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By D. Constantinides

In 1981 a Zn-Ag-Pb deposit was discovered in the vicinity of Molai, Greece. Subsequently, it was determined to be of the Kuroko type. The geology of various areas in the southeast Peloponnesean Peninsula is similar to that of the Molai deposit. Since favorable geologic criteria are present, absent, or unknown in varying degrees in all areas, it was deemed necessary to classify and rank the prospective areas according to the level of information available. For each level of information, an ore discovery model based on pragmatic exploration criteria was developed, enabling the favorability of occurrence to be calculated for each area. A Monte Carlo simulation was used to calculate the probabilities, the input data consisting of quantitative and qualitative estimates of the geologic criteria for each area. Three levels of information were modeled : Level A consisted of 9 criteria, level B of 12 criteria, and level C of 20 criteria. The three levels of information were tested on the Molai area. The results exceeded expectations, showing the gen¬eral trends which control mineralization at the lowest level of information. With an increase in the level of information, geological trends become more evident and a differentiation can be made between areas containing Cu mineralization, exhibiting a low probability, and areas likely to contain Zn-Ag-Pb mineralization. The models were then applied to the neighboring areas - only level A and B were available.

Jan 1, 1986

By H. Köse, C. Tatar, C. Helvaci, F. Simsir

The Çayirhan coal basin is located 124 km (77 miles) west of Ankara,Turkey. With approximately 520 Mt (570 million st) of lignite reserves, the Neogene Çayirhan basin is one of the important coal districts of the central Anatolia region. The Çoraklar formation consists of crossbedded sandstone, channel fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower and upper lignite seams occur, respectively, in the lower and the uppermost parts of the Çoraklar formation. The lignite deposits are in the Çayirhan and Koyunagili portions of the Beypazari Neogene basin. The Çayirhan coalfield consists of lower and upper lignite seams. The lower lignite seam does not outcrop at the surface. Its lateral discontinuity and relatively low sulfur content, plus sedimentologic and stratigraphic features of the associated sediments, indicate a fluvial origin. Thus, the lateral spreading and geometry of the lower lignite deposits were controlled by the channel, flood plain and well drained marshes of a fluvial system. The mining method employed at Çayirhan is the fullymechanized, retreat, working longwall with caving system. Due to ventilation, haulage and tectonic conditions, panel lengths from 0.6 to 1.7km (0.4 to 1.1 miles) are chosen, and 220-m (720ft) face lengths are used. The annual coal production is 2.2 Mt (2.4 million st).

Jan 1, 1994

By Walter Keune

Object Modeling Technique. This formal descriptive language makes it possible to formulate requirements in the real world in such a way that they can be implemented in the form of entities (cf. Entity Relationship Model[Che83]) and methods (see Figure 1). The object {Roadway} is graphically depicted by means of the Polygon method.

Jan 1, 1996

The advantages of quantitative environmental risk assessment techniques over the more commonly used qualitative approach is widely accepted. One important parameter related to the level of risk is the extent and geographic spread of pollutants. Geographic Information Systems (GIS) provide a powerful and highly flexible tool that increases the sophistication of the risk assessment methodology. Through spatial representation, the estimated risk becomes more comprehensive, thus facilitating the decision making process. In addition, valuable qualitative information can be incorporated into the risk assessment procedure with the help of GIS. This paper illustrates a methodology for quantifying risks posed to human health, by exposure to contaminated land, in a manner, which gives a measure of the uncertainty in the assessment and preserves the spatial distribution of the risks. The case study utilised to illustrate the methodology is a large industrial area around a number of decommissioned minerals production and processing sites with known high heavy metal loads at Lavrio, Greece. The spatial distribution of Pb concentration in soils was derived from 425 soil samples collected over a total area of 120 km2. Indicator kriging was used to quantify the spatial distribution of the risk and related uncertainty and the results displayed in map form using GIS.

Jan 1, 2003

By S. A. Sanderson

The last two decades have witnessed the resurgence in popularity of a century old tool for shaping laws and public policy – the ballot initiative. In recent years, anti-mining special interests have used the initiative process to secure voter approval of measures to ban modern surface mining for gold and silver. In November 1998, voters in Montana approved such a measure1 – the effects of which have been devastating to the mining industry in that state. In November 1999, anti-mining groups sought to place a nearly identical provision on the general election ballot in Colorado. They did not succeed, but the battle over mining’s future continues in the most important forum of all – the court of public opinion. The Colorado measure failed, in large part, because its proponents failed to convey a positive environmental theme. The mining industry also exercised early-on the rights available under state law for administrative and judicial review of the initiative, instead of relying upon the limited relief that would have been available had it waited until after the secretary of state approved the measure for the November election ballot. This article will summarize the ballot initiative process in Colorado and the proceedings that took place over Initiative No. 215.

Jan 1, 2001

By D. M. Hausen

The role of applied mineralogy in mineral beneficiation begins with early prospect evaluation, and continues through stages of amenability testwork and pilot plant studies to the ultimate development of viable processes for mineable orebodies. After plant construction, mineral products from various locations, i.e., grinding circuits, flotation cells, gravity circuits, kilns, smelters, etc., require quick identification and control monitoring for optimum efficiency and recovery. Ore/gangue minerals are identified, quantified, and textural associations investigated by microscopic, spectrographic, and electron-optical instruments. Mineralogic analyses of large numbers of samples have required the development of sophisticated computer systems that merge analytical and mineralogic data into useful diagnostic data bases

Jan 1, 1991

By Arthur W. Darby

Heathrow Airport is owned and operated by BAA who are engaged in a major programme of expansion. In order to link the expansion of the airport in the west with the existing central terminal area, a twin bore, 8.8m outside diameter, road tunnel,1280m long, is being constructed. The tunnel drives pass over, with limited clearances, an operating railway tunnel, and pass under, with about one diameter cover, the airport taxiways and aircraft stands. Selection of the machine was heavily influenced by the need to minimise settlement.

Jan 1, 2003

By E. V. Kuzmin

The rock properties improvement means the exchange of natural properties: increase of stability, strain and compress tension, reduction of gas-liquid filtering property, increase Jung- module, other mechanical and physical parameters of rocks by injection the hardening materials, such as polymeric pitches, micro-or geocements by special technology under high pressure, to fill cracks. Flow of liquid materials between the rock units and hardening under high pressure create full redistribution of rock pressure in rock massif. There are many reasons to use this technology in underground mining, tunnelling, creation barrier technology in raioactive, chemical and other danger material site etc.

Jan 1, 1996

By J. R. Mattern

The engineering geology of the Rio Tinto Borax Boron Mine creates challenges in providing practical slope design recommendations to mine planning engineers. Low strength sedimentary units interbedded with very low strength lakebed clays surround the orebody. Faulting has offset and juxtaposed these units into variably adverse orientations, while groundwater is compartmentalized both vertically and horizontally within fault blocks. A collective program of geologic data collection, geomechanical strength testing, geologic modeling, slope depressurization, confirmation of underground stope locations, and documentation of slope behavior provides vital information for design investigations and sensitivities. Analysis results lead to risk assessments and operational procedures that add value to the business by optimizing slope configurations and minimizing risk.

Jan 1, 2004

By S. Veeramasuneni, Qingxia Liu, Susan Dichter

Gypsum (CaSO4-2H2O) is an abundant and naturally occurring mineral. Under elevated temperatures (250 to 300°F) gypsum loses its crystalline water and is converted to hemihydrate (CaSO4 -0.5H2O). The hemihydrate form is also called plaster that is widely used in wall- board, joint compound, and many other industrial applications. At temperatures higher than 450°F (up to 1,200°F), gypsum loses all crystalline water and is converted to anhydrite form (CaSO4). The loss of crystalline water at elevated temperatures is an endothermic reaction. This property makes gypsum an attractive filler and fire retardant in certain thermosetting plastics. The applications of gypsum in plastics, food, pharmaceutical, and paper coatings will be reviewed in this paper. The future of synthetic gypsum, a by product of various industrial processes, will also be discussed.

Jan 1, 2003

By Martin Herenknecht, Michael Knabe, Ulrich Rehm

In Switzerland at present, the longest railway tunnels in the world, the Gotthard(57 km) and the Loetschberg base tunnel (34km) are under construction. For thischallenge six high-tech HERRENKNECHT Hard Rock Tunnel Boring Machines (TBM)are applied, which have to excavate approx. 80 km at the Gotthard and 20 km at the Loetschberg Tunnels. The machines being used are of a single Gripper-TBM type, which are equipped with the latest rock support techniques, in order to optimize the quality of the working conditions for the personnel which have direct impact on the quality of the tunnels. The different requirements of the projects based on different speci?cations within the tender documents led to completely different TBM concepts which will be reviewed in detail in this paper.

Jan 1, 2003

By Thomas W. Traylor

Today, in Detroit, Michigan, a 14 ft. 6 in. diameter soft ground tunnel is being mined at penetration rates limited only by the logistics of liner handling and spoil removal. Soil conditions are highly variable and include clays ranging from very plastic to very hard, gravels, sands, silts and boulders. The permeable soils contain high concentrations of methane gas, compressed by groundwater levels some 40 ft. above tunnel invert. Despite these adverse conditions, mining crews frequently complete their 70 ft. production quota in six hours and go home. In one 4000 ft. reach of tunnel, progress averaged 68.9 ft. per mining shift. This paper has been written to explain this extraordinary accomplishment, and to demonstrate that truly continuous rapid excavation in difficult grounds is now limited by factors other than the excavation process itself. BACKGROUND The Detroit metropolitan area has a long and interesting history of soft ground tunneling. From 1949 to 1968 the city of Detroit alone constructed some 75 miles of soft ground tunnel. During this period the development and common usage of rotary or "wheel-type" soft ground tunneling machines was pioneered in the Detroit area. These machines are designed for, and were successful in, the cohesive or clayed soils that predominate the downtown Detroit geology.

Jan 1, 1997

By F. Repmann

Waste-dumps originating from the mining industry constitute a serious environmental problem if they are not properly rehabilitated. Industrial and domestic sewage sludge from waste water purification plants on the other hand constitute a problem of environmentally acceptable disposal as these residues contain a large number of potential contaminants. The current project aims at developing an integrated methodology to rehabilitate the mining waste-dumps by the use of sewage sludge so that the two mentioned problems will be solved at once.

Jan 1, 2002

Open pit optimization and mine design depend upon a realistic estimate of the grade-tonnage dis¬tribution. The estimate should reflect what can be reasonably recovered and processed. The McCoy/Cove operation in central Nevada is a gold and silver mine. Recoverable reserve estimations of gold and silver were made using indicator kriging and the indirect log normal variance correction to construct the grade- tonnage distribution. Optimal pits were generated using this distribution, and the results were compared to the pits generated by ordinary kriging and indicator kriging block mean methods. The results indicate that the proposed method for multimetal recoverable reserve estimation shows an improvement in terms of predicting the recoverable tons and grades. The optimal pits generated from the recoverable resource model are larger than those generated by the ordinary kriging and indicator kriging block mean methods. This model maximizes the overall recovery of the mineral resource.

Jan 1, 1999

By F. J. Menzer, E. M. Schern

The Morenci/Metcalf porphyry copper mining operation, located in southeastern Arizona, currently processes approximately 91,000 tonnes of ore per day and has copper ore reserves estimated to be in excess of one billion tonnes. Functional groups within the Geology Department (currently staffed with six professional and two support personnel) include mine geology, project geology, and hydrogeology. The primary task of mine geologists is daily preblast bench face mapping with grade and mill amenability estimates. Auxiliary duties include detailed in-pit metal distribution evaluation, mineragraphic work and flux quarry geology. Project geologists conduct exploration and preliminary development projects both within and outside the Morenci district and provide support to ore reserve block modeling and geotechnical work performed by the Morenci mine engineering group. Hydrogeologists handle exploration for and development of groundwater resources and groundwater flow modeling, mine dump leach solution penetration and recovery evaluation, and tailing dam water reclamation.

Jan 1, 1992

By Joseph A. Whitchurch

The N20 to N25 Tunnel (basic) segment was the second tunnel contract awarded for construction by The PB/MK Team. This project embodied 3.9 km (2.4 miles) of tunnel and was located within the northwest quadrant of the 86.9 km (54 mile) long main collider ring. The contract required the excavation and initial support of a 54.3 m (178 vlf) deep ventilation shaft, a connecting horseshoe shaped Adit and TBM starter tunnel and 3,865 m (12,680 If) long main collider tunnel with a 4.3 m (14 ft) minimum finished diameter. This paper discusses the construction methods, equipment utilized and the production achieved in the construction of the ventilation shaft, connecting adits and the main collider tunnel.

Jan 1, 1995

By R. D. Willette

The Hector Mine deposit in the California Mojave Desert has a magnesium-rich clay that formed when lithium and fluorine were introduced into isolated fine lacustrine volcanic sediment during the Pliocene. The intensely deformed deposit has been supplying the highest grade thixotropic clay to the coatings industry for over half a century. A thixotropic clay displays the property of changing from a gel to a sol when shaken, and increases in strength upon standing.

Jan 1, 1995

By K. Sasaki, T. Murakami, S. Akibayashi, Q. Wei

A numerical analysis and an experiment were done on groundwater flow past a bore hole with a cylindrical obstacle at its center. Flow around the obstacle in the bore hole was studied in detail. Two dimensional governing equations to simulate this flow were written for the hydraulic head and seepage velocity in a porous medium and for the vorticity, stream function, and velocity in the bore hole. These equations were non-dimensionalized and solved by using the alternating direction implicit and successive-over-relaxation finite difference methods. Flow visualization experiments and velocity measurements in the bore hole were done with a two dimensional model composed of a porous medium. The numerical analysis procedures were validated by a comparison of numerical and experimental results. Effects of the Reynolds number and obstacle size on flow in the bore hole are clearly shown in the velocity and streamline profiles. The quantitative relation between the seepage velocity in the porous medium and the velocity of flow around the obstacle in the bore hole also were estimated.

Jan 1, 1996

By K. C. Ko, M. D. Bunnell

The studied coal mi1e is an underground coal mine located in the northern Wasatch Plateau of central Utah (Figure 1) . Since operation began in 1981, in situ stress conditions have been encountered which differ from the assumed conditions utilized during early mine design efforts. Geologic structures also varied somewhat from those projected during initial geologic interpretations of the area. The encountered geologic conditions combined with the unusual stress conditions prompted a combined study of in situ stress and stress-related geologic structures. The study was conducted in two phases, with phase 1 consisting of detailed underground mapping and analysis of stress-related geologic structures to determine stress orientations from which they originated; and phase 2, consisting of over- coring two sites within the mine to determine present in situ stress orientations and magnitudes. GEOLOGIC ANALYSIS Three types of geologic structures have been encountered in the mine that act as indicators of stress orientations of the geologic past. Two of these structures, faulting, and igneous dikes, are directly measurable in the mine. A third type of structure, photolineation, was detected through remote sensing methods and shoe god correlation to roof conditions in certain areas of the mine. Faults Two major orientations of faulting have been encountered in the studied coal mine, including a system of N 80 W striking normal faults and a system of N 55 to 70 W striking oblique-slip faults. Only data collected from the oblique-slip faults were used for this study due to the fact that these faults offset the N 80 W faults wherever the two systems intersect, indicating that the N 55 to 70 W system was created by a more recent stress field. Figure 2 shows locations within the mine where data were collected from seven locations along oblique-slip faults. Data collection consisted of measurement of fault plane strike and dip, fault slickenside trend and plunge, and slip direction. The data are tabulated in Table 1. The fault data were then plotted on stereo nets to determine the stress orientations present at the td of faulting (Figure 3). The determined stress orientations are 32~0 included in Table 1. The stereo net plots show average principal stress orientations of: 1) [ ] plunge 1 degree. These data suggest that the N 55 to 70 W oblique-slip faults were produced by a nearly

Jan 1, 1986

By K. Kuhnhenn, G. Prommersberger

General aspects In Germany, swelling rock is mostly found in the keuper formation. Keuper is a sedimentary rock formation of varying composition. It mostly consists of fine or medium layers of clay/silt/marl/dolomite stone with intercalations of gypsum or anhydrite in strips or nodes. After disintegration of the top layers and tectonical incidents, the gypsum level, i.e. the upper [ ]

Jan 1, 1989