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Council for 2003/2004 President T.R. Stacey President-elect F. M. G. Egerton Vice-presidents Senior W. H. van Niekerk Junior R.P.H. Willis Immediate Past-president S.J. Ramokgopa Honorary Treasurer J.A. Cruise

Jan 1, 2004

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook contains injury experience and related employment information for the coal-mining, coking, oil and gas, peat, and native asphalt industries in the United States for 1963. No attempt has been made to combine these data and present injury-frequency rates reflecting the mineral-fuel industries because the hazards of the separate industries are not comparable. Tabulations showing the trend of injuries and employment for all mineral industries are presented in Volume III of the Minerals Yearbook. COAL Injury experience of the coal-mining industry was improved slightly in 1963, as measured by the 2-percent decline in the Injury-frequency rate. Although the total number of fatal and nonfatal injuries increased 1 percent, the greater proportional increase of 3 percent in man-hours worked accounted for the improved frequency rate. Employment and injury data for 1963 are based on final data for anthracite mines and preliminary data for bituminous coal and lignite mines.

Jan 1, 1964

A physical modelling study has been carried out to simulate the slag-metal dispersion induced by a high-strength bottom gas injection. Water and kerosene were utilized to simulate metal and slag respectively. A water model of CLU (Creusot-Loire Uddeholm) vessel was used with three different nozzle orientations, namely, off-centre, triangular off-centre and centre. The gas flow rates changed from 0.00599m3/sec to 0.01081m3/sec. Height of heavy and light phases was kept fixed at 0.23 m and 0.02 m respectively. The dispersed phase holdup was determined at various axial and radial distances, gas flow rates, and tuyere configurations. The observations revealed that at a fixed gas injection rate, as the vertical distance increased in the centerline, straight off-centre orientation resulted in greater dispersed phase hold up values than those of the centre configuration and the triangular off-centre orientation. The dispersed phase holdup was found to increase with gas injection rate and decreased with axial distance. The variation of the dispersed phase hold up with the dimensionless axial distance and the gas injection rate was correlated by using the Modified Froude Number. The experimental values of the dispersed phase holdup were found to be in good agreement with the correlated values obtained from the modelling equations. The findings of the present study may be utilized in the ferroalloy refining vessels in terms of designing tuyere locations for optimum processing conditions.

Jan 1, 2004

By J. A. Organiscak

In the United States, respirable coal mine dust exposures are limited to a 2 mg/m3 time weighted average for a working shift. If the silica content of the sample exceeds 5 percent, the 2 mg/m3 standard is reduced according to 10- (% silica) to limit silica dust exposures to 100 µg/m3. Examinations of dust sampling data collected by the federal coal mine inspectorate showed that roof bolter occupations continue to be at risk for overexposure to respirable silica dust. Testing at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health assessed the effectiveness of a canopy air curtain for controlling occupational exposures to respirable silica and coal dusts. Initial testing found that zones of higher velocity airflow shrank as distance beneath the canopy increased. This suggested that protection from occupational dust exposures would likely decrease as distance beneath the canopy increased. Further testing revealed that coal dust reduction efficiencies were most affected by changes in interference air velocity and, to a lesser extent, changes in canopy air quantity. However, respirable silica dust percentages under the canopy were not affected by such changes and, in fact, were not significantly different from silica percentages measured outside the canopy. This implied that the air curtain was equally effective on both respirable coal and respirable silica dust particles.

By G. H. Babcock, D. A. Knight, V. G. Medina

"Production commenced at the Golden Sunlight Mine in 1983 and at Kidston Gold Mine in 1985. These projects were both constructed under the management of the Placer Dome Inc. (Technical Services) group of Vancouver, B.C.Golden Sunlight uses a conventional rod mill/ball mill grinding circuit while Kidston uses a SAG /ball mill, and later on, SABC circuit. Since the hardness of the ore and the fineness of the primary grind in both mines are about the same, a meaningful cost comparison can be made. The comparison is made on the basis of capital and operating costs.The result of this study indicates that a significant capital cost savings can be achieved in favour of the SAG /ball mill circuit when the ore is amenable to semi-autogenous grinding. With a good maintenance program, the operating cost for the SAG /ball mill circuit could also be lower that the conventional rod mill/ball mill circuit.HISTORYGolden Sunlight MineGolden Sunlight is a 5 530 t/d gold mine located near Whitehall, a small town 60 km east of Butte, Montana. Originally optioned by PDI U.S. in 1958, the development of the property waited until 1981 when economic conditions became favorable for the project to proceed.Semiautogenous grinding tests were conducted during the final stages of the feasibility study. The hard near surface ore was not quite amenable to semi-autogenous grinding. The best result produced from a series of tests using a 1.83 m diameter mill was a semiautogenous work index of 39. This is substantially higher than the 22 Bond work index of the sample used in the testwork. A conventional SAG/ball mill circuit for this ore will be extremely inefficient, and for this reason, this circuit was rejected in favour of a conventional rod mill/ball mill circuit."

Jan 1, 1991

By C. Musingwini

In the past ten to fifteen years, many organizations have applied business process re-engineering (BPR) to significantly improve their business competitiveness or stave off closures. The mining industry in Southern Africa is no exception and documented examples can be drawn from South Africa. Although the concept is superficially simple, its application has been marked by a high failure rate of about 70 per cent because it has been generally misunderstood. Shabanie mine, a chrysotile asbestos fibre producer in Zimbabwe took cognisance of this fact by cautiously embarking on a modular BPR programme in October of 2002. A year was used as a complete cycle or module for re-evaluation of the programme. Shabanie mine adopted BPR as part of management efforts to remain competitive amid serious threats to operational viability. These threats included hyper-inflation driven rising production costs, a declining world asbestos market and a possibility that Russia could take over the shrinking world asbestos market by dumping low-priced asbestos fibre. The only competitive advantage that the mine had was the high quality of its long-fibre chrysotile asbestos. The major BPR thrust was therefore to redesign processes for improved productivity and ultimately achieve a lower cost per ton of final asbestos fibre product. In addition, corporate culture change and cost-saving were also factored into the programme. This paper discusses the implementation experience of the BPR programme at the mine. The main BPR beneficial highlights are improved productivity, sizeable cost-savings, positive corporate culture change and identification of secondary projects. One of the lessons learnt from this programme is that mining companies will have to deal with the HIV/AIDS pandemic if they are to sustain high levels of productivity into the future.

Jan 1, 2005

By J. S. Stachulak

The Diesel Emissions Evaluation Program (DEEP), a research consortium formed in 1997 by Canadian mining companies, labour unions, and provincial and federal government departments, completed its work by mid-2006. This program, in which Vale Inco participated with both direct funding and in-kind contributions, investigated the ability of currently available technology to significantly reduce underground concentrations of diesel particulate matter (DPM) with high efficiency and low maintenance over a long-term period (years of life).While DEEP?s testing showed that engine maintenance is a critical component for lowering DPM, it was clear that reduction of DPM to the very low target levels of ~0.05 mg/m3 was not possible with maintenance alone. The best candidate technology for achieving low DPM levels was particulate filter systems. Furthermore, successful deployment of such systems was highly dependent on removing them from having to rely on human intervention for their regeneration. The search continues within Vale Inco to identify a reliable and rugged system.

Jan 1, 2009

By G. Wahl, H. Danilkewich, T. Mann

Developers of advanced mining projects face the challenge of how to craft a “Request for Proposal for a Feasibility Study” that will result in bids that are comparable and will lead to a successful execution of the study. Mining engineering consulting firms are challenged by “Request for Proposals” that may consist of a limited description of the Scope of Services and other items, which could present difficulties in the subsequent financing and/or development of the project. Changes in international disclosure requirements have also changed the landscape on how resources and reserves are reported by introducing new disclosure requirements and concepts such as qualified persons. This paper lays out a strategy for preparing a Feasibility Study “Request for Proposal” based on the experiences of a mining engineering consulting firm working on a diversity of projects around the world, and in light of the recent changes in international reporting standards for reserves.

Jan 1, 2002

By Robert B. Hopler

Explosives, originally used only in fireworks and warfare, became legitimate contributors to human progress when miners in Eastern Europe began using them to break rock in the early 1600%. Since that time these powerful materials have had a dual role in the world: as agents of destruction in war, and as irreplaceable tools necessary to advance civilization. In the latter role, they serve as agents to enable mankind to produce metals, build roads, and drive tunnels. In other words, to provide those materials, services, and infrastructure without which the modern world could not exist.

Jan 1, 1997

By Daniel D. M. Adams

Over the last 100 years industry in general has been trying to advance the ability to maintain systems through management processes. Mining has looked to utilize onboard data systems in our mobile mining fleets to compliment these processes. Combining the two concepts build the concept that Rio Tinto refers to as asset health. These programs can generate a cost shift between $20,000 and $100,000 per piece of equipment annually. Even with the documented savings many operations struggle to justify the systems, why?

May 1, 2011

Geological information is essential for a diversity of public and other purposes, including land use planning, hazard mitigation, and the exploration and sustainable use of natural resources. This is especially important in New Zealand, where the complexity of the geology is due to its position on an active plate boundary - the ultimate cause of earthquakes, mountain building, subsidence and volcanic activity. The geological setting also controls the origin and distribution of New Zealand's varied mineral and energy resources. Providing information about the origin, quality and quantity of mineral resources has long been seen as a key function of national geological organisations such as the Institute of Geological and Nuclear Sciences. Such information is essential for wise land-use decisions under the Resource Management Act. One of the major goals of the Institute is to quickly and effectively disseminate research results to interested users. The most effective and internationally accepted method of presenting geological data is by means of geological maps, which show the distribution of rock types and structural features at the surface. Most countries have ongoing gelogical mapping programmes, and in recent years the need for up-to-date, reliable information has led to a trend to accelerate basic geological mapping (eg US National Geological Mapping Act 1992; Australian National Mapping Accord 1990; Plan 2000 in the UK). Over the last 25 years, the Institute of Geological and Nuclear Sciences and its predecessors (NZ Geological Survey and DSIR Geology and Geophysics) have concentrated on detailed mapping of priority areas selected on the basis of economic and scientific interest. This has included remapping of Nelson-West Coast and Coromandel, regions with high mineral potential, for which 1:63 360 or 1:50 000 maps have been prepared.

Jan 1, 1994

By L. J. Olivier

The possible closure and subsequent flooding of South Deep Gold Mine?s (SD) neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding SD. This paper describes the proposed controlled flooding of REL 4, the planned in-service monitoring of the five plugs and the water barrier between REL 4 and South Deep Mine, and the long-term maintenance of the plugs and rock mass in the immediate vicinity of the plugs.

Jan 1, 2006

Dynamic Simulation of an Alumina Refinery

Sep 13, 2010

By Scott D. Thomson

The client for this project specializes in the use of state-of-the-art technology to fabricate and assemble composites and metal-bonded structures for commercial and military aircraft programs. One of the key components for this operation at the client's plant is a highly precise computer-numerical-controlled router known as the Shoda Machine. This machine tool was installed at the plant in July 1998 for the manufacture and inspection of aircraft parts, and it is extremely sensitive to deflections. To monitor the occurrence of deflections, an internal laser system continuously checks the machine calibration. Deflections in excess of 5/1000-inch in the foundation on which the machine rests require costly periodic re-leveling and recalibration of this tool. Therefore, a significant problem arose when measured deflections during machine operation were as large as 20/1000-inch. In addition, the foundation was cracked in at least three places as a result of elastic foundation movement caused by dynamic loading as well as shrinkage and loss of base support. Deciding on a remediation procedure to alleviate or eliminate these problems involved the following important considerations: (1) achieving the client's need for reducing deflections to less than 5/1000-inch, (2) minimizing the repair cost as much as possible, and (3) reducing the time required for implementation of the foundation remediation solution. After evaluating the advantages and disadvantages of several alternatives, jet grouting was selected as the most suitable solution. The jet grouting program provided columnar elements of soilcrete to remediate the Shoda Machine foundation.

Jan 1, 2003

By S. Banisi, M. Poorkani

The Sarcheshmeh copper deposit contains 1 billion tones of ore averaging 0.7% copper and 0.025% molybdenum. It is located southeast of Iran and currently processes 41,000t/d. Molybdenite as a by-product is recovered in two separate stages. First, a bulk coppermolybdenum concentrate is produced and in the second stage these two are separated. The recovery of molybdenite in the first and second stages is 65% and 85-90%, respectively. The yearly production of molybdenite concentrate varies between 3500 and 4000 t. Sodium sulphide is used as the depressant of the copper and iron bearing minerals which due to a rather high consumption (17.7 kg/t) constitutes one of the major cost items of the plant (i.e., 58% of total reagents cost). A detailed laboratory scale study showed that replacing air with nitrogen could reduce the consumption of sodium sulphide (i.e., H2S or mineral origin). Nitrogen for the plant was supplied from an oxygen plant used for the smelter through a 1400 m long pipeline. The existence of the oxygen plant at the Sarcheshmeh complex was a key factor in the implementation and success of this project. After using nitrogen in the plant for a period of twenty one months, the consumption of sodium sulphide was reduced from 17.7 to 14.2 kg/t at constant metallurgy. The reduction was lower than expected which was mainly due to the type of sodium sulphide used and the lack of any automatic instrument to control the depressant (sodium sulphide) dosage. The latter in turn caused the operators to overuse sodium sulphide in order to reach and maintain the target metallurgy (i.e., higher molybdenite recovery along with lower copper content of the concentrate).

Jan 1, 2005

By Ian Sherrell, Christian Cardoso, Henri Vepsäläinen, Guillermo Bermudez

Performance of mixing mechanisms in flotation cells is paramount, as inefficiencies can lead to financial losses through valuable minerals lost to tailings. Technological advancements have been implemented in flotation cells to optimize performance, but regardless of the efficacy of these developments, room for improvement may persist. Since its launch in 2005, FloatForce® has set a high industry standard for flotation mixing mechanisms. However, current mining trends call for sustainability-driven developments while improving metallurgical performance. Metso has recently introduced FloatForce®+, the latest iteration of FloatForce, developed through extensive laboratory, pilot, and industrial testing, aligning with mining sustainability trends. It has been designed to maximize recovery, reduce power draw and optimize manufacturing materials. This development stems from a redesigned rotor profile paired with a harmonizing stator configuration. This paper presents the development journey of Metso’s latest patented flotation mixing mechanism, an advancement to improve metallurgical performance at a high sustainable standard in flotation cells. The theory, CFD modeling and test work are discussed in detail.

Feb 1, 2025

By Dziurzyn&apos, W. ski

This article outlines the results of a computer simulation reproducing the transport of a mixture of air and methane following the outburst on 25 November, 2005 in transport gallery D-6, bed 409/4, at the ?Zofiówka? hard coal mine. Based on a mathematical model, numerical method and boundary conditions from the disturbance caused by the outburst, the Ventgraph system of computer simulation programs was adopted for the study. We performed a computer simulation of the influence exerted by the outburst on the propagation of the air and methane mixture, and compared the results of this simulation with those of the actual event as registered by sensors of the mine monitoring system. A validation of the model allowed us to present temporal changes in the concentration of methane and air along flow routes. Keywords: mine ventilation, outburst of methane, numerical simulation, monitoring system.

Jan 1, 2008

By Stephen C. Tadolini, Gabriel S. Esterhuizen, Anthony T. Iannacchione

A Major Hazard Risk Assessment (MHRA) was developed in Australia after a series of mine disasters in the 1990’s. A MHRA is used to help prevent major hazards, i.e. fire, explosion, wind-blast, outbursts, spontaneous combustion, roof instability and chemical and hazardous substances, from injuring miners. A MHRA is a structured process that identifies the characteristics of major hazards, assesses and ranks the risk they present, and evaluates engineering and administrative controls to mitigate them. These controls typically consists of a broad spectrum of prevention, monitoring, first response, and emergency response techniques and helps to move an operation from a reactive to a proactive approach towards safety. This paper documents a MHRA performed at an underground mine where strata instabilities and fire hazards may threaten the condition of its escapeways. The objective of this MHRA is to 1) identify what hazards could affect the egress through the mine’s escapeways, 2) determine what unwanted events pose the greatest threat for the mine, and 3) recommend a plan to prevent or recover from the potential disruption of egress through the escapeway. The plan provides information on the key existing controls that should be monitored and audited, and makes recommendation of new potential controls to further reduce related risks. By documenting the use of MHRA to this specific ground control issue, this paper provides a framework for others to judge the merits of this approach and to help design and perform these activities.

By E. Chen, M. Barati, K. Coley

The reaction between carbon and slags is of significant importance in direct smelting of iron ores, EAF slag foaming and copper slag cleaning processes. This reaction is known to occur via gaseous intermediates and it is important to have fundamental data to understand the relative importance of each reaction step. In this study, the rate of CO2dissociation on different slag surfaces is measured using an isotope exchange technique. It was found that increasing iron oxide content up to 30 wt per cent does not have a significant effect on the rate constant while increasing from this limit, increases the rate constant dramatically. Activation energy of CO2dissociation on slags of unit basicity and different iron oxide contents is in the range of 180±40 kJ/mol. It is found that rate constant dependence on oxygen potential in the slag phase is increasing with iron oxide concentration. In the case of copper making slags, the influence of copper oxide is found to increase the magnitude of apparent rate constant, while decreasing the activation energy considerably. Key words: Gas-slag reaction, CO2dissociation, copper slag, kinetics, isotope exchange

Jan 1, 2004

By Priyadharshini M. R., Premalatha K

"Abstract With the development in the construction of heavily loaded structures, the necessity of pile foundations has increased. For the transfer of heavy loads, it is mandatory that the piles need to be socketed in the underlying rock strata. The load transfer in bored rock socketed piles is by end resistance or the combination of shaft and end resistance which in turn depends on the length of the rock socket. The determination of socketing length of the pile at present is mostly based on a few factors which affect the pile load transfer mechanism. The effect of all the possible factors involved, need to be studied in proposing guidelines for the design of rock socketing length of the pile. Analyses are carried out using finite element analysis software (PLAXIS 3D Foundation) to understand the influence of the thickness of overlying strata for different socket lengths of piles in weak rock. From the load settlement curves, the influence of the overlying soil on the rock socket length isobserved and an effective rock socket length is proposed.IntroductionThe determination of socketing length of the pile at present is mostly based on a few factors affecting the pile load transfer mechanism, which sometimes give a better design and sometimes an uneconomical design. Too much socketing length results in more construction time and higher costs. Therefore, the effect of all possible factors involved need to be studied in proposing guidelinesfor the design of t h e r o c k socket length of the pile.The factors that affect the termination criteria of the rock socketed pile are the capacity requirement, thickness and properties of the overlying soil, characteristics of the founding strata, drilling tools used, roughness of the rock socket and nature of loading.A comprehensive study was performed to understand all the above mentioned factors in different types of rocks. In this paper discussion is made on the settlement results, specifically the influence of overlying sand of different densities above a weak rock. The influence of stress developed is not discussed, keeping in mind the size of the paper under study."

Jan 1, 2014