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By R. G. Burn

"A brief outline will be given of the concept of risk and its implications with regard to investment in exploration. The relationship between risk and decisions under uncertainty will be examined as a prelude to identifying those factors which contribute to exploration risks:consideration of the effects of corporate objectives (e.g. survival, expansion, diversification) on exploration strategy and ultimately on success or failure, exploration and mining as an investment (the relationship between risk and reward) and the desired return on investment; exploration odds, funding levels, staying power, financial exposure and the concept of gambler's ruin;origins of uncertainty in exploration decision-making-man-made risks and natural hazards; the nature of introduced constraints at each exploration decision stage and their effect on the rate of success;improving the chances of success and the invest reduction of risk through sound exploration strategy, effective project generation and efficient target detection capabilities."

Jan 1, 1984

By B. M. England, L. C. Mackey

Magnesia minerals are included in most iron ore sinter mixes to provide the MgO requirements of blast furnace slag. The properties of these minerals have an influence on the eventual sintering properties of the mixes. A detailed study was undertaken of serpentine and dolomite and the use of limestone, olivine and magnesite was also investigated. A consideration of particle properties indicated that as these materials calcine a reduction in size can occur together with cracking and changes in surface properties. These changes could affect the permeability of the sintering bed and sintering performance. Studies of sintering reactions showed that magnesium and calcium, formed from the calcination of dolomite, are extremely mobile before the formation of melt. Evidence suggests that the movement of these oxides into surrounding areas is via a solid-state diffusion process. The diffusion of Ca into the surrounding hematite particles is faster than that of Mg, resulting in the formation of dicalcium ferrite and magnetite or magnesioferrite, the last two subsequently being converted to dicalcium ferrite in the presence of Ca with removal of Mg from the structure as ferroan periclase. Studies of pilot-plant sinters indicated that reaction mechanisms formulated from the bench-scale studies were occurring in actual sintering processes. The differences in sintering reactions between dolomite and serpentine were considered to be the major cause of differences in the availability of lime for bonding phase formation. Pilot-scale studies indicated that the sintering properties of a mix containing dolomite could be improved by increasing the basicity of the sinter mix while keeping the MgO level constant

Jun 18, 1905

A method for the detection and analysis of tin in cassiterite ores is discussed. An empirical relationship was established between the tin content of an ore sample and the percentage absorption that this sample produced in a Mossbauer experiment. The time taken to complete an assay with this method is much less than with any of the methods currently in use. The equipment can be adapted readily for use in the field.

Jan 1, 1969

By Pat McLaughlin

Environmental constraints are pushing many operators to change from large rotary blastholes to the smaller diameter holes drilled with down-hole or top-hammer rigs. Productivity improvements over the years with these two drilling techniques has taken some of the bite out of the transition, while improved fragmentation and more uniform muck due to the tighter patterns can help offset increased explosives costs.

Jan 1, 1995

At last year's. annual meeting of The Institute, Sir George Fisher, as President, compared it somewhat nostalgically with a meeting of its kind in the 1920s when comment was expressed on the decline of Australianmining and on the lack of new mineral discoveries.I feel that tonight's annual meeting is even more an occasion for nostalgia, for it represents the seventy-fifth anniversary of the founding of The Australasian Institute of Mining and Metallurgy. I hope, therefore, that I may be allowed to retrace some of the circumstances of this Institute's origin and at the same time to look at some of the broader happenings of those 75 years.From this distance in time it is, of course, much easier to get things in perspective and one of the things that compels enormous admiration in looking back over the history of our Institute is to note the qualities of foresight and keen concern for professional standards which moved the pioneers in this Institute. They had no benefit of hindsight to aid them.Just over 75 years ago, a small group of men met in Broken Hill to discus.s the possibilities of forming an association of mining engineers. The moving spirit was Uriah Dudley, our first secretary, manager of the Umberumberka mine at Silverton. The first formal move to form an association of mining engineers came from the Amalgamated Mining Managers Association of Australasia. At the time, this association was a fairly new group, being 5 years old.It had been formed to try to raise the standard of management throughout the industry. Uriah Dudley and our first provisional president, John Howell, held their first talks in 1891 and further meetings at Broken Hill followed. The inaugural meeting, attended by 200 members, was held in Adelaide in April, 1893.

Jan 1, 1968

By Syd S. Peng, C. Y. Chen

Introduction The Surface Mining Control and Reclamation Act was passed in 1977 to put an end to the uneven environmental standards and enforcement established by various coal mining states in the US. One year after passage, the Secretary of Interior was directed to promulgate permanent program regulations implementing Title V provisions of the Act. These regulations were to form the basis for state regulatory programs under the Act and to allow states to assume primary regulatory responsibility. To implement the underground mining provision of the Act, the Secretary is directed in section 516(a) of the Act to promulgate rules. But they must take into consideration the differences between surface and underground coal mining. The regulations developed by the Secretary in 1979, with respect to subsidence control, included: • a subsidence control plan as part of the permitting process; • substantive provisions establishing performance standards for subsidence control; and • provisions providing for the prohibition of mining under perennial streams, impoundments larger than 24.6 dam3 (20 acre ft), and certain public facilities and urban areas. Industry challenged the Secretary's regulations implementing the subsidence control provisions. The litigation was consolidated with all other challenges to the permanent program regulations. (Permanent Surface Mining Regulation Litigation, Civil Action No. 79-1144; D. D.C., May 16, 1980.) In two opinions dealing with the multitude of issues raised by both industry and environmental groups, the US District Court of the District of Columbia ruled against industry. It upheld the promulgated subsidence control provisions. The US Court of Appeals stayed the appeals pending the agency's review and revision of its regulations. The regulatory reform was conducted in accordance with the order from the Secretary of Interior and the President in 1981. As a result, the subsidence control regulation was revised, reproposed, and finalized in June 1983 (Federal Register). This regulation, along with others, was again challenged by environmental groups and industry. On Oct. 1, 1984, the court, after finding the Secretary's reading of the Act reasonable, upheld the 1983 subsidence regulation except for one section. On Feb. 21, 1985, in accordance with the court's ruling, the Office of Surface Mining (OSM) suspended a portion of 30 CFR 817.121 (c)(2) concerning the damage correction requirement for structures or facilities and reproposed it on July 8, 1985 (Federal Register). In conjunction with a request for public comments, OSM now also seeks comments on the omission from the 1983 rule of the requirement in the 1979 rule regarding a presubsidence survey and monitoring of damage to structures. Technical issues related to subsidence regulations The subsidence regulations of June 1, 1983, consist mainly of two parts: a subsidence control plan as part of the permitting process; and substantive provisions establishing performance standards. The latter also includes provisions for prohibiting mining under certain areas. Under subsidence control plan section 784.20, minimum require-

Jan 2, 1986

Several factors contributing to the loss of fibre during treatment are a function of the paragenesis of the veins. The occurrence, of magnetite from the cap rock within the veins prevents complete fiberization. There is a marked similarity between these veins and those in the Koegas-Westerberg area of South Africa.INTRODUCTIONAn investigation of the mineralogy of the Wittenoom Gorge crocidolite veins was undertaken in the latter part of 1962 at the request of the Colonial Sugar Refining Co. Ltd. It was anticipated that such a study might reveal the cause or causes of the lack of recovery of some asbestos during beneficiation. Some interesting features of the mineralogy and paragenesis of the crocidolite veins become apparent, but it is emphasized that the investigation is far from complete, as the study did not extend to the field occurrence.The samples examined were selected from the mill and from the untreated ore.GEOLOGICAL SETTINGWittenoom Gorge is situated on the Fortescue River in the Hammersley Ranges of Western Australia and is one of several gorges in these ranges, on the sides of which 'crocidoIite asbestos is known to occur. The Hammersley, Ranges consist essentially of a series of quartzites, shales, ferruginous quartzites and dolomites. These' rocks are part of the Nullagine Formation (Proterozoic) and are usually either horizontal or gently folded. In some 'areas small beds of riebeckite as well as crocidolite are known to occur interbedded in the sequence.Riebeckite is a monoclinic amphibole, the formula of which may be stated as Na2Fe2"Fe2" (OH) 2Si8O22, and crocidolite is a fibrous variety of this mineral. This formula...

Jan 1, 1963

By William A. Hustrulid

The subject of surface mine development is large. This section covers the fundamental concepts involved in both the open pit mining of thick or steeply dipping deposits as well as the strip mining of thin, shallow, and relatively flat-lying seams or beds. Design involves the marrying of geometries, ore and waste characteristics, equipment, and economics so that the desired result is achieved. Generally, there are many possible combinations from which to choose. For example, extraction over a short time period requires one strategy while quite another is applied for longer times. Variations in supply and demand require some flexibility of operation. Customer requirements impose certain constraints regarding the set of possible designs. Over recent years, planning and operating considerations for surface mining imposed by environmental requirements have increased markedly. There have, at the same time, been enormous advances made in the design aids available to the mine planner. Computer simulation of the various options, whether it be for mine design or equipment selection, provides detailed information for decision making in real time. A significant challenge to the engineer/planner is how to best use the aids avail-able. Because of the widespread use of commercially available and in-house computer software by industry, this section does not deal with the details of planning (for basic coverage of mine development, see Section 7). Rather, some of the basic concepts are stressed. The principles involved in equipment sizing and selection are discussed. A highly important but sometimes over-looked aspect of planning, haul road design, is also covered. For surface mining operations of the future, in-pit crushing and conveying will become even more important. Some of the considerations for application evaluation are included. The section concludes with some future concepts for surface mining.

Jan 1, 2008

By Don Rose

INTRODUCTION A number of tunnels supported and permanently lined by steel-fiber-reinforced shotcrete (SFRS) have been built in North America in the 1980s. The material is more economical than, and technically equal or superior to, conventional shotcrete using wire mesh. The design and construction of SFRS-lined tunnels is straightforward, and only a few new design principles, laboratory tests or construction equipment modifications appear necessary in order to use this material. Modern tunnel Contractors may use cyclic drill-and-blast methods on some tunnels, with intermittent shotcreting as part of an orderly cycle. The Dry Mix method is most suitable for cyclic, intermittent, relatively small-scale shotcreting. However, modern Contractors excavating tunnels continuously using large long Tunnel Boring Machines (TBMs) or Roadheaders may prefer Wet Mix shotcreting on a mass production basis. In either case, the use of steel-fiber-rein¬forced shotcrete (SFRS) promotes the rapid and economical excavation of tunnels. The addition of microsilica will improve SFRS properties and reduce rebound, and is expected to become standard practice with SFRS in North America, as it now is in Scandinavia. HISTORICAL REVIEW Steel-fiber-reinforced shotcrete (SFRS) at the present time (1985) is essentially conventional shotcrete with straight or deformed steel fibers added, and in general SFRS for tunnel linings encounters the same problems that conventional shotcrete does. Shotcrete history is well known. The use of sprayed plaster on wire frames for mounting animal skins by Carl Akeley of the Smithsonian

Jan 1, 1985

By J. Kendall Hales

Jan 1, 2005

Advances in Optical Image Analysis and Textural Classification of Iron Ore Fines

Sep 13, 2010

By Tom Ireland, Tony Rock

The proposed 1.83km long twin bore A3 Hindhead road tunnel planned for contruction in 2008 is being delivered under a Highways Agency Early Contractor Involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunneling medium is a ‘soft rock’ sandstone for which there was little previous tunneling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m long portal section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels, and the innovation included in the ‘permanent’ primary lining design.

Jan 1, 2007

For a large scale open pit mining and concentrating operation, on a low-grade disseminated ore body, it is possible to set an approximate lower bound on economically feasible operating scales and an approximate upper bound on economically desirable scales in a relatively straight forward manner. The optimum scale ofplanned operations, with respect to the objective ofmaximisation ofthe net value ofthe orebody, will have to be arrived at by iterative planning runs, but it may be expected to lie close to this upper bound. The effects of infrastructural costs and of the addition of a risk premium to the cost of capital, to form the discount rate for planning purposes, are considered theoretically and by worked example. It is concluded that a perceived special, unsystematic, risk should not be accounted for by the use of such a risk premium as this is inducive to placing a greater amount of investment capital at risk, for no greater return-rate to investment.

Jan 1, 1986

Remediation of Mine Seepage at Batu Hijau

Sep 13, 2010

By Michael G. Rulff, Tracy M. Holmes

"Vast amounts of time and money are spent fighting flow problems in plants that involve the handling or processing of industrial minerals. Because these types of projects tend to be capitalintensive, the right decisions, made at the design stage, can have a substantial positive effect on the economics of the project.Some of the problems related to solids flow in mineral processing plants include:•,Flow stoppages•,Uncontrolled flow•,Segregation of blended materials•,Build-up and dead material resulting in loss of live capacityUnfortunately few Universities in North America provide courses in the design or selection of bulk solids handling equipment, let alone the theory of bulk solids flow, with the result that engineers do not fully appreciate the effects of bulk solids handling on their process. The usual method of selecting “standard” equipment, all too often, leaves plant operators hammering on hoppers to promote flow, a technique that is not only usually ineffective but also unsafe and often causes damage to equipment. In short, too little consideration is given, at the design stage of projects, to the particular material and operating environment involved and how these will affect handling between process steps.This paper seeks to give a general understanding of bulk solids flow theory including flow patterns and flow property tests, and presents functional design guidelines to ensure reliable flow. As well, a case history will be presented. Our message is clear: To ensure uniform, reliable flow, a plant design must take into account the specific flow characteristics of the bulk solid to be handled or processed."

Jan 1, 2008

THE art of mine surveying has made very great progress in recent years, and is still advancing, perhaps faster than any other branch of surveying. The scope of the mine surveyor's duties has greatly increased, his instruments and methods have improved, the responsibility of his position is greater, and the end is not yet in sight.It might be supposed that such a steadily growing subject would have an adequate literature, but this is by no means the case and outsiders commonly judge mine surveyors by their text-books. Hardly any condemnation can be too strong for most of these books. The English books truckle to the antiquated and crude methods apparently still in use in England, and thereby largely aid in perpetuating them; they commonly in illustrative examples give the distances in fathoms, feet, and inches; they spend page after page discoursing on instruments that should have been forgotten long ago; they try to antagonize theory and practice by detailing such calculations as that a certain vein will contain 2,003.907 pounds of galena per square fathom, and then reduce this amazing quantity to hundredweights, quarters, and pounds. Nothing can be more unscientific, or, for that matter, less businesslike, than unwarranted assumptions of accuracy; it is, perhaps, the greatest curse of applied science. Here we have a calculation to thethousandth part of a pound, when there is probably an unavoidable error of two hundred pounds. What shall we say of a man who explains how to measure the depths of shafts to the hundredth part of an inch by means of short brass rods screwed together...

Jan 1, 1909

By Flavio Begazo Mamani

Recientemente Southern Perú desarrolló un nuevo proyecto donde se modernizaba la planta de Fundicion y se reemplazaba el convencional horno reverbero por la tecnología del ISASMELT, capturando más del 92% de los gases generados durante el proceso de fusión de los concentrados de cobre. En ese sentido, el presente texto describo los efectos de la modernización de la Fundición sobre la calidad anódica. Antes de la modernización de la Fundición, los ánodos fueron producidos en la planta de ánodos ubicada en la Refinería de Cobre de Ilo. Ahora los ánodos son producidos directamente en la Fundición y como resultado, la composición química de los ánodos ha cambiado, principalmente en el contenido de bismuto, antimonio, plomo y zinc, siendo diferentes a los parámetros de diseño original de la Refinería. Asimismo, este factor impulsó a revisar el proceso de remoción de impurezas y los parámetros de la refinación electrolítica en la Refinería para evitar la contaminación del cobre refinado, logrando mantener la continuidad de la producción de cátodos de cobre de alta calidad superando los estándares interna-cionales de la norma ASTM-B115.

Sep 12, 2011

By Madgwick J. C

A new strain of Thiobacil/us ferrooxidans (SPK I) has been isolated which has a higher copper to iron release ratio (2.04) than the standard T ferrooxidans (CPBI) (1.12). The diminished iron oxidizing ability enables almost quantitative release of copper (93 per cent) from a chalcopyrite-rich concentrate without interference by iron reprecipitation. In a single batch leach, Bougainville copper concentrate yielded 9.3 grams/litre soluble copper from a 4 per cent w/v suspension in 100 days at 32°C.Solvent extraction recovery of soluble copper is recommended as a final step in a leaching process.

Jan 1, 1983

By Terry A. Kirk

"This paper describes Derrick High Frequency Vibrating Screens and their process performance in grinding circuit applications. The benefits of screen sizing in closed circuit grinding are illustrated by case histories from a wide spectrum of mineral industries.INTRODUCTIONHigh capacity, reliable wet screening equipment is increasingly in demand by the mining and allied industries for separations finer than 1/.7 5mm (I/ mesh). The continuing search for improved energy efficiency and reduced steel consumption in comminution has Jed to greater scrutiny of every aspect of circuit design and operation, including the classifier efficiency (selectivity) function.Derrick Manufacturing Corporation has been developing high frequency screening machines designed specifically for grinding circuit applications since 1973. Successful installations are currently operating in iron ore, copper, coal, uranium, phosphate and other extractive industries."

Jan 1, 1984

By E. A. van Wyk, M. R. de Villiers

"Mining companies strive to increase and maintain production, while simultaneously remaining competitive in the global economy. Furthermore, they must ensure workers’ safety and maintain good safety records. The use of virtual reality (VR) facilitates the development of tools and systems for various purposes that can improve knowledge and understanding of the work environment. VR is a rapidly growing technology that uses the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and standard 3D graphics card, make VR technology viable and attractive for mainstream training applications. The design, development, and implementation of interactive VR training systems is proposed as an innovative approach to augment safety training. However, in order to assess the impact of such VR training systems it is of particular importance to determine the effectiveness of the design of such systems. This article proposes an evaluation framework for this vital purpose. This framework comprises criteria to assess VR training systems, specifically relating to usability, instructional design, VR systems design, and mining industry context-specific aspects. Although the framework was developed as an evaluation tool to assess effectiveness of the design of such systems, it can equally well be used as a set of design principles to inform the design of VR training systems for mining. IntroductionMining in South Africa has been the main driving force behind the history and development of Africa’s richest and most advanced economy (Coka, 2012). The South African mining industry is frequently criticised for its poor safety record and high fatality rate (Stoddard and Skweyiya, 2016). Inadequate or insufficient training is often cited as a root cause of accidents (Van Wyk and De Villiers, 2009; Tichon and Burgess-Limerick, 2011). Virtual reality (VR) is a rapidly growing technology that utilizes the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction (Webber-Youngman and Van Wyk, 2013). VR is currently being used or investigated as a training solution in a variety of industries. VR technology has developed rapidly and costs have fallen to levels where it can now be considered for mainstream training applications. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and a standard 3D graphics card, make VR even more attractive to mine training centres (Van Wyk and De Villiers, 2009)."

May 1, 2019