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By K. Soucek

Extraction of hard coal reserves, but also of mineral resources in general in the underground coal mines includes in itself many anthropogenic interventions in the earth crust. These interventions are closely associated with the solution of stability problems in the mine and with occupational safety. One of potential applications of such geo-technical interventions in rock mass is the chemical grouting technology. The chemical grouts are very suitable to affect the physical and chemical properties of rock mass. With the present development of chemical grouts, primarily based on polymers, there come into existence new composite materials during the grouting process (the so called geo-composites), which properties significantly differ from the original rock. An important factor, which affects a choice of chemical grouts and at the same time the effectiveness of grouting technology is the resulting properties of geo-composites. The properties of a coal geo-composite differ from the ones of the unmodified coal seam. On the basis of the laboratory geo-mechanical tests, the differences of properties of both material types were found. While the pure coal samples were destroyed very brittle and explosive, the geo-composite samples were making higher level of tenacity and load bearing ability after overstep of material strength. The presented paper discusses the different behaviour of these original and modified coal samples. The X-ray CT scans were used for observation and demonstration of failure evolution in these samples of pure coal and coal geo-composites after compressive loading.

Jan 1, 2006

By V. Nenov

The study is based on the so called METASEP process which includes selective sorption of heavy metals by special bonding agents (BA), separation of boding agents from the water by means of microfiltration and/or flotation and regenerating the loaded bonding agents, leading to a metal concentrate for reuse or discharge. The bonding abilities of different bonding agents suitable for application in METASEP process were evaluated. Two groups of BA are studied, namely: chelating ion exchange resins and water soluble oligomers. The group of ion exchange resins studied includes eight organic resins, mostly chelating cation exchangers and representatives of conventional strong and weak cation exchangers. The resins with iminodiacetic and aminomethyl phosphoric acid groups showed highest affinity towards several heavy metals. The study of resin particle size showed that this parameter is a key factor influencing the kinetics of heavy metal sorption. The group of water soluble oligomers (WSO) includes polyvinyl alcohol, carboxyl-methyl-cellulose, polyvinylethylenimin and pectin. The Metal-WSO complexes were separated by Ultra Filtration. The effect of Metal-WSO mole ratio and pH was studied. Depending on the operational conditions the heavy metal retention varies within 68-99%. It was shown that regardless of pH and mole ratio Metal-WSO, separation of certain ion from the metal mixture is not possible.

Jan 1, 2006

By R. L. Derick

On a regular basis, mine personnel should obtain air samples directly from active underground areas as well as remotely from sealed locations. These samples provide mine officials with data relative to the makeup of the various atmospheres. Should conditions underground change, these results can provide a baseline that can assist officials in determining the extent of change. Relating the concentrations of individual gases to time, applying gases to equations, and examining their change over time are tools that have been successfully used to determine if a heating event exists and, if so, the extent of the emergency. These atmospheric status equations have either been developed for the mining industry or adapted from other industries. They serve as tools to assist personnel in determining the condition of underground mine atmospheres. As long as the problem area continues to be ventilated, certain gases, gas ratios, and equations can be used to determine if a fire exists, what type of material could be burning, and what quantity of coal is burning. Once the mine or the involved section has been temporarily sealed, gases, ratios, and gas-derived equations can assist personnel in determining how conditions within the sealed volume are changing over time. To alleviate potential explosions when fresh air is once again introduced into the sealed volume, equations and a diagram have been developed to predict the likelihood of an explosive atmosphere. Similarly, prior to commencing recovery of a mine or section, equations exist that can assist in determining if the fire will rekindle when air is reintroduced. This paper serves as an overview to remind and/or instruct readers about gas-sampling methodologies and gas analyses to assist in determining the status of underground atmospheres.

Jan 1, 2006

By F. Habashi

Siberia, a vast country rich in mineral resources and a large number of different ethnic groups. To the east of Lake Baikal is Buryatia with capital Ulan Ude. The Buryat are closely related to the Mongolians. Ulan Ude is connected to Ulaan Baatar (Ulan Bator) the capital of Mongolia by train – a 26 hours trip. Getting a visa to Russia is not a simple case. Visits to metallurgical research laboratories, Lake Baikal, and historical museums are enriching experience.

Jan 1, 2006

By R. Debkowski

The current underground infrastructure of an old monumental salt mine along with using it as a tourist, museum, nature, resort, conference and cultural events place is presented in the paper. At present, mainly in the monumental part of mine, only a small part of the historical chambers, which together with galleries form a tourist route available to visitors. Moreover, the essential activities aimed to make the tourist route more attractive and to change the decor of the underground sites are discussed.

Jan 1, 2006

Current design guidelines for the surface catalysed oxidation of Fe(II) on Fe(OH)3 (Ochre) in passive mine water treatment systems are based largely on empirical data as the details of rates and mechanisms have not fully been revealed. Also the effects of elevated carbonate concentrations, typical of many UK minewaters, on the surface catalysed oxidation rate are unclear. In order to move away from empirical design and towards sound engineering that is based on geochemical and hydrological understanding it is necessary to quantify these reaction rates. In this study the effects of Fe(OH)3 and carbonate on the rate of Fe(II) oxidation by dissolved oxygen have been investigated with an aim to delineate the reaction mechanism. Experiments were conducted under well-controlled conditions. Preliminary results indicate that the surface catalysed reaction is an order of magnitude faster at pH ~6.4 with 200 mg/l Fe(OH)3 than the homogeneous rate and is dominated by an elevated rate of removal and oxidation of Fe(II) from the solution phase. It is also apparent that the oxidation rate of actual adsorbed Fe(II) is substantially retarded with respect to the homogeneous rate. Carbonates were not shown to affect the surface rate within the bounds of this preliminary study.

Jan 1, 2006

By Z. Stanojevic-Simsic

The aim of this paper was to study sludge dewatering. The sludge which was examined in laboratory scale was produced by neutralization of a mixture of metallurgical wastewaters. Experiments were carried out using synthetic wastewaters with chemical composition similar to that of metallurgical wastewaters, resulting from electrolyte regeneration, copper refining and precious metals recovery. During investigations gravitational and vacuum techniques were examined. Parameters such as water volume, height of sludge and time of dewatering were monitored. In this paper the results obtained are presented and discussed. The application of vacuum filtration enables better dewatering and compaction of sludge.

Jan 1, 2006

By H. Lind

The consumption rate of Estonian oil shale increases due to the growing rate of exported oil-shale oil. Estonian oil shale active resources in working mines are predicted until the year of 2025 when the consumption rate stays at the level of 12 tons per year. If the consumption rate stays at that level, new mines should be opened after 20 years, if the rate increases new mines should be opened even earlier. The predicted active resources in Estonian oil shale deposits are calculated for 60 years, based on the parameters of the power station technicoeconomics. As a result, there is a need to open new mines. One of the potential areas for surface mine is the Tammiku-Kose prospect area (Rheinbaun Engineering, 1996).

Jan 1, 2006

The present study refers to passive systems for the treatment of acidic liquid effluents emanating from mixed-sulphide mines by means of an-aerobic compost wetlands. An effort was made for the thermodynamic study of the chemical systems that are involved in the reactions during the simulation of this specific system using laboratory columns and a pilot scale application. The substrate used was a mixture of cow manure, a high alkalinity organic substrate and chestnut woodchips, while the synthetic solutions prepared for the laboratory experiments contained the three basic metal contaminants i.e. Fe, Zn and Mn. The precipitation mechanism of the contained metals and the form in which these are precipitated was therefore investigated by constructing the equilibrium phase diagrams (Eh-pH diagrams) of the Me-S-C-H2O systems. Based on the experimental results from laboratory and pilot scale tests the stability conditions of the chemical species taking part in the aqueous solutions were also determined and verified with the thermodynamic data available. The thermodynamic analysis of the system was performed for ambient temperature, which is the prevailing temperature on field constructed compost wetlands. Results were further validated with the results obtained by the application of a five step sequential extraction procedure in the remaining substrate in order to determine the form in which the metals were precipitated.

Jan 1, 2006

By A. Mertzanis

The way and methods used for the surface mining of bauxite until the end of the twentieth century in the area of Ghiona, resulted in a significant burden to the natural environment, especially in the cases where it covered extended parts of forests and forest areas as well as important geomorphological formations. The impacts from the surface mining of bauxite which in fact constitute the object of this study relate mainly to the interruption of the natural continuity of the land relief and the alteration of the natural geomorphological activities and are due to: a) the alternating excavations with fronts of great heights, b) the depositions of large volumes of waste materials which originate from the revealing of the ore and c) the dense road network constructed in order to get access to the mine locations.

Jan 1, 2006

By N. Dahotre, C. Blue, C. Zhao, B. Parekh, D. Tao, G. Engleman, R. Honaker

Equipment wear is one of the major concerns in screening of coal and minerals. Not only does it decrease the screen service life, it also results in inconsistent aperture sizes and deteriorates the efficiencies of downstream operations. In this research, a coating technique based on laser surface engineering (LSE) was successfully developed to increase the life span of raw coal screens. The microstructure and wear properties of the coating were investigated in this study. Enhanced wear resistance performance (up to 11-fold increase) of coated screens has been achieved in laboratory wear tests.

Jan 1, 2006

By M. Gouet-Kaplan, J. A. Finch, S. Gélinas

Methylisobutyl carbinol (MIBC) and methoxy polypropylene glycol (Dowfroth 250) bubble thin films were characterized by composition and thickness determinations, using FT-IR spectroscopy and UV-Visible spectrophotometry, respectively. The infrared investigation indicates that the role of frother molecules in creating bubble thin films is based on their effectiveness in inducing H-bonding reorganization of the surrounding free water molecules into a coherent network. From UV-Visible interference patterns, it is found that MIBC forms films with a measured critical end thickness of less than 160 nm, compared to 612 ± 30 nm for Dowfroth 250. The observed values of the free water layer thickness are comparable at 5.65 ± 0.28 µm for MIBC and 6.75 ± 0.34 µm for Dowfroth 250. A higher stability of an MIBC bubble over a Dowfroth 250 bubble is related to the different polarization and orientation of the molecules sustaining the boundary surface water network. The findings are used to explain the different action and associated froth characteristics of the two common industrial frothing agents.

Jan 1, 2006

Acid Mine Drainage (AMD) is the most serious environmental problem facing the Canadian Mineral Industry today. Acid Mine Drainage results from oxidation of sulphide minerals (e.g. pyrite or pyrrhotite) contained in mine waste or mine tailings. It is characterised by acid effluents rich in heavy metals that are released into the environment. A new acid remediation technology is presented in this paper by which metallurgical residues from the aluminium extraction industry are used to construct permeable reactive barriers (PRB) to treat acid mine effluents. It describes column tests performed to simulate a PRB using Bauxsol?, a chemically and physically treated bauxite refinery residue, as a reactive material. This experimentation shows promising results for the Bauxsol? PRB method in neutralizing pH and removing metals from acidic mine effluents.

Jan 1, 2006

By G. I. Karydakis

Geothermal energy is an important energy asset which can play a significant role in providing energy resources to cover energy needs of a country while it can play a primary role in a particular region where it is abundant. Greece is especially rich in geothermal energy. The collision of Euroasiatic and African plates coupled with the strong tectonic tension, particularly in north Greece, resulted in the formation of important geothermal fields of low, medium and high enthalpy. These fields are in the Aegean islands, in central and east Macedonia, in Thrace and in central Greece. This work presents and analyzes information about the drilling activity for exploration and production of geothermal fields of low, medium and high enthalpy in Greece for the past thirty years. The number and type of wells drilled together with the spatial and the yearly distribution are given. Depth data has been analyzed according to the fluid temperatures and to the geological formations. Cost data are presented and analyzed for the total number of wells drilled giving also the cost per meter drilled.

Jan 1, 2006

By S. Harteis, D. Dolinar

Many mining operations rely on bulkheads to provide a barrier between impounded water or slurry and active mine workings. However, bulkhead failures could cause and have caused catastrophic flooding that puts the underground workforce at risk. The National Institute for Occupational Safety and Health1 (NIOSH) in collaboration with the Mine Safety and Health Administration (MSHA) is conducting research to evaluate the adequacy of existing design practices for water and slurry bulkheads. A key component of this research effort is documentation of the performance history and design parameters for bulkheads installed in underground coal mines during the last 20+ years. This research is part of a larger effort to develop general design guidelines and procedures for constructing and maintaining bulkheads that will help to ensure their long-term structural integrity, while significantly reducing the inundation risk for miners. This paper presents the results of NIOSH’s research to identify state-of-the-art bulkhead designs, including design criteria, leakage monitoring systems, and emergency warning systems. Underground observations and evaluations of existing bulkheads suggest that the most important design factors influencing their performance are the interface of the bulkhead with the surrounding strata and the potential magnitude of the hydraulic pressure to which they may be subjected. When a bulkhead has failed, leakage has generally been through the surrounding strata or along the bulkhead/strata interface, with the failure potential along the interface increasing with hydraulic head. It was also determined that development of a monitoring program to ensure the long term structural integrity of bulkheads is an important safety consideration. Current monitoring procedures range from weekly visual inspections to constant monitoring via pressure transducers and fluid level indicators. Where possible, these devices are used in conjunction with a computer based mine monitoring system to alert mine personnel when an emergency condition exists at the bulkhead installation.

Jan 1, 2006

By Gh. Crutu

This paper treats some aspects of the research completed on the impact of the waste generated in the production process of a chemical fertilizer, phosphogypsum, on crops and yields. The article starts with the basic data and the research methods, and continues with details about the research results on the heap waste of phosphogypsum and the soil from its vicinity along with the content in radioactive elements, humus, macro elements and mobile forms of heavy metals. Finally, the absorbtion of radioactive elements from the soil and the uranium concentration in the agricultural cultivations is presented.

Jan 1, 2006

Accidents that resulted in 16 deaths in three West Virginia coal mines, two in Kentucky and one in Utah have government and industry re-evaluating current safety regulations. Even though U.S. mines continue to improve on their safety records, the deaths reminded the industry and state and federal agencies that mining remains a dangerous business. Even so, data from the U.S. Mine Safety and Health Administration (MSHA) show that new technologies and a highly trained workforce has allowed the nation’s coal mines to increase production while providing safer workplaces. Since 1970, coal production at U.S. mines has increased by about 83 percent. During the same period, fatal injuries have fallen by 92 percent. And more than half of the U.S. coal mines operate each year without a lost-time injury. In 2005, there were 22 deaths in U.S. mines, a record low.

Jan 1, 2006

By J. Bleeck, G. Mahrt

INTRODUCTION Many excellent papers have been written and presented regarding agricultural lime and the subject has been covered extensively in books concerning soil science, fertilizing, limestone, etc. We felt challenged to construct a paper that wouldn’t merely be a repetition of past presentations. Therefore, we chose to begin with factors having the most impact on plant growth realizing that the audience is likely to be relatively unfamiliar with this subject. So, we decided to dig deep into the roots of soil and plant growth science in order to better understand the significant role of limestone in this important area. The soil with the higher plants growing upon it forms an open and dynamic ecosystem in which there is flux of energy and material (heat, light, water, nutrients, mineral and organic matter, organisms). Plants root in the soil and then take up oxygen for root respiration, yielding energy for nutrient uptake, water for turgescence and transpiration and use in photosynthesis and the mineral nutrients needed for the synthesis of organic matter. Above the ground the plant takes in light energy and heat using them in photosynthesis to assimilate atmospheric CO2. Photosynthesis is the basic life process of creation. However, we will look at the root room where soil, water, air, and heat economy and the supply of nutrients determine soil fertility and the important role lime plays here. Location is the primary point to be considered when discussing agriculture (climate and soil); secondly, the dynamic and mobility of the minerals (plant nutrients) in the soil; and thirdly the conversion of organic substances into humus. And then there is a great deal of water involved in the growing process. In order to produce 1 kg of dry plant substance, 300 to 800 kg of water must be pumped through the plant and is then lost by transpiration. Cereals, vegetables, and sugar beets consume between 400 to 500 kg of water during the growing process and long-growing crops, such as alfalfa and clover, can consume 600 to 800 kg of water per kg of finished product. Without water, a plant cannot grow. (Reference 1)

Jan 1, 2006

By I. Mikov

Established in the 60-ies, the Zlatna Panega quarry is a cement raw materials quarry supplying 95% of the needs of the Zlatna Panega Cement Plant with limestone, marl and other silica-aluminates. The two major types of raw materials are formed by accordingly dipping strata of Upper Jurassic limestones and lower Cretaceous marls. Between them there is a ?transition-zone? or ?contact-zone? of a high-silica content layer, about 5-m thick, defined as ?flint? by investigations including spot sampling throughout the quarry. For many years this ?contact-zone? layer was neglected due its negligible thickness. Further, with the increasing demand on the quality of the raw materials feed to the Plant and the focus on variability of the chemical and mineralogical components, it was decided not to mine any of the parts of the quarry contaminated by this material, for about three years. The latter had an impact on the availability of operating benches that could result in a substantial decrease in the total recoverable re-serves of Zlatna Panega, particularly with respect to marls. There were considerations for resorting to a partial, selective excavation of the quarry pit with a reduced lifetime for the lime-stones and re-opening of an other (currently in-active) marl quarry at a distance of 6 Km from the Plant. The Quarry Team of the Zlatna Panega quarry was assigned to study the problem. The ?contact? layer was duly confirmed with systematic geological (including mineralogy) studies, statistical analysis of available data, surface sampling and shallow exploration drills, resulted into distinguishing a third type of reserves and their credible subsurface delineation by means of geological 3-D modeling and quarry design. A new quarry design was finally elaborated with a view of providing flexibility in mining, utilization of the total volume of all available reserves and maximizing the mine life of Zlatna Panega quarry. An industrial test took place in December 2005, by using the contaminated parts of the quarry (co-mining of the ?contact-zone? materials) at a contribution of 15-20% in the raw materials mix, as dictated by their contribution in the total recoverable resources of the quarry. The purpose was to investigate the viability of this solution ? in line with improved quarry planning ? without compromising the quality of cement production and the efficiency of Plant Operations. Results were overall successful.

Jan 1, 2006

By William R. Yernberg

The Fifth International Heavy Minerals Conference (HMC) was held Oct. 16-19, 2005, at the Marriott Sawgrass Resort in Ponte Vedra, FL. With SME as sponsor, the 2005 conference marked the first time that the HMC was held in North America. The conference is held every two years and provides an important forum for professionals in the heavy minerals and related industries to meet and discuss issues related to heavy mineral exploration, mining, processing and marketing. Previous locations included Australia and South Africa. The conference consisted of technical presentations, field trips to heavy mineral operations, a trade show and social activities. It was appropriate that Ponte Vedra was selected as the location for the conference. Ponte Vedra, located on the Atlantic Coast 17 km (10 miles) southeast of Jacksonville, FL, is the birthplace of heavy minerals mining in North America. Ponte Vedra beaches were mined from 1916 to 1929 in what was then called Mineral City. Though Ponte Vedra is now a golf and beach resort, there are still four heavy mineral mines operating within an hour’s drive. Today the Ponte Vedra Country Club and Golf Course is situated in the center of the former mining site.

Jan 1, 2006