Specific conductivity (SC) and total dissolved solids (TDS) are increasingly being used as a parameter used to judge the aquatic health of streams that are impacted by coal mining operations in the Appalachian region of the United States. Due to this, government environmental regulatory bodies have been considering issuing a regulation on SC for all mining operation outfalls. Sulfate typically has the greatest dissolved ion presence in coal mine waters. In literature examining the treatment of mine waters, SC and TDS analysis is typically not reported. The technologies examined in this study were nanofiltration membrane technology and biological sulfate reducing bioreactors. In the nanofiltration study, three different nanofiltration membranes were evaluated for SC reduction: NF270, DK, and NFX. The DK and NFX nanofilters were able to reduce SC levels by an average of 84 percent for both mine waters tested and were able to reach SC levels below the proposed limit of 500 S/cm. The SC levels achieved by the NF270 nanofilters were observed to have much higher variability. The inclusion of microfiltration and simulated-sand filtration were also introduced as a pre-treatment stage in order to determine whether or not nanofiltration performance would improve in terms of SC reduction. In the biological sulfate reducing bioreactor study, multiple bioreactors were established to identify the optimal organic mixture to foster both SC and sulfate reduction. Sulfate reduction began to occur approximately 20 days after the establishment of each bioreactor. SC levels were greater than 13,000 S/cm in each of the bioreactors sampled by the fortieth day of sampling. The probable cause of the increase SC was identified to be the manure/compost used in the study. Future testing should incorporate more sampling in the early phases of experimentation in order to ensure the ability to monitor changes in water quality. / MS

A large percentage of Southern Appalachian coal reserves are located in seams less than 36" thick. As thicker and currently more mineable, deposits are exhausted, methods of underground thin-seam extraction will have to be developed. These methods must be capable of removing coal efficiently and economically. Past experience with highwall mining of thin-seam coal has indicated that recovery rates tend to be lower than in conventional operations. It is suspected that this will also apply to underground thin-seam mining, regardless of proposed technology or mining method. A method of increasing recoveries from thin-seam mining operations is necessary in order to exploit thin-seam reserves. Backfilling is one alternative that may find applicability in thin-seam coal mining. The ability of backfill to provide additional ground support may enhance coal recovery by allowing for the design of undersized pillars. Backfill has been used extensively in hard rock mining but has found limited use in coal mining. Its adaptability to thin-seam coal mining has been examined and is presented in this thesis. Backfill is capable of providing additional ground support by restricting lateral deformation of surrounding coal pillars and roof. This additional support can result in significant increases in recovery from thin-seam coal deposits. However, the overall feasibility of backfill is dependent on the in situ behavior of the fill material, the properties of the fill, the effects of the filling method on the total mining operation, and the cost of filling per extra ton of coal recovered. The influence of these parameters has been studied and indicate that, in certain situations, backfilling for the purpose of increasing recovery rates from thin-seam coal mines is feasible. / Master of Science

It is predicted that coal mining in Southwest Virginia, and the economic stability that it brings to the area, will continue to decline over the next decade unless an environmentally sound, and economically viable means can be found to extract seams of high quality coal in the thickness range of 14 to 28 inches. Research into autonomous machine guidance, coupled with developments of thin-seam mining equipment, offer new opportunities for devising mining layouts suitable for extracting these thin seams in a cost effective manner. These layouts must involve well-planned transportation and ventilation routes that will allow safe conditions for personnel. This implies that the mining face, where coal is extracted, will be completely automated, ensuring the safety of the workers. This thesis presents a brief overview of current technologies utilized for underground coal mining in the United States. This is followed by a review of developments in highwall mining that are potentially applicable in underground mining of thin seams. Some past attempts at thin seam mining are discussed, and evaluated for their short comings. An overview of the more recent advances in the guidance systems for use in autonomous mining machines is also presented. The new advances that several manufacturers are developing to address the integration of mining and continuous haulage systems are also investigated. That background is employed in devising a conceptual mining system for the underground mining of coal seams in the 14 to 28 inch range of thickness. This thesis proves that adapting new technologies and concepts from existing ones can lead to meaningful advances in the field of natural resources recovery. This system utilizes a newly designed panel layout that takes into account haulage, supplying, ventilation, equipment, and machine guidance. This system is proposed to show that new ways can be developed to take advantage of the reserves in the 14 to 28 inch range of thickness. This shows that new technology and design innovation can turn currently uneconomic resources, into economic reserves. This kind of innovation is what is needed to keep this region of Southwest Virginia economically viable. This system is a huge step in the direction that thin-seam research needs to take. Most of the equipment suggested for this proposed system is already available. / Master of Science

Hollow fills are composed of excess spoil and debris produced from surface coal mining that is not returned to the original mined site. Hollow fills are often constructed in the head of hollows nearby or adjacent to the mined land area, which may be the origins of headwater streams or drain into low order systems. Eleven hollow fills were utilized in evaluating the influence fill drainages had on low order streams in Virginia and West Virginia. The study was conducted in six watersheds including; Five Mile Creek in Mingo County, West Virginia, Trace Fork in Mingo County, West Virginia, Lavender Fork in Boone County, West Virginia, Middle Creek in Tazewell County, Virginia, South Fork of the Pound River in Wise County, Virginia, and Powell River in Wise County, Virginia. Bioassessment procedures used in the evaluation of hollow fill drainages included water/sediment chemistry, acute water column toxicity testing using <i>Ceriodaphnia dubia</i>, chronic sediment toxicity testing using <i>Daphnia magna</i>, benthic macroinvertebrate surveys, and <i>in situ</i> Asian clam (<i>Corbicula fluminea</i>) toxicity testing. Common significant differences in water quality between reference and fill influenced sites, among all watersheds, were elevated conductivity and water column metal concentrations, particularly aluminum and copper. Water column and sediment toxicity testing reported limited significant mortality or reproductive impairment associated with hollow fill drainages. The West Virginia watersheds used in the study consisted of headwater streams originating directly from the settling ponds, placed at the base of the hollow fills, receiving drainages from the fills. Benthic macroinvertebrate analysis reported no significant alteration in total taxa or EPT richness downstream of the ponds. Yet, collector filterer populations, including benthic macroinvertebrates and <i>in situ</i> Asian clams, were enhanced directly downstream of the ponds due to organic enrichment originating from the ponds. A decrease in collector filterer populations and lowered clam growth suggested the organic enrichment dissipated downstream from the ponds. Chlorophyll <i>a</i> analysis of the phytoplankton community was not significantly related to the enhance collector filterer populations in the streams, however the high concentrations in the settling ponds suggest abundant algal communities. The hollow fills evaluated in Virginia drained into receiving systems, whose headwater origins were not directly related to hollow fill drainages. Low taxa richness was associated with the hollow fill and settling pond drainages, however receiving system sites were minimally influenced. Yet, as reported in the West Virginia watersheds, the settling ponds input organic enrichment that enhanced collector filterer populations, including benthic macroinvertebrates and <i>in situ</i> test clams. An analysis of the hollow fills' age, or maturity, reported no significant difference between young and old fills. In general, a common feature of among the various aged fill drainages was elevated conductivity, compared to reference sites of the watersheds. / Master of Science

Mining induced seismicity can lead to bumps which cause problems at many mines within the United States and around the world. This seismicity, often referred to as bumps or bursts, can result in injuries, fatalities, and expensive capital damage and production interruptions. There are many factors that contribute to mining induced seismicity but there is still no concrete method to forecast future seismic activity around a mine. One of the main precursors to large seismic events is an increase in situ stress. One way to find areas within geological strata that are highly stressed is to measure p-wave propagation velocities. High p-wave propagation velocities are associated with high in-situ stress levels. By using tomography programs a three-dimensional velocity model can be constructed. When seismic activity is present the event arrival times at each geophone, the locations of each geophone, and the three dimensional velocity model are used in conjunction with one another to locate the seismic events. This research compares the locations of seismic events from a deep coal mine longwall panel in the western United States with the associated p-wave propagation velocities from the previous 24 hours. The aim of this comparison is to provide a link between high velocities and seismic activity that could potentially be used to forecast future seismic activity. The comparison is completed both qualitatively through the use of a visual analysis, and quantitatively using various numerical and correlation comparisons on the seismic and velocity data. The qualitative comparison is completed using the event locations from the tomography program SIMULPS. The quantitative comparison is completed twice using two different tomography programs, SIMULPS and TomoDD, which use different methods for locating the seismic events. Before these comparisons were completed the stresses around the longwall panel were first modeled using the boundary element modeling program LAMODEL to study the effects of three backfilled cross panel entries which were located ahead of the mining face. The modeling showed similar vertical stress distributions as a panel without cross panel entries but higher stress magnitudes. The qualitative analysis involved comparing tomograms created with SIMULPS with seismicity plots from the following day. One noticeable feature of these tomograms is the presence of a stressed area directly ahead of the face. This stressed area represents the forward abutment. The results of this qualitative analysis illustrate a correlation between high p-wave velocities and seismic activity 24 hours later for several of the days studied. The other days showed little to no correlation. Additionally, not all high p-wave velocity regions resulted in seismic activity. Due to these inconsistencies visually analyzing velocity plots obtained from the program SIMULPS is not a reliable way to forecast the locations of seismic activity 24 hours later. The result of the quantitative comparisons completed with the programs SIMULPS and TomoDD further highlighted inconsistencies in the correlation between high p-wave velocities and associated seismic activity 24 hours later. TomoDD provided better correlation values than SIMULPS and generally showed that as the level of seismicity increased the p-wave propagation velocities 24 hours prior also increased. Although TomoDD provided good correlations for some of the data pairs studied, the overall inconsistencies prompt the need for further study in this area using TomoDD to find the optimal forecasting time period. / Master of Science

This thesis presents a demand reduction and responsive strategy for underground mining operations. The thesis starts with a literature review and background research on global energy, coal mining and the energy related issues that the mining industry face everyday. The thesis then goes on to discuss underground mine electrical power systems, data acquisition, load profiling, priority ranking, load shedding and demand side management in mining. Other areas presented in this thesis are existing energy reduction techniques, including: high efficiency motors, motor speed reduction and low energy lighting. During the thesis a data acquisition system was designed and installed at a UK Coal colliery and integrated into the mines existing supervisory control and data acquisition (SCADA) system. Design and installation problems were overcome with the construction of a test meter and lab installation and testing. A detailed explanation of the system design and installation along with the data analysis of the data from the installed system. A comprehensive load profile and load characterisation system was developed by the author. The load profiling system is comprehensive allows the definition of any type of load profile. These load profiles are fixed, variable and transient load types. The loads output and electrical demand are all taken into consideration. The load characterisation system developed is also very comprehensive. The LC MATRIX is used with the load profiles and the load characteristics to define off-line schedules. A set of unique real-time decision algorithms are also developed by the author to operate the off-line schedules within the desired objective function. MATLAB Simulation is used to developed and test the systems. Results from these test are presented. Application of the developed load profiling and scheduling systems are applied to the data collected from the mine, the results of this and the cost savings are also presented.

Erfahrungsbericht zum Steinkohlenbergbau in Mosambik: Die Republik Mosambik ist ein schwach entwickeltes Agrarland mit einer bescheidenen Verarbeitungsindustrie, vorwiegend in den Hafenstädten, und einer Infrastruktur, die viele Wünsche offenlässt. Reich ist das Land an unterschiedlichen Rohstoffen. Neben Vorkommen an NE-Metallen, Tantal, Halbedelsteinen und Erdöl sind die umfangreichen Steinkohlenlagerstätten vor allem in der Provinz Tete am Sambesi zu nennen, die jedoch bis zum Ende des 20. Jahrhunderts nur in sehr bescheidenem Umfang erschlossen waren.

Seepage from steelmaking coal mine waste rock dumps in the Elk Valley, British Columbia, Canada can contain selenium (Se), cadmium (Cd), and sulfate (SO42-) from the oxidation of sulfide minerals, and nitrate (NO3-) from blasting. The impact of these constituents of interest (CIs) on receiving groundwater systems and the potential for their natural attenuation is investigated. A 10.7 km2 mine-impacted research catchment (West Line Creek) was instrumented with 13 monitoring wells and 8 drivepoint wells to characterize the hydraulics and geochemistry of the aquifer system downgradient of the waste rock dump. These data were augmented with geophysical surveys and by characterizing the lithology, geotechnical properties, and geochemistry of core samples obtained during drilling. Furthermore, the groundwater monitoring program also facilitated the development of a conceptual model of hydrogeology in a small montane valley. An unconfined aquifer at the overburden/fractured bedrock interface, i.e. the basal alluvial aquifer was identified as the primary groundwater conduit for the migration of water and solutes from the waste rock dump toward Line Creek. Vertical and horizontal dispersion of CIs was confirmed with porewater analysis of core samples, with Se concentrations exceeding the BC water quality guideline (2.0 µg/L) in 98% of samples (n = 223). Residence time for groundwater in the overburden aquifers was determined using 3H/3He age dating (n = 3) and estimates of groundwater velocity to be less than three years across the 650 m study site. The chemistry of groundwater was compared with rock drain water samples to evaluate CIs from their source through to identified discharge locations. Linear correlation of CI concentrations with SO42- concentrations in water samples showed that Se and NO3- were conservative solutes, whereas Cd was non-conservative and may be undergoing mineral precipitation or adsorption reactions in the groundwater system. The distribution of CIs in the overburden aquifers was seasonally variable and dilution was determined to be the dominant mechanism controlling the concentrations of conservative CIs (Se, SO42- and NO3-) away from the toe of the waste rock dump and during the spring freshet. The basal alluvial aquifer downgradient of the waste rock dump was estimated to annually discharge 16% of the water and 7% of the SO42- load from the catchment.

No description available.

The goal of this research project is to identify the efficacy of the ground penetrating radar (GPR) technique in locating underground coal mine related subsidence features at Malakoff and Bastrop, Texas. The work at Malakoff has been done in collaboration with the Railroad Commission of Texas (RRC). RRC has been carrying out reclamation of abandoned underground coal mines at Malakoff since the early 1990’s. The history of the specific mining operations (at Malakoff and Bastrop) that took place in the early 1900’s has been difficult to ascertain; therefore, the use of a geophysical techniques like ground penetrating radar to identify hidden voids and potential subsidence features is vital for future reclamation process. Some of the underground mine workings at the field site have collapsed over time affecting the topography by creating sinkholes. GPR data, employing 25 MHz, 50 MHz and 100 MHz frequency antennae, have been collected in common offset patterns and azimuthal pattern. GPR data indicate the mine tunnels possibly connecting existing sinkholes by radargram hyperbolae that correspond with mine openings observed visually or during reclamation. This study also denotes the importance of understanding the variable physical properties of the stratigraphy, which could lead to false alarms by misinterpretation of the radar signals. Natural and man-made above-ground structures cause obstructions in data collection, and hence an optimal design is required for each survey. RRC successfully ground-truthed the data during its reclamation process. In turn, the acquired geophysical data helped to guide the reclamation. At Bastrop, GPR data along with historical documentation led to the conclusion that coal mining did exist in this region but is not a major concern to the immediate stability and safety of the field site. It can be concluded from both the studies that the GPR technique identifies anomalous shafts/tunnels possibly connecting potential failure.