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By Ismet Canbulat

"In order to ensure the stability of roadways, Anglo American Metallurgical Coal (AAMC) has developed a roof support design methodology that integrates analytical, numerical and empirical modelling. This methodology currently is based on a deterministic approach (a single factor of safety against failure is calculated). However, an improved methodology, based on stochastic modelling technique, has also been developed and currently being evaluated. The main advantage of this methodology is that the design is based on the probability distributions of input parameters; thus the outcome is based on a distribution of factors of safety rather than a single factor of safety. An evaluation of factors of safety may also be used to determine the likelihood of failure, which in turn may be utilized to quantitatively determine and evaluate the associated risks in decision making process. This methodology has been evaluated at Grasstree and Moranbah North Coal Mines in the designs of roof support in various critical areas and has been proven to be successful and a better way of determining the roof support requirements.This paper demonstrates the application of this methodology in a design of an install road roof support at Moranbah North Mine, where the 1,750 tonne capacity ''world's highest rated longwall"" has recently been installed.INTRODUCTIONAnglo American Metallurgical Coal Australia (AAMC) operates three longwall (LW) mines located in Central Queensland. There is an increasing emphasis on the reliability at these operations, as the longwalls are getting deeper and facing more geologically challenging conditions. In addition, the Anglo American Vision is to achieve ""Zero Harm"" through the effective management of safety at all businesses and operations. In order to accomplish this vision, AAMC has developed a proactive ground control management system for a safe and efficient production of underground reserves.Proactive ground control management involves understanding the impacts of the geotechnical environment on likely ground behavior, and it consists of approximately 15 major elements. One of the most essential fundamentals of proactive ground control management is to utilize a roof support design methodology that considers different failure mechanisms and also takes into account all important elements. The design methodology becomes even more important when the area in question is a critical area, which is defined as a high risk roadway where any failure may cause increased levels of safety and financial risks to underground workforce and operations."

Jan 1, 2010

By P. Momni, D. Ersenkal

Equator Principles (EPs) are a set of guidelines developed and adopted by a series of financial institutions for assessing and managing social and environmental issues in project financing. Established in 2003, EPs are now adopted by some 68 financial institutions from 27 countries. As more and more financial institutions join this global initiative, it is important for project owners to have a logical framework embedded into the project lifecycle to reduce the risk of non-compliance which could result in costly delays. This paper outlines a proactive approach for project developers in order to integrate environmental and social aspects into entire project lifecycle.

Jan 1, 2010

By Victor E. Kral

The Valery fluorspar deposit , also known as the Hamilton deposit , is northeast of Lovelock and 4 miles by poor dirt road east of U. S. Highway 40 . It is in the Humboldt Mining District , on the west side of the Humboldt Range , at an altitude of 6,000 to 6,500 feet . The property was examined by the Bureau of Mines on February 83/ and April 8 , 1944.4/ The last examination was made with an engineer of the Geological Survey.5/ Exploring by means of trenches , cuts , shaft sinking , coyote holes off the shaft , and a small amount of prospecting with short drill holes , was begun in January 1945 and was completed June 30 , 1945. An engineer6/ of the Geological Survey visited the property in April and again in June 1945 to complete a topographic map of the area and to note the results of exploration by the Bureau of Mines . Only minor surface exploring had been done on fluorspar occurrences previous to the Bureau's work . No mining equipment or living facilities are on the property .

Feb 1, 1947

By A. S. Choudhary

Most of the coal reserves in India are of drift origin and have very poor washability characteristics and a high level of near gravity materials. At least 30 new coal wash plants are expected to be set up in the next 5years.In such a scenario, adequate sampling followed by sink float test work for washability analysis becomes very critical for designing these new plants. For coal sampling purpose, stipulations of different standards are sometimes formidable and on the border of ?impracticality?; sometimes are self contradictory in terms of gross sample weight vis-a-vis minimum number of particles required in each size fraction and in each relative density fraction and also the minimum mass in the latter. Validation of the generated data is another important aspect of washability analysis. These issues can easily be addressed by using straight forward mathematical relationships, well known RR plots and by using simple MS Excel tool, etc.

Sep 1, 2012

By A. M. Glendinning

"IntroductionLocationTHE PROPERTY of Aunor Gold Mines, Limited is in Deloro township, Ontario, about three miles southeast of the town of Timmins. It consists of a group of eleven claims located between those of Buffalo-Ankerite Gold Mines, Limited, and Delnite Gold Mines, Limited.GeologyThe ore zone at the Aunor mine consists of a narrow band of fine grained pillowed andesite, irregular bands of 'brown to green carbonated andesite, and lenticular bodies of quartz feldspar porphyry. The zone strikes N.80°E., dips 60 North, and has been traced for 5,000 feet across the property. It varies in width from 0 to 250 feet and is bounded on the north and south by masses of dark bluish-grey tale chlorite schist. These schist bands have widths up to 500 feet.The ore occurs in a series of parallel and branching veins confined to the limits of the zone. These veins tend to terminate and die out on the footwall schist contact, striking generally parallel with the ore zone. In wide sections of the zone, 150 to 250 feet, the veins range in width up •to 3.5 feet and may occur in two or three horizons across the width of the zone, each mineable independent of the other. They tend to dip a little flatter than the general dip of the zone. Where the zone is narrow, the veins are so closely spaced and numerous they can be mined together and in some places the complete zone has been mined from schist to schist."

Jan 1, 1953

By Manuel Gomez

Low-temperature carbonization product yields for 129 coals representative of 12 Utah coalfields were estimated, using regression equations developed from heating value and proximate and ultimate analysis data. It was shown that yields of char, tar plus light oil, water of decomposition, and gas, as well as the gas volume and the heating value of the gas, could be predicted with reasonable accuracy. Published and experimental results from eight Utah coals carbonized at selected temperatures in the 4500 to 1,000° C range were used to determine the effect of temperature on product yields. Carbonization temperature, heating value) oxygen, and volatile matter of coal appear to be the principal variables influencing carbonization product yields. Data presented show that the heating value and the residual volatile matter in low-temperature char may be predicted using relationships developed from proximate analysis data for 220 coals.

Jan 1, 1967

By John R. Parker

Work places of an underground coal mine are required (30 CFR 1719) to be illuminated while self-propelled equipment is used. Permissible machine mounted systems have been developed and applied satisfactorily to many mining operations. However, some low seam and thin seam equipment has been difficult to illuminate because reliable, direct current systems and compact, low output, low glare luminaires were not available. This program resulted in the design and prototype construction of compact, low glare luminaires and AC and DC power systems, particularly suited to resolving illumination problems on low and thin seam mining equipment. Design objectives were based on enhancing the prospects for thin seam illumination solutions through definition of a product which could challenge markets enjoyed by higher glare luminaires and through reduction of technical risks associated with any new product development as well as the MSHA certification process.

Jan 1, 1982

By I. Yochev, A. A. Metelev, A. I. Stepanenko, A. P. Purgin, M. G. Viduetsky, A. M. Panshin, I. F. Garifulin

"Pneumatic flotation cells of the KFM series are intended for the concentration of various ores and technogenic materials. The key operating principle of the flotation cells of the KFM series is the preparation of pulp for flotation in blowers, offering the advantage of an accelerated flotation process. This report summarizes the results of the implementation and operation of the KFM cells at Russian and foreign projects in 2015-2017. Their implementation and operation experience confirms the high efficiency of the KFM cells, especially in the head of lead and zinc, copper and zinc, copper flotation processes:head KFM-600 flotation cell recovers from lead-zinc ore (Rudmetal AD modular concentrator) up to 52% of lead in a single stage (without cleaner flotation) in a salable lead head concentrate (grade of up to 76% lead, 2.3% zinc). The flotation cell proved to be much more efficient than originally expected in the process description in the design phase,flotation of the copper-zinc ore from Novo-Shemur deposit (PJSC Svyatogor concentrator) in two KFM- 1400M cells recovers up to 65% of copper and 70% of zinc in a high-grade bulk copper-zinc concentrate containing 12-13% of copper and 25-28% of zinc. The installation of the two cells with a combined capacity of 26 m3 allowed to decommission 4 chambers of FPM-16 pneumomechanical flotation cells with a combined capacity of 64 m3 with a simultaneous increase in the overall ore concentration performancea single KFM-1400M cell (13 m3) recovers from the copper ore from Volkov deposit (PJSC Svyatogor concentrator) 53% of copper into a high-grade copper head concentrate (33.0% of copper). For comparison, the pneumomechanical cell FPM-16 (capacity 16 m3) has almost half as low copper recovery (29.6%) into the head concentrate at a lower grade (30.5% copper)."

Jan 1, 2018

By M. Knot

Fans delivered to the Russian Federation, and eventually to countries of the former U.S.S.R., for mine ventilation must meet the legislative requirements of local jurisdictions. This paper presents a discussion of these legislative requirements and presents examples of fan equipment designed to meet the requirements. The legislative obligations discussed include four (4) separate requirements, including: ?Technical design requirements ? The Federal Agency for Technical Regulation and Metrology is responsible to issue a GOST R certification declaring conformance to the requirements ?Operational requirements ? A ?License for Application? must be obtained prior to operation ?Explosion risk requirements ? If the area of operation includes potential for explosion a special certificate must be obtained ?Technical condition requirements ? Market segments within the mining industry require special conditions that must be satisfied Examples of fans designed specifically for use in the Russian Federation are also discussed and examples provided. Designs for fan volume flow control will be highlighted.

Aug 1, 2013

By Matthew Price, Laura Brown, Atulya Verma, Samantha Espley

Burst-prone conditions are a significant hazard in deep hardrock mines, elevating the risk to excavation stability and, more importantly, to worker safety. As mining progresses deeper, induced stress changes may trigger the initiation of rock failure processes which can be detected and recorded as mine seismicity. The implementation of seismic monitoring and routine seismic data analyses enables mine seismicity to be quantified spatially, temporally and on scale. The ability to quantify and characterize mine seismicity offers the opportunity to gauge seismic hazard, identifying high risk zones for mitigation against burst-prone excavation failure. Over the last decade, the Mines Technical Services (MTS) group at Vale Canada Limited’s Garson Mine assessed seismic hazard with the objective of assigning practical mitigating controls to zones identified as having a high rockburst potential. Initially, seismic hazard was computed using the Seismic Excavation Hazard Mapping (SEHM) software developed by the Mining Innovation Rehabilitation and Applied Research Corporation (MIRARCO) at Laurentian University, Canada. More recently, Vale Sudbury Operations partnered with the Australian Centre for Geomechanics and the University of Western Australia’s mXrap consortium. Through the consortium partnership, MTS at Garson Mine implemented the mXrap seismic data analyses platform, including the grid-based seismic hazard assessment tool. Building on 10 years of seismic hazard assessment experience at Vale Garson Mine, this paper summarizes a comprehensive case study, comparing the two tools (SHEM and mXrap) used at Garson Mine to assess, quantify, and represent seismic hazard. Subsequently, results of the Garson Mine comparative seismic hazard study will be discussed, emphasizing the need for an all-inclusive hazard assessment tool, focused on delivering practical mitigating controls that further enhance the overall safety of seismically active underground mines.

Apr 26, 2022

By R. D. Leitch, W. P. Yant, A. C. Fieldner, R. R. Sayers, S. J. Pearce

"The detection of leakage is a recognized problem in the safe and economic distribution and use of natural gas. Natural gas is practically odorless and therefore lacks he property of indicating significant leakage by the sense of smell, the means most widely used by gas employees and consumers for detecting leaks of the more odorous types of fuel eases. In view of the recognized value of the odor of gas for indicating leakage at the time of occurrence the Bureau of Mines has studied' the possibility of adding small amounts highly odorous substances to types of fuel gas (such as blue water gas and natural gas) that lack warning properties. These studies revealed that the mercaptans were promising substances to accomplish this purpose, not only for odorizing fuel gases but for other purposes° where it was desired to give warning through the sense of smell.Since completing the studies mentioned, the Bureau of Mines jointly with the American Gas Association has conducted further investigations dealing with the use of warning agents for fuel gases. The results of this work will be published later.The Bureau of Mines had been desirous of observing the practical use of ethyl mercaptan for detecting leakage of natural gas, particularly to determine whether the odor would permeate the ground and give indication of lea's in underground pipes. Opportunity for making these observations was recently given by E. A. Munyan, manager, gas department, Union Gas t Electric Co., who requested the bureau's cooperation in making leakage surveys of the company's distributing systems at Franklin and Middletown, Ohio."

Jun 1, 1930

By George T. Faust

The petrographic microscope plays an important role in the mineral dressing of nonmetallic materials. Petrographers and mineral technologists have evinced an interest in the technique developed, specifically, for mineral-dressing problems. The following dissertation makes the informa¬tion more generally available. ACKNOWLEDGMENTS The authors are indebted to O. C. Ralston, chief engineer, Nonmetals Division, and to Will H. Coghill, supervising engineer of the Southern Experiment Station for a critical reading of the manuscript. They are also indebted to their colleagues for technical information obtained in the course of cooperative work, in particular to J. B. Clemmer for the use of the data on fluorite.

Jan 1, 1940

By Gregory M. Molinda

Large structural faults create serious ground control hazards, as well as adversely affect coal mineproduction. Two faults related to the Pine Mountain overthrust sheet in Buchanan County, VA, were investigated by the U.S. Bureau of Mines to determine their effect on ground control and to develop recognition criteria for prediction. Five underground mines encountering these faults were visited and mapped for structural information. This information, along with surface mapping, indicated that Pistol Gap and Keen Mountain Faults show right-lateral, strike-slip faulting and bedding planes slippage, which can be projected linearly and vertically. These fault zones are up to 200 ft wide, with coalbed offsets up to 18 ft vertically, coalbed swags (depressions) up to 15 ft, and roof falls up to 20 ft high. Recognition criteria include bedding plane slips, coalbed offsets, fault gouge, coalbed swag (depressions or synclines), and disturbed bedding. These recognition criteria will help an informed operator realize that many sudden coalbed discontinuities are related to larger geologic events (in this case thrust faulting) and can be projected linearly and vertically. Ground control strategies include mine designs that minimize fault exposure. Mining plans can be adjusted based on type and extent of fault movement.

Jan 1, 1989

By John J. Moore

This paper discusses the application of a video technique to construct stability diagrams for the combustion synthesis of ceramic-metal composites. Several model exothermic combustion synthesis reactions have been used to investigate the effect of the reaction parameters, eg. stoichiometry, green density, etc, on the stability of the propagating combustion reaction front and subsequent product morphology. The effect of varying the reactants and their stoichiometry to provide a range of reactant and product species ie. solids, liquids and gases, in the synthesis of both dense and expanded (foamed) ceramic and ceramic-metal composites was also investigated with respect to their corresponding combustion front stabilities.

Jan 1, 1993

By I. C. Howard, E. J. Palmiere

"Heat transfer and friction in hot flat rolling have traditionally been characterised by an average heat transfer coefficient (h) and an average friction coefficient (p.). However, the presence of oxide scales and asperities at the interface question the use of such averages. The apparent irregularity and lack of pattern of interactions at the interface has prompted this present investigation to move away from averaged h and 11 values, and to study their local evolution based on probabilistic rules. The approach is based on the probability of finding the workpiece surface in a specific configuration at a particular instance of time in the roll gap. These rules are based on observations of surface phenomena such as scale behaviour during hot rolling. The model is implemented using user-subroutines integrated with the commercially available finite element program ABAQUS™. The results show the strong dependence of h and u on the local scale interactions. In particular, the effect of scale thickness, material behaviour and processing conditions on the evolution of hand 11 are discussed. Finally, the development of a Cellular Automata based Finite Element (CAFE) model is proposed to model the combined interfacial phenomenon of friction and heat transfer at the tool-work piece interface.IntroductionIntricate interactions between process variables in hot rolling of steels make it a challenge to the modelling community. For a given material and geometry combination, reducing interfacial power losses can increase the efficiency of the rolling process. The roll-strip interface, therefore, forms the critical zone and is currently the domain of intense investigation, especially to characterize interfacial frictionl • 2 and heat transfer3 • 4 . These interfacial phenomena are inter-related and cannot be studied in isolation. However, very few mathematical models4 • 5 combine an analysis of friction and heat transfer and deformation of the strip-roll interface taking into account the role of asperities and oxide scales."

Jan 1, 2001

By John T. Whetton

"FROM 1850 when the annual production was around 50 million tons, coal output in Great Britain expanded rapidly to 225 million tons in 1900 and 287 million tons in 1913. However, during the First World War, countries which had previously bought large quantities of coal from Britain sought other sources of sup-ply or developed their own coal re-sources. Thus from the record figure of 73 million tons exported in 1913, Britain's coal exports declined until in 1938 they stood at 39 mil-lion tons. An important reason for this was the development of oil engines for marine propulsion. Today, nearly all the navies and mercantile shipping in the world have turned to oil engines. Sometime in the future, however, it is reasonable to expect nuclear power to replace oil.During the Second World War, coal output in Great Britain and manpower at the mines were reduced considerably and in 1.945, 175 mil-lion tons were produced by 709,000 miners. Exports were meagre, only 8.""7 million tons went to foreign consumption. During the severe winter of 1947, inland demand for coal exceeded production and exports were prohibited. Even importation of coal was required to meet inland demand. These were years when the coal industry of Great Britain made immense efforts to secure maximum output irrespective of economy. The energy needs of Great Britain appeared insatiable; but had it been possible to export, the nationalised mining industry could have made huge profits as there was a world shortage of coal. However, home needs were considered to be the priority and many overseas markets were lost. Other producers moved in and secured long-term contracts. Not only was the British export market lost, but also the nationalised industry had to sell the imported coal at the same prices as home-produced coal and suffered losses up to of:3 per ton. Bence, at a time when the National Coal Board might have ac-cumulated a reserve fund to cope with less prosperons times, it was having to spend large sums of money securing sufficient coal for inland consumption. This was a time when intensive efforts in the mining industry, comparable with those of many industries and establishments inclusive of the armed services during the war, would have produced a greater amount of coal and have been of immense value to the country as a whole."

Jan 1, 1960

By E. R. Hughes

Introduction Situated 182 miles east of Vancouver, on the Kettle Valley branch of the Canadian Pacific railway, the Princeton coal field is readily accessible to the Coast markets. The area covers approximately forty square miles and present indications are that the deposits should contain at least 300,000,000 tons of coal. Comparatively little development has yet taken place in this coal field. Since the commencement of recorded output, the collieries operating in this area have produced 1,640,518 tons of coal. The coal field proper includes only the Tertiary deposits adjacent to the town of Princeton and does not include the Coalmont or Nicola deposits. Production has never been on a large scale. The largest annual output from any property was 81, 780 long tons mined at the Granby colliery in 1940. Coal output was first recorded in 1909 and since that time fifteen properties are reported to have either mined coal or to have done prospecting or development work; of these, only two are presently active. However, none of the properties now inactive were closed because their coal resources were exhausted. The accompanying key map shows the extent of the Princeton coal field, and the location of the coal mines and prospects in this field General Geology The Princeton field is underlain by rocks of Oligocene age and is one of the series of more or less isolated Tertiary lake basins in which coal, or lignite, has been found in the interior of British Columbia. Resting on the Nicola group rocks of Triassic age, the Princeton sedimentaries consist of sandstones, conglomerates, shales, bentonite, bentonitic clays, and several seams of coal. Tertiary volcanics occur both above and below the stratified rocks and in places they have been thrust through the overlying measures. In some areas, the coal has been burned to a red ash as the result of vulcanism, while in other parts some of the moisture has been driven from the coal, thus improving the grade. The field can best be described by dividing it into two areas: the Southern area, lying to the south of the town of Princeton, where most of the mining has been done; and the Northern area, to the north of Princeton, where very little development has taken place.

Jan 1, 1947

By Hai Lin, Renshu Yang, Yongliang Li, Shizheng Fang

With the aim of solving the large deformation problem of surrounding rock in coal mine roadways with a thin sand-mudstone interbed roof, transportation roadway 1603 in Haoyuan Mine was considered. The failure mechanism of surrounding rock was studied through comprehensive on-site investigations, borehole image analysis, mineral composition analysis, and other means. Numerical simulations were performed to determine the influence of roof layer thickness, lateral pressure coefficient, and coal rib strength on the stability of the interbedded roof. The main reasons for support failure and deformation of the roadway are softening and swelling of the sand-mudstone interbed roof upon exposure to water, insufficient support capacity of the roof due to the soft coal rib, an unreasonable support scheme, or poor construction quality, which can reduce the bearing capacity of surrounding rock. Based on our analysis, a control strategy was devised for a thin coal-mudstone interbed roof. The support scheme combines long and short cable support, strengthening of the coal rib to consolidate the roof, and partially shotcrete grout, and was found to improve the overall mechanical strength of surrounding rock and maintain the stability of the thin sand-mudstone interbed roof. The results of the numerical simulations and monitoring data indicated that the proposed support scheme effectively controls the deformation of the surrounding rock of thin sand-mudstone interbed roof of coal mine roadways while maintaining the safety and stability of the surrounding rock and supporting structure.

Dec 12, 2022

By Gopala N. Krishnan

The most promising candidate for the recovery of alumina from non-bauxitic sources is the leaching of clay by HCL acid followed by crystallization of aluminum chloride hexahydrate (ACH) by hydrogen chloride sparging. Hydrothermal precipitation of boehmite ( ?-A100H) from aluminum chloride solution will simplify the process, will reduce energy consumption and will eliminate corrosion problems involved in calcination of ACH to obtain alumina. This report summarizes the results of Phase I of a program to study the precipitation of boehmite from AlC13 solutions. The amount of boehmite precipitation from dilute A1C13 solutions (5 wt%) is . negligible below 200°C. Above 200°C the precipitation increases with increasing temperature approaching 40% at 300°C. Addition of HCl acid to the dilute A1C13 solution even in small quantities drastically reduces boehmite precipitation. Solution impurities such as Fe, Ca, Mg, or Na substantially promote the precipitation of boehmite. No precipitation is observed from concentrated A1C13 solution (30wt%) representing the leach liquor.

Jan 1, 1980

By Henry D. Hibbard

A NOTED ordnance engineer once said to a friend, in speaking of the production of great steel guns, "How is it? We design our guns with a factor of safety of eight, and the guns burst." The vague way in which internal stresses and strains in iron and steel are often considered and spoken of makes it worth-while to examine them, as to their nature, their causes and results, how they may, for useful purposes, be advantageously dealt with, and how, when detrimental or dangerous, they may be reduced or kept within harmless proportions. Rankine defines ?strain " as a change of form or dimensions of a solid or liquid mass produced by a stress. This definition seems not intended to cover strains due to internal stresses, and it will help us in the present inquiry to consider strain as a tendency to change as well as an actual change of form. Internal strains in iron and steel are the result of stresses within the mass of the piece, some parts pulling and others pushing in resistance to them; or, in other words, some parts are in tension and some in compression, each part striving to relieve itself from strain and make the piece assume a form in which all parts are at rest. Subdivision, so that each part could relieve its strain by motion relative to the other parts, would, if carried out far enough, practically obliterate strain. The internal strains we are now to consider are not those due to the stresses of the service which the piece is rendering, either alone or as, a part of a structure, which may be termed service-strains, but those which originate or at least are contained in the piece itself. Internal stresses in a piece of metal are, like action and reaction, always equal and in opposite directions. The stresses

Sep 1, 1906