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By Bhargav Dhavala, Sristy Raj, Ashok Kumar, Suman Krishna Sit, Adity Ganguly, D. P. Chakraborty

"Tatasteel’s West Bokaro washery#3 is designed to deslime raw coal at 0.5mm; the oversize (+0.5mm) is beneficiated in dense media cyclones (DMC) while the undersize (-0.5mm) is beneficiated in froth flotation (FF) cells. Nearly, 80% of the raw coal feed reports to the DMC circuit consisting of four parallel streams. Presently, the performance of DMCs at washery#3 is interpreted by: (a) comparing the actual plant yield w.r.t the lab predicted yield and (b) misplacement of clean coal to middllings.However, the comparison between actual & lab predicted yield is fallacious given the fact that the lab predicts yield of the borehole sample while the feed received at the plant has different characteristics altogether due to the dilution during mining. To mitigate the said limitations, a quick diagnosis tool using the past data has been developed that will give a prediction of performance of different coal seams in the DMCs, inputs being feed ash to DMCs and stream wise feed specific gravity (coal & magnetite combined).The tool also will help in identifying the root cause on real time basis thereby helping the operator to take necessary corrective actions. The operator can intimate the mining personnel in cases of shale reporting to the feed as a result of dilution during mining. In events of higher standard deviations between the parallel streams w.r.t feed specific gravity, the operator can adjust the parameters accordingly to minimize the yield loss. INTRODUCTION West Bokaro came into existence in 1948, as an independent coal company, managed by M/S Anderson Wright. Tata Steel acquired the Company in 1956 to meet its requirement of metallurgical grade coal for Iron making. Subsequently, in 1976, it was made a division of Tata Steel. In 1974, when coal mines were nationalized, West Bokaro was exempted as it produced coal only for captive consumption of the Steel Works. The first washery of India was set up in West Bokaro. The business objective of the West Bokaro division is to produce clean coal at optimum cost for captive use in the steel plant of Tata Steel at Jamshedpur. The strategy is to reduce ash with minimum loss of yield so that quality of coal improves and yet the cost is beneficial vis-a vis imported coal. The primary product is the metallurgical grade coal for coke ovens, which converts coal into coke for use in the Blast Furnaces."

Jan 1, 2018

By T. Fernandez, V. Juchen, C. Petter, F. Cantini, V. Lenz, V. I. Araújo, R. Petter, R. Darrigo, A. Young, I. G. da Costa, J. Oppermann

There are many methods to estimate costs quickly. One of these is the Parametric Method, where costs are estimated from general algorithms (or curves). Derived from an original tool based on the O’Hara model, a software called MAFMINE was developed. MAFMINE is based on parametric models to estimate investment and operational costs in mining. The software itself is based on the use of a computer model known as client-server. However, the model needs new inputs from advances made by the mining industry, mainly in terms of electrification, automation, digital transformation and preconcentration to face Environmental, Social and Governance (ESG) concerns. Thus, this work was to prepare a new core module ready to incorporate the new technologies aiming to deliver operation and capital costs associated with environmental impact mitigation. The tool generates an order of magnitude estimate for CAPEX and OPEX to establish a very first Discounted Cash Flow (DCF) in a mining venture. For quick evaluations, at a preliminary level, the results are very promising.

Mar 2, 2022

By E. J. Wasp

The transportation of mine products incurs a cost which can have a significant bearing on the competitive position of the manufactured product. Clearly, the engineer who is responsible for selecting a mode of transport must base his decision, at least in large measure, on economic comparisons. And today, the engineer usually finds that he has to choose between several modes, including slurry pipelines. For the purpose of an initial economic screening, it is not necessary to go deeply into the technical details of a slurry system. What is usually needed, however, is a method with which the engineer can make a quick economic assessment to determine whether a slurry pipeline should be included in the detailed final analysis. This paper presents a rapid method for making such a preliminary appraisal. Experience with commercial slurry pipeline systems in several countries and with a variety of solid materials has shown that if several assumptions pertaining to critical design variables are made, it is possible to roughly estimate the transportation cost of a slurry system on the basis of only three factors: the specific gravity of the solid material, the length of the system, and the quantity of slurry to be pumped each year. It is assumed that conditions pertaining to field construction, corrosion inhibition, and the like, will be favorable. This assumption is critical because any factor which analysis shows to be particularly unfavorable will raise the total transportation cost estimate which this paper establishes. If the engineer employs this estimating procedure and decides that the use of a slurry pipeline is economically unattractive, his chances of being wrong are small. Conversely, if his quick appraisal indicates that the use of a slurry system is economically favorable, the engineer is justified in committing the time and money needed to make a more detailed investigation of the slurry pipeline potential.

Jan 1, 1969

By G. L. Mowrey

In addition to developing various types of coal interface detection systems, the U.S. Bureau of Mines is actively involved in developing a coal rib thickness monitoring system for high wall mining applications. One particular system that appears to show promise uses a ground-penetrating radar system to detect the coal-air boundaries of coal ribs. Based on preliminary laboratory and field tests, results indicate that this method can be applied successfully in highwall mines to maintain a constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

Jan 1, 1995

By Robin P. Gardner

The mechanistic approach to comminution consisting of incorporating particulate breakage functions into a suitable population balance equation has been developed by a number of researchers over the past decade or so. (1) To date this approach has been developed and demonstrated primarily for batch-operated, laboratory or small-scale ball mills. However, since industrial mills are mostly quite large and operated in the continuous mode; suitable population balance models and methods for obtaining the necessary breakage and other model parameters must be developed. This paper describes and investigates a radioisotope tracer technique for this purpose, Population balance models previously developed(2,3) are adapted for this study.

Jan 1, 1974

By M Logsdon, B Johnson, M Fordham

The underground Neves Corvo copper-tin mine in southern Portugal currently disposes of its tailings in a ætraditionalÆ wet tailings impoundment. With the development of new technologies for preparation and transport of thickened tailings or paste, alternative tailings disposal options have become available that provide a more sustainable water management system and a higher degree of environmental protection. In addition, growing European resistance towards subaqueous disposal may well result in mandatory use of dry disposal methods in the near future. Twenty-four tailings disposal alternatives were evaluated through a cost-effective and easily-implementable bench-scale geochemical screening program conducted at site. Since the tailings are pyrite-rich and highly acid generating, particular emphasis was placed on monitoring likely indicators of sulfide oxidation under the various simulated disposal scenarios. Dependent parameters investigated as part of the program included moisture content, use of alkaline additives (lime, cement), use of a bactericide, and agitation. Response parameters included paste pH, specific conductance, and temperature as indicators of oxidation. The testing was carried out for 30 weeks. Results indicate that a number of relationships between the geochemical stability of the samples (ie sulfide oxidation) and sample characteristics can be readily identified. Based on the results of the screening program, a limited number of tailings mixtures have been selected for further long-term testing in field weathering cells to aid in the identification of the optimal mix design for future tailings disposal at the Neves Corvo Mine. This type of testing provides an inexpensive and reliable methodology for semi-quantitative comparison between tailings disposal alternatives, in particular at locations where more rigorous evaluation through long-term, fully replicated testing is not immediately feasible.

Jan 1, 2003

By Enrique Llewellyn

North River Energy Company a previous subsidiary of Republic Steel Corporation commenced development of the Number One Mine in mid-1972. The mine is located in West Alabama and presently employs a total of 632 people. Production capabilities have increased to 1.4 million clean tons of steam coal per year with the newly purchased Longwall System. Washer recovery averages 57 percent. The seam being mined is the Pratt or Corona with an average height of 52 inches and an average cover of 540 feet. The immediate roof is laminated sandstone and the floor is composed of a hard fireclay. Total production out of the mine is provided to Alabama Power Company under a longtime contract.

Jan 1, 1981

By L. G. Austin

A simple finite difference algorithm has been used to compute a simulation model for unsteady-state ball milling. The model considers the mill to act as if it were three fully-mixed reactors in series (one-large/two- small), it incorporates the-Rogers-Austin mass transfer law relating mill hold-up to flow rate through the mill, and it allows for the reduction in breakage rates caused by over-filling of the mill at high flow rates. The computation is rapid and requires only small storage space. Examples are given of use of the model.

Jan 1, 1984

By T. F. Dumm, O. Trass, V. R. Koka, L. G. Austin

"The size distributions of carefully screened 2 size fractions of ground materials were determined using a Microtrac laser dif-fractometer. The size distributions were fitted to the empirical function P(x) = 1/[1 + (x50/x)1] where P(x) is cumulative mass fraction less than Microtrac size, x. The standard deviation of A for a 50 second test time was approximately 0.5, so that seventeen test times give a mean with an estimated error within t 0.25 (95% confidence level). Values of were 5.44, 4.82, 4.40 for a coal ground under different conditions, indicating statistically different shape distributions; the average value for mica was 2.91 owing to the high aspect ratio of the particles. The ratio of x50 to the geometric mean sieve size was 1.2 for the coal and 0.70 for mica.1 IntroductionKoka and Trass have presented evidence [1,2] that materials ground in the Szego mill [3] give different shapes depending on the milling conditions. The variations in shape were deduced qualitatively by viewing SEM photomicrographs of selected 1/2 screen fractions. This paper quantifies their observed differences in shape by using measurements of the size distributions of screen fractions examined in a laser diffractometer [4] (Microtrac, Model 7991). The basic concept is that particles of 'a given ""screen"" size will give a wider distribution of ""Microtrac"" size when the particles are flaky with high aspect ratios, and a narrower distribution when the particles approach the cubical and spherical geometries.2 TheoryAustin and Shah [5] have shown that coal screened within a 1. 1/2 upper-to-lower sieve size range will give rise to a much wider distribution of Microtrac size. They found that the screen interval of irregular fragments of comminuted coals or quartz gave Microtrac size distributions which could be described by the simple function"

Jan 1, 1988

By JOHN HOMER, Jacob L. Carr, Jonathan K. Hrica, Kathleen M. Stabryla, Iman Benbourenane, Jennica L. Bellanca

Given the recent focus on powered haulage incidents within the US mining sector, an appraisal of collision avoidance/warning systems (CXSs) through the lens of the available research literature is timely. This paper describes a rapid review that identifies, characterizes, and classifies the research literature to evaluate the maturity of CXS technology through the application of a Technology Readiness Assessment. Systematic search methods were applied to three electronic databases, and relevant articles were identified through the application of inclusion and exclusion criteria. Sixty-four articles from 2000 to 2020 met these criteria and were categorized into seven CXS technology categories. Review and assessment of the articles indicates that much of the literature-based evidence for CXS technology lies within lower levels of maturity (i.e., components and prototypes tested under laboratory conditions and in relevant environments). However, less evidence exists for CXS technology at higher levels of maturity (i.e., complete systems evaluated within operational environments) despite the existence of commercial products in the marketplace. This lack of evidence at higher maturity levels within the scientific literature highlights the need for systematic peer-reviewed research to evaluate the performance of CXS technologies and demonstrate the efficacy of prototypes or commercial products, which could be fostered by more collaboration between academia, research institutions, manufacturers, and mining companies. Additionally, results of the review reveal that most of the literature relevant to CXS technologies is focused on vehicle-to-vehicle interactions. However, this contrasts with haul truck fatal accident statistics that indicate that most haul truck fatal accidents are due to vehicle-to-environment interactions (e.g., traveling through a berm). Lastly, the relatively small amount of literature and segmented nature of the included studies suggests that there is a need for incremental progress or more stepwise research that would facilitate the improvement of CXS technologies over time. This progression over time could be achieved through continued long-term interest and support for CXS technology research.

Jun 17, 2022

By JOHN HOMER, KATHLEEN STABRYLA, JACOB L. CARR, JONATHAN K. HRICA, JENNICA L. BELLANCA

Given the recent focus on powered haulage incidents within the U.S. mining sector, an appraisal of collision avoidance/warning systems (CXSs) through the lens of the research literature is timely. This paper aims to evaluate the maturity of CXS technology through the application of a technology readiness assessment (TRA) to research literature identified by systematic search methods. Results indicate that much of the evidence for CXS performance is at lower levels of maturity: that is, components and prototypes tested in a laboratory and in relevant environments. Less evidence exists for CXS performance at higher levels of maturity — that is, systems evaluated within operational environments — despite the existence of commercial products in the marketplace. This lack of evidence at higher maturity levels within the scientific literature highlights the need for more peer-reviewed research to evaluate CXS technologies. Additionally, results of the review reveal that most of the literature relevant to CXS technologies is focused on vehicle-to-vehicle interactions, which contrasts with haul truck fatal accident statistics that indicate most are due to vehicle-to-environment interactions, such as traveling through a berm. Lastly, the relatively small number and segmented nature of relevant studies suggest there is a need for more incremental research that would better facilitate the improvement of CXS technologies. This progression could be achieved through continued long-term interest and support for CXS technology research.

Mar 1, 2023

By D. A. Trotter

"Low-pressure sodium light sources have been available for several years, but have not received wide acceptance in underground mining. This is because they are difficult to operate using DC power, they are not an intrinsically safe light where explosive gases may be encountered and they give poor colour rendition.With the need for energy conservation, several Canadian hard-rock metal mines are now changing their lighting to low pressure sodium, as it has the highest efficacy of any light source in terms of lumens per watt. Studies have pointed out several other advantages as well. Glare can be controlled, they penetrate fog well, they are easily maintained, they have a long life and they give the highest visual acuity when compared to other types of lighting. As well, in an underground mine, contrast is much more important than colour for task identification. For close work, the colour problem is alleviated with the use of cap lamps.Case studies are presented from Canadian practice. These show how the lights are modified for underground use, calculations preceding light installation, and how and where the lights are installed in the underground environment. Mention is made of worker reaction to the lights and possible physiological effects.IntroductionThe importance of good underground lighting to the total environment of mining cannot be overemphasized. In addition to the obvious benefits of improved worker morale, available studies show that good lighting practices reduce accident severity and frequency as well as increase production."

Jan 1, 1982

By David J. Kerr, Robert Mason

"From1927 to1989, the Hornemineproduced53.7 Mt of ore grading 6.1 g/t Au and 2.2% Cu from two large volcanogenic massive sulphide deposits composed primarily of pyrrhotite, pyrite and chalcopyrite. The ore bodies were hosted by a package of chlorite-sericitealtered epiclastic rhyolite tuffs which were deposited in a narrow palaeo-graben located on the flank of a major felsic volcanic centre. M ineralizingfluids percolated upward through the permeable footwall rocks and were further focussed along syn-volcanic, graben-bounding faults. Sulphides were deposited by a process of sub-seafloor replacement of the rhyolite tuffs.Gold-copper-(zinc) mineralization, including ore zones mined between 1985 and 1989 as the REMNOR ore zones, is present throughout the 900 m of felsic volcanic stratigraphy at the Horne. All the deposits were formed by syn-volcanic hydrothermal processes active during felsic volcanism. There is no evidence to indicate that any economic gold mineralization was introduced by a post-volcanic hydrothermal episode.RESUMEDe 1927 a1989, /amineHorneaproduit53.7 Mt de minerai avec une teneur de 6.1 g/t Au et 2.2% Cu provenant de deux grands amas de sulfures massifs volcanogeniques comprenant esentiellement de la pyrrhotite, de la pyrite et de /a chalcopyrite. Ces gites font partie d'une séquence de tufs rhyolitiques epiclastiques chloritises et sericitises qui ont ere déposes dans un paleo-graben étroit situe sur le flanc d' unimportant centre vo/caniquefelsique.Lesfluides mineralises ont circule de bas en haut a travers /es roches perméables sous-jacentes; ils ont été également canalises par les failles syn-volcaniques en bordure du graben. Les sulfures se sont déposes par remplacement des tufs rhyolitiques immédiatement et sous /e plancher océanique.Les zones minéralisées en or et cuivre (±zinc) - y compris celles qui ont ere exploitees au cours de l’opération Remnor (1985-1989) - se retrouvent, sans discontinuité, à travers les roches volcaniques felsiques dont l' epaisseur atteint 900 m. Ces gites se sont formes par le biais d' un processus hydrothermal qui ag issait pendant le volcanisme felsique. II n'y a aucune évidence de minéralisation aurifère d'importance économique qui soit postérieure a l' activité hydrothermale syn-volcanique."

Jan 1, 1990

By B. J. Madden

The formula developed by Salamon and Munro in 1967 has been used for the past 22 years in the design of bord-and-pillar workings in South African collieries. This paper re-assesses the formula In the light of Its past performance and examines the effect of mining method on coal-pillar strength. An account is given of the extension of the formula so that it can be applied beyond the empirical range for which it was derived, and the advantages of the extended formula (the squat-pillar formula) are described.

Jan 1, 1991

By G. W. Sparkes

The use of CR-39 plastic polymer as a solid state nuclear track detector in the textural analysis of radioactive minerals in geological samples was first described by I.R Basham in 1981. CR-39 autoradiographs provide a detailed, high-resolution image of the in situ distribution of the radioactive minerals within geological samples on both the macroscopic and microscopic scales. This technique is an inexpensive and effective means of obtaining detailed textural information that provides insight into the style of mineralization, its relationship to primary and secondary structures in the host rock, and its association with particular geological features or mineral phases. Although this technique does not provide any information on the identity of the minerals responsible for the radioactivity, the resultant autoradiographs can be used to select regions for further detailed analysis such as petrography, microprobe analysis, or SEM imaging. This paper summarizes the procedure and outlines the appropriate time and materials required for both the exposure and etching of the CR-39 with respect to the intensity of the radioactivity emitted by the geological samples.

Jan 1, 2013

By Charles E. Barker

Jan 1, 1985

By M. Melashvili

"The SART Process was introduced to the gold mining industry in the late 1990s and several commercial plants were built over the following 10 to 15 years. Most of these plants have operated well and enjoyed plant performance in line with expectations based on the underlying chemistry of the process. However, two of the plants have consistently suffered from high reagent consumption and poor product quality, which has motivated a re-examination of the process fundamentals in the hope of understanding the reasons for poor performance when it occurs, and developing mitigating strategies.This testwork along with a review of the relevant literature has demonstrated that the amount of sulphide added to the primary reactor, relative to the copper concentration, is the most critical parameter dictating plant performance, with pH and residence time important secondary factors. The primary product in the SART Process is synthetic chalcocite, Cu2S, and the stoichiometric requirement for sulphide addition is therefore 0.5 moles per mole of copper in solution. Testwork shows that when sulphide is added in excess of this amount (generally with the express purpose of lowering residual copper in solution) it not only fails in its intended purpose, but can have a negative impact on the settling and filtration characteristics of the copper sulphide product, as well as the final product quality. Moreover, these problems are exacerbated the higher the selected operating pH in the pH 3 to 5 range, and the longer the residence time of slurry in this pH range.Freshly precipitated copper sulphide compounds are known to be very fine and slimy, with poor settling and filtration characteristics. It is therefore important to engineer the SART Process in such a way as to encourage growth in the average particle size of the precipitate crystals. This was the rationale for recycling a portion of the thickener underflow to the primary reactor when the SART Process was developed. The theory of crystallization predicts that compounds of extremely low solubility, such as chalcocite (Cu2S: KSP = 10-48), are likely to experience growth in crystal particle size through aggregation rather than heterogeneous nucleation. On this basis, the SART practice of recycling a portion of thickener underflow to the primary reactor in the commercial plants is unlikely to lead to crystal growth via nucleation, and could in fact promote breakage of the aggregates that formed in the thickener. Recycling thickener underflow could therefore have the opposite of the desired outcome. The result of testwork that is reported here lends credence to this theory and questions the wisdom of recycling in the SART process.There is evidence to suggest that operating the copper sulphide thickener in the SART Process without flocculants may be beneficial. Thickener underflow densities could improve from the current 10 - 15% range to 40 - 50%. This will not only reduce the flowrate of slurry to the filter, but the filtration properties of the slurry (filtration rate, filter cake moisture content) will also improve. This is one of the most critical engineering and design aspects of the SART Process, and the achievement of high solids density in the thickener underflow will not only improve the health and safety aspects of the operation, but also has the potential to lower capital costs and improve the quality of the final product."

Jan 1, 2016

The Burra Burra Mine is situated in complexly folded Torrensian dolomites and limestones forming the faulted axial region of a major anticline. The orebody mined was largely of secondary origin and confined between two faults, Kingston's on the west and Tinline's on the east. The orebody occurred at the junction between cherty dolomites and a clastic limestone with a large mass of marble breccia along its western margin. Secondary ore consisted of carbonates and oxides in the breccia and the ore bed and detrital copper minerals deposited as part of a clastic breccia in sinkholes and solution cavities in the dolomites and ore beds.Primary sulphides occur disseminated in the marble breccia and in stratiform habit in the ore bed. Kingston's so-called "lode" may be mineralized marble breccia.The marble breccia appears to be of diapiric or sedimentary origin and there is evidence to support a sedimentary origin for some of the copper sulphides. No igneous rocks have been discovered within 20 miles of the mine and any hydrothermal activities were probably at comparatively low temperature. The possibility of extensive stratiform and disseminated copper sulphide mineralization in the marble breccia and ore bed requires testing by further drilling and geophysical surveys.INTRODUCTIONThe re-interpretation of Burra Burra geology and ore formation discussed in this paper resulted from a comprehensive investigation of the mine and its surrounding district begun in December 1961 and in progress at the time of writing. (February 1963). The decision to investigate Burra Burra was taken after a thorough examination of records and reports of all non-ferrous metal deposits throughout South Australia and was given impetus by a report by Thomson (1963) suggesting a sedimentary origin for the copper mineralization. Although the author does not concur fully with Thomson's interpretation there is no doubt that sedimentary processes have played an important part in the formation of the Burra Burra copper deposit, nor is there any doubt that igneous activity played no part.

Jan 1, 1963

By J. Botin

Traditional risk quantification methods provide little information on the sources of risk, and tend to produce static over-conservative evaluations, which do not account for changes in the performance of the project. Capital investment decisions for large mining projects require more complex risk evaluation models that include the value of flexibility and the different risk levels associated with uncertainty on project variables (price, grade, dilution, and production rates, among many other). In this context, real option valuation (ROV) methods have proven potential to quantify the risk associated with such variables and integrate alternative scenarios and management strategies into the evaluation process. In this paper, a risk quantification model is developed that successfully quantifies the risk associated with dilution, as a function of production rate. This model is then validated in a case study on the Chuquicamata Underground Mine project. Keywords real options, risk management, risk quantification, dilution, minine planning.

Jul 1, 2013

By Kubik K

Recent significant advances in the Global Positioning System (GPS) have contributed to making real-time kinematic/dynamic process for decimetre to centimetre-level positioning more reliable and ready for the production-use. As a result of research and development efforts in this area, a robust real-time kinematic (RTK) GPS positioning prototype system has been established at QUT for both scientific and engineering purposes. This system is finding applications in a wide range of automobile robots or automatic guidance vehicle systems. This paper first summarises the theoretical basis necessary for centimetre real-time kinematic positioning, then gives a brief description for the real-time dynamic GPS system developed at QUT. The paper summarises the results of a designed vehicle tracking test. The results demonstrated that the differences between RTK filtering solutions and OTF solutions are in the order of magnitude of about 20 centimetres and the accuracy of OTF solutions are in the levels of two centimetres. This confirms that the RTK system delivers three-dimensional position with decimetre-to-centimetre accuracy. This particular RTK processing system is robust and reliable, although the system is referred to as a prototype and will be further developed.

Jan 1, 1997