Search Documents

By G. L. Brooke

At present, there are two known cobalt deposits in the 48 contiguous states. This paper is a brief description of one of these deposits. It is a Mississippi Valley type deposit, but somewhat atypical in that the metal of greater interest is cobalt as opposed to lead, zinc, and copper. The history and present work are outlined along with a discussion of the geology and mineralogy.

Jan 1, 1981

By B. Denby, R. Hollands, S. Cooper

Augmented Reality (AR) is a technology that can be used to mix computer-generated images of data with views of the real world. The University of Nottingham is developing AR technology in a major research project which can be used to assist mining companies in visualising complex mine data whilst out in the field. The technology comprises of integrated GPS surveying technology and electronic orientation devices to provide location and viewing information, video capture via digital camera and portable computing hardware to overlay 3D models on views of the real world. The paper describes the concepts of the technology in some detail and concentrates on the possible applications of this in the surface mining and exploration industries.

Jan 1, 2002

By Robert A. Irvine

Traditionally, cost effective gains in the capacity of material handling systems were a result of increases in equipment size. In general, the use of maximum capacity components in a system optimizes the production "costs per ton." The trend-"Bigger is Better" will continue in material handling equipment. Since it is rare for plant operators to lament an over abundance of screening capacity, one can safely predict that vibrating screens will follow this trend. Large Vibrating Screens - The Challenge Large vibrating screens represent a unique challenge for Manufacturers, Plant Designers, and Plant Operators. The inherent mode of operation for vibrating screens is self-destructive. More often than Manufacturers admit, Designers plan for, or Operators staff for, a vibrating screen succeeds and self-destructs. This is a problem. It can magnify with larger vibrating screens.

Jan 1, 1983

By Manuel Pérez-Tello, María M. Salazar-Campoy, Óscar Rodríguez-Hoyos

The Kaldo furnace is a type of top-blown, rotary reactor that is widely used for the production of precious metals. During the production of doré, a gas jet of compressed air is injected through a water-cooled lance to impinge upon the molten bath surface in the presence of molten metal and a slag phase. A common problem during operation is the difficulty in controlling the distance that the injection lance can penetrate through the reactor mouth without being splashed by the molten phases. Splashing may produce accretions on the lance surface as well as plugging of the nozzle at the lance tip. An additional problem may occur when the gas jet impinges upon the furnace wall and causes rapid wearing of the refractory linings. Because the conditions prevailing in the Kaldo furnace offers poor visibility to the human eye, its operation mostly relies on the empirical knowledge of plant operators and process engineers. A systematic study in a scale model of the Kaldo furnace under controlled laboratory conditions may be valuable to estimate the maximum penetration distance of the injection lance, and thus help improve the operation of an industrial reactor. From a fundamental perspective, the observation of the basic features of the flow patterns in the scale model may help elucidate the relevant phenomena governing the hydrodynamics in this type of system.

By Andrzej M. Wala

A knowledge of the friction factor (K-factor) is necessary in planning and designing mine ventilation systems for least cost and highest effectiveness. The friction factor used must be accurate and reliable for correct estimation of airway resistances. At present, the friction factors are determined by using tables of published values. These values were established principally for metal-mine openings having small effective areas. This presents a problem to the ventilation design engineer whose responsibilities center around the design of effective ventilation systems for large room-and- pillar mechanized underground coal mines. Friction factors selected from these tables could be excessively conservative for large scale room-and- pillar operations. With only limited data on the K-factor (which are considerably site dependent) for Kentucky's coal mines and for all the above mentioned reasons, it was concluded that there is a need for field investigations to determine these values in-situ for existing mining conditions in Kentucky. The author describe the study carried out in ten coal mines located in eastern and western Kentucky and present the results of the investigation in both tabular and graphical form.

Jan 1, 1991

By J. R. J. Edwards

Jaspilite, a mineral consisting of silica and iron oxide in varying proportions, is one of the host rocks of the high grade ore deposits situated in the Middleback Range of South Australia. As a result of laboratory investigations, a flowsheet was postulated for the beneficiation of jaspilite to produce an acceptable grade product for feeding to blast furnaces, The flowsheet involved the reduction of the hematite in the haspilite to magnetite, the grinding of the reduced product to 95 pct minus 325 mesh Tyler followed by wet magnetic separation, hydroseparation and filtration to yield a magnetite concentrate. Agglomeration of the fine concentrate would then be necessary to meet the physical requirements of blast furnace feed. To prove the postulated flowsheet, to obtain a more accurate estimate of costs and to obtain design data for a commercial installation, a pilot plant was constructed at Whyalla, South Australia.

Jan 1, 1960

By Fred D. Wright, Stefan H. Boshkov

12.1-BASIC AND PARAMETRIC CRITERIA IN THE SELECTION, DESIGN AND DEVELOPMENT OF UNDERGROUND MINING SYSTEMS STEFAN H. BOSHKOV AND FRED D. WRIGHT The criteria governing the selection of an underground mining system relate to several factors the importance of which varies with geographic location, the state of development of the industrial technology, the economic climate in the Nation and, perhaps, in the world-all these as functions of time. Thus, the best choice of a mining method depends upon sets of definable and undefinable values for numerous factors that may be considered fixed at the precise point in time. Subsequent changes in economic and/or technological developments may necessitate modification or complete revision of the existing mining system. A classification of criteria for selecting a mining system must be based on the broadest definitions. Specific cases may present simple solutions or pose very intricate questions, the answers to which are frequently based on judgment rather than explicit logically reasoned and derived results. Specific criteria may be of negligible consequence in some instances and of overriding importance in other cases. It would be foolhardy to attempt to point out, in the limited space available, all possible variations and interplay of factors, as well as to define the setting in which this interplay can take place. The reader is, therefore, referred to the case histories described in the subsequent parts of this section where actual practice will point out the variability of the problems encountered in the selection of a mining method. A popular thesis suggests that the proper approach to selecting the method of mining should be rooted in the inverse solution, whereby the limitations of the various methods in use serve as criteria to eliminate most of these methods from consideration in the specific case. This narrows the ultimate selection to one or perhaps two most appropriate methods. At this stage, a critical comparison analysis will lead to the ultimate choice. Although such a negative approach un¬questionably is valid in discarding obviously inapplicable mining systems from consideration, it falls short in defining the best system, which in practice quite often turns out to be a variation of a textbook standard, or a combination of two or more such standards. Because the deployment of capital and manpower over a long-term commitment closely follows the selection of the mining system, the decision-maker can well afford to spend a great deal of time and effort in evolving the optimum solution for the peculiarities of his specific case. Within the basic engineering tenets of economy and safety to which the design of a mining system must adhere lie numerous factors of constraint which may be grouped, somewhat arbitrarily but for ease of discussion, into several categories. The criteria that enter into the choice of a mining method derive from the following groups of factors: 1. The shape, size and spatial position of the ore deposit.

Jan 1, 1973

By Yiyin Ma, Yuqi Chen

Based on two in-situ measurements and mathematical analysis, the micro-climate in a large central underground pump and power station has been discussed in this paper. It is found from the research that the "semi- infinite" body model in the general heat transfer can closely represent the heat exchange process in the air flow-surrounding rock-adiabatic intermittent heat source complex in the station. Finally, computer simulations were made to calculate the micro-climate in a similar pump and power station where power machines operate intermittently. The simulation results are quite satisfactory. It can provide useful information for decision- making in the air conditioning of such stations.

Jan 1, 1991

By J. J. Scott

Friction Rock Stabilizers, trade name Split Set*, is a new support system invented by the author and under development by Ingersoll-Rand and Lee-Norse Company. Split Sets are a substitute for standard bolts or fully grouted resin bolts and have certain advantages which are: 1. Improved safety for the miner 2. A rational design is possible based on rock mechanics principles 3. Supports can be made either to be yieldable or rigid 4. Supports can be used to build a roof beam or to suspend roof material 5. It is cheaper than the resin system and costs about the same as standard bolts.

Jan 1, 1974

By L. Valentik

Many attempts have been made during the last forty years to evaluate the performance of gravity separation equipment, that is, the effectiveness with which light and heavy particles are separated. The most comprehensive treatment of the subject was made at the 1st International Conference on Coal Preparation held in Paris (1950) by Cerchar. The methods suggested by the Conference were accepted and very widely used in the last 25 years. This paper discusses an improved method of evaluation in the light of the now accepted standard presentation. The float and sink analysis of the product is presented on a Gaussian distribution curve, resulting in an easier visualization of the inherent difficulties of separation. The ogives of the distribution curve are then plotted, giving a quantitative measure of the deviation from perfect separation as an error distance instead of an error area. Illustrations of the new method are given both for gravel and for coal preparation, but the concept is valid and applicable to other types of minerals which are separated by gravity methods.

Jan 1, 1968

By J. G. Groppo

Lowering of filter cake moisture of ultra-fine coal to a 20 percent level using conventional vacuum filtration could be achieved using a combination of metal ion and surfactants. Pretreating coal slurry with about 0.2 Kg/ton of a surfactant and 50 ppm of copper or 10 ppm of aluminum ions provided filter cake containing 22.8 percent moisture. The lowering of moisture is explained due to formation of hydrophobic micro-agglomerates which facilitates dewatering.

Jan 1, 1994

By A. Moergeli, Philip Sander, John Reilly

"SUMMARY While the basic elements of risk management, including probability, consequences, risk registers, mitigation measures, etc., are now well understood, the process to include correlation, dependencies and linkage of risks and risk scenarios is less well defined and not well understood. To perform accurate and complete risk analysis and risk management, it is necessary to include correlation, dependencies and linkage between risk events, as well as risks that may occur multiple times. In this way, owners and contractors can more accurately determine risk-based costs, risk impacts and risk mitigation strategies. This paper will outline methods to deal with correlation, dependencies and linkage and will consider risks that may occur multiple times. Practical result comparisons – with or without these elements – will be presented. INTRODUCTION We believe the reader is familiar with basic concepts of risk, risk management and mitigation and the use of probabilistic cost-risk processes versus deterministic ones (Reilly et al. 2015; Sander et al. 2015). The probabilistic approach, compared to the simpler and more common deterministic approach (unit prices times unit costs plus a contingency), offers more useful information with respect to the range of probable cost as well as cost “drivers” and better quantifies the effects of risks, opportunities and variability – which improves understanding, leading to a better potential for profit (or loss) for contractors and added value for owners. In this context, a valid and sufficient quantification of correlation, dependencies and linkage of risk events, plus the impact of risks that may occur multiple times, is essential. Components of Cost Estimates – Base Cost, Risks and Other Uncertainties The components of cost that need to be correctly addressed in an estimate include (Moergeli et al. 2015): •,Base costs – the costs that will result if “all goes according to plan” (Reilly 2004) •,Risk costs – the resulting costs of threat and opportunity events, if they should occur •,Escalation costs – costs resulting from normally expected inflation with variability •,Other uncertain costs – costs that result from other events, normally external to the project team’s control, which may include unanticipated events, politically related changes and “black swan” events (Talib 2007)"

Jan 1, 2016

By Michael Rehbock-Sander

The Gotthard Base Tunnel (GBT) is 57 km (35 miles) long and consists of two par-allel single-track tubes with an ex-cavation diameter ranging from 8.8 to 9.5 m (28.8 to 31.2 ft). These are interlinked by cross-passages every 312 m (1,000 ft). Two multifunction stations (MFS) are located in the sections Sedrun and Faido, at one-third and two-thirds of the entire tunnel length (Fig. 1). These will be used for the diversion of trains to the other main tube via tunnel crossovers, for the housing of tech-nical infrastructure and equipment and for potential emergency stops. To reduce construction time, the GBT was divided into five sections and was excavated from several sites simultaneously. The tunnel was excavated from the two portals, Erstfeld in the north and Bodio in the south, and also from three intermediate attacks, with their corresponding access tunnels, in Amsteg and Faido and two vertical 800-m (2,624-ft) deep shafts in Sedrun.

Jan 1, 2012

By S. Agarwal, S. Frimpong

The creation and maintenance of a healthy working environment in surface mining operations require sustained efforts in pursuing advanced research initiatives toward the development and deployment of powered haulage technologies. This paper contains progress summary on a frontier research in truck dynamic control, vision and collision avoidance. This research is required to provide solutions to challenging problems regarding operator visibility in truck haulage in a surface mining environment. The paper focuses on truck control kinematics and dynamics, truck-haul road interactions, intelligent truck sensing, intelligent truck collision avoidance system, integrated system for situational awareness, augmented visualization and operator interface, and field testing and error variance modeling of developed technologies. A sensor suite of four subsystems, including front-side stereo-camera, front-side Doppler radar, close range sonar proximity sensors, and rear-side camera system have been recommended for developing a 360° truck operator vision to allow safe operations. This research initiative is significant because it will provide a strong basis for developing technologies to improve truck haulage safety in surface mines and construction sites.

Jan 1, 2007

By J. H. Daniel

Dust-related respiratory disease remains the major health concern in mining, and health agencies are proposing more stringent standards. The U.S. Bureau of Mines (USBM) is investigating techniques to continuously monitor respirable dust in real-time during the coal or ore extraction process. Continuous monitoring will allow mine operators to evaluate hazardous dust concentrations and adjust the operations to produce less dust. Mine instrumentation applications include machine-mounted and hand-held monitors, personal monitors, and area/environmental monitors. Six dust detection methods have been considered to meet application requirements. These are: light-scattering instruments, a smoke-particle detection technique, correlation of pressure drop across the collection filter with amount of dust deposited, the Tapered-Element Oscillating Microbalance (TEOM) instrument, a method that relates the amount of dust collected on a filter with the vibration of the filter, and beta attenuation measurement of dust. Studies to date have identified the TEOM instrument and the technique of correlating the amount of dust collected with the vibration ofthe filter as having the most promise for success. Development of the machine-mounted monitor is the highest research priority. The application options and progress to date in developing continuous monitoring instrumentation are presented.

Jan 1, 1995

By Maurice Deul

For the first half of the 21st century, the United States will rely on the same mix of fuels it has for the past 50 years. Petroleum for the United States will cost more and availability will decline as developing nations modernize. Increased use of natural gas for electric power generation will result in stress on the gas supply. Coal will be the fuel of last resort. More than half the petroleum used is imported, about the same amount as used for transportation. Only coal can provide relief by fueling railroads through electrification while encouraging “piggy-back” trailer haulage, co-generation for manufacturing and expanded passenger service.

Jan 1, 2002

By M Aboagye, K Appau, W. Assibey-Bonsu, C. Muller

A case study based on two recoverable resource modelling techniques (indirect and direct or localised methods) have been derived using typical feasibility study or new mine drilling data configurations from the extensions of an existing mine’s massive production database. The database is from the Gold Fields Tarkwa Gold mine (~6Moz Mineral Reserves and 13-year Life-of mine). The corresponding recoverable resources from the various techniques are then analysed using the open pit Whittle optimisation process. The results were then compared based on the Whittle optimisation results to determine the efficiencies of the approaches and the validity of the recoverable mineral resource estimates for mine planning and financial forecasts (including Cash Flows etc). Based on historical production metal recovery, the paper also assesses the corresponding orebody and mine planning as well as financial risks with regards to the modelling techniques. The study shows that the localized direct and somewhat more straight forward approach if applied efficiently can provide an equally useful tool for computing recoverable resources for mine planning and financial forecasts, as compared to the indirect approach as presently in use.

Jun 25, 2023

Conventional logging tools such as density, neutron, and acoustic have ranges of investigation of tens of centimeters. The borehole gravimeter, however, has a range up to hundreds of meters. For example, from the center of a cylindrical orebody 0.22 g/cm3 denser than its surroundings, one can detect the boundary of the orebody at a radius as large as five times its height. More complex structures can be investigated with computer programs. We can predict the usefulness of proposed gravity surveys, or decide which suggested structure is most likely to have caused the results of existing surveys.

Jan 1, 1985

By G. G. Marino, J. W. Mahar

This paper provides an utierstanding of the betivior and potenttil damage of homes resulting from sag-type mine subsidence. This is done with extemive research of numerom case histories in Illinois collected by the authors. The howe response to substience-itiuced ground displacements are summarized and evaluuted. A damage level criteriu, specifically developed for residenttil structures, is presented based primarily on repair costs. Damage levels and the associated subsidence profile characteristics for each case history are compared.

Jan 9, 1985

By E. R. Phelps

It is very seldom that a completely new project is initiated. Most projects consist of a new and different combination of proven techniques or a combination of proven and new techniques. The theme of my discussion today falls in the second category. Proven methods of water transportation and proven methods of bulk material handling were combined with some new techniques which resulted in a new market for the coal industry and a cheaper fuel supply for the power industry. In this respect I refer to the water transportation of coal from the West Kentucky coal fields to coal burning power plants on the west coast of Florida. Peabody Coal Company, Florida Power Company, Gulf Coast Transit, and Mid-South Towing combined their individual requirements and "know how' to make this project possible. I feel the results speak for themselves since it proves that coal can be mined in the West Kentucky coal fields, transported some 1,200 miles by river barge and some 450 miles by ocean going barges, be delivered to power plants on the west coast of Florida and still meet the competitive prices of gas and residual oil. The unique parts of this project concerns the storage and trans loading facilities for coal from river equipment to ocean equipment near New Orleans; the return haul of phosphate and it's trans loading from ocean to river equipment at the same facility and the use of large ocean going barges. In detail it works as follows: Coal is mined in West Kentucky and loaded into 1,500 ton river barges on the Green River. It is then transported some 100 miles to the mouth of the Green on the Ohio River, then 200 miles down the Ohio to it's convergence with the Mississippi, and then 900 miles down the Mississippi to the trans loading facility some 40 miles South of New Orleans. There it is transferred from the 1,500 ton river barges to 18,000 ton ocean going barges and hauled some 450 miles across the Gulf of Mexico to the Gannon Station of Tampa Electric at Tampa entailing a total haul of approximately 1,650 miles.

Jan 1, 1966