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By S. Hicks

This technical note describes an alternative procedure that can be used in linear programming calculations where the compliance limit of lbs SO2/million Btu for the blending coal is subject to change. Dr. Mateer in his technical note titled "Coal blending for sulfur compliance" (ME, September 1994, p. 1103) defined an "excess sulfur" parameter that provides a valid constraint equation for a linear program optimization. The coals used by Dr. Mateer in his examples are shown in Table 1. To create the parameters for the constraint equations to blend to an SO2 content of 1.2 lbs SO2/million Btu, the excess sulfur for Coal A was defined as Sulfur excess% = 0.5 - 0.6*13,000/10,000 = -0.28 This equation was used to create the constraint equation -0.28A + 0.44B + 1.36C[<] 0.0 Another way to create the parameters for the constraint equation is given below. In these equations: •W is the total weight; •A, B and C are the fractional proportions of each potential blend stocks; •Sa, Sb and Sc represent the percent sulfur content of the blend stocks; •Ha, Hb and Hc represent the calorific content of the blend stocks in Btu/lb; and •H and S represent calorific and sulfur contents of the composite blend. The weight of blend to produce one million Btu is [ ]

Jan 1, 1998

By William R. Sharp

This paper describes a graphics station and graphics software designed specifically for use within the minerals industry. Through the graphics station, a user is able to recall maps for modification, display them on a color CRT, send the work to a plotter, and restore the work when finished. The engineer may use the system for the storing of data, per- forming engineering calculations, doing word processing, and performing general file maintenance. In addition, the system may be used to communicate with a mainframe computer for such purposes as: transmission of large data files, graphic 3-dimensional rotation of a mineral deposit or mine design, contouring of spacial data, and other data processing work.

Jan 1, 1982

By Michael J. Pyrcz, Clayton V. Deutsch

Strategic project decisions are based on the distributions global variables, for example, total mineable resource, or recoverable oil volume. These global variables distributions are very sensitive to the input one point statistic, that is, histogram and rock type proportions. Representivity in the one point statistic retains significance in all spatial models. Spatial sampling bias and nonrepresentative sampling complicate this process of building representative one point statistics. This work outlines the cause of bias, the inability of standard declustering to correct for this bias and two methods for correcting bias in the one point statistics: "trend modeling for debiasing" and "debiasing by qualitative data". An example is presented of each technique based on a poly metallic data set.

Jan 1, 2002

By V. Srajer

Several optimization approaches used by the Canadian mining industry were used to investigate surface coal mining operations in Canada. A computer program was applied to optimize truck/shovel systems and for various analyses. The analyses of eight western Canadian coal mines included investigation of fleet imbalance, under- and over trucking, development of the criteria for automated truck control, comparison study of various haulers and loaders, haulage layout, driving conditions, machine performance, servicing and maintenance policies, etc. Each property investigated supplied background information for the study and cooperated in optimization studies. The truck/shovel system optimization study is demonstrated as a test case to outline procedures and step-by-step instruction for similar applications.

Jan 1, 1989

By Robert A. Hains, William P. Balaz, K. Payne

Ceramics are usually used to line chutes, pipes, dust collectors, separators, cyclones or bins where abrasive or corrosive material is moving. Improvements in ceramic manufacturing methods and quality, use of other abrasion resistant materials in combination with Alumina ceramic, improved adhesives and installation methods allow the use of Alumina ceramic tile in applications with impact. This paper discusses the criteria to determine if ceramics can provide a cost effective alternative to other liners for abrasive material handling applications, design parameters for liner systems, system costs, and case histories. The goal will be to provide a practical guide for improving the performance of existing ceramic lined systems or determining if ceramics is a cost effective solution for your abrasive material handling applications.

Jan 1, 1996

By Thomas C. Wilder, Firoze E. Katrak

As part of a survey on the long range supply of gallium, a comprehensive review of the chemistry of commercial gallium extraction was undertaken Owing to its very small concentration in all commercial minerals, gallium can be produced economically only as a by-product of major extraction processes for other materials. A summary is presented for the chemistry of gallium extraction from many of these process streams included are several procedures for gallium recovery from bauxite, currently the most prevalent source Other processes described are from waste streams from the production of zinc, phosphorus from phosphates, aluminum from kaolin clays, and from coal ash, the largest potential resource A brief review of development of solvent extraction as a unit process for gallium recovery is also presented

Jan 1, 1983

By T. V. Vasudevan

Floc properties such as density, size, size distribution, porosity, and shear strength govern the effectiveness of flocculation as a process for solid-liquid separation. The floc characteristics desired for removal of suspended solids by sedimentation or filtration, for example, are known to he different. In this study, an attempt has been made to evaluate the effects of various physical and chemical factors on the density and shear strength of the flocs.

Jan 1, 1990

By Ronald J. Doll, John Elkin, M. P. Evans

The application of "Alignment Free” right angle shaft mounted drive systems offers improved reliability and reduced costs for surface and underground belt convey- ors. Comparisons to conventional approaches will cover installation, operating, maintenance, and spares inventory cost savings. Various options for belt acceleration and load control on fixed and variable length (booster) belt conveyors will be reviewed for operating performance, reliability, and total cost. Lastly, a case study of a successfully operating installation will be highlighted.

Jan 1, 1996

If a fire occurs outby an underground coal mine section, the immediate safe evacuation of miners from the working section should always take precedence. Unfortunately, in many cases, the dedicated escapeways (escape routes) for the evacuation of the miners become contaminated by the byproducts of fire from the adjacent entries. The purpose of this paper is to present the ventilation-control process that would keep the escapeway free from contaminants and, thus, available for travel. A few scenarios of mine fires in longwall development panels are analyzed and discussed. To perform these studies, a mine fire simulator (MFS) was used. This (MFS) provides a dynamic representation of the fire&apos;s progress (in real time) and gives a color-graphic visualization of the spread of oxygen, combustion products and temperature of the gases throughout the ventilation system. Also presented and discussed are ways in which the MFS can be used as a training and teaching tool for miners and, particularly, for ventilation and safety specialists.

Jan 1, 1997

By D. G. Mirakovski, B. Krstev

The paper presents models of auxiliary ventilation systems with leaky ducts and algorithms for calculations of pressure loss, air leakage, and volume flow ratio and pressure fans. Two basic models are discussed: 1st model for a duct with leakage through the flange joints; 2nd model for a duct with an equivalent longitudinal aperture. The present analytical system has been successfully applied to developing of computer software named DAVentS. A. sample problem is used to illustrate efficiency and accuracy of DAVents software in solving most common problems in process of designing AVS.

Jan 1, 2002

By A. W. Swanson

Iron carbide, containing 93.3% Fe and 6.7% C, is a tailor made feed for the electric arc furnace (EAF) and has recently gained worldwide attention as a possible replacement for premium quality scrap. With 38% of the steel in the United States being produced in EAFs, iron ore producers have an interest in becoming direct suppliers to the EAF industry. This paper explains the advantages of using iron carbide in an EAF and describes test work on the product and development work being per formed on engineering designs for a commercial plant.

Jan 1, 1994

By D. R. Zhu, H. S. Chiang, Y. M. Jiang, S. S. Peng

Two types of underground tests on three types of shield supports, 2-leg, 4-leg, and chock shield, were con- ducted to measure the horizontal movement of the canopy against the immediate roof. In no friction tests, steel rollers were placed between roof and canopy top, while in friction tests normal direct contact was used. Results indicate that the canopy for 2-leg shields always moves forward during setting, whereas there was no forward movement for 4-leg or chock shields. Based on the test results, a model for active horizontal force was proposed.

Jan 1, 1990

By T. D. Rourke, E. J. Cording, O&apos

INTRODUCTION Detailed investigation of a 60-ft-deep excavation in a mixed profile of sands and stiff clay was performed by the University of Illinois for the Washington Metropolitan Area Transit Authority (METRO). The work was coordinated through DeLeuw, Cather and Co., the General Engineering Consultant of METRO. Instrumentation was concentrated in a portion of braced excavation for the Gallery Place Station near the intersection of 7th and G Street. The early construction date, the 60 ft depth of cut, and the proximity of large buildings formed the basis for selection of this site as the focal point of observation and measurement. A history of lateral and vertical displacement is provided wherein movements which occurred during excavation to the full depth of cut and, subsequently, during station construction and the removal of braces are described in detail. Observations of preloading and the consequent brace loads and wall displacements are described. The effect of temperature change on brace loads is discussed and the measured apparent earth pressure for the 60-ft cut is provided. The paper discusses the relationship of lateral displacements of the cut wall to the construction procedure, and compares the lateral wall displacement with both lateral and vertical movement in the surrounding soil mass. Based on observed movement, the method by which displacement was predicted for a nearby 82-ft-deep excavation is described. The performance of the 82-ft-deep excavation has been summarized elsewhere (2).

Jan 1, 1974

By T. O. Price

In 1969 Holosonics designed and developed a portable system for conducting acoustical surveys in metal mines, with lead-silver veins as the principal targets. Recently this system has been proven useful in describing rock structures for advance geologic information in civil engineering application and underground construction applications. This paper discusses a case history of acoustical surveying from a series of pilot drill holes in an advancing tunnel. In acoustical surveying a pulsed acoustic signal is used to generate reflected signals from the rock formation. Arrival time, amplitude and phase of the returned signals can be determined. These data became the basis for a signal correlation program designed to relate the signals to their respected pseudo-planar reflecting interfaces. An application of acoustical surveying has recently been conducted in a portion of the excavation for the Washington Metro Area Transit Subway. The data results and conclusions of the program are discussed in the paper. Acoustical surveying was successful in predicting the occurrence of major jointing and foliation plane shearing ahead of the tunnel advancement.

Jan 1, 1974

By K. Valta

This paper presents an approach for developing a Sustainable Development Indicators (SDIs) framework tailored to the Greek Industrial Minerals sector, due to its importance for the national economy. To achieve this goal, an overview of the Greek mining and minerals, and especially the Industrial Minerals sector, from a technological and a financial perspective, is presented. In addition, a brief description of the global initiatives to this direction is given. The proposed indicators are based on those presented in 2006 by the Greek Mining Enterprises Association (GMEA) adjusted for the sector of industrial minerals by taking into account economic, environmental and social issues, known as the Triple Bottom Line (TBL) approach.

Jan 1, 2007

The development of a successful restoration strategy for any drastically disturbed site is dependent upon a thorough understanding of the chemical properties of the spoils or mining wastes that need to be stabilized. The majority of revegetation research in the USA has been conducted on coal mining spoils and coal preparation wastes, and this paper will focus on these two materials and their modification for plant growth and water quality protection. Potential acidity derived from the oxidation of pyritic (FeS2) materials is the most important chemical factor that must be estimated and managed, but physical properties such as severe compaction or excessively low water holding capacity are also very limiting. Conventional soil fertility tests are very difficult to interpret for mine soils because of their tendency to extract elements from fresh, unweathered surfaces that are soluble in the extract, but not plant-available. A wide array of waste products such as sewage sludge biosolids and coal fly ash are readily available for use as mine soil amendments, but their utilization must be carefully matched against the needs of the post-mining plant community and their potential water quality impacts.

Jan 1, 2002

This paper discusses how the link between design software tools and recycling models can be established in order to predict the recyclability of the car during the design phase, as well as to be able to apply design for recycling on a solid technological basis. Due to the complexity of the design of the car, optimisation of recycling can only be realised based on a sound technological basis, in which the dynamic and statistically distributed parameters affecting the recycling rate are described and understood. This paper gives a brief overview of the dynamic and recycling models, which are developed for optimisation of the recycling of the car and the calculation of recycling rates of the car in the design phase in view of EU legislation. Moreover the possibilities for modelling of shredding and liberation within the recycling system are discussed. The performance of experiments on a fundamental basis in order to collect statistically correct industrial data, supported by a closing mass balance, is referred to on the basis of a large scale industrial recycling experiment. It will be shown how design for recycling and environment can be supported by the sophisticated models as developed by the authors.

Jan 1, 2005

By D. R. Baughman

Copper oxide deposits that may be considered for in situ leaching exist in unique geologic settings, different from uranium deposits. A large number of interrelated factors must be considered in wellfield design. Many of these factors are hard to quantify and are directly related to geologic features of the orebody. This paper discusses some of the important factors in wellfield design and suggests an outline for a design procedure.

Jan 1, 1988

By Graham E. Rawlings

Geotechnical investigations for underground projects are subject to a variety of constraints, including factors such as accessibility, geological complexity, thickness of oberburden and finance. As a result, the extent of geological data available for route selection and assessment of underground design and construction problems may vary between wide limits. It is essential that the data collected, the degree to which it is representative, and the confidence with which the problems can be anticipated, should be reflected in the type of contract set up and the way in which the contract documents are written. The paper addresses the methods by which investigations can be focussed to make suitable overall ground assessments for feasibility level studies. Subsequent investigations can then be objectively directed toward obtaining data on specific geotechnlcal problems or aspects which impact tunnel, cavern and shaft design and construction. The extent of investigations at the preliminary and design engineering stages must be closely related to the geotechnlcal surveillance and control during excavation. Fixed-price contracts necessitate a secure geotechnical data base prior to bidding, and the provision of that to the tenderers. By contrast, &apos;design-as-you-go&apos; contracts minimize the geotechnical information needed before construction, yet require immediate assessment of the excavated ground for determination of support requirements and payment category.

Jan 1, 1983

By J. Loredo

Asturias, in northern Spain, emits 18 Mt CO2/year to the atmosphere, which supposes the biggest industrial CO2 emissions in the country. In order to avoid CO2 emissions to the atmosphere, keeping the availability of energy from fossil fuels, background studies focussed to the selection of favourable sites for CO2 geological storage are necessary. In Asturias, the options for CO2 geological storage are sequestration in deep saline aquifers or sequestration in unexploted coal beds. In the area, there is the biggest coal basin of the country and a great Palaeozoic sedimentary basin with appropriate silicoclastic or carbonated reservoirs and impermeable caprock for CO2 geological storage, located in proximity to thermoelectric power plants and other sources of CO2 emissions. All evidences suggest that CO2 storage in deep aquifers is the most interesting option but a legal planning and a technical regulation are still to be done. The possibility for CO2 sequestration in coal beds is modest and associated to the CBM commercial exploitation. It is necessary to have in mind that the feasibility of CO2 geological storage in Asturias apart of technical factors will depend on price of CO2 ton, legal conditioning and possibility to apply emission rights to projects.

Jan 1, 2006