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By Robert J. Clarke

Reflections on over ten years experience handling bituminous coal from railroad cars to ground storage and lake vessels. The arrangement of the facilities is described but the basic theme of the discussion is the experience gained and lessons learned from facility operation. The Great Lakes provide the maritime environment for the economical transport of vast quantities of raw materials from their source in the Upper Lakes (the Mesabi Range, for instance) to Lower Lake Ports. Lake Erie, because of its proximity to the steel centers , blossomed with the great ports that now line its southern shore - Toledo, Sandusky, Lorain, Cleveland, Huron, Ashtabula, Conneaut and Erie.

Jan 1, 1981

By B. Denby, D. J. McMlarnon

During the ongoing research into the possible applications of Virtual Reality in underground operations, the AIMS Research Unit has developed a user-interface driven program which enables a user to input the geometry of underground mines, and add equipment and working processes in order to produce an accurate simulation of their operation. This paper describes the main features of this system (VR-MINE). Virtual Reality is a field which has grown out of three dimensional computer graphics techniques, and allows a user to move freely around a model held within the computer's memory. Movement around this model is carried out by the use of intuitive peripherals such as joysticks, with the user's view from their position within the model being produced in real time on a computer monitor or other device (such as a headset). This enables a user to interact with any three dimensional model and see the results of their actions immediately. VR-MINE is broken into two separate programs, both running under Microsoft Windows 3.1 or above. The first, the editor, allows the user to develop the mine layout and add equipment and personnel. The mine geometry is considered to be made up of various types of objects, for example a straight roadway segment which can be inclined, a junction roadway segment, and a turning segment. The geometry can then saved into a file to be loaded in by the second program of VR-MINE, the viewer. This generates a real- istic representation of the mine, with undulating floors and walls. It also has the ability to display multiple windows on the mine at the same time, which are arranged interactively. The simulation occurs within this program, with the user traversing the model in real time to examine possible areas of improvement in operations. This paper gives a number of examples of how the AIMS Re- search Unit has applied this technology to a range of underground mining scenarios to improve the safety of workers in the under- ground environment. The application discussed include computer graphics and Virtual Reality systems to training, risk analysis, visualisation, simulation, accident investigation and major hazard planning.

Jan 1, 1996

By G. Swiatnicki, w. Chruscielewski, T. Domanski

INTRODUCTION The inherent errors of simple passive track detectors /SPTD/ used for estimation of exposure to the radon daughters /RnDP/ amount to about 30% /Do75/ while for active detectors only reach about 3 - 4% /Ph78, Du79/. The large error inherent in SPTD is the result of strong dependence of its calibration coefficient on the equilibrium Rn RnDP in the vicinity of detector /0r80/. Nevertheless the SPTD shows many advantages and seems to be very useful for to the estimation of individual exposure of miners to RnDP /Do81a/. For this reason the investigations are undertaken to improve SPTD so that it might provide information about the equilibrium Rn : RnDP during exposure. If the equilibrium would be known then one could use a suitable calibration coefficient yielding a better precision of the measurement. So far, some investigations of the improved type of SPTD have been conducted. One was based on the concept of using the so called diffusion barrier permitting to differentiate the tracks originating from Rn and RnDP /Fr77/. Such improved detector has been named a passive differentiating track detector /PDTD/. However, own investigations have shown /Do81b/ that this type of detector cannot provide precise informations about equilibrium Rn : RnDP. For this reason the investigations of the new idea of PDTD have been carried out. The new model presented below is based on the use of the absorbers of alpha particles. THEORETICAL CONSIDERATIONS The first variant of the concept is as follows: The differentiating detector consists of two portions of detective foil /track detector/ but only one is covered with an aluminium absorber. Thickness of the absorber is carefully selected so that only RaC' particles /7.7 MeV/ can pass the barrier. The second portion of the detective foil records all alpha particles originated from Rn and RnDP i.e. works like a SPTD. The scheme of such a detector, the so called two-fields passive differentiating track detector /PDTD-2/ is shown in the Fig. 1. It is possible to introduce a parameter that can characterize the equilibrium Rn RnDP, namely, the so called track density ratio /TDR/. The definition of this parameter for the considered type of detector is TDR2 = D1•D2-1. One can expect the simple proportion to hold: [ ]

Jan 1, 1981

By Dipl. -Ing. H. -J. Sager

The ‘Westerschelde Tunnel’ underpasses the estuary of the Schelde in the Netherlands. The tunnel will consist of two tubes which are driven by two hydroshields (slurry shields). The tunnels will each have a length of approx. 6.6km and a bore-diameter of 11.33 m. Demanding ground conditions had to be considered during the design of the shield machines. Loose sands, extensive clay formations and high ground water pressures of up to 6.5 bar will be encountered during the tunnel drive. The tunnelling activities will start in the middle of 1999 and are scheduled to end by the end of 2001.

Jan 1, 1999

By Peter G. Chamberlain

Novel and innovative mining methods are attracting the attention of mining engineers at an unprecedented level. Historically, the US mining industry has responded rather conservatively to new technology. The financial difficulties affecting the domestic mining industry in the early 1980s changed attitudes toward new technology. The market contraction during that period, coupled with an expanding world mine capacity, created a serious oversupply of many raw mineral products. Many mining companies found that retaining a share of world markets while making a profit required drastic cost-cutting measures.

Jan 1, 2008

By Somia Gurunathan, Harry Castrantas

Hydrogen peroxide and calcium peroxide are used to improve the extraction of gold/silver and reduce cyanide consumption in heap leaching and mill leaching operations. FMC's standard grade H2O2 and FMC's Permeox™ solid peroxygen, a formulated product containing cao2, was used for the experimental work. It was found that the rates of release and the longevity of these peroxygens in ore-cyanide mixtures are significantly different. When choosing a peroxygen, one of the key factors is extrac­tion time, with the longer extraction times of heap leaching primarily favoring calcium peroxide and the shorter extraction times of mill leaching primarily favoring hydrogen peroxide. A series of laboratory leach tests showed the choice between H2O2 and CaO2 to be ore and process specific. H2O2 and/or Permeox™ improved the gold extraction in four out of five ores tested. (2 sulfide and 2 oxide). Mixtures of H2o2 and Permeox™ were also found to significantly increase the gold extraction rate. A fifth ore (sulfide) did not respond to peroxygen treatment. In addition, savings in NaCN consumption was obtained with Permeox™. Both peroxygens offer economic incentives to gold processing.

Jan 1, 1992

By C. A. Fleming, K. W. Sarbutt, P. K. MacPhail

The SART process has been developed for Teck to treat bar­ren solution from the cyanidation/CIP process that has been developed for the Lobo-Marte project in Chile. The objective of the process is to recover cyanide in a form that is suitable for recycling to the leaching part of the process. The Marte and Lobo ore bodies require a dosage rate of about 2 kg/t NaCN, of which only 0.5 kg/t is truly consumed (as thiocyanate, cyanate and ferrocyanide species). The remaining -1.5 kg/t is present as cop­per cyanide (-1 kg/t) and free cyanide (-0.5 kg/t), and is poten­tially recoverable and recyclable. SART is an acronym that describes the unit operations in this cyanide recovery process; namely, .. Sulphidization .. Acidification .. Recycling of precipitate " Thickening of precipitate The basic chemistry has been applied previously, and has also been the subject of two patents (American Cyanamid Company, 1965, Potter et al., 1986). The process involves the conversion of all free and WAD cyanide in solution to hydrocyanic acid by acidification of the tailings solution to pH :s,4, and the conversion of all copper in solution to cuprous sulphide (synthetic chal­cocite) by the addition of a sulphide salt:

Jan 1, 1998

By Clarice L. Amaral, Ricardo Melamed

Clay-coating has been used as an environmental technology tool for the immobilization of toxic elements. The mechanisms of arsenate retention in clays suggest that not only the system pH is of fundamental importance in the process but also the character of metals and ligands that compose the electrolyte system. The goal of this study was to investigate the interactions between system pH and electrolyte ions on the retention of arsenate in an Oxisol soil. The sorption of arsenate decreases with the increase in system pH, reflecting the competitive sorption of arsenate with OH groups. Solutions containing Ca tend to favour the immobilization of arsenate in a relatively broad pH range.

Jan 1, 1998

By J. Moreno, P. Sinton, R. Vogwill

Groundwater models are often used to estimate and optimize dewatering volumes, locations, and rates, as well as water supply production for mines. Projections of future dewatering rates are highly dependent on the conceptual model used as a basis for the numerical model. This paper presents an audit of modeled dewatering rates versus actual data and an examination of the reasons for discrepancies. The setting is a gold mine, in a collapsed volcanic crater breached by the ocean. Mining will occur to about 200m below sea level within a remnant geothermal system. A detailed hydrogeologic investigation was conducted to support dewatering and geothermal depressurization design for future mining operations. These studies included development of a three-dimensional model to simulate heat and density-coupled groundwater flow, using software developed by URS/Dames & Moore. In this paper, the groundwater modeling results prepared 5 years previously by others was audited using operational dewatering data. This model was then extended using the new mine schedule and actual locations for dewatering wells to predict future dewatering requirements. In addition, a comparison between “hot” and “cold” model results was used to assess the need to use a heat-coupled versus a standard groundwater model for dewatering predictions.

Jan 1, 2003

By Kevin Sharman, Peri Mehling

A detailed assessment of acid rock drainage (ARD) potential was conducted at the Quintette Coal Mine site in northeastern British Columbia The site is unusual in that the coal seams contain low sulphur levels as compared to eastern coals (typically less than 0.5%), and the non-coal wastes generally do not to have the potential to generate acid on the basis of static ABA tests. The presence of small iron-stained seeps on the pit walls indicate localized sulphide oxidation, while the overall mine site drainage has remained of excellent quality with extremely low levels of metals after approximately 15 years of mining. Thus the site provides an excellent comparison to more problematic coal mine sites. For the Quintette assessment, static acid-base accounting (ABA) analyses of individual samples were compared to criteria for potentially acid generating materials developed for the U.S. Appalachian coal, as well as criteria developed in British Columbia for hard rock mines. Geologic units were characterized by the percentage of samples, or weighted thickness, that was deemed potentially acid generating (PAG). Links were then made to actual seepage and water quality emanating from geologic units around the site. Seeps at the site demonstrate a large range in pH (2.32 to 8.18). The few acidic seeps (pH < 4.0) were found to contain elevated levels of sulphates, dissolved iron, manganese and aluminum, consistent with the metals typically of concern in Appalachian coal mines. Other heavy metals that were detected in acidic seeps at Quintette included copper, zinc, nickel and cadmium. The use of simple ABA tests, and comparison of individual sample results with the Appalachian and British Columbia criteria, was found to be useful in predicting the probable sources of the small localized acidic seeps.

Jan 1, 2000

By C. McDonald, S. Slottee

Deep "paste" thickeners have been used in the alumina industry for several decades to improve chemical recovery and allow “stacking” of the red mud for disposal. These paste systems have eliminated many traditional tailings ponds in addition to providing better tails washing and better water recovery. This technology is not widely used or understood in other mineral processing applications. However, there is growing worldwide recognition of the advantages of concentrating mill tailings to a “paste”, i.e. a solid suspension that does not settle or segregate. This technology offers several alternatives to the traditional tailings pond such as “stacking” or mine backfill. More water recovery is possible than with high rate thickeners. Process benefits come in the form of better chemical and metals recovery through better washing in counter current decantation (CCD) applications. Obtaining a true paste (non-segregating suspension which exhibits a yield stress) and understanding the handling characteristics for applications outside alumina, are recent developments. Achieving all of the benefits available from a paste system requires careful design that takes into account the specific requirements of the disposal application along with the peculiar difficulties in producing and handling paste. In fact, design of a paste system is markedly different from a conventional system. Project design usually requires the cooperation of experts in several interrelated specialties including geotechnical, thickener design, pumping and discharge design and controls. A successful project must coordinate all activities to ensure that the overall objectives for the project are achieved. This paper describes the properties of paste, reviews the applications, and discusses the design of a complete paste deposition system.

Jan 1, 2003

By G. A. Dawe, E. G. Kelly

Because of the nature of the breakage in the Barmac vertical spindle impactor, the 80% reduction ratio is very small, so that when an energy efficiency is calculated from Bond&apos;s method, it appears to be very low. However, the product size distribution contains a high proportion of fines. It is argued that the production of these fines accounts for the high energy consumption, and Bond&apos;s method is modified to account for this, by considering the crusher to be, effectively, a number of smaller crushers in parallel, each having a different reduction ratio.

Jan 1, 1990

By C. Patrick, T. Combs

The purpose of this paper is to provide a method for analyzing the sequencing of mining production processes and predicting the effects of any planned changes. Included is a description of the development and utilization of a project-scheduling simulation that combines analytical scheduling with stochastic-activity durations. The simulation is demonstrated in two realistic examples: a longwall face-to-face transfer sequence and the effect of varying advance rates on longwall development sections. Statistical data that can provide a basis for more informed production decisions are generated in the form of project activity/path criticality and project-duration distributions. In both examples, a quantitative risk assessment, regarding subjective decisions in underground production sequencing, is presented.

Jan 1, 1996

By David J. Akers

INTRODUCTION The variety of uses of coal and the wide range of characteristics of coal combine to produce a need for a wide variety of laboratory analysis. Coal is used to heat homes, produce electricity, and make coke for steel manufacture. It can also be used to produce both gaseous and liquid fuels as well as a variety of chemical products. Various applications may require specialized analytical procedures. For example, some of the procedures developed for the coke industry, such as expansion or contraction during carbonization, have little value to the power generation industry. Even for a single application, the type of analysis needed can depend on the source and/or general nature of the coal. This section provides a general overview of the types of analytical procedures commonly applied to coal from the perspective of the user of this information, not the producer. The intent is not to detail laboratory procedures, but rather to discuss the application of commonly used laboratory tests in coal preparation. Accordingly, laboratory procedures are categorized by type of information produced. Gravimetric Analysis Procedures that produce weight-based information (parts per million, pounds per cubic foot, or weight percent). Such analyses can relate to the coal&apos;s physical, chemical, or mineralogical characteristics. Volumetric Analysis Procedures that produce volume-based information (amount of a mineral present as a volume percent). The primary source of volumetric information is from petrographic analysis. Application Tests Procedures that measure some characteristic of coal that has been empirically related to some application or handling or processing step. Typically, these procedures attempt to duplicate some aspect of the commercial application at laboratory scale and may produce information in the form of an index. Applications procedures do not measure a single component of the coal but infer the combined effect of multiple components. Each class of information is discussed in the order listed. References are provided as a source of more detailed information. The American Society for Testing and Materials (ASTM) publishes the most inclusive reference to analytical procedures. This publication,16 which is revised annually, provides extensive information concerning generally accepted methods of laboratory analysis. ASTM also provides standards for sampling and some information concerning sample handling.

Jan 1, 1991

By Y. H. Zhan

In beneficiation of phosphate ores it is common to use screening to produce the coarse "pebble" concentrate, and flotation to process the -1+0.1 mm size fraction. The -0.1 mm desliming product is treated as tailings. A new partially hydrophobic flocculant, P(MAAA) latex was developed to enhance flotation recovery of fine apatite particles through selective flocculation.

Jan 1, 2002

By R. F. Korcak

There exists a wide array of industrial byproducts that produce beneficial responses in the soil/ plant environment. These materials range from clean-coal-technology residues produced during the generation of electric power (particularly those high in gypsum) to mineral fines produced by the aggregates industry (i.e., sand, gravel and crushed stone). A number of these materials are examined in relation to potential nutritional interactions in soils and crops with emphasis on trace elements. The significance of utilizing these materials in agriculture as a component of sustainable agricultural systems are discussed.

Jan 1, 1997

By J. W. Merks

At mineral processing plants the accuracy and precision characteristics of assays in mill feed, tailings and concentrate largely determine the reliability of the metallurgical balance. The accuracy of measurements is ensured by selecting effective sampling methods and efficient sample preparation procedures, and by effecting each phase without introducing a systematic error while the precision of measurements is determined by the sampling regime. Sampling systems and components, sampling methods and regimes, and sample preparation procedures will be reviewed. Different techniques to determine variance components for sampling, preparation and analysis, and to detect systematic errors in assays at mineral processing plants, will be discussed.

Jan 1, 1986

By S. D. Thompson, L. Adler

This study reviews and analyzes the empirical methods available for designing the capacities of coal mine gathering belts. The analyses lead to recommendations concerning the application and implementation of each empirical method. Operations research techniques, mainly simulation models, are also briefly mentioned, and a few recommendations are made concerning their selection and application. The objective of the study is to provide a reliable basis for the practicing engineer to properly select, apply, and implement a capacity design method.

Jan 1, 1988

By R. Tanaskovic

Unfavourable climatic conditions in stopes are of significant economic and social importance due to the following reasons: - Working effect is much lower leading to decreased output and work productivity disregarding implementation of mechanization. - Manpower operating capability decreases much faster under unsatisfactory climatic conditions. Under normal climatic conditions a workman would expend much less effort in line with a shorter effective time for the achievement of identical production effects since the work would be more efficacious. The objective of study of problems and climatic conditions is to make the working environment in mines suitable for normal development of operations. Lowering of mining works to increasing depths and winning of a growing number of small orebodies over a broad area makes the problem of creating suitable climatic circumstances more complex. Mining costs are growing due to bench conditions in line with decreasing metal content in the ore, so frequently the investments required for creating favourable climatic conditions represent, in addition to the selection of mining technology, a very important parameter when making decisions regarding exploitation. As known, the basic factors affecting climatic operating conditions in mines-are: temperature, humidity and speed of air flow, implying that the climatic operating conditions are closely related to mine ventilation. Usually, the concept of unfavourable climatic operating conditions includes increased mine air temperature and humidity and low air flow velocity so that heat exchange between human organism and the working environment is impeded or reduced to minimum. Metal mines in Yugoslavia are characterized by the existence of a large number of active faces - stopes and horizons and lowering of mining operations to increasing depths, so that face ventilation solutions are more and more complex. Since its foundation (1961), our Institute is engaged in investigation of factors influencing climatic circumstances improvement of calculations for air distribution and distribution control in complex ventilation networks and study of problems related to ventilation of large volume and irregular configuration faces, as well as application of gained knowledge in our mines. The paper presents the knowledge and experience gained in the case of Lead and Zinc Mine "Trepca" - Stari Trg.

Jan 1, 1980

New South Wales (NSW) and Queensland dominate Australian black coal production and exports. NSW produced 86 Mt (95 million st) of saleable coal in 1994, a doubling of output since 1980. Asian demand for thermal and coking coal has driven this growth. This high Asian demand is expected to continue and NSW will seek to secure its share. History The history of the New South Wales (NSW) coal industry can be traced to 1797 when coal was first taken from Newcastle to Sydney (Ellis, 1969). At that time, NSW was a British colony, independent from the other colonies, such as Victoria and Queensland. Australia, as a federation of colonies, did not exist until 1901. The Newcastle coal industry grew through the 1800s in line with the growth of the colonies. Several events spurred demand for Newcastle coal. These included: ? The NSW and Victorian gold rushes of the 1850s and associated population growth. ? The development of steamship traffic at the expense of sail. ? The development of railways and town gas supplies. By 1900, Australia was producing 6.4 Mt (7 million st) of coal, most of it from NSW. By then, NSW had established strong export markets in Indonesia, China, Japan and New Zealand. The history of energy consumption is marked by continual competition, changing intensity of use and substitution. From 1900 to 1940, the Queensland, Victorian and Indonesian coal industries developed at the expense of NSW exports. Similarly, New Zealand developed its hydroelectric industry and thus declined as the largest customer for NSW coal. Oil replaced steam in the shipping and railway markets and electricity replaced gas for lighting. Industrial efficiencies also affected coal. Between 1928 and 1938, coal consumed in generating power fell from by 17% on a kilowatt hour basis and, during the same period, the amount of gas produced per ton of coal rose by 18% (Shaw and Bruno). Faced with these pressures, production and exports stagnated. By 1941, Australian black coal production was 14.2 Mt (15.6 million st). NSW&apos;s production was 11.7 Mt (12 million st), up only 19% from 1912. Exports had virtually ceased (Fig. 1). In such circumstances, the industry had lost focus. Unions resisted the need for mechanization, for security of employment reasons, and owners were loath to invest. This reluctance to mechanize and the associated in-

Jan 1, 1997