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By Noel A. Warner

Modern steelmaking is based on direct use of oxygen in high intensity batch reactors. A totally new approach is proposed in this paper, based on the view that pursuit of high intensity is unlikely to lead to successful coal-based continuous steelmaking. By substituting carbon dioxide and water vapor as the oxidants rather than using oxygen directly, the intensity is greatly reduced. Accordingly, subsurface formation of carbon monoxide bubbles can be avoided by careful manipulation of the three participating rate processes, gaseous diffusion, interfacial chemical kinetics and liquid phase mass transfer. Steelmaking can then be carried out without explosive ejection of molten droplets and the generation of micro-spray but rather in a controlled and fume less fashion. The vital component is the introduction of generic melt circulation technology. Three melt circulation loops in series are envisaged. Starting with a composite feed of iron ore fines, pulverized coal and lime flux, a metallized solid raft floating on molten iron is propelled out of the ironmaking loop onto the first of two downstream steelmaking loops. In the first, a liquid slag is formed, primary decarburization is undertaken not with oxygen but rather with CO2 and H2O and the melt is desulfurized. The semi-product stream enters the third melt circulation loop, where open-channel decarburization is effected along with dephosphorization to yield a low carbon steel product. Alternatively, the melt leaves the last loop to irrigate a packed tower countercurrent to argon at around 100 mbar to continuously produce ultra-low carbon (ULC) steel.

Jan 1, 2003

By R. J. Caine

Like most major firms engaged in project management, Dravo Corporation faces a constant challenge to keep its management systems in tune with the ever-increasing demands imposed by larger and more complex projects. This paper suggests that one of the key elements in meeting this challenge is more effective organization of project data. It reveals some of the details of a program at Dravo's Minerals 6 Metals Division which seeks, through better organization of project data, to improve Dravo's capabilities in estimating, cost control, scheduling, performance reporting and material control. In particular, this paper discusses ideas Dravo is developing for improved job numbering, codes of accounts, requisition and purchase order numbering, inventory cataloging, and employee/badge numbering.

Jan 1, 1980

This paper will review some of the work conducted in the past at the Dynamic Effects Laboratory to examine the use of stress waves and fracture mechanics in understanding dynamic fracture and fragmentation in blasting applications. Along the way, we will use photoelasticity and high speed photography to better understand the mechanisms of fracture and fragmentation.

Jan 1, 2015

By K. D. Hester

This paper will review the metallurgical aspects of the completed expansion program at Quirke, and the current rehabilitation and refurbishing program at Panel. During the Quirke program, completed at the end of 1977, the plant capacity was increased from a nominal 4,500 to 7,000 short tons per milling day. The expansion of crushing, grinding, neutral thickening and filtering, leaching, partial neutralization, sand-slime separation, sand washing, C.C.D., clarification, ion exchange, mine water treatment, and tailings neutralization and pumping will be considered. The application of Enviro-Clear thickeners in the mine water treatment circuit and in the C.C.D. will be briefly reviewed. An automatic grinding and classification circuit for limestone will also be covered. The refurbishing program underway at Panel will be discussed. The Quirke and Panel plants will be contrasted and compared. In particular, reference will be made to environmental considerations. The innovative system for producing yellow cake at Panel, LAMIX, will be considered as well as the proposed treatment system for Panel tailings.

Jan 1, 1979

By Michael A. Redfearn

The use of nitrogen in molybdenite flotation circuits is a relatively new concept utilized by only a few mines around the world. This paper briefly discusses circuit chemistry and the reason for its success. It follows the entire testing process which resulted in a sodium hydro-sulphide dosage reduction from 18.5 to 4.4 lbs/ ton (9250 to 2200 g/t) through to the final installation of an inert gas generator which will produce reagent savings in excess of one million dollars annually. A description of the various types of nitrogen generators commercially available is included.

Jan 1, 1983

By Eric R. Bauer

The ground control aspects of extended depth-of-cut mining are presented in this U.S. Bureau of Mines report. A trend analysis of extended cut approvals was performed. A comparative review of roof fall fatalities for extended and nonextended cut mining is included. Current ground control guidelines for extended cut approval are summarized. The problems and concerns of this extraction system are addressed, and typical extended cutting face operations are described.

Jan 1, 1993

By R N. Humphries, R J. K Thompson

Large-scale coal mining in South Wales dates back to the late 18th and early 19th centuries with the birth of ironmaking on an industrial scale. This rapidly gave rise to new and large communities with immigration from far and wide across the United Kingdom (UK). These new communities were largely dependent on coal mining and served as the main form of employment and social cohesion until the industry’s demise in the 1990s. With wholesale mine closure and the concomitant loss of employment, the extensive environmental degradation and chronic mine-related illness left a deep scar on the psyche on many still living in the South Wales mining communities. This coupled with memories of strife in the 1980s has resulted in ongoing hostility toward the surface coal mining of the remaining accessible coal reserves in the proximity of these communities.The purpose of this paper is to set out the historical basis of the concerns of these legacy mining communities in South Wales and explain how they are being positively addressed by both the recently evolved planning and regulation system and by today’s surface mining industry. Reference is made to experience gained from two recent applications for surface coal mining adjacent to former mining communities. Ways are suggested in the approval process that surface mining can work in more harmony with the local communities through working partnerships between the mining company, the authorities and regulators and the affected communities. It is concluded that partnership is key to creating a more responsive mine-operating culture and a means to securing approval for future surface coal-mining prospects in South Wales, and probably elsewhere too.CITATION:Humphries, R N and Thompson, R J K, 2014. Surface mining and legacy mining communities in South Wales, UK, in Proceedings Life-of-Mine 2014 , pp 399–412 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

About 90 per cent of the pre-mining BIF-hosted iron ore resource of the Hamersley Province of Western Australia is of the Phanerozoic supergene martite-goethite type. The remaining ten per cent formed as supergene deposits at ~2000 ¦ 200 Ma, and were later modified by burial to form the Proterozoic martite-microplaty hematite ores. The supergene-metamorphic segment of this general unified model has been challenged by three recently published hypogene-based genetic models for the hematite ores, all requiring meteoric oxidation to produce the ore. The most recent and detailed, by Taylor et al (2001), is based on data from the small Southern Batter and North deposits of the Mount Tom Price mine. The authors proposed that during Stage 1 æoverpressured bicarbonate-saturated basin brines from the dolomite aquifer of the Wittenoom FormationÆ at 150 - 250¦C, dissolved free silica from BIF to produce a stratigraphically thinned, magnetite-carbonate-silicate-apatite rock. In Stage 2, meteoric oxidation of siderite to secondary microplaty hematite + ankerite, and magnetite to martite, at unspecified elevated temperatures and pressures, was followed by carbonate leaching (Stage 3). Finally, during Stage 4, weathering with removal of apatite, produced the typical low-phosphorus, porous martite-microplaty hematite ores of the Tom Price-Whaleback type. However, evidence of both microplaty hematite and martite reduced to magnetite, and of infill silica, apatite, and ferroan chlorite, with late-stage pyrite, in the pore space of martite-microplaty hematite ore, shows that the hydrothermal activity at Mount Tom Price is a post-ore event. Neither pyrite nor ferroan chlorite could resist the oxidation required to form hematite ore. Recrystallisation of microplaty hematite in these infilled zones to a typically coarser form than present in most of the normal ores, is a further supporting factor. A more credible, post-ore alternative to the hypogene genetic model is suggested here. Re-exposure to leaching by ground water of the metamorphosed ore deposits in the Phanerozoic resulted in the partial removal of remnant goethite. Localised modifications in the porous BIF/ore contact zones were driven by exothermic oxygen/pyrite/carbon reactions in the footwall Mt McRae Shale. Cool descending oxygenated meteoric water in the permeable ore horizons, acted as one limb of a thermal convective cell. In the other limb, heated reducing solutions rose through the permeable contact zones, to produce the observed localised modifications of BIF and ore. Expelled silica from the carbonatised BIF invaded adjacent porous ore to form erratic silicified ore zones, and to produce the local quartz vein systems found in the associated overlying BIF.

Jan 1, 2002

By L. Xingwana

"The purpose of this study is to understand how ore loss and dilution affect the mine call factor, with the aim of subsequently improving the quality of ore mined and fed to the mill. It was necessary to know the relationship between ore mined and delivered for processing in order for the mine to operate efficiently. A review of the literature suggested the mine-to-mill integration approach as a standard intervention to address declining mine call factors. A case study was undertaken at a gold mine in the Free State on the influence of the fragment size distribution on ‘free gold’, the effect of ore loss and dilution on the mill efficiency, and time tracking of ore movement from source to the plant. The study revealed that fragmentation, underground accumulation of ore, and dilution have a significant influence on the mine call factor and mine output. It was difficult to quantify the total ore loss due to the time lag between mining and milling, which is extremely variable, when estimating the mine process inventory. However, it was possible to estimate the total dilution with some degree of precision by analysing the daily blast and head grades. It is therefore recommended that mines accept that some gold loss and dilution will always occur during blasting and transport of broken ore, and this loss must be minimized.IntroductionThe mining of high gold grades is obviously very beneficial for the economic viability of an operation, but optimum recovery of the product is required to maximize profits (Chapman and Bindoff, 2010, p. 13). Although integrating these two requirements is very difficult, due to the various activities occurring between mining and processing, it is indispensable. The main driver of this integration is the impact that different ore types and characteristics have on head grade. According to Isokangas et al. (2012, p. 871), mining and processing operations involve a series of well-defined sequential stages that are complementary in an efficiently operating mine, with the performance of one operation affecting that of another. An attempt to optimize each function separately without considering the whole extraction process will not result in the optimum efficiency of the entire mine. Several researchers have developed a proven methodology for revealing these inefficiencies (Dance et al., 2006, p. 1)."

Jan 1, 2016

By M. J. Beus

Researchers at the U.S. Bureau of Mines have developed personal-computer-based data acquisition, instrumentation, and mine visualization and modeling techniques to evaluate a mine accessway in a deep hard-rock mine in northern Idaho. These techniques were applied to a mine shaft in a large silver mine that has been in operation for many years. A very deep, rectangular, timber-supported shaft extending to depths exceeding 2.3 km (7,500 ft) had been deforming continuously as a result of nearby mining, resulting in operational problems. Preliminary visual observations and rock and support monitoring confirmed that severe diagonal distortion was occurring. Extensive field measurements and data analysis confirmed initial observations, provided insights into the cause of deformation, and defined a general approach to structural modeling. Computer analysis of the problem was initiated by developing a three-dimensional model of the terrain. This represented a volume of rock approximately 80 km3 (40 x 1010 ft3) and an area on the surface surrounding the mine 9 km2 (3 square miles). Based on this model, a three-dimensional, finite- element analysis was conducted to establish boundary conditions for sequentially more detailed two- and three-dimensional submodels of the shaft area. Results from the computer study are being used to develop new approaches to mine design and to provide design guidelines for deep mine accessways subject to severe rock-mass loading conditions.

Jan 1, 2010

By Arthur B. Yates

"The nickel deposits of Sudbury, discovered in .1885, have probably commanded as much attention as any single group of orebodies in the world. They have been the major source of the world's nickel supply since 1903, when their production first surpassed that from the Pacific Island of New Caledonia. From 1903 to 1914 the production from New Caledonia remained essentially constant, whereas that from Sudbury increased from 13,000,000 to 50,000,000 pounds a year. After 1914 the production from New Caledonia gradually dropped to about 4,000,000 pounds in 1919, where it remained until 1923. During these years the Canadian production increased steadily and since 1923 has gone up at an amazing rate to a peak of over 280,000,000 pounds in 1941. Meanwhile the New Caledonia production increased to about 10,000,000 pounds until the pressure of war raised it to roughly 14,000,000 pounds a year.The Sudbury deposits, because they have been the source of 80 per cent of the world supply of nickel, because of their economic importance to the world of metals, and because they are geologically unique in their occurrence, structure, and genesis, have attracted foremost consideration and the literature relative to their geology is voluminous. This is particularly true in regard to genesis.There is a significant and interesting parallel in time between the advancement of the science of economic geology and the great expansion of the nickel industry. The controversies regarding the fundamental classification of orebodies into generalized types were in full swing during the height of the development and expansion of the great nickel mines, and the Sudbury deposits, being the most important and the only ones of the sulphide type extensively developed, have been the chief source of information in regard to this type. The observations and the conclusions drawn thereon from numerous studies of the various mines of the district have not only influenced, but are the essence of, this chapter of the science."

Jan 1, 1954

As the title indicates the central themes discussed in this contribution are sustainable development, information systems, and extractive industry. More specifically, the objective is to present a prototype for the systematic generation of extractive industry (henceforth: EI) û specific sustainability information. The paper begins with the authorÆs viewpoints on the core notions of sustainability, and development, as well as their relationship to information. These set the stage for the introduction of the information system (IS), as well as the follow-up sustainability information system (SIS) extractive industry sustainability information system (EISIS) concepts and related discussions. The paper continues with a second part, in which, efforts to research and develop an EISIS prototype are described. First, the team is presented. Second, the systemÆs aim and target groups are briefly discussed. After, an articulated overarching EISIS conceptual model emphasising capital accumulation, and service flow concepts û is presented. This is followed by a detailed description of the assembled prototype with a focus on data and information generation. The formulation of data generation, storage and transmission processes, as well as its use in sustainability interpretation rules and their embedment in the conceptual model is made with respect to monetised stock and flow parameters, measured in the appropriate dimensions. In the third part, the author presents and discusses the results of a first round of prototype experimental development in three major EI firms. First, the system observation, and data analysis protocols are described. Second, a review of protocol implementation, and respective results, is made. Finally, the overall performance of the proposed prototype, and development process issues are discussed, before suggesting areas for improvement and future research. The paper ends with a conclusion in which the author provides a retrospective balance of the æknowledge creation projectÆ, as well as a prospective outlook for research in this field; before acknowledgements are made and references provided.

Jan 1, 2009

By M. T. Shehata, R. W. Revie, M. Elboujdaini

Environmentally assisted cracks in linepipe steels are initiated either as a result of stresses in combination with environmental effects, as in stress corrosion cracking (SCC), or as a result of trapped hydrogen in the steel, as in hydrogen-induced cracking (HIC). To understand better the mechanism of the crack initiation process, key metallurgical and environmental elements that can affect the cracking phenomena were investigated and are reviewed in this paper. The complexity of both cracking phenomena results from the dependence of SCC and HIC on multiple metallurgical, mechanical, and environmental parameters that may all influence both crack initiation and propagation; e.g., composition, microstructure and non-metallic inclusions in the steel, applied stress, water chemistry in the field, and ionic concentrations in the groundwater near the pipe surface to name a few for SCC. In addition, for HIC phenomena, one can add the concentration of H2S in the fluids transported in the pipe as well as concentration of CO2, pH, etc. In this paper, cracking of linepipe steels is analyzed critically, with particular attention to the crack initiation process. The paper is divided into two parts: The first part covers SCC and the second covers HIC.

Jan 1, 2005

By A. S. Knight

THE breaking and handling of ore is obviously the most important consideration when the layout of a new mine is contemplated. The problem must be attacked with due regard to the claim area of the property, the dip of the orebody, the anticipated percentage of payability, the width of the reef, and the amount of dislocation anticipated by dykes, faults, or sills. Among these, as far as East Geduld is concerned, the three most important items are: Area. 2,640.5 claims. Average dip 12° (from flat to 35°) Average channel width 36 inches. We are fortunate on the Witwatersrand in 'chat there is usually sufficient information available from surrounding properties to determine, within narrow limits, the factors mentioned above. With this information avail-able, the choice of layout is not limited, and it will be found that on the Witwatersrand each group has developed its own technique to suit its individual requirements. On East Geduld, the layout of the property for handling ore is known as the endless-rope haulage system. Following is a brief description of the general principles followed.

Jan 1, 1942

By John H. Schilling

The Gabbs magnesite-brucite deposit is unique in size and is one of two magnesite deposits being exploited in the United States. It is near the town of Gabbs, which is one hundred miles southeast of Reno, in west-central Nevada. The brucite was discovered in 1927; the magnesite was found while exploring the brucite. During World War II, more than 80,000 tons of magnesium metal was produced from about 900,000 tons of magnesite ore mined from these deposits. An additional 5,000,000 tons of magnesite and 1,000,000 tons of brucite have been produced for use in making magnesia refractories and chemicals. Basic Inc., presently the only producer, mines 1.5 ± 0.25 million tons of ore and waste annually using high-selective open-pit rriethods; the ore is up-graded, calcined, and processed into a variety of products. Known reserves of highgrade (less than 5 per cent CaO) magnesite ore total more than 25,000,000 tons, and there are larger tonnages of lower-grade material; brucite reserves are small. The magnesite and brucite are in generally west-dipping dolomite of the upper member of the late Triassic Luning Formation, in the over-riding plate of the Paradise thrust fault. A great variety of dikes and a stock of Cretaceous granodiorite intrude the Luning Formation in the vicinity of the magnesite-brucite deposit. The magnesite bodies are scattered over an area of about a square mile around a prong of granodiorite which extends north from the stock. The brucite is mainly in two bodies in contact with the prong of granodiorite; at the surface and along deeper cracks the brucite has weathered to hydromagnesite and artinite. In the area of magnesite-brucite mineralization, much of the dark, fine-grained, schistose, regionally-metamorphosed dolomite of the Luning Formation has been marmorized to a lighter-colored, coarser-grained, massive dolomite that is intergrown in varying proportions with the magnesite. The magnesite and marmorized dolomite can not be distinguished visually. In addition to the two varieties of dolomite, the gangue in the magnesite and brucite bodies mainly is the various varieties of dike rock, serpentine and a variety of other "contact" minerals, and "post-ore" dolomite and calcite. The magnesite ( and recrystallized dolomite) is believed to have formed by the hydrothermal replacement of the regionally metamorphosed sedimentary dolomite; alternatively it has been suggested that the magnesite is sedimentarv and formed contemporaneously with the dolomite in an embayment of the Triassic sea. Because all the igneous rocks exposed in the immediate vicinity of the magnesite deposits appear to be younger than the magnesite, the ore-forming solutions are thought to be related to a somewhat older granite which crops out elsewhere in the area. The brucite is the result of contact-metasomatic replacement of magnesite during the emplacement of the granodiorite stock.

Jan 1, 1968

By Kent E. McElhattan

The selection of efficiency machinery for an underground mining system is a highly skilled art. Modern techniques of mining, based on sound engineering principles, increase the probability of success. These techniques alone, however, will not guarantee maximum productivity. Human judgement, based on experience with mineral seams and geological conditions, remains the single most important input of the decision-making techniques in selecting high production equipment. The myth of a "Scientific Selection Factor" is absurd. The belief that such a factor exists can waste the time and resources of mining management. Until now, mineral extraction from the original desposit has defied all attempts to systematize the knowledge. Computerized programs are excellent for solving underground transportation and ventilation problems. The variables can be defined by mathe¬matical techniques in this type of problem. By the same, token, "Trial and Error" is not an acceptable method in today's technology-minded world. The candid truth of the matter is that practically nothing is known of the phenomenon of extracting a mineral from the solid. Likewise, local conditions make it nearly impossible to predict accurately the reaction of surrounding strata after the mineral has been removed. The unpredictability of the environment resulting from extracting minerals underground will remain a challenge to mining engineers for many years. In fact, we are barely beyond the trial and error stage at this point in time.

Jan 1, 1969

By C. C. Furnas

Despite the fact that a great many industrial processes depend on efficient contact between a gas stream and a bed of broken solids for their operation, the data in the literature are very meager. Several investigations3 have been undertaken, but the work has been limited in scope and application. BUREAU OF MINES PROGRAM OF RESEARCH For the past 10 years the United States Bureau of Mines has been engaged in research with the object of formulating a more or less complete quantitative theory of the workings of the iron blast furnace. Obviously, in order to do this one of the essentials is to have considerable definite information on the laws of gas flow through beds of broken solids. This report in a brief summary of the experimental work on the problem which has been done at the North Central Experiment Station. The complete report with more detailed tabulation of the data and explanations of the experimental procedure is in process of publication in the form of a bulletin.

Jan 1, 1928

By R. S. Dean

T HE theory of hardening by heat treatment was, as usual, the most actively discussed phase of metal working theory and in spite of the fact that it is now ten years since the dispersion theory was proposed by Messrs. Merica, Waltenberg, and Scott, it still retains a dominating influence. It is being increasingly recognized. however, that in its simplest form, that is, the purely mechanical effect of very fine crystallites distributed through a groundmass, it is distinctly in- adequate. To explain the observed facts we are obliged to assume some well-defined intermediate stage between supercooled solid solution and conglomerate, however fine be the particles of the latter. This intermediate has been inferred by Gaylor and Preston to be "the rejection of the atoms of the dissolved metal from the lattice of the solid solution accompanied by the possible formation of molecules."' Perhaps this may well be designated as the formation of supersaturated solid solution. Some very definite evidence of such an inter- mediate stage has been found in the hardening of steel where it appears that the very hard martensite may be considered as a supersaturated solution of carbon in a iron. The X-ray spectrometry of drastically quenched steel shows a tetragonal lattice whose parameter changes by tempering at 100" until it coincides with the cubic lattice of iron.? The same gradual change of the tetragonal to the cubic lattice has been observed by Sekito when esamining layers on increasing depth below the surface of a quenched carbon steel.

Jan 1, 1930

By D. F. Malan, J. A. L. Napier

This paper describes some important aspects associated with historical underground measurements in South African gold and coal mines. Deformation measurements were used to confirm the use of elastic theory to simulate the rock mass behaviour in the Witwatersrand gold mines in the 1960s. Although a prominent time-dependent component of stope closure was measured as early as the 1930s, it was ignored owing to the benefit of adopting elastic theory. Neglecting the time-dependent response of the rock for many decades resulted in important aspects such as the effect of mining rate, the effect of advance per blast, and the need for enhanced design criteria not being explored. Recent work is only now starting to address this gap in knowledge. In-situ measurements of large coal specimens in the 1960s and 1970s indicated that a linear formula may possibly be a better approximation of coal pillar strengths. This alternative formulation was never adopted, however, as the power law strength formula was already deeply entrenched in the industry at that stage. In spite of these apparent failures to continuously generate and adopt new knowledge, a key lesson learnt is that major advances in rock mechanics will not be possible without careful monitoring of the rock mass behaviour in experimental sites. Areas requiring further research, such as pillar strength formulae for the Bushveld Complex and enhanced design criteria for the gold mines, can only be developed using extensive undergroundmonitoring programmes.

May 1, 2021

By J. M. Ríos

"Without conscious effort and understanding, a number of factors unique to mineral exploration often hinder building sustainability in host communities. These include the episodic and transitory presence of an exploration team in the community and the inherent uncertainty of outcomes— most projects fail from an exploration perspective. Experience in rural communities across Mesoamerica, however, has shown that it is possible to go beyond pragmatic philanthropy and infrastructure improvements to promote positive, sustainable outcomes in communities. Examples are provided of lessons learned and proven practices that improve quality of life and support a strong social license to operate.RÉSUMÉ Sans une compréhension et un effort réfléchis, de nombreux facteurs uniques à l’exploration minérale nuisent souvent à l’établissement d’un développement durable dans les communautés d’accueil. Ces facteurs comprennent la présence épisodique et transitoire d’une équipe d’exploration dans la communauté et l’incertitude inhérente des résultats – la plupart des projets échouent après l’étape de l’exploration. L’expérience dans les communautés rurales à travers la Méso-Amérique a toutefois démontré qu’il est possible de dépasser la philanthropie pragmatique et les améliorations des infrastructures pour promouvoir des résultats positifs et durables dans les communautés. Des exemples qui améliorent la qualité de vie et soutiennent un solide permis social d’exploitation sont présentés; ils sont tirés de leçons apprises et de pratiques éprouvées."

Jan 1, 2015