Even after so much modeling effort, questions regarding the accuracy and reliability of the predictions remain. We have performed a new analysis of the proposed mine using the two-dimensional analytic element code GFLOW coupled with the nonlinear parameter estimation code UCODE. The new model is parsimonious, containing fewer than 10 parameters, and covers a region several times larger in areal extent than any of the previous models. The model demonstrates the suitability of analytic element codes for use with parameter estimation codes. The simplified model results are similar to the more complex models; predicted mine inflows and UCODE-derived 95% confidence intervals are consistent with the previous predictions. More important, the large areal extent of the model allowed us to examine hydrological features not included in the previous models, resulting in new insights about the effects that far-field boundary conditions can have on near-field model calibration and parameterization. In this case, the addition of surface water runoff into a lake in the headwaters of a stream while holding recharge constant moved a regional ground watershed divide and resulted in some of the added water being captured by the adjoining basin. Finally, a simple analytical solution was used to clarify the GFLOW model's prediction that, for a model that is properly calibrated for heads, regional drawdowns are relatively unaffected by the choice of aquifer properties, but that mine inflows are strongly affected. Paradoxically, by reducing model complexity, we have increased the understanding gained from the modeling effort.

Groundwater mixing dynamics at a Canadian Shield mine

Temporal and spatial variations in geochemistry and isotopes in mine inflows at the Con Mine, Yellowknife, are studied to access the impact of underground openings on deep groundwater flow in the Canadian Shield. Periodic sampling of inflow at 20 sites from 700 to 1615 m depth showed that salinities range from 1.4 to 290 g/l, with tritium detected at all depths. Three mixing end-members are identified: (1) Ca(Na)–Cl Shield brine; (2) glacial meltwater recharged at the margin of the retreating Laurentide ice sheet at ∼10 ka; and (3) modern meteoric water. Mixing fractions, calculated for inflows on five mine levels, illustrate the infiltration of modern water along specific fault planes. Tritium data for the modern component are corrected for mixing with brine and glacial waters and interpreted with an exponential-piston flow model. Results indicate that the mean transit time from surface to 1300 m depth is about 23 years in the early period after drift construction in 1979, but decreases to about 17 years in the past decade. The persistence of glacial meltwater in the subsurface to the present time, and the rapid circulation of modern meteoric water since the start of mining activities underline the importance of gradient, in addition to permeability, as a control on deep groundwater flow in the Canadian Shield.

Effect of subsidence on recharge at abandoned coal mines generating acidic drainage: The Majestic Mine, Athens County, Ohio

This paper addresses the relationship between the geology, hydrology, and transient variations in discharge and water chemistry of acidic water discharged by an abandoned underground coal mine: the Majestic Mine in Athens County, Ohio, a partially-flooded, downdip, drift mine. The Middle Kittanning (No. 6) Coal (Allegheny Series, Pennsylvanian System) was mined room-and-pillar until 1921. Loss of support from mine collapse has created large vertical subsidence fractures along the naturally occurring joints within the brittle sandstone overburden. The mine discharge hydrograph, temperature, and pH of the mine discharge indicate that the hydrology of the Majestic Mine can be explained in terms of pseudokarst hydrology. During rainfall events, water is preferentially recharged through the subsidence features. Increased pressure from the mine inflow is transmitted through the flooded workings, causing a rapid increase in discharge, and forcing older mine water out of the mine. A stream draining an overlying watershed is captured by one of the subsidence features, contributing 60 to 80% of the mine water outflow. During the summer, recharge to the mine is negligible because potential evapotranspiration is higher than precipitation. During late summer and fall months, when the mine pool is at its lowest elevation, atmospheric oxygen penetrates back into the mine workings, enhancing the oxidation reactions. During the increased discharge of the spring months, washing of the reaction products from the mine walls produces the highest metals concentrations and chemical loads. *** DIRECT SUPPORT *** A03BX002 00004

Application of fracture-flow hydrogeology to acid-mine drainage at the Bunker Hill Mine, Kellogg, Idaho

The mechanics of groundwater flow through fractured rock has become an object of major research interest during recent years. This project has investigated the flow of groundwater through fractured Precambrian metaquartzite rocks in a portion of the Bunker Hill Mine near Kellogg, Idaho. Groundwater flow through these types of rocks is largely dependent upon the properties of fractures such as faults, joints and relict bedding planes. Groundwater that flows into the mine via the fractures is acidic and is contaminated by heavy metals, which results in a severe acid mine drainage problem. A more complete understanding of how the fractures influence the groundwater flow system is a prerequisite of the evaluation of reclamation alternatives to reduce acid drainage from the mine. Fracture mapping techniques were used to obtain detailed information on the fracture properties observed in the New East Reed drift of the Bunker Hill Mine. The information obtained includes fracture type, orientation, trace length, the number of visible terminations, roughness, waviness, infilling material, and a qualitative measure of the amount of water flowing through each fracture. The hydrogeologic field data collected include routine measurements of the discharge from four individual structural features and four areas where large quantities of water are discharging from vertical rock bolts, the depths to water in three piezometer nests at the ground surface, the pressure variations in four diamond drillholes, and constant discharge flow tests conducted on three of the diamond drillholes. The field data indicate that relict bedding planes are the primary conduits for groundwater flow, and suggest that the two major joint sets that are present connect water flowing through the discontinuous bedding planes. The three minor joint sets that are present do not seem to have a significant impact on groundwater flow, but along with the two major joint sets may store relatively large quantities of water. It appears that rock-bolt holes in the central portion of the drift primarily intersect relict bedding planes, whereas rock-bolt holes in the southeastern portion of the drift primarily intersect joints; this probably is related to the shallower angle of dip of the bedding planes in the central portion of the drift. It also appears that recharge from the surface directly above the mined-out openings is the primary source of water in the upper workings of the mine, and that the large seasonal head variations in the potentiometric surface are primarily responsible for the observed temporal variations in mine inflow. Infilling material may control the hydrogeologic character of the faults, with those filled with gouge having low hydraulic conductivities and those filled with breccia having relatively high hydraulic conductivities. In addition, one of the faults may act as a positive (constant head-recharge) hydrogeologic boundary. A double-porosity approach probably is the most appropriate for simulating the groundwater flow system in the vicinity of the New East Reed drift. Finally, grouting of a combination of breccia-filled faults and relict bedding planes may offer the best hope for minimizing mine-water inflow or recharge.