Search Documents

By Broggi Andrea

Condensates produced by SiO(g) and CO(g) have a crucial importance in silicon production. Condensation will follow the reactions 3 SiOðgÞ+COðgÞ→ 2 SiO2 + SiC and 2 SiO ðgÞ→Si+SiO2. Solid compounds generated during silicon production contain Si, SiO2 and SiC in different microstructures and amounts. In industrial systems, condensates limit the SiO(g) escape to the off-gas system. On the other hand, they can block the gas flowing from the high temperature zone, hence the necessity of studying an optimized condensation process. This review discusses SiO(g) condensation and its interaction with CO(g). The report gives an overview of the condensates found both at laboratory and at industrial scale. The two main compounds are the Si–SiO2 and the SiOx–SiC mixtures. The hypothesis on the mechanism of formation of SiC–SiOx condensates is presented through a wide selection of performed works. The advantages and disadvantages of the former experimental procedures are discussed.

By Enrui Dai, Weibing Chen, Bin Yang, Wenhui Ma, Haisheng Fang, Hui Wang

LiMn0.8Fe0.2PO4/C composite was prepared by an improved solid-state method and the effect of calcination temperature on properties of the obtained materials was investigated. The results showed that increasing calcination temperature from 600 to 700 oC improved the performance of the LiMn0.8Fe0.2PO4/C due to enhanced crystallinity and increased conductivity, but further increase in calcination temperature to 800 oC led to degraded performance due to particle growth and decrease in porosity. Therefore, the LiMn0.8Fe0.2PO4/C composite prepared at 700 oC exhibited the best electrochemical performance, and could deliver a high capacity of 152 mAh g−1 at 0.1 C, 147 mAh g−1 at 1 C and 114 mAh g−1 at 10 C. In addition, the performance of the LiMn0.8Fe0.2PO4/C and LiMn0.8Fe0.19Mg0.01PO4/C was compared when they were obtained at the optimum calcination temperature.

Jan 1, 2015

By S Lehane, S Pearce

The characterisation and assessment of waste rock has been the subject of considerable research, and many guidance documents have been published both internationally and within Australia. While these documents provide detailed information on how to characterise waste rock, there is not a great amount of detail on how to determine the optimal waste management options from an operational viewpoint. For example, typical questions that a mine operator would seek answers to include: What placement method should be used (eg end tipping versus paddock dumping)? What is an optimal tip head height for waste placement in a storage facility? How should sulfide grade control be carried out?Defining the contributing factors to waste management and waste material placement and assessing the contribution of each variable directs these assessments towards a semi-qualitative and quantitative methodology. Quantitative methodologies show an increase in the confidence of these assessments by providing logical, measureable assessments.As part of a strategic assessment for waste management at an active mine site, a detailed risk-based investigation of the influence of variables common to waste placement was completed. These variables included placement method, placement height, sulfur grade and material conditioning (eg compaction) on the associated risks of waste material storage. The assessed risks include temperature assessments (potential for thermal take-off as a result of spontaneous combustion), toxic gas production and flow and acid production potential. Applying a numerical modelling approach to the assessment of the different waste material placement strategies allows for the variation in risk to be graphically presented and communicated through risk matrices and histograms.CITATION:Pearce, S and Lehane, S, 2015. Quantitative risk assessment tools to assist with waste management and placement guidelines, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 353–364 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By F. G. Rinker

The world demand for metallized iron continues to increase, keeping pace with steelmaking requirements for lower cost hot metal. Virgin iron ore and in-plant oxide fines can be reduced to direct reduced iron (DRI) and hot briquetted iron (RBI). MR&E has developed an improved coal-based process for cost-effective production of either DRI or HBI. Starting with dry compaction, the process combines the latest technology for material preparation, rotary hearth furnace construction and environmental control. Coarse iron ore fines are blended with pulverized non-metallurgical coal to produce a highly metallized (>90%) product. This paper presents production and installation cost data based on operating and under-construction iron oxide reduction facilities.

Jan 1, 1999

By M J. Schultz, R L. Rude, D M. Tomko

The US Mine Safety and Health Administration (MSHA) conducted compliance assistance diesel particulate matter (DPM) sampling throughout the underground metal and non-metal mining industry. Based on that sampling, MSHA identified mines that were having difficulty meeting the DPM limit. To provide further assistance, MSHA then visited approximately 60 of the mines that were experiencing difficulty complying with the DPM standard. As part of these visits, DPM exposures were measured and control technologies for DPM were observed and assessed. Controls consisted of ventilation, clean engines, environmental cabs, alternative fuels, diesel particulate filters (DPF) and work practices. The focus of the follow-up compliance assistance visits was to assess control effectiveness and to make recommendations to mines experiencing difficulty in meeting the DPM standard. At each mine visited, the ventilation controls were evaluated, engine emissions were determined for equipment in use, environmental cabs were examined, and operational practices were noted. Additionally, control technologies, including alternative fuels and DPF were evaluated in several mines. A comparison was made of mine and section airflow to equipment particulate indices. Based on engine emissions, horsepower and operating time, the contribution of individual engine emissions to total emissions was made. Environmental cab integrity, positive pressure and air filtration systems were checked and operational practices relating to DPM exposure were assessed. This paper summarises the preference and magnitudes of controls that were typically used or needed for successful control of DPM. Additionally, results of the assessments of alternative fuels (including bio-diesel and water emulsion fuels) and DPF are presented.

Jan 1, 2005

By K. C. Kocsis

"Diesel-powered equipment has allowed the mining industry to raise production rates and significantly improve productivity, as it is rugged, mobile and reliable, but its widespread use in underground mines has generated concerns regarding the exposure of mine workers to harmful diesel engine exhaust gases and particulate components such as diesel particulate matter (DPM), which has recently been classified as a human carcinogen by the International Agency for Research on Cancer. The agency expressed further concerns that workers’ exposure to high DPM concentrations can increase the risk of cardiovascular, cardiopulmonary and respiratory illnesses. Three emerging technologies could have the ability to replace dieselpowered equipment and remove DPM from underground mines: fuel-cell-powered mining equipment, battery-powered mining equipment and advanced material handling systems. This paper reviews them and assesses whether they have reached the point where the pollutants emitted by diesel-powered equipment can be removed from underground mines through the introduction of zero-emission mining equipment and power systems. Information is also provided from the results of a feasibility study, including a detailed cost benefit analysis, carried out at six Canadian and nine U.S. underground mines, which looked at the possibility of replacing diesel-powered production equipment with fuel-cell-powered equipment. The remarkable pace at which battery technology is progressing is also reviewed, and the feasibility of replacing diesel-powered mining equipment with battery-powered equipment is assessed. IntroductionHazardous pollutants in underground mines. Why is it important to remove diesel particulate matter (DPM) from underground mines? Over the past 40 years, diesel-powered equipment has allowed the mining industry to achieve rising production rates and major improvements in productivity, as the diesel engine is an economical source of power and diesel-powered equipment is usually rugged, mobile and reliable. On the negative side, the toxicity of some diesel exhaust gases is well known (Grenier et al., 2001), and the widespread use of diesel-powered equipment in underground mines has generated increasing concerns about the occupational exposure of mine workers to harmful diesel engine exhaust gases and particulate components such as DPM. Diesel equipment also entails other hazards like heat and humidity. Exposure to excessive heat can cause heat illnesses, such as heat rash, heat exhaustion and heat stroke (Donoghue, 2004; Roghanchi et al., 2016), and a hot and humid underground environment negatively affects the efficiency of the workforce, which may result in a decline in production output (Roghanchi et al., 2017)."

Jan 10, 2017

By Aleksandar N. Nikoloski, Rorie Gilligan

Brannerite, UTi2O6, is the most common of the refractory uranium minerals and requires leaching under intense conditions to effectively extract the uranium contained within. Brannerite is often found together with apatite in metasomatic uranium deposits. Apatite and other phosphate gangue minerals can inhibit uranium leaching by generating phosphate ions which interfere with the reactions between acidic ferric sulphate and uranium minerals. As part of a detailed fundamental study on the leaching reaction mechanisms for brannerite, tests under a range of selected leach conditions were carried out with the addition of 10 g/L fluorapatite with the goal of identifying conditions where the negative effects of phosphate are reduced. Leaching was carried out for 5 hours with 0.05 mol/L Fe3+ as Fe2(SO4)3 with 0.25–1.00 mol/L H2SO4 and at temperatures between 25 and 96 °C. A single test was performed with 0.05 mol/L Fe3+ as FeCl3 and 1.00 mol/L HCl. In the sulphate system, the effect of phosphate was weakest at the highest acid concentration (1.00 mol/L H2SO4). In the chloride system, phosphate did not suppress uranium extraction, suggesting that HCl leaching could be a viable alternative for the leaching of high-phosphate refractory uranium ores.

Mar 17, 2021

By Joseph A. Meyers

NYC has always been a high-profile target for both foreign and domestic terrorists. Explosives have always been the go-to tool for terrorists to bring about serious physical injury, death, and property damage in our society. Today with the anti-police movement gaining traction in the United States and anarchists groups using homemade explosives against law enforcement and municipalities, it is the responsibility of the explosives industry to ensure that every explosive product on a blasting site is secure. We must prevent the theft of these energetic materials used on projects and sold by vendors so they are not used by these terrorists. We have learned many lessons here in NYC which began with the theft of explosives used for blasting projects in NYC to supply the IRA (Irish Republican Army) 50 years ago. The liability is too significant to take short cuts in securing energetic materials. Over the years through cooperation with all agencies and the industry we in NYC have developed certain proven protocol and procedures we would like to share with the industry. An efficient and effective security plan for the logistic movement of explosives, as well as for the blast site is imperative to keeping the good name of the industry from negative repercussions and possible additional bureaucratic oversight of an industry that is highly regulated and still recovering from the pandemic. Communication, security assessments and transparency with all stakeholders and the Authority Having Jurisdiction (AHJ) will greatly improve the overall security for the blasting project. This SOP (standard operating procedure) will allow the AHJ to become a proactive partner in the security of the blasting project. If the AHJ is not a law enforcement agency, the law enforcement agency specialty unit must be notified and included in all phases of the project. The security for a blasting project with AHJ and law enforcement input starts at the inception of the project when the memorandum of understanding (MOU) is obtained, and involves the AHJ through all steps of the approval process. This includes threat assessments on new and existing structures. SME’s (Subject Matter Experts) must be present at all stages. The blasting industry and regulators must work collaboratively to improve safety, security, and create a dialogue with law enforcement and the AHJ. Relationships are built through trust, teamwork, transparency, and communication and greatly improve the safety of our great country.

Jan 21, 2025

By V. Bazhko, V. Yahorava

The calcium sulphate waste stream of the wet phosphoric acid process, commonly called phosphogypsum (PG), contains the majority of rare earth elements (REE) initially present in the apatite feedstock. Mainly light and middle REE are present in PG and their total concentration ranges from 0.27% to 0.35% by mass. Worldwide, around 7 billion tonnes of PG have been produced to date at a current growth rate of 150-200 million tonnes per annum. In total, an estimated 21 million tonnes of REE are locked in PG waste dumps around the world. Due to the value of the REE contained in PG dumps a number of processes have been devised for their recovery. The majority of these processes applied complete or partial gypsum dissolution, but were deemed not viable due to high capital and operating costs. Mintek developed an alternative method for the recovery of REE from PG by applying Resin-in-Leach (RIL) technology. This technology was tested on PG sampled from dumps and current arisings from South African phosphoric acid production plants. The extensive testwork program included evaluation of various lixiviants and optimisation of lixiviant additions, optimisation of REE leach and adsorption conditions, batch equilibrium and kinetic adsorption tests, continuous RIL testwork and numerous variability tests. It was found that PG from different sources was highly variable, both in terms of REE recovery as well as physical properties of the material such as viscosity and filterability of the slurry. The recovery of REE varied from 15% to 80% depending on the origin of the samples. A high-level economic study indicated that at a price of >21 $/kg for mixed REE oxide product in conjunction with an overall REE recovery as low as 15% the economics of REE recovery from PG via RIL technology may already be favourable.

Jan 1, 2016

By J. Douglas Causey

In 1986 and 1987, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied 73,010 acres of the 76,480-acre Lower Owyhee Canyon Wilderness Study Area (OR-003-110) in order to evaluate its identified mineral resources. The study area is in Malheur County, OR, about 8 miles north of Rome. There are approximately 7.7 million tons of subeconomic zeolite (heulandite and/or clinoptilolite) resources with ammonia ion exchange capacities as high as 1.75 milliequivalents per gram in the Chalk Basin-Lambert Rocks area. The bed is 25 ft thick with less than 100 feet of overburden. This resource probably will not be mined in the foreseeable future.

Jan 1, 1989

By Sidney Katell

This report, covering the period January 1968 through December 1968, is a continuation of a series that began with the publication of Information Circular 7516 in October 1949. It is the tenth in a series of reports prepared in cooperation with the American Association of Cost Engineers. The abstracted articles are concerned with all phases of cost of engineering in the field of chemical and petroleum plants and related subjects. They are from the following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Lines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress s 6. Chemical Week. 7. Coal Age. 8. Coal Mining and Processing. 9. Cost Engineering. 10. European Chemical News. 3 11. Hydrocarbon Processing. 12. Industrial and Engineering Chemistry 13. Oil and Gas Journal. 14. Petroleum Engineer. 15. World Oil.

Jan 1, 1969

By D. F. Malan, U. Du Preez, P. S. Heyns

South Africa has two main platinum reef deposits, namely the Merensky reef and the UG2 reef. These reefs are currently mined using traditional drilling and blasting methods. Mechanized cutting could potentially enable continuous mining, which would offer significant advantages. This would require thorough understanding of the cutability of the rock. To explore this, a linear cutting machine was developed to conduct laboratory scale cutting tests. This work describes the development and commissioning of the cutting machine using sandstone, as well as subsequent characterization tests on UG2 reef samples. UG2 reef has large variability in strength on a millimeter scale. This introduces uncertainty in the test results due to added variance from one cut to the next for the same UG2 reef sample. Another problem is the variability in rock properties of the UG2 reef, when testing samples from different mines. The cutting tests led to fine fragmentation, which is known to be a significant problem for cleaning operations in underground stopes and warrants further research. A finite element method simulation of the rock cutting was conducted using ANSYS LS-DYNA and the continuous surface cap model to simulate rock cutting in the UG2 reef. It was found that it is possible to use LS-DYNA with the continuous surface cap model to model rock cutting of UG2 reef and get acceptable results, but the user must calibrate the model parameters using the experimental results. Therefore, the model is only fit for one set of cutting parameters and further work is required to generalize results.

Nov 27, 2024

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

Preliminary design is underway for a new Southern Nevada Water Authority (SNWA) project that will ensure one of America’s most reliable water systems by providing continued, reliable water service to existing and future customers. The Horizon Lateral is a $1.6 billion water transmission pipeline that includes 7–10 miles of 108-inch finished diameter rock and soft-ground tunnels. The tunnels will traverse volcanic rock in or around the McCullough Mountain Range and the surrounding alluvial basin. The tunneling community will find relevance in hearing about this critical infrastructure project from a leading wholesale water utility owner with a proven track record for on-time, collaborative projects.

Dec 1, 2022

By C. Özgen Karacan

Longwall mining is an underground mining method during which a mechanical shearer progressively mines a large block of coal, called a panel, in an extensive area. During this operation the roof of the coal seam is supported only temporarily with hydraulic supports that protect the workers and the equipment on the coal face. As the coal is extracted, the supports automatically advance and the roof strata cave behind the supports. Caving results in fracturing and relaxation of the overlying strata, which is called "gob." Due its highly fractured nature, gob contains many flow paths for gas migration. Thus, if the overlying strata contain gassy sandstones or sandstone channels, gas shales or thinner coal seams which are not suitable for mining, then the mining-induced changes can cause unexpected or uncontrolled gas migration into the underground workplace. Vertical gob gas ventholes (GGV) are drilled into each longwall panel to capture the methane within the overlying fractured strata before it enters the work environment. Thus, it is important, first to understand the properties of the gas reservoir created by mining disturbances and, second, to optimize the well parameters and placement accordingly. In this paper, the production rate-pressure behaviors of six GGVs drilled over three adjacent panels were analyzed by using conventional multi-rate drawdown analysis techniques. The analyses were performed for infinite acting and pseudo-steady state flow models, which may be applicable during panel mining (DM) and after mining (AM) production periods of GGVs. These phases were analyzed separately since the reservoir properties, due to dynamic subsidence, boundary conditions and gas capacity of the gob reservoir may change between these two stages. The results suggest that conventional well test analysis techniques can be applicable to highly complex gob reservoirs and GGVs to determine parameters such as skin, permeability, radius of investigation, flow efficiency and damage ratio. The insights obtained from well test analyses can be used for a better understanding of the gob and for designing more effective gob gas venthole systems.

Jan 1, 2009

By C. J. Toberman

Improvements in fine (28x0) and ultrafine (200x0) coal cleaning is an acknowledged goal with potential benefits in both steam and metallurgical coal markets. This work focuses on adaptation to fine coal flotation of FLOTE, a computer simulation model of the froth flotation process originally developed in the hard minerals field. FLOTE describes the flotation of solids based on particle surface activity, composition, and size. The quasi steady state model was applied to predict flotation performance at an Eastern Kentucky, full scale metallurgical coal preparation plant. Parameter estimation and model testing used detailed flotation test data from a five stage rougher flotation bank. Overall grade/recovery predictions compared well with known plant performance under variation of principally feed grade, plant throughput and reagent addition; however, grade/ recovery predictions for each cell weaken under overloading conditions. Analysis of grade/recovery over a range of sizes is presented. Suggested model improvements and extensions are discussed.

Jan 1, 1984

By Gordon R. Haworth

Conditions affecting minerals investments are continuing to change at an increasing rate, and in this paper we will attempt to predict the course of mine financing in the future. We will first review the situation historically and then examine the problems and constraints that are now making the financing task more difficult. Suggested solutions are discussed, and a new method of financing a group of mining projects is hypothesized.

Jan 1, 1977

By Thomas M. Barczak

Roof support technology for longwall tailgates has changed dramatically during the past decade. Filling tailgates with conventional wood cribs is becoming the exception rather than the rule. Modern engineered timber support systems and a host of other alternative support products provide far greater capacity as well as stiffer response, thereby allowing the supports to resist roof movement with much less displacement than the soft wood cribbing used in the past. For these reasons, these products can provide superior roof control. In addition, the material handling requirements for support installation have now become a major consideration in the support design and selection process. Products such as conventional wood cribbing that require piece-meal construction of bulky, heavy components have diminished, while prop-type supports and products that can be installed with machinery and pumpable support technologies have grown in use resulting in fewer injuries to mine workers. Now, the opportunity exists to provide the safest, most cost effective support system, through engineering design rather than by trial and error and to optimize the use of the support system chosen. Yet this is rarely done. The key to accomplishing this task is to understand the interaction of the support system with the ground conditions at the installation site. A major focus of the paper is to conceptualize the support and interaction through the use of a ground reaction curve which relates the support resistance to the convergence of the longwall tailgate. The goal of any roof support design is to control the ground deformations and maintain the structural integrity of damaged or broken ground to the extent possible to provide a stable mine opening. In general, deformations will be a function of the stress environment and inherent strength of the surrounding rock mass. However, if the deformations are intimately linked to the stress changes such that the deformation can be controlled by the load resistance or reinforcement provided by a roof support system, then the loading behavior can be described as load-controlled. Conversely, if the deformation occurs irrespective of the installed support (assuming practical limitations), then the loading behavior is described as displacement-controlled. In this case, the deformation can be considered irresistible from a practical standpoint. In this context, the nature of the loading has significant consequences on the support design requirements. Finally, examples using the NIOSH Support Technology Optimization Program (STOP) to develop design criteria using ground reaction data from underground studies and ways to include uncontrolled convergence as part of the design criteria for standing roof supports will also be discussed.

By Gökhan Çevikbilen, Ümit Karadoğan, Sevde Korkut, Berrak Teymur

This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse

Sep 29, 2022

By Nasri Munfah, Steffen Matthei, Vojtech Gall

"Conventional tunneling as defined by ITA WG19 is also known as the New Austrian Tunneling Method (NATM) or Sequential Excavation Method (SEM) was transformed in the US to deal with challenging tunneling conditions as an alternative to the more traditional tunneling methods. It is being used more often in urban areas, under difficult ground and ground water conditions, and with limited cover. Often the tunnel is of a large and non-uniform cross section in soft soils or weak rocks. The intent of using this tunneling method is to minimize impact on traffic and utilities and reduce disruption of everyday life of people and businesses. To meet these challenges, the industry developed technical approaches and implementation techniques and established sophisticated contractual relationships and collaboration in the field among various parties for successful implementation. This paper examines the development of conventional tunneling (NATM/SEM) in the US to deal with these challenges using recent examples such as Russia Wharf in Boston, Northern Boulevard Crossing, in New York, and Chinatown Station in San Francisco. INTRODUCTION / HISTORY Conventional tunneling or NATM/SEM is a concept that is based on the understanding of the behavior of the ground as it reacts to the creation of an underground opening. In its classic form the SEM/NATM attempts to mobilize the self-supporting capability of the ground to an optimum thus achieving economy in ground support. Initially formulated for application in rock tunneling in the early 1960’s, NATM has found application in soft ground in urban tunneling in the late 60’s and has since then enjoyed a broad, international utilization in both rural and urban settings. In the US the NATM/SEM tunneling method has been used successfully to address challenging tunneling conditions in urban areas. A large number of tunnels have been built around the world using a construction approach which was loosely termed NATM. During the years of discussions and the application of NATM a variety of terms have been used for the same construction approach. These terms were primarily aimed at describing the construction approach rather than the region of its reported origin."

Jan 1, 2016

By Jimenez Leon, Christopher Newman, Boede Gabriel, Zacharias Agioutantis

"Ground movements due to longwall mining operations have the potential to damage the hydrological balance within as well as outside the mine permit area in the form of increased surface ponding and changes to hydrogeological properties. Recently, the Office of Surface Mining, Reclamation and Enforcement has completed a public comment period on a newly proposed rule for the protection of streams and groundwater from adverse impacts of surface and underground mining operations (80 FR 44435). With increased community and regulatory focus on mining operations and their potential to adversely affect streams and groundwater, there is now a greater need for better prediction of the possible effects mining has on both surface and sub surface bodies of water.As mining induced stress and strain within the overburden is correlated to changes in the hydrogeological properties of rock and soil, this paper investigates the evaluation of the hydrogeological system within the vicinity of an underground mining operation based on strain VALUES (calculated through a surface deformation prediction model. Through accurate modeling of the pre- and post-mining hydrogeological system, industry personnel can better depict mining induced effects on ground water flows through the overburden material aiding in the optimization underground extraction sequences while maintaining the integrity of surface and subsurface bodies of water.INTRODUCTIONThe utilization of high-recovery underground mining methods, such as longwall or high-extraction room-and-pillar operations, have the potential to cause adverse impacts to both surface and subsurface bodies of water as strata movement and deformations propagate from the mined seam through the overburden to the surface (Peng, 2008).Previous research has indicated that mining induced strains are the most damaging to surface streams (Singh, 1992) as well as greatly affecting the integrity of subsurface bodies of water and groundwater flow conditions (Booth, 1986). On the surface, adverse effects to the stream can occur due to the development of either tensile or compressive strain in the stream bed. The development of tensile cracks along the bedrock allows for a potential loss of stream flow through developed fissures. In fact, water flow in the Cataract River of Australia ceased in 1994 as a result of mining-induced strains from longwall operations in the Bulli seam 430 meters (1320 feet) below the river gorge (McNally and Evans, 2007). On the other hand, the development of compressive strains within the rock layers can cause rupturing or buckling of the stream bed, blocking stream flow and/or diverting flow into the fractures at the base (Iannacchione et al, 2010). While these localized fractures can contribute to the loss of stream flows, given time, damaged streams have the ability to self-heal through the regeneration of near-surface aquifers as well as the sealing of mining-induced fractures with rock debris, gravel, sand, clay or other soil particles carried from upstream sources and deposited in the river bed (Waddington and Kay, 2002)."

Jan 1, 2016