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By Abigail Styer, Paul Holmgren, Josh Calnan

Detonating cord is a staple of the explosives industry, used widely in the civil and defense industries. Detonating cord is a thin, flexible plastic tube filled with pentaerythritol tetranitrate (PETN). It has many applications in mining, construction and military disciplines. For civil applications, it is used to connect and initiate a series of blastholes in a desired pattern. In the defense sector, it can be used as a detonating agent, a priming agent or alone as an explosive charge. Research has been done to understand the initiation and detonation physics on the detonating cord. However, its sympathetic detonation characteristics needed to be further analyzed. The sympathetic detonation of the detonating cord can lead to the poor performance of production shots in mining or civil applications and unsafe conditions in defense applications. This paper focuses on the analysis of different factors involved in the sympathetic detonation of various sizes (grain weights) of detonating cord. The variables analyzed include the minimum distance between segments of detonating cord and grain weights. These variables were analyzed by securing segments of detonating cord at measured distances apart on a steel plate and detonating them. The physical examination of the aftermath of this detonation included a qualitative recording of data. Applications of detonating cord that could be affected by this research include mining and construction blast initiation, explosives disposal, and breaching.

By M. C. Irani

The Bureau of Mines, in cooperation with the Mine Safety Appliances Co., has developed a continuous-recording methanometer utilizing a catalytic combustion detector. The methanometer, which is presently operating at 22 exhaust fans at 14 mines in the Eastern coalfields, is reliable and simple to install, operate, and maintain. The instrument and the details of its installation and calibration are described. Analytical data obtained by infrared spectrophotometer and gas chromatograph are presented to substantiate its re liability.

Jan 1, 1974

By Steve Kral

A few months ago, Congress passed, and President Bush signed, a national energy bill. Designed to decrease the nation’s dependence on foreign sources of energy, the bill earmarked several billion dollars to increase the use of U.S. coal reserves. The bill also modified permitting regulations to speed up development of the coal reserves located on federal land. Coal currently supplies more than half of the nation’s electricity needs. And as housing starts continue to in-crease and with the nation’s appetite for electronic gadgetry, the demand for energy in the United States will only go up. That means coal producers must expand production while at the same time containing costs so they can enjoy this period of improved coal prices.

Jan 1, 2005

By S. K. Oraee

Managers always look for systems with minimum hazards. The hazards create problems for performance of projects. The largest and most important hazards of working underground mine can be related to health, safety and environmental, because if one of these sectors be in hazard, maybe lead to close mine. Failure mode and effects analysis (FMEA) is a widely used quality improvement tool to identify the potential failure modes for measuring reliability of a product or a process. FMEA is performed by developing a risk priority number (RPN), which is the product of severity, occurrence, and detection ratings. On the other hand, with regard to uncertainty in the decision-making, fuzzy theory will be able to model this uncertainty. Fuzzy FMEA provides a tool that can work in a better way with vague concepts and without sufficient information than conventional FMEA. This article by using Fuzzy FMEA and based on HSE criteria evaluate hazards of Parvade No. 1 Mine in Tabas Coal Mine. The results demonstrate the most hazardous parameter is rock burst in this mine.

Jan 1, 2011

By X. Yuan

"The processing behaviours of ores such as their liberation characteristics in comminution and their response in separation processes are affected by their mineralogical characteristics. Key ore characteristics which are relevant to processing, such as mineral proportions, mineral grain size, grain shape and mineral associations are routinely measured at the micro-scale in polished section using optical microscopes and SEM-based automated mineralogy systems. The application of X-ray micro-tomography to mineral processing provides the means to quantify these important micro-textural characteristics in three dimensions, removing the stereological issues encountered when measuring volumetric information in two-dimensional polished sections. In this paper we present several examples of ore textures to illustrate where X-ray micro-tomography can be applied successfully to obtain quantitative measures of ore characteristics which are useful in a variety of process modelling applications.INTRODUCTION X-ray tomography has been used as a tool in medicine for some years and is being applied in a wider range of fields including geology, palaeontology and mineralogy. In this paper we present some applications of X-ray tomography in mineral processing applications being developed at JKMRC. The availability of SEM-based automated mineralogy systems such as MLA and QEMSCAN has seen the increased use of quantitative mineralogical data measured in two dimensions in the design, operation and simulation of mineral processing plants. When the ore is amenable to measurement by X-ray tomography this technique can provide quantitative data for characteristics such as mineral grain size, shape, mineral associations and liberation in three-dimensions. The advantage of measuring these characteristics in three-dimensions is that the stereological issues which bias measurements made on polished sections are removed. X-ray tomography also quantifies the location of mineral grains relative to one another in space - a useful descriptor of ore texture. Like many measurement techniques X-ray tomography has advantages and disadvantages when compared to other techniques. One limitation is that the ability of the X-ray tomography system to discriminate between minerals is a function of the X-ray attenuation of those minerals. While the X-ray attenuation of many common minerals is sufficiently different for X-ray tomography to distinguish between them, there are some where the overlap in X-ray attenuation makes discrimination on the basis of this characteristic alone impossible. An example of this would be chalcopyrite and magnetite. However where the ore mineralogy is suitable to apply X-ray tomography, the technique provides some exciting opportunities to explore the relationship between texture and ore processability."

Jan 1, 2012

By P. Mokwena

Paper written on project work carried out in partial fulfilment of BSc (Hons) in Chemical Engineering Diamond synthesis has attracted a great deal of interest because of its exceptional properties and various applications. In this study, the chemical catalytic vapour deposition (CCVD) method was used to synthesize diamond films using acetylene as carbon source and hydrogen as carrier gas at a temperature of 1000°C, and their thermodynamic stability was studied. Photographic analysis revealed that these products are diamond films, Ramman spectroscopy confirmed that they are graphitic while confocal laser scanning microscopic image analyses proved that these diamonds films have structural defects due to iron impurity from the catalyst precursor. The quantity of diamonds films produced is also proportional to the acetylene to hydrogen ratio but these films are larger in size at lower acetylene to hydrogen ratio. Thermogravimetric analyses showed that transformation of these materials begins at 25°C but could not be used to determine if a temperature range below 25°C exists. The stability of these CCVD-synthesized diamonds also increases below 25°C when stored at different temperatures.

Jan 1, 2007

By Sam S. Taylor

In most oil fields, natural gas is the major source of energy causing flow of oil to the well. The amount of gas produced With the oil generally exceeds actual energy requirements, so that in time the gas reserve of the field becomes seriously depleted and the oil production nest be stimulated by some auxiliary means. One of these is to repressure the oil formation with natural gas; or, where a gas supply is not available, often air is used. Although air is a cheap and convenient repressuring medium, its use sometimes is attended with several disadvantages. First, the return air-gas mixture decreases rapidly in fuel value, often until it can be used no longer as a source of power. At the same time, explosive mixtures may result if recycling is used, causing hazards to life and equipment. Second, some fields experience considerable trouble with the formation of emulsions which become increasingly difficult to treat. Although there is no definite proof that air repressuring always causes these emulsions, many operators are convinced that this is the case.

Jan 1, 1934

By David H. Carlson

The paper presents background information including data on diesel exhaust pollutants, amounts produced and standards, a desscription of mine characteristics that affect air monitoring techniques and a review of portable measurement techniques and instruments for gas and particulate matter sampling. A general review of the laboratory and field research being conducted at Michigan Technological University in the area of diesel emissions is presented. The facilities involved with this research are also described. These are the Experimental Mine, the diesel dilution tunnel test cell, the Mine Air Monitoring Lab (MAML), the portable instruments and the production mines used.

Jan 1, 1979

By A. W. Khair

In 1985, an extensive longwall mining research project was initiated by the West Virginia University Research Center entitled "An Improved Longwall Mining Technique" with the purpose of providing operational guidelines for the mining industry to enable efficient operation of its existing and projected longwall installations. One task involved in this extensive research project was monitoring ground movements due to longwall mining and evaluating their impact on surface and subsurface structures. This paper presents an analysis of the effects of topography on quasi-static and dynamic ground movements and the severity of damage inflicted on surface structures. The site was chosen for the study with an attempt to obtain a representative account of the topography experienced in the Northern Appalachian region, and more importantly to contain a substantial number of varying topographical features i.e., mountains, hillsides, valleys, and flat bottom land. The study was made possible by typical subsidence monitoring technqiues, however subsidence monuments were surveyed on a frequent basis, intermittently during face advancement. Ground movements were investigated under both quasi-static and dynamic conditions. This provided insight into the propagation of subsidence and the dynamic affects it has upon surface structures.

Jan 1, 1987

By J. L. van Niekerk

The research project reported on represents the first comprehensive attempt to measure the vibration levels of a variety of tools and equipment in the South African mining industry to determine the effect thereof on the health of workers and operators. Although human vibration has been studied extensively internationally only one reference pertaining to the South African mining industry could be found. From studies conducted in Canada and elsewhere it was evident that rock drills do have potentially hazardous levels of vibration. The scope of the research included measurements on a broad spectrum of tools, machines and vehicles used in the South African mining industry. Both hand-arm vibration, where the majority of the vibration enter the body through the hands, and whole body vibration, where the whole body is exposed to vibration through contact by the buttocks or feet, were investigated and measured. More than 700 sets of vibration data measured on 70 machines at 15 mines and workshops were obtained. Data were obtained for at least 24 different types of equipment and machines that were previously judged to have medium to high levels of vibration. All measurements were conducted in accordance with the international standards: ISO 5349, on hand-arm vibration, and ISO 2631-1, for whole body vibration. The equipment with the highest vibration levels in the hand-arm category was: rock drills, both pneumatic and hydraulic; pavement breakers and jackhammers; hand-held compactors; pneumatic wrenches and electrical hammer drills. Of these the rock drills had weighted vibration levels in excess of 20 m/s2. As far as whole body vibration was concerned the highest values were measured on earth-moving equipment. The major conclusion from this study is that the measured vibration levels are sufficiently high to create an enhanced level of risk of vibration-induced disorders in a significant proportion of the operators of hand-held equipment. The most notable examples are hand-held rock drills, pavement breakers, jackhammers and certain selected workshop tools. The results of the study indicate that a comprehensive epidemiological study should be undertaken on present and past workers to determine the prevalence of vibration-induced disorders.

Jan 1, 2000

By Thomas D. Boyce

Minewater from many western U.S. uranium mines often contains radioisotopes in concentrations higher than permissible for discharge to unrestricted areas. .Radium 226 has the lowest permissible concentrations of all radioisotopes and usually greatly exceeds this limit in untreated effluents. This radionuclide is derived from the natural radioactive decay of uranium: [ ] The treating of minewater effluents has been studied previously (1) and the classical removal method for radium has been adsorption on barytes or freshly precipitated barium sulfate. This paper describes the removal of radium from minewater by utilizing a selective complexer based on a crosslinked organic polymer matrix.

Jan 1, 1982

By Fred Leonard

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel/ trucks, shovel/crusher/conveyors, and shovel/rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel/trucks, front-end loaders trucks, and shovel/crusher/conveyors were studied in a multi-seam, dipping geologic area of the Four Corners Region. The Texas lignite engineering and economic research involved bucket-wheel excavators (BWE), BWE/backhoes, and scraper/backhoe combinations for overburden and coal excavation. The PRB truck/shovel study utilized the most recent computer simulation available in both the design and cost analyses. Detailed engineering analysis, followed by in-depth operating costs (operating and depreciation), result in a complete evaluation of each mining system. Cost comparisons of the different mining systems under similar geologic and production constraints are presented in the report to illustrate the estimated capital investment and production costs per ton of coal and bank cubic yard of overburden.

Jan 1, 1980

By Hyung-woo Kim, Kiyoung Sung, Sup Hong, Jung-Yeul Jung

Many concepts for the commercial production of deep-seabed manganese nodules have been studied since the 1970s. However, the bearing capacity of the deep seabed is not strong because it is composed of fine particles with high moisture content. So it is impossible to carry manganese nodules in the collection system. Therefore, the validity of continuous mining by riser pipe from the seabed to the vessel is highly appreciated. A continuous mining system is composed of mining vessel, lifting pipe, buffer system, transport tube (flexible pipe), and self-propelled mining robot. A conceptual diagram of this system is shown in Fig. 1(a). Korea Research Institute of Ships and Ocean Engineering (KRISO) developed a deep-seabed self-propelled mining robot called "MineRo" to collect manganese nodules in 2012 (as shown in Fig. 1(b)). In 2013, real sea experiments at around 1380 m depth were carried out to evaluate the collecting and driving performance of MineRo. However, we found that the roller in MineRo did not work well at times. To elucidate the problem, we analyzed the rheological characteristics between the bushing and drive shaft under deep-water conditions.

Sep 1, 2014

Choosing the correct delay time for many blasting applications is an important and critical blast design parameter for controlling fragmentation, muckpile shape, swell, digability, throw, ground vibration and airblast. BAl and its affiliates have monitored thousands of full scale blasts in a variety of field conditions, spanning over 15 countries, with sophisticated blast monitoring instrumentation. In some blast environments, a small change in the choice of delay times used had a dramatic and pronounced effect on the overall blast results. In other blast environments, large changes in the choice of delays used had absolutely no effect on the final results in terms of specific outputs. In environments which were sensitive to the delay selection, the type of explosive, dynamic response time of the rock mass (TMIN), integrity of the material, burden and rock mass geometry, all played a very important ,role.

Jan 1, 1998

By Gary Choate

The work presented in this report represents the background activity which led to the fabrication and testing of a greenhorn and crowd limit switch system for electric shovels. The program began With a literature search and manufacturers product review to gather material as a basis for concept generation. Visits to three open pit mines provided information from operation and maintenance managers which was useful in preparing design concepts. These concepts were evaluated through laboratory tests and engineering analysis to select a final design concept. The resultant greenhorn is four separate shock absorbing pads each enclosed in a housing which bolts to the end of a dipper handle adaptor. The plungers impact against stops mounted to the saddle block. The crowd limit control is a nonmechanical device which senses the location of the dipper and makes appropriate commands to the crowd motor to insure against impacting the greenhorns. The electronic crowd limit control is redundant and indicates malfunction modes. The greenhorn prevents shovel damage in the unlikely event of impact.

Jan 1, 1983

By D. W. Partridge, W. Lamb, A. E. Lamb, S. Bird

Due to the constant need to improve SAG mill performance and efficiency, extensive research into all aspects of SAG mill optimization has been performed. This paper will review the current evolution of SAG mill shell liner design and their performance at the Copperton Concentrator. The effect of these liner design changes will be discussed with respect to: • Liner configurations • Mill operating performance, i.e., throughput, power draw, mill control • Mill mechanical performance, i.e., liner wear profiles, liner life, liner breakage, liner hardness • Foundry manufacturing considerations • Economic evaluation of throughput versus liner life This paper will discuss the results of Kennecott Utah Copper’s (KUC) and ME International’s (MEI) test work, providing an insight into the past, present and potential future opportunities of SAG mill liner design.

Jan 1, 2002

By Qing Wang

In this method the state of an open-pit mine is represented by the number of benches that are mined in each predesigned mining phase (or pushback). Consequently, a specific mining schedule can be represented by a sequence of states which starts with the topography of the mine site and ends with the ultimate pit. For a given set of mining phases all feasible states are first generated and sequences of states are then evaluated for technical and economical feasibility. The best sequence, which gives the maximum net present value (NPV), is found by applying a dynamic programming optimisation algorithm. The algorithm also optimises the cut-off grade which satisfies the mill feed requirement for each planning period. It was found that the algorithm can be used not only for scheduling but also as an effective tool for analysing the effects of mining and milling capacities and cut-off constraints on the mining schedule and the total NPV. The algorithm, which was programmed in C, was successfully applied to a large Au-Cu deposit

Jul 1, 1996

By T. Burchett, F. Stanley, K. McGough, G. Luttrell

The vast majority of U.S. coal preparation plants utilize screen-bowl centrifuges to dewater their fine clean coal products. In light of this popularity, researchers at Virginia Tech have engaged in a variety of laboratory and industrial field test programs to develop technological enhancements that have the potential to further improve the performance of this important solid-liquid separation process. These enhancements, which include simple design modifications and new reagent packages, have been shown to significantly improve solids recovery and reduce product moisture in several experimental trials.

Jan 1, 2006

By O. A. Olaseinde

The 2101 lean duplex stainless steel has wide potential application in storage, heat exchangers, and in the oil and gas industries. This work investigates the electrochemical behaviour of 2101 duplex stainless steel with an addition of 0.15 wt% ruthenium, using potentiodynamic techniques in 1M H2SO4 at 25º, 40º, 60º, and 80ºC. The microstructures of samples were characterized using optical metallography and scanning electron microscopy. The results showed that the ruthenium addition moved the corrosion potential of alloy 2101 to a more positive potential. All samples containing ruthenium displayed longer passive regions at 25°C and 80°C compared to those without ruthenium. Alloys without ruthenium had higher critical current density (icrit) values when compared to the alloys with ruthenium. Ruthenium additions decreased the passive current densities and inhibited anodic dissolution. At room temperature the corrosion rate of alloys with ruthenium was lower than these without ruthenium.

Jan 1, 2012

By R. V. Petrella

The flash induced combustion of Sewell and Pittsburgh coals was studied in air and in oxygen. The primary decomposition and combustion processes occur within the first 300 ~sec in oxygen and slightly later in air. Strong absorption spectra of CN and OH are indicative of the decomposition and combustion processes, respectively. Kinetic spectroscopy and combustion product analyses indicate that only about 35% of the coal dust is consumed in the explosive combustion which takes place in several (1-5) distinct but similar steps. The combustion-modifying effects of (NH4)2HP04, NH4H2P04, KHC03 and Rock Dust were studied in the 1-20 wt % range in coal dust flash com-busted in air and oxygen. The study reported herein shows Rock Dust to be the most efficient coal combustion inhibitor. KHC03 is the least effective agent, with the phosphate salts showing marginal effectiveness.

Jan 1, 1976