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By A. H. Swart

Rock engineering is concerned with the design of rock structures generated by mining activities. Therefore, rock engineering designs have major implications for the safe recovery of mineral deposits and operating costs. The paper deals with a few challenges facing rock mechanics engineers operating in the hard rock underground mining environment in South Africa. Finally, examples are included, which may assist rock mechanics engineers in providing better designs, which could ultimately lead to further improvement in safety and lower operating costs.

Jan 1, 2005

By Z. A. Md-Nor

Risk management is an established loss-control methodology that has been applied successfully in many industries. Recently, interest in this structured approach has grown in the mining industry. The main objective of this research was to develop a risk-assessment process, which is a part of risk management, that can be used by the U.S. mining industry to more thoroughly characterize risks associated with haul truck-related fatalities. The assessment is based on historical data obtained from the U.S. Mine Safety and Health Administration (MSHA) investigation reports, which includes 113 fatal incidents that occurred from 1995 through 2006. The risk-assessment process used in this research involves the following basic steps: identification of the risks, risk analysis and risk evaluation. The preliminary hazard assessment (PHA) method is used in identifying and quantifying risks. Risk levels are then developed using a pre-established risk matrix that ranks them according to probability and severity. The resulting assigned risk value can then be used to prioritize control strategies. This paper is a part of a detailed study on risk assessment for equipment-related fatalities in mining sponsored by the Western U.S. Mining Safety and Health Training and Translation Center.

Jan 1, 2008

By David Baughman, Steven Axen, Ray V. Huff, Donald H. Davidson

Introduction In situ leaching (ISL) is an alternative method of mining uranium from deposits that are low-grade, deeplying, and water-saturated. ISL recovers uranium by transporting fluids through rock rather than by moving rock, a concept the Chinese developed over 2000 years ago for water production. This technique eventually evolved into production systems for oil, gas, sulfur, and salt. More recently, in situ methods have been developed to produce shale oil, gasified coal, geothermal energy, uranium, and copper. ISL uranium operations began in the early 1960s with Sabine Production Co. in south Texas. About the same time, Utah Construction and Mining Co. (Anderson and Richie, 1968) started similar operations in Wyoming's Shirley Basin. During the 1970s, six commercial operations were started in south Texas, (USBM, 1978) and a number of pilot operations were in various stages of development in Colorado, Wyoming, and New Mexico. This paper reviews some of the technical and economic aspects of the ISL process and briefly discusses key subsurface engineering functions as¬sociated with well pattern design and operation. While flow characteristics of a deposit are of prime importance, the following information is also needed: Depth, ore grade, total contained metal, ore thickness, flow conductivity (permeability), void space in rock (porosity), mineral type and distribution, natural groundwater flow, and structural features. Solvent selection, which is important to the economic success of the operation, takes these factors into account: Composition, rate of metal solubilization, interaction with gangue minerals, impact on rock permeability, impact on materials of construction, trace metal solubilization, cost, availability, and handling problems. Overview of ISL An ISL operation consists of these functions (Fig. 1): 1. Chemicals to dissolve and maintain uranium in solution are prepared at the surface extraction facility. 2. A set of injection wells forces the solvent into rock pores of fractures using pressure in excess of the deposit's hydrostatic pressure. 3. Solvent travels through the rock and reacts with uranium minerals to dissolve them. The solvent usually consists of an oxidant and a complexing agent in an acidic or alkaline medium. 4. A set of production wells creates a low-pressure sump where metal-enriched solution is collected for transport to the surface. 5. The enriched solution is processed to recover uranium and to separate the leaching solution for recycling through the system. The economic performance of an in situ operation may be estimated by integrating these related factors: (1) the flow rate of solution processed through the system, (2) rates of fluid injection and production from wells, (3) the rate of mineral solubilization in the liquid phase, and (4) the volume of rock swept by the fluid. As these factors reveal, ISL involves the technical disciplines of petroleum engineering, ore deposit geology, and hydrometallurgical processing. Wellfield Design Just as mineral engineers use drillhole information to plan a conventional mine, in situ engineers use similar information to design a well field. A thorough knowledge of deposit geology and reservoir properties is required. Early application of pressure transient testing, such as

Jan 2, 1980

By Li Jiuping, Zhong Gang, Chen Yong Zhang, I. Michael Gowring

The Liaoning Dahuofang Reservoir Water Transfer Project is an important development for the Department of Water Resources of Liaoning Province in northeastern China. The 85.3 km water conduit will transport water from the Hun River downstream of the Huanren Reservoir to the outlet on the Suzi River leading to the Dahuofang Reservoir. The additional water is required to sustain the growing cities of Fushun, Shen-yang, Liaoyang, Anshan, Panjin and Yingkou. The project is divided into seven contracts. Three TBM contracts comprise almost 75% of the work and the others are drill and shoot. The focus of this paper is about the creditable TBM performances achieved and some of the problems encountered by Chinese contractors; notably two having had no previous TBM experience.

Jan 1, 2007

By O. I. Ostrovski, D. K. Belashchenko

The aim of this paper is the construction of models of systems with ionic and ionic-covalent bonds (molten salts) using experimental diffraction data and the calculation of their structure and thermodynamic and transport properties. Modelling was performed using algorithm BELION, in which the non-coulomb part of interaction potential between ions in the model was determined by the method of iterative simulation which targeted agreement between calculated and experimental partial pair correlation functions (PPCFs). The ionic charges in salts, which can be fractional, were determined by minimization of internal energy. In this paper, the algorithm BELION is applied for chlorides of alkaline-earth metals. Pair potentials, PPCFs, atomization energies, self-diffusion coefficients and electric conductivity are calculated. The charge of alkaline-earth metals was in the range of 2.0-2.1, slightly increasing from Mg to Ba. Partial pair correlation functions and atomization energies of models agree well with experimental data for MgCl2, SrCl2and BaCl2. Keywords: molten salt, molecular dynamics, partial pair correlation function, ionic charge, atomization energy, diffusion.

Jan 1, 2004

By H. Warlimont

In recent investigations of the microstructure and crystallographic features of martensite by electgon microscopy,', '9 thin films (about 50 to l000A in thickness) have been used as specimens. It was found by W. Pitschl ,2 that the lattice relationships between the supefiaturated fcc matrix and the martensite formed in thin films were different from those observed after transformation in bulk material. Corresponding differences are to be expected in nucleation and in reaction kinetics in the formation of martensite in thin films, but have not yet been reported. In the course of the preparation of thin films of iron-base alloys for investigation by electron microscopy it was observed that films of alloys, whose martensite formation temperature (Ms) was below room temperature, formed martensite during the electrochemical thinning process conducted at or above room temperature. The chemical compositions and approximate bulkM,-temperatures of the three materials on which this observation was made are listed in Table I. The alloys were vacuum-melted from high-purity metals. It can be seen that the effect occurred in alloys that contain only sub-stitutional components as well as in alloys that contain carbon as an interstitial solute. The appearance of martensite formed in this manner is illustrated in Fig. 1, which represents a polished film of alloy No. 1 at XI0 magnification. The martensite plates can be recognized by their surface relief effects. In addition, heavily strained (owrinkledo) austenite can be seen near the edges of the film where it is thinnest and transformation stresses or strains can be accommodated by plastic deformation most easily. The nonuniform distribution of transformed regions is probably due to the varying thickness of the film. These observations were common to all materials listed in Table I. Because effects of supercooling or straining can

Jan 1, 1962

By A. Thielen

In experiments for the production of steel the principal problem has always been the introduction into, or removal from, the iron of a definite quantity of carbon. Although the solution of this problem had engaged a more or less blindly and empirically directed effort for a long time, it was only with the development of analytical chemistry that the rôle which carbon plays in the constitution of steel was disclosed in its full significance, and that many of the problems confronting the steel-maker were thereby more clearly defined than before. For a long time, and to a certain extent even to this day, the percentage of carbon in steel has been the controlling means of deter mining its quality and hardness. In many cases the percentage of carbon alone has been relied on for judging large consignments, such as the large deliveries of wire-billets and blooms to America during the past twenty years; and though to-day the influences of the other constituents are recognized and many other considerations are taken into account, and though, moreover, some special steels, such as the Hadfield manganese steel, apparently dispense to a certain extent with the assistance of the carbon, yet fix our Bessemer, Thomas, Siemens and crucible steel the carbon still remains one of the most important constituents, and I venture to say it is indispensable. In order to produce in the Bessemer converter a steel of a certain required percentage of carbon, two methods, as is well known, present themselves. By the one the decarburization process is stopped when the desired carbon limit in the bath has been reached ; by the other the bath is completely decarburizecl, and then a calculated amount of carbon added in the form of spiegel, ferro manganese, etc. In Germany the latter method only was adopted, and it was retained when the Thomas-Gilchrist process for the production of low-Phosphorus steel from high-phosphorus iron eame into use, since from the nature of the new process complete decarburization is neces-

Jan 1, 1891

By D. François-Bongarçon

When it comes to sampling theory, a bad sampler is a bad sampler, no matter what, and a sampler is either bad or good. It also is of critical economic importance to tell and understand the difference, especially in a metallurgical plant. In this paper, the grand principles of Sampling Theory are first recalled, then the most popular types of sample cutters for plants are critically reviewed. It is concluded that the industry has a lot of progresses to make in that direction, although improvements usually pay for themselves very quickly.

Jan 1, 2002

By Donald James Butler

Problems resulting from underground mines in three inactive mining districts in Colorado were investigated. The purpose was to determine how these problems could be reduced or eliminated in new closings -- essentially by benefitting from lessons of the past. Mines in Leadville, Westcliffe and the Cripple Creek-Victor districts were evaluated. Two basic types of problems were found to exist in the districts: environmental degradation and hazardous conditions. Environmental problems result largely from acid and toxic drainage from the runes and from leaching of surface waste rock piles and mill tailings impoundment. The acid drainage contributes high levels of metals to streams and deposits sediment in the stream bottoms. Erosion of waste piles is a lesser problem. Hazardous conditions from open or improperly sealed mine shafts and adits, mine subsidence pits, and from deteriorating and unsafe surface structures are common to the three districts. These problems become worse with the ravages of time and vandalism. Engineering solutions which would correct or reduce many of these problems are presented. These recommendations should also be applied to new mine closures, however, more basic changes are needed to effectively implement improved mine closures. The changes must take place in the areas of legislation, mining practices and education. Legislated regulations should realistically reflect the needs of both the mine operators, protection of the environment and the best interest of the general public. Benefits should be provided for compliance with regulations instead of penalties being assessed for noncompliance. Hazardous conditions and environmental problems associated with mines can be alleviated through improved mine design and effective cloning procedures. Education should provide an appreciation by the general public of past and present problems facing mine operators. This will result in an improved mining climate which, in turn, will insure a continuing supply of minerals to meet increasing needs.

Jan 1, 1983

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. (a) In-shaft equipment design and specification criteria are considered as they influence guideline preparation. (b) A comprehensive review of hoist electric drives and controls as applied to mine hoists is set forth with special reference to duty cycle calculations and their effect on electrical component selection.

Jan 1, 1988

By E. R. Maize

This report is the third of a series on convergence of roof and floor in coal mines and subsidence of surface that accompanies it. The first papery dealt with extraction in a mechanized mine (Montour 10) having relatively short rib lines that retreat rapidly. The second 6/ dealt with extraction in a mine (Crucible) in which coal was loaded by hand and in which the rib lines were long and slow-moving. The present report deals with a mine (Gibson) in which conditions approximated those in the Crucible mine, except that the distance between room centers was considerably less and the pillars were narrower in consequence. Moreover, the average cover was less and the studies were made under the steep hillside of a stream valley compared with a gently rolling surface over the portions of the second mine studied. Gibson mine lies in the east-central part of Washington County, Pa., approximately midway between the Montour 10 and Crucible mines on a north-south line. A cooperative agreement covering the work was made with the Hillman Coal & Coke Co. through W. L. Affelder, vice president. This paper describes the methods used in the investigation, gives excerpts from the data obtained, and offers such generalisations as appear to be justified.

Jan 1, 1940

By J. Nielen van der Merwe

This investigation was done to develop a method to predict the lie of coal pillars. It has long since been known that coal pillars deteriorate over time, but there was no method to quantify the deterioration. It was found that the rate of pillar deterioration was essentially a function of two parameters, namely mining height and time. The higher the mining height, the more rapidly the pillars deteriorated. The rate of deterioration is not constant, but decreases exponentially with time. The pillar life should be viewed in conjunction with the safety factor. While the relationship between safety factor and pillar life is ambiguous, the trend is nonetheless for higher safety factor pillars to have longer lives. The safety factor can be used to quantify a failure probability. The pillar life prediction indicates when the pillars which are predicted to fail, can be expected to do so.

Jan 1, 1998

Provide the U.S. mining industry with technology for designing environmentally sound, low-cost in situ leach mining operations to produce copper from small, deep, and/or low-grade copper oxide deposits. Approach Investigate the feasibility of a new mining method--in situ leach mining-as an alternative to conventional mining for copper. Study fundamental leaching technology that will facilitate future commercial operations. Develop guidelines and procedures that will enable mine operators to design and evaluate in situ leach mining operations for any specific copper oxide deposit.

Jan 1, 1989

By Lance A. Roberts

Expansive soil formations can be found throughout the United States. When subjected to wetting, these formations have the potential to swell and exert large uplift forces on buildings and foundations. Lightly loaded structures, such as single family residences founded in areas of expansive soils, can be significantly damaged due to uplift movement from swelling actions. Designing an economical deep foundation that can resist uplift forces is critical to prevent damage to these structures. The current solutions to control uplift due to swelling soils, such as over-excavation and replacement of the expansive material or the use of drilled shafts can be costly. Piles made from recycled polymer materials could provide a solution. Due to a lower coefficient of friction along the interface of the soil-pile interface compared to traditional pile materials, solid recycled plastic piles can allow expansive soils to move nearly independently from the pile when wetted. This results in a much smaller magnitude of uplift force being transferred to the structure, which minimizes the risk of significant structural damage from excessive movements. This paper presents the results of research conducted on the use of recycled plastic piles in an expansive shale environment. The preliminary phase of the project involved the installation of six recycled plastic piles at a test site on the South Dakota School of Mines and Technology campus. Two of the piles were subjected to a full-scale compression load test in order to determine ultimate capacity. The remaining four piles were subjected to long-term monitoring of uplift movement during the course of the project. A concrete anchor was also installed at the test site for uplift monitoring. Data gathered during the field and laboratory testing was utilized in a non-linear soil-structure interaction model to predict the displacement behavior and internal stresses within a plastic pile and concrete anchor subjected to uplift forces from the swelling shale. While more research is needed to further understand the application for recycled plastic piles, the results from this research indicate that their use is a viable alternative for support of lightly loaded structures in expansive soil environments.

Jan 1, 2010

On the more important mines it is almost essential to have a general plan of the surface. A special feature of this plan should be the indication thereon of a suitable arrangement of contour lines, either wholly over the surface of the property or at parts where may seem most useful. The importance of having these contours marked on the plan will be best appreciated by the engineer, in selecting the best available site for a proposed new plant, in locating a tramway, in connecting the surface with the underground workings to the best advantage, or in solving many similar problems that come within his province. The closer the contours are together vertically the better, the limitation being the trouble and expense of getting them on to the plan. They may range from five to fifty feet apart but a distance of ten feet will be found, in most cases, to be the most useful.In deciding the datum level from which these contours are to be measured, it is best to depart from the ordinary sea level datum, and use instead the highest available point on the property. This datum will be called zero and all levels will be reckoned so many feet below it; thus by a contour marked 160 on the plan, it will be understood that the level of the plane of the contour is 160 feet below the highest available point on the property. This system of measuring levels downward is readily suggested from measuring the depths of shafts from the brace or of excavations from the original surface.

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to all aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, and Treasury, and the Central Intelligence Agency, whose primary mission is the collection of data in non mineral subject areas, but in which the mineral industry is a component.

Jan 1, 1982

By K. Ding

The thermodynamic activity of MnO was measured in MnO-CaO-MgO-SiO2slags that are typically encountered in the production of manganese containing stainless steels. Gas equilibration-quenching technique was employed in measuring the activities. Activity of Mn in Pt-Mn alloys were redetermined at 1600°C which reconfirmed earlier results of strong negative deviations. MnO activities were then measured by equilibrating slags of various compositions based on a statistical experimental design procedure with Pt-Mn alloys under controlled partial pressure of oxygen in MnO saturated platinum crucibles at 1600°C. Activities of MnO were found to increase with increasing concentration of MnO, basicity and CaO to MgO ratio. Two multi-coefficient repression models were developed to predict the activities and activity coefficients of MnO in slags at 1600°C. Keywords: activity, MnO, slag.

Jan 1, 2004

By D. Zhou, T. Hamano, Tsukihashi. F., W. -G. Seo

The thermodynamic properties for the CaO-CaF2and CaO-BaO systems were calculated by molecular dynamics (MD) simulation using Born-Mayer-Huggins type pair potential. The parameters of interatomic potential were obtained by fitting the thermodynamics properties of CaO, CaF2and BaO with the experimental data. The phase diagrams for the CaO-CaF2 and CaO-BaO systems were calculated by the thermodynamic properties obtained by MD simulation. The eutectic composition and temperature of the CaO-CaF2system calculated by MD simulation were about 28 mole per cent CaO and 1575K, respectively. The calculated eutectic point agrees very well with experimental data, which are about 22 mole per cent CaO and 1633K, respectively. Keywords: molecular dynamics simulation, thermodynamics, phase diagram, calcium oxide, calcium fluoride, barium oxide.

Jan 1, 2004

By Masaki Kitazume, Yoshiaki Kikuchi

"Abstract Pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The deep mixing method, an in-situ admixture stabilization method, was developed in 1970s in Japan and the European countries, and has been frequently applied to many construction projects for various improvement purposes such as increasing bearing capacity and horizontal resistance, reducing ground settlement, preventing liquefaction and so on. The design methods, execution procedure and quality control and assurance (QC/QA) of the method are standardized or specified in many countries. These standards, specification and/or technical manual have been a remarkable contribution to spread the techniques throughout the world. The QC/QA is one of the major concerns for clients and engineers who have poor or no experience of the technologies. In order to assure the high quality of deep mixing work in the global market, it is necessary to establish the concept of QC/QA and correlate the output of different procedures. Upon the request by the organizing committee of the DFI-EFFC International Conference on Piling & Deep Foundations, the authors conducted survey of the specifications and standards on the piling and deep mixing technologies in Asian countries. In this manuscript, the results of survey are briefly introduced by comparing these specifications and standards.IntroductionThe pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The design method, execution procedure and quality control and assurance of pile foundations are standardized in many countries based on the accumulate research results, laboratory and field experiences. In Japan, steel pipe piles are mainly constructed by hammer driven in port construction. On the other hand, precast pre-stressed concrete piles or cast-in-place piles are mainly used in on land construction. When precast pre-stressed concrete piles are constructed, piles are usually set by inner excavation method because of preventing noise and vibration problems. More than 50 years ago, noise and vibration problems had not been serious problem in Japan, but around 50 years ago, they became serious and now less noise and vibration construction methods are used for pile construction on land in Japan. In Asian countries, though piles used for construction have a lot of variety, precast pre-stressed piles are commonly used. In this report, execution controls of construction methods of steel pipe piles and precast concrete piles are mainly considered."

Jan 1, 2014

By Sheryl D. Gallagher

The project consisted of filling an abandoned underground limestone mine to facilitate construction of a new entrance ramp to I-470 in Lee?s Summit, Missouri. Due to collapse of mined areas near the project site, design included determination of the limits of remediation for the project and minimum construction requirements for mine infilling. The Judy Company, contractor selected for the mine infilling, experimented in the laboratory with several grout mixes to determine the appropriate mix for the project. Infilling was accomplished from the ground surface, and camera observation was used to monitor the barrier wall construction and infilling process. It was discovered that some of the mapped rooms were larger and some were smaller than indicated on the construction plan.

Jan 1, 2009