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By M. Morrongiello

The Kalgoorlie Consolidated Gold Mines Fimiston Open Pit is mining through a dense network of disused level workings and stopes of varied sizes and orientations. This study investigated the interaction between underground workings and the pit slope stability, in particular for the ultimate pit depth of over 600 metres. Parametric analyses were conducted on the structural and rock mass properties in order to provide realistic input. Several cases in both 2D and pseudo 3D using UDEC were modeled and analyzed to investigate the performance of the rock mass at various mining stages. The concept of equivalent property factor was also introduced to model the 3D behavior using 2D models. Based on the modelling results, the possible failure mechanisms and deformation of the pit walls were assessed. Factors of safety have been derived for the pit slope at different mining stages using the strength reduction technique. The modelling results agree well with pit performance monitoring results to date. The concept and results presented in this paper could be a useful reference for operations with similar circumstances and stress regimes.

Jan 1, 2005

By Douglas B. Silver

Addwest Minerals' turnaround of the Gold Road Mine in 1996 proves the old adage "mines are made, not found." The underground mine, located in Arizona's San Francisco mining district, was reopened in 1995. Start-up proved difficult because the initial mining method created significant ore grade dilution. With the operation's viability in question, only management's belief in the property and tenacity in the face of changing corporate ownership kept Gold Road from losing in the same year it opened. y changing mining methods in early 1996, Addwest re¬duced operating costs and created a profitable mine that continues to add to its reserve base.

Jan 1, 1997

By Matthew E. Eisenmann, Gerald H. Luttrell

Performance data from phosphate plants are often untrustworthy because of difficulties associated with highly variable feeds and unstable equipment operation. In some cases, this problem is further compounded by improper sampling procedures and unreliable laboratory analyses. Questionable data often lead to misleading conclusions that result in lost productivity and profits. Data reliability may be checked using mass balances, but the mathematics associated with this procedure can be overwhelming when multiple data sets or complex circuits are evaluated. To overcome this problem, a simple spreadsheet-based mass balance program has been developed specifically for plant operators. To use this program, operators simply enter a description of their circuit and input the assay values (e.g., % BPL, % Insol, etc.) for each stream. The program then generates the best estimates of the assay values and flags values that may be unreliable. The spreadsheet is specifically designed to be easy to use and requires no knowledge of statistics or programming. This manuscript reviews the mass balance problem and describes how spreadsheet programs can be used to evaluate plant data. An example problem involving the analysis of data around a two-stage phosphate flotation circuit is presented.

Jan 1, 2002

By George E. Williamson, Mikiya Higuchi, Michael T. Traylor

Extensive soil conditioning was required to allow Earth Pressure Balance(EPB) tunneling on the South Bay Ocean Outfall tunnel project in San Diego, California, near the Mexican border. This tunnel extends 19,000 feet out under the Pacific Ocean and was mined through soil formations including silts, sands, gravels, cobbles, and boulders. EPB pressures ranged from 3.0 to 7.0 bar, with the maximum pressures required when mining through the highly permeable granular formations.

Jan 1, 1999

Maptek, an international development software company, released version 3.2 of its Vulcan three-dimensional mining and geological software package. This latest release is expected to give clients better graphics performance and improved overall solutions. In addition, the company also released the NT version of Vulcan for Unix and personal computers. More than 800 code changes have gone into the 3.2 release, the Lakewood, CO-based company said. Many of these changes were in response to requests from Maptek's customers. Others have been motivated internally by the company to achieve better performance in its Envisage graphics interface. The introduction of hot keys and user-defined menus makes Envisage a more flexible interface and a more productive working environment. A new animation option provides new ways to enhance the organization and display of data. The animated data can include point, string, grid, triangulation and photographic-draped data. The shaft-mapping facility is also included in version 3.2. It enables the cylindrical view of the shaft to be unwrapped and displayed on the screen while the data remains in its true world coordinates. Major upgrades to Vulcan include underground blast design and geotechnical modules. The new blast design module allows the user to develop a ring design in any plane defined by the stope layout. Radial and offset holes can be developed. User-friendly editing tools make adjustments to the initial design a simple task. The user defines the plotting and reporting of rings and plot style templates allow flexibility in reporting. New features in the geotechnical toolbox include options to create daylight windows and pitch lines on the stereo nets. Geotechnical databases can be directly updated from the interpretation of the stereo net. Direct annotation of the symbols on the net is now possible and the stereo net display can be customized. Improvements to the documentation and links within the text have made the on-line help easier to navigate. Maptek also released the NT version of Vulcan soft- ware. The comprehensive design of the software pack- age for Unix and personal computers provides a three-dimensional geological modeling and mine planning system within a natural graphics environment. Users who require the power to manipulate extra- large and complex data sets will still be served by the Unix platform. Users who handle small-to-large datasets can now choose between Unix and personal computer platforms. The NT version will appeal primarily to companies that already have a personal computer network. Response to industry feedback was the basis for developing the NT version. "We want to ensure that our clients receive the optimal product for their needs," said Nicolas Simon, vice president of Maptek in North America. Some advantages of the NT version include: ? Most mining professionals are familiar with the personal computer platform. ? All of the familiar personal computer tools are now available to Vulcan users. ? Resource modeling tools that previously required the powerful Unix workstations have been brought into the personal computer environment. This will help mining companies save money. From a binary data point of view, the personal computer NT version is compatible with other platforms, such as SGIIDECIHPISUN, allowing integrated personal computer and Unix environments For more information, contact Cherie LeDoux, Maptek, 165 So. Union Blvd., Suite 777, Lakewood, CO 80228, fax 303-763-4921, e-mail: info@maptek.com, Internet: http:llwww.maptek.com.

Jan 1, 1997

By Ann M. Gosier

Over the past 20 years, diesel-powered equipment has been introduced into the underground mining environment in increasing numbers. While the introduction began years earlier in the metal-nonmetal sector, the exponential growth in coal mining use during this time has been more pronounced. Reasons for the continued use and rapid growth of diesel equipment in underground mines are easily understood. The safety and operational advantages afforded by this equipment in production and support systems are demonstrable. As other mine operators witness the advantages enjoyed by their competitors, they too move to introduce an increasingly diverse array of such equipment into their underground mines. As with any industrial technology, the use of diesel-powered equipment entails potential safety and health concerns. Existing Mine Safety and Health Administration (MSHA)approval regulations (30 CFR Parts 31, 32 and 36) apply only to diesel locomotives and mobile diesel-powered equipment for noncoal mines. In the absence of specific regulations, MSHA has required the use of equipment approved under Part 36 (gassy noncoal mines) for areas of underground coal mines where permissible electrical equipment is required. However, a considerable amount of diesel-powered equipment without explosion-proof or fire prevention features is in use in areas of coal mines where permissible electrical equipment is not required. It is on the use of this latter class of equipment that MSHA is focusing much of its regulatory attention relative to coal. The agency also is focused on revising existing occupational exposure limits for gaseous emissions and instituting limits on diesel particulate emissions for both coal and metal-nonmetal mines.

Jan 1, 1993

By R. H. King

The US coal industry has been using continuous room-and-pillar mining (CRPM) machines for more than 30 years for longwall development. This equipment has also been used for production mining in areas that are not appropriate for longwall mining. From 1977 to 1987, the portion of annual US production mined by continuous miner (CM) sections grew slightly from 65% to 70%. Over this time, mine operators and manufacturers have made some advances to attain the full production potential of this method. This is evidenced by the fact that average tons per eight hour shift for continuous miners in the US grew from 180 t (200 st) in 1977 to 431 t (475 st) in 1987. The authors (1990) reported that the increase in productivity was due to several factors: • a drop in prices; • a more mature workforce; • union stability and incentive programs; •procedural improvements; and •technological advances. The authors estimated that about one-third of the increased production came from the first three and other unaccounted for factors and one-third each for the last two. Even though improvements were considerable, continuous miner capacity is much higher than 431 t/shift (475 st per shift). For example, the machinery is capable of mining more than 9 t (10 st) per machine for the 6.5 available hours per shift or 3.5 kt (3900 st). However, this has never been attained on development. The averages of most mines are less than 900 t/shift

Jan 1, 1991

By Bruce D. Hulman, Robert .. F. Gorman

Introduction Groundwater resource evaluation has historically required extensive field investigative work, usually at great cost. More recently, the advent of the microcomputer has made difficult aquifer and groundwater evaluations comparatively simple and less expensive. A groundwater model is a numeric solution to a set of equations that calculates the water level in an aquifer or other types of water bearing strata. A computer will execute the solution of the set of equations rapidly and thereby permit evaluation of large amounts of hydrogeologic data rapidly. Computer modeling of groundwater resources is very often used to forecast the effects of multiple uses of a single groundwater resource. Modeling of heavily used aquifers has proven to be beneficial for averting problems arising from competitive use of a groundwater resource. This paper describes the work tasks performed in order to evaluate a large alluvial aquifer and thereby predict the hydrologic impact of additional groundwater withdrawal. Purpose and Scope Neyer, Tiseo & Hindo, Ltd. (NTH) was retained to evaluate the groundwater supply potential of the Missouri River alluvium underlying the Fairfax District in Kansas City, Kansas (Figure 1). The proposed groundwater supply is being considered for industrial use as non-contact process water and a heat exchange medium for plant climate control. The anticipated peak groundwater demand is estimated to exceed 30 million gallons per day (MGD) during the summer months, with an average daily demand of nearly 25 MGD. The proposed groundwater supply was to be developed from 15 large-diameter production wells located at positions that would minimize potential interference.

Jan 1, 1987

By K. T. Dreher, J. A. Brierley, C. L. Brierley

Water from underground uranium mines located in the Ambrosia Lake district near Grants, New Mexico, U.S.A., is treated to reduce levels of uranium, selenium, radium and molybdenum. The treatment system consists of a series of ponds and an ion exchange plant. Bacterial and algal populations present in the pond system are considered agents which actively assist in removal of the pollutants present in the water. Pondbottom sediments maintain a reducing zone and a large population of sulfate-reducing bacteria of the genera [Desulfovibrio] and [Desulfotomaculum]. Uranium, molybdenum, and selenium accumulate in the pond sediment. Stimulation of the microbial sulfate-reducing activity resulted in a decrease of soluble concentrations of these elements in laboratory systems. Predominant components of the treatment ponds’ algal flora are the filamentous [Spirogyra] and benthic [Chara]. Laboratory study indicates that [Spirogyra] is more active than [Chara] in removal of uranium and molybdenum from solution. However field-collected algal samples of both of the genera contain uranium and molybdenum. Laboratory studies indicate that death and decay of the algae in association with pond sediment does not result in return of cellbound uranium and molybdenum to the water. The algae appear to act as bio-filters for accumulation of particulate pollutants and agents for adsorption and/or absorption of soluble pollutants.

Jan 1, 1980

By I. Shah, L. G. Austin

A method for quantitative investigation of the phenomena involved in fine grinding of materials that follows the changes in the breakage rates of fine particles has been presented. For relatively hard, brittle, non-coating material like quartz, the slowing down effect of breakage rates starts to be significant at relatively coarse sizes, which goes often undetected in closed circuit grinding systems, producing relatively coarse product, say P80=75µm However, for fine grinding systems, as the -10µm fractions begin to build-up, and classification becomes more difficult, the build-up of fine sizes causes a slowing down effect Compounding this problem is the difficulty of obtaining accurate cumulative weight size distributions in the fine size region.

Jan 1, 1983

By Robert H. Merrill

7.1-STABILITY OF SLOPES IN SOIL AND ROCK ROBERT H. MERRILL 7.1.1-DESIGN ANALYSIS APPROACHES The analyses of slopes in soil or rock can be made through application of soil- or rock-mechanics principles. In most cases, the material in the slope wall can easily be identified as either a soil or a rock. However, there will be instances where, because of unique characteristics, the soil may behave as a rock structure, or vice versa. By necessity, these unique cases must be identified through experience or critical observation by the engineer, because there are no definitive rules clearly establishing the differences. The most important step in a solution to a slope problem is to define it. Normally, once the problem is identified, a solution usually can be found or a reasonable estimate obtained. The design analysis of a slope wall implies an evaluation of the stresses or forces in the wall, and of the ability of the material in the wall to withstand them. Therefore, the factors influencing a design analysis can be divided into two categories: those which influence stresses, and those which influence the ability of the wall to withstand stress. For simplification, the latter is termed the strength of the soil or rock. Perhaps the basic difference between analyses for soils and those for rock is in the identification of the failure surface. Soils generally do not have an identifiable failure plane. However, some soil layers in a slope wall may have different strengths. A soil slope wall may consist of a thin layer of topsoil overlying a thick, uniform clay, or a topsoil over a gravel or other materials. Therefore, the soil generally does not have a potential plane of weakness that can be identified through observation. On the other hand, rocks normally contain planes of weakness in the form of fractures, faults, joints, bedding planes or other discontinuities weaker than the intact rock, which can be found through observation and/or tests upon rock samples. If the failure surface cannot be identified, the principles of soil mechanics should apply because, in soil mechanics, the failure surface usually is assumed. If it can be identified, then the principles of rock mechanics should apply. 7.1.2-ANALYSES OF STRESSES OR FORCES IN SLOPES All existing methods of soil-slope analysis are based upon interpetations of the Coulomb and Coulomb-Navier failure criteria, commonly termed the total-stress 2nd the effective-stress criteria (Sec. 6.1). The total-stress criterion may be illustrated by the diagram in Fig. 7-lA, which relates the total stress, S, to the cohesion, c: the normal stress, u, and the angle of internal friction, 9, by the expression

Jan 1, 1973

By Tso-Min Shih, Ching-Hua Liu, Chung-Jen Lin, Hsi-Chiang Fang

This paper presented herein, describe the special design of an open type coal dust explosion apparatus and the laboratory works for investigating the effectiveness of the parameters on coal dust explosion and the prevention of the propagation of the coal dust explosion flame. Coal sample which were taken from the San-Ying collieries, were passed through the process of crushing ,grinding and screening to get the required particle size, ranged from 40 mesh to 200 mesh under size for testing purpose, the rock dust spreaded on the surface of coal dust and water mixed with coal dusts were employed for preventing the coal dust explosion and the propagation of the explosion flame.

Jan 1, 1991

By L. Mao, R. Yoon

The thin film balance (TFB) technique was used to measure the equilibrium thicknesses of the water films formed between two oil phases. The measurements were conducted with dodecane at varying concentrations of dodecylammonium chloride, pH, and electrolyte concentration. The data obtained in the present work were used to calculate the surface forces acting between the two oil phases. The calculation was carried using the Extended-DLVO theory with the surface potentials calculated from the Gibbs adsorption isotherm. The results show that oil droplets suspended in water are hydrophobic and the hydrophobicity changes with surfactant and electrolyte concentrations.

Jan 1, 2004

By K. N. Han, Y. Guan

The dissolution behavior of silver and copper from silver/copper alloys in ammoniacal solutions was investigated using a rotating disc. Oxygen was used as an oxidant. The effects of the alloy composition, concentration of lixiviants, stirring speed and temperature on the overall dissolution kinetics were studied. Three silver/copper alloys (containing 76.7, 46.9 and 24.1% silver) were used in this study. The rates of dissolution for these alloys were compared to that of pure silver and copper under the same testing conditions. Emphasis was given to the galvanic effect on the overall dissolution rates.

Jan 1, 1995

By A. Unal, R. L. Grayson

The use of radio frequency identification (RFID) technology to solve informational needs in isolated and restricted underground mining environments are reviewed, and the specifications of some of the past and currently available systems are presented. The advantages and disadvantages of using various frequencies, system configurations and specific components, including their construction standards and capability, are also discussed. The remaining challenges to the more widespread use of RFID systems for personnel and vehicle tracking are identified, and recommendations concerning the operating environment capabilities are detailed. Finally, the ultimate requirements for maintaining system integrity during and following a coal mine emergency are discussed.

Jan 1, 1999

By J. B. Gwiazda

S.S. Peng The highlights of this paper are: The shield supports with lemniscate links will exert a tangential force on the roof strata, causing unnecessary and harmful roof movements, thus damaging the roof structure. The principal source of the tangential force is the horizontal movement of the point O, the pivotal joint between the canopy and the caving shield. When the support height is changed during setting, the point O will move along a curve upward and rearward toward the gob. As a result, it produces a vertical movement, causing the roof to move up a distance of t d, and a horizontal movement toward the gob, creating vertical fractures in the roof. The major purpose for employing the lemniscate- link system is to protect the hydraulic legs against the action of the bending moments induced by the tangential force that causes deformation or destruction of the legs. Based on these two points, the author suggested that, in order to eliminate the harmful effects of the lemniscate-link system and strengthen its advantageous features, a shield support with a new design of that mechanism has been developed. With the new design, the conventional rigid lemniscate links are replaced by hydraulic rams. When the pressure inside the rams reaches a certain level, the ram will yield.

Jan 1, 1987

By Ing. E. h. Martin Herrenknecht, Werner Burger

In recent years, there has been a dramatic increase in the number of machine driven soft ground tunnelling projects. This increase is largely due to the technological development of slurry and EPB Shield systems. A new generation of soft ground tunnelling machines, markedly different from those of five years ago, now overcomes ground conditions that until now were too costly and impractical to undertake. The paper reviews the latest soft ground tunnelling machine developments in material transport, guidance and control, seismic surveying, soil conditioning, settlement control, cutting tool applications and variable mode operating systems. Specific projects where this technology has been applied will be highlighted.

Jan 1, 1999

By H. Para, A. Aguirre, G. Artadi

Mining is a very important economical activity in Peru which has been recently developed without considering environmental aspects. Here, we show an experience at the Milpo mine, situated 4,200 meters above sea level; a mining company that has the value of being one of few from the last decade that is engaged in consolidating a model of environmental protection. The model includes aspects of contamination prevention and control, with bioindicators such as pasture cultivation, vegetables, forests, and hydrobiological species breeding. Socially, through means of development programs in natural areas, forestation and support to rural agriculture, together with environmental education, it is being demonstrated that it is possible to ensure tangible results in environmental conservation and the well-being of the populations around the mine.

Jan 1, 1998

By Berthold Pilz

The importance of a power economy that is efficient both in technological and economic terms has been clearly recognized in recent years. In 1977 the German Federal Government therefore introduced its Energy Research and Energy Technologies Program 1977-1980, which consolidates the government activities in the field of nuclear and non-nuclear energy research. The priority objectives of this program can be summarized as follows: safeguarding the medium- to long-term energy supply in the Federal Republic of Germany at reasonable overall macroeconomic cost, taking into account the requirements of environmental protection and the safety of the population. In the field of coal mining technologies, about 200 research projects are currently under way. A total of DM 1.7 billion is earmarked for research to be conducted in this area between 1977 and 1980.

Jan 1, 1979

By Arthur F. Eidson

INTRODUCTION If a uranium mill worker is involved in an accident, analysis of excreta for uranium content and[in vivo] counting methods are used to estimate the extent of the possible exposure and to predict the pattern of uranium distribution among tissues (Spitz, [et al]., 1980). Interpretations of urinary excretion data are based on studies of human exposures to single uranium compounds including U02, U308, U03, UF4, U02F2 and UF6 (Alexander, 1974). Refined uranium ore (yellowcake) is a variable mixture of U03-NH3-H20 adducts (ammonium diuranate, ADU) and their thermal conversion product, U308. The variability in composition of yellowcake (Kalkwarf, 1979; Eidson and Mewhinney, 1980; Dennis, Blauer and Kent, 1981) complicates the interpretation of bioassay data from individuals that might have inhaled any single yellowcake material. A test system would be useful to estimate the dissolution behavior of a particular yellowcake aerosol inhaled by a worker and aid in the interpretation of bioassay data collected before and after an accident. A series of experiments was conducted for this purpose. The objectives of these studies were to: 1) develop specific criteria for comparing [in vitro] dissolution systems and 2) use the criteria to evaluate solvents, methods and experimental temperature and pH conditions used in previous studies. Dissolution experiments were conducted using different combinations of solvents, conditions and methods with a common yellowcake sample. Because little information is available from human yellowcake inhalation exposures to evaluate the [in vitro] results, criteria for evaluation of different tests were derived from a model of yellowcake dissolution in lung constructed from a number of cases in which humans were exposed to single uranium compounds known to be in yellowcake (Mercer, 1975). MATERIALS AND METHODS Materials The powder used in the tests was taken from one lot of yellowcake obtained from a commercial uranium mill. The same powder was previously designated as Mill D in Eidson and Mewhinney, 1980 and Mill 2 in Kalkwarf, 1979. The ammonium diuranate content was measured by infrared absorption to be 25% ± 1% (Eidson and Mewhinney, 1980). Solvents The compositions of the two biological fluid simulants used are compared in Table 1. Simulated lung fluid (SLF) (Kalkwarf, 1979; Dennis, Blauer and Kent, 1981) was chosen to simulate the composition [ ] of lung fluid as closely as practical (Moss, 1979). Simulated blood serum ultrafiltrate (SUF) (Eidson and Mewhinney, 1980) was chosen because of previous successful efforts to model human urinary excretion of inhaled plutonium aerosols (Kanapilly Raabe and Boyd, 1974) and the dissolution rate of 241Am02 in Beagle dogs (Mewhinney and Griffith, 1981). Major differences are that simulated lung fluid contains Mg2+ and a higher Ca2+ concentration than SUF and that SUF contains ammonium ion. Both solvents include protein substitutes; acetate is used in SLF, while amino acids are used in SUF. Both solvents include phosphate but the chelating agent diethylenetriaminepentaacetic acid (DTPA) is included in SUF to prevent possible formation of insoluble uranyl phosphate precipitates that would result in an underestimation of solubility. In addition to the above solvents, modified solvent compositions were prepared to investigate the role of specific salts in yellowcake dissolution studies. Solutions of SUF (Table 1) were prepared without DTPA (SUF-DTPA) and without amino acids (SUF-amino acids). No solution excluded both DTPA and amino acids. The SLF solutions were prepared with DTPA (SLF + DTPA) and without phosphate

Jan 1, 1981