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By J. -F. Lessard

Most underground mines rely on ore pass systems to ensure the transport of ore and waste. The design and operation of ore pass systems often rely on past experience, which is often anecdotal and at times contradictory in nature. This paper summarizes the current practice in Quebec underground metaliferous mines. The information was collected during a series of site visits in ten underground mines. The database includes information on ore pass configuration, support, materials transited, and overall ore pass performance.

Jan 1, 2006

New developments in the non-invasive and real-time measurement of the velocity profile of slurry flow in horizontal pipes will be described. This information can be used to determine the approach and onset of solid deposition on the bottom of the pipe. Having this information in real time can enable operation at lower velocities or higher solids concentration or both while avoiding solids deposition or plugging and their associated operational costs. In addition, advances have been made in the measurement and trending of pipewear on slurry lines. In contrast to manual methods, CiDRA?s system uses a permanently or semi-permanently installed ring of conformable ultrasonic transducers clamped onto the outside of the pipe. These transducers are used to measure the thickness of the pipe under their respective locations. This results in better repeatability, accuracy, and failure prediction, along with reduced labor costs. The benefit is significantly improved pipe wear monitoring in pipelines with abrasive solids. This provides an improvement in the ability to insure safe operation and avoidance of costly operational and environmental damage due to leaks caused by pipe wear.

Jan 1, 2009

The material presented in this paper describes experimental work to determine the effect of variations in suction nozzle design upon inlet flow conditions. Four entrance profile shapes were examined under controlled conditions of slurry flow and it was found that the straight ended nozzles had consistently higher entrance losses than the straight taper or the ellipse, and that the circular arc profile nozzles were the most efficient. Subordinate considerations were the measurement of the quantities and the forces involved.As the work progressed, three distinct phases in the pattern of flow were apparent and the static pressures in each were carefully examined. An inlet zone was found to be unstable in changing boundary conditions, a transition zone was largely independent of slurry density and in a zone of stability the pressures were found to be directly related to the characteristics of the flowing pulp. In this zone pressure measurements were reproducible within ± 2 per cent regardless of changing boundary conditions.The effect of varying the "1" parameter of nozzles with a part circular entrance profile was examined and it was found that flow conditions approaching the ideal were obtained when the radius of curvature was between 0·40 and 0·550.

Jan 1, 1966

By C. J. Brown

Controlling the level of impurities in copper refinery electrolytes is essential to achieving acceptable cathode purity. Purge of electrolyte is not an entirely satisfactory solution since the cost of neutralization, waste disposal, and replacement acid can be appreciable. The APU® process utilizes ion exchange resin to sorb sulphuric acid while rejecting metal salt impurities. Extensively employed for recovery of waste pickling and anodizing acids since 1977, the system is now being used at several refineries for removal of contaminants such as antimony, bismuth, iron, and nickel. The purified acid, which is recovered from the resin by water elution, is recycled back to the refinery tank-house, while the metals are typically recovered from the de-acidified by-product solution by precipitation.

Jan 1, 2005

By John E. Rourke, O&apos

This paper describes some of the results of a project for the design and demonstration of subsidence monitoring systems for underground coal mines. The project was designed to test monitoring systems described in an earlier feasibility report (O'Rourke and others, 1979). General objectives of the project were to develop reliable cost- effective monitoring systems for use above caving- type mining operations, over supported mines, and in urban undermined areas. Topics selected for discussion in this paper include a description of the instrumentation systems, the site conditions, problems of installation, resulting recommendations and an over- view of subsidence performance data obtained. There were some particularly difficult problems of installation to overcome at this site. Some of these could be experienced at any surface or under- ground project, others are probably more directly related to Western coal fields. Almost any subsidence monitoring program may face the following difficulties:

Jan 1, 1982

Fresh coal refuse was sampled at 21 US mines. Five of the sites were drilled, sampled and tested more extensively. Field tests included Standard Penetration tests, and in-situ density determinations. Laboratory testing included specific gravity, gradation, maximum, and minimum density tests, as well as 9-inch) drained triaxial tests, 9 and 10-inch, permeability tests, slake-durability tests, and accelerated slaking tests. Some refuse sites had significantly lower shear strengths and permeabilities in old, slaked or weathered material than in fresh refuse. Testing did not show useful correlations between strength and permeability changes and other material properties which could serve as "predictors". Testing of refuse under "accelerated slaking" conditions showed promise as a comparative tool and as a potential means of preparing artificially aged samples for evaluations of long-term behavior. The state-of-the-art in slaking research, and the implications of slaking on coal refuse disposal, and on practical methods of managing slaking, were also studied.

Jan 1, 1981

By Misra V. N, Cheng C. Y

Two types of Mt Tom Price hematite iron ore from Hamersley Iron P/L were tested using a Humboldt Wedag Jones P40 wet high intensity magnetic separator (WHIMS). The parameters tested were magnetic intensity (7000, 9000 and 11 000 Gauss), groove plate type (8R and 12R) and gap width (2.5 and 1.8 mm). It was found that at 9000 gauss magnetic intensity, reasonably high-grade and recovery in the concentrate were obtained. At 2.5 mm plate gap width, the 12R groove plate performed slightly better than the 8R groove plate. Further testwork is recommended to optimise the magnetic intensity, feed flowrate and pulp density, wash water pressure and flowrate with 12R and 8R groove plates at 2.5 mm gap width.

Jan 1, 1999

By S. T. Kok

This paper presents a case study in West Malaysia for passive piles failure in very soft marine clay in open excavation. In this particular case, the thickness of the very soft marine clay ranges from 5 m to 7 m (16 ft to 23 ft) from the ground surface. Preliminary site investigation reported SPT ?N? value of zero for the very soft marine clay. The design was based on a deep foundation utilizing driven piles to support the superstructure. During pile cap construction, the piles were subjected to uncontrolled open excavation, inducing bending moment in the piles, resulting in some cracked and broken piles. Analyses were carried out using an existing three-dimensional finite element code with a non-linear soil model to predict the response of these piles during excavation. Finally, the predictions of pile responses during excavation were compared satisfactorily with the observed results.

Jan 1, 2009

By A. du Plessis

The study summarized in this paper focused on expanding existing South African mine closure cost calculation models to provide a new model that incorporates risks, which could have an effect on the closure costs during the life cycle of the mine. This research is important because currently there are a number of mines that do not have sufficient financial provision to close and rehabilitate the mines. The magnitude of the lack of funds could be reduced or eliminated if the closure cost calculation is done in a more risk-orientated manner. The model consists of an expansion of existing closure cost calculation models, by applying the Monte Carlo risk simulation technique to model influences of external and internal changes affecting closure costs. It is shown that the proposed risk-based model provides a way to understand better the implications of uncertainty on the closure costs.

Jan 1, 2006

By H. E. Bartlett

In the operation of some flotation plants treating platinum ores it was found that there were imbalances between the inputs and outputs. The inputs and outputs were sampled as slurries and it was determined that the imbalances arose from biases in the sampling, despite the samplers having been designed according to well-established rules. The launders feeding the sample cutters, and the sample cutters themselves were redesigned using finite element analysis to model the flows. A new set of design rules were formulated. The application of a Components of Variance Analysis, to determine the variance of primary and secondary sampling and of analysis in the lab for a concentrate is presented to illustrate the need for frequent sampling of process streams.

Jan 1, 2002

By C. Pelley, S. Kelebek, S. Gregersen, P. Katsabanis

A series of small scale tests have been conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the physical properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Young’s modulus, Poisson’s ratio, P-wave, S-wave velocity, point load strength index and grinding work index were evaluated for samples without any blasting load and for samples which had received a variety of blast loads, such as a simple side impact from a detonating cord, or combined impacts without any delays and with very short delays. The investigation covered two types of rock, granodiorite and limestone. The effect of blasting load on the physical and rock mechanics parameters of the rock was clearly shown and damage was quantified and related to loading. However the work index did not show significant differences between blasted and not blasted samples, probably due to the relatively low level of impact. Numerical modelling using the AutodynTM code was used to demonstrate damage development in the various configurations tested.

Jan 1, 2003

By N. Hmidi, T. Yalcin, M. Papadakis, B. Hilscher

Mill tailings, containing iron sulphides in particular, pose an environmental concern since they constitute a potential source of acid mine drainage which can damage vegetation, harm soil and living organisms, and contaminate groundwaters. Proper disposal of acid generating tailings is therefore an important issue that must be addressed and resolved in a satisfactory manner. Placer Dome Canada operates a 4000 t/d gold cyanidation facility at Musselwhite mine, in northwestern Ontario, where the mill tailings have been classified as acid generating. This study was conducted to explore the effectiveness of froth flotation in removing the sulphide minerals from these tailings and producing a low-sulphur, non-acid generating material that could serve as a capping material for previously deposited tailings. Laboratory semi-batch flotation tests were carried out in accordance with an experimental design procedure, and a computer simulation program was developed to facilitate the evaluation of flotation performance. In this investigation, pH, collector concentration, and airflow rate were considered as the relevant flotation variables, and their effects were examined both experimentally and by simulation. Results have demonstrated that flotation can successfully desulphurize the Musselwhite mine tailings and render them non-acid generating.

Jan 1, 2004

By John Wise

Significant movement to an existing slurry wall which serves as a retaining wall on 'O' Street in Southeast Washington, D.C. initiated the Department of Public Works for the District of Columbia to invite specialty contractors to propose a rehabilitation and stabilization for the failed slurry wall. Nicholson Construction Company proposed and was awarded a contract for the construction of an anchored precast lagging and soldier pile wall to be located approximately 4 feet in front of the existing structure with granular fill placed between the new and existing walls. Stabilization of the existing slurry wall also included drilling horizontal weep holes and demolishing the failed panels down to the existing ground surface. A new and improved drainage system was also constructed to increase the amount of water directed toward the existing storm sewer system running along 'O' Street. This paper provides a detailed account of these construction activities.

Jan 1, 2003

By Christy Z. Lueders

Introduction More and more women engineers are joining the traditionally male mining industry. Are they successful? Do they encounter special problems? How do men in mining respond? How can the mining industry effectively use its female resources? What contributes to the success of a woman in mining? What can male engineers do to ease the entry of female professionals into the workforce? An STM survey conducted last spring provided some answers to these questions. All BS graduates in mining, mineral engineering, and extractive metallurgy from 1960-1979 were surveyed. Nearly 60% of the female graduates, from 17 universities, completed questionnaires. The women were asked why they chose mining, how they relate to predominantly male co-workers, what job skills they have gained, and what areas of work they most enjoy. They were also asked how problems of a two-career family are solved. Data were gathered on salaries, titles, specialties, and products handled. Respondents, assured of confidentiality, are identified only by title. Many male mining executives were also questioned for their advice to women in mining. Profile of the Survey Participant The "typical" female mining engineer works with coal, is employed by an operating company, feels she works very hard to prove her abilities, does not want to be treated as an anomaly, and someday wants to be an independent consultant. Of the respondents, 44% listed coal as the most familiar product, 12% said copper, and the rest listed products from industrial chemicals to oil. Titles varied widely but women managers are rarely found. However, the majority of the survey population graduated after 1976 and thus lacks substantial experience. Of 102 female graduates, only 25 graduated before 1977. Since then, there has been a steady increase. The American Association of Engineering Societies reported that in 1980 more than 100 degrees were awarded to women in minerals engineering. Education Highly Valued Twenty-two percent of the women surveyed had graduate degrees, 38% planned further education, and 12% listed a PhD as their goal. The majority of graduate degrees are in technical fields. There were only two MBAs. Five women intended to pursue law degrees, and one woman, with a mining engineering degree and an MBA, is a part-time law student. Along with advanced education, the women agree that production experience is needed for career advancement. However, only 28% of the women have worked in production. Many women, especially younger grads, commented that these are the toughest jobs to get. This is a universal complaint, from males as well as females, though women seem to encounter more opposition. Several women mentioned they were small or slight of build and managers tended to shy away from hiring them for production jobs. Two-Career Marriages The most difficult problem for two-career couples is relocation. Whose career takes priority? Fifty percent of the women said transfers or offers would be examined on a case-by-case basis, weighing pros and cons for both parties. The husband's career took priority with 47% of the women; their own careers, with 3%. These statistics conflict with comments from two employee relations managers. Both said most female engineers they've encountered are married to men who follow their wives' careers. Seventy per cent of the married respondents said their husbands were also engineers. Four said their husbands were engineers at the same company. Some male and female engineers met on the job; others joined the company as a "package deal." Both partners being engineers can ease relocation problems, since an area or company offering one spouse a job can often provide a spot for the other. A company may benefit by getting two new hires for the relocation costs of one. Most companies contacted have policies that allow married couples to work at the same division, but discouraged them from working in the same department. With 40% of today's marriages ending in divorce, one risk is that one or both parties may quit. One personnel executive said there were several couples, each spouse in a different discipline, who were work¬ing out very well at his division. However, he recognized the potential for problems if, for instance, one gets promoted and the other doesn't, or salary increases are unequal. The personnel executive said he has actively recruited married couples, and would again, were each person competent.

Jan 10, 1981

By B W. Riddol1s

The 1983 Energy Plan calls for an increase in North Island coal production from both underground and opencast sources from the 1982/1983 production of 843 000 tpa to approximately 3.4 Mtpa within the ten year period to March 1993. This increased production is scheduled to come from the following sources: Huntly West No 1 underground mine reaching full production of 1.26 Mtpa. Huntly East underground mine increasing production to 750 000 tpa. The proposed new Huntly West No 2 mine producing 100 000 tpa in its first year of operation û 1992. The proposed Ohinewai opencast producing 920 000 tpa for supply to the steelmaking plant at Glenbrook, replacing Weavers opencast which will be worked out in 1990. Rotowaro opencast producing at 220 000 tpa (currently being achieved). Two additional sources of supply which are not scheduled to begin production for at least ten years, and both of which have been designated for coal fired thermal power generation, are the Maramarua and Mokau coalfields. It was originally envisaged that development of both coalfields would be a combination of underground and opencast mines. The form of development is yet to be confirmed by detailed feasibility studies. The location of the Maramarua, Ohinewai (Waikare Coalfield) and Mokau deposits is shown on Figure 1. Worley Consultants Limited, in conjunction with their partners Rheinbraun Consulting GmbH (Germany) and Longworth McKenzie Pty Limited (Australia) have been involved with investigations and mining assessments for the Maramarua, Mokau and Ohinewai prospects. The Maramarua and Mokau studies form part of the New Zealand Coal Resources Survey programme of updating information to the Pre-Feasibility Mining Assessment level before proceeding to detailed feasibility studies. The Ohinewai study was commissioned directly by Mines Division to investigate the feasibility of mining coal by 1989 before reserves at Weavers opencast are depleted. This paper describes typical studies which are now being commissioned by Mines Division to investigate large-scale mining development and the effect geotechnical-conditions may have on coal recovery. The magnitude of these projects is reflected in the proposed outputs û up to2 Mtpa from individual mines û and the introduction of new continuous mining systems for both underground and opencast mines on a scale which has not previously been contemplated.

Jan 1, 1984

By R. F. Lynch, F. E. Goodwin, A. F. Skenazi

"The Gal/an alloy has been developed for continuous galvanizing of steel. The choice of the eutectic zinc-aluminum alloy with addition of misch metal gives a coating with specific characteristics as far as structure, analysis, surface chemistry and surface morphology are concerned. The performance of the uncoated Galfan coating is superior when compared to conventional galvanized particularly for corrosion resistance and ductility. For coil coating applications, these two assets are of the utmost importance but in order to benefit from these two advantages, good paint adherence and high resistance to edge creep and blistering have to be obtained. Despite Galfan's unique features compared to other zinc based or aluminum zinc based coatings, existing pretreatments and painting conditions are used with only minor modifications in order to assure good adherence and edge creep resistance. With compatible processing, Galfan can outperform galvanized and Galvalume as a substrate for coil coating as is demonstrated with various test results.IntroductionThe technical and commercial development of Galfan, a 95% zinc-5% aluminum-0.1% lanthanum-cerium hot-dip coating for steel, has been rapid. From its identification as a promising coating in late 1980, it has evolved from a research product to a fully commercial product with over 100 000 metric tons of coated sheet produced to date, and another 90 000 tons, at minimum, scheduled for 1986. The great majority of tonnage produced to date has been coil coated for use in building panel , appliance, and similar applications. Much technical work has been done to determine the suitability of Galfan for these applications and the proper way of processing sheet for best results. The present state of knowledge is discussed in this paper, along with some recent applications which are given asexamples"

Jan 1, 1987

By Zephaniah Varley, Satoshi Akai, Richard Sage, Steve Redmond, Mike Murray, Rohit Shetty, Gerald Skalla

One would be hard pressed to find another project as complex as this one given its configuration, the variety of issues to address and the required construction techniques. Contract C710 is currently under construction as part of Sound Transit’s Link Light Rail, connecting downtown Seattle with Sea-Tac Airport. The paper describes the construction-to-date of the deep mined station under Beacon Hill using the Sequential Excavation Method (SEM). This deep “binocular” station is being mined through some of the most challenging soft ground conditions in the USA. The excavated volume of the station is approximately 60,000 cy (46,000 m3) and the station comprises a variety of geometries and cross sections ranging from 235 sf (22 m2) up to 1,670 sf (155 m2). This underground complex includes platform, concourse, cross-passage and emergency ventilation tunnels together with station egress and ventilation shafts. Various excavation sequences are in use for the different tunnels including the twin-sidewall drifts for the impressive45 ft (13.7 m) wide by 42 ft ( 12.8 m) high concourse cross adits. This station has two train platforms approximately 165 feet (50m) below the surface. This station, constructed in highly variable glacial deposits including water bearing sands and silts approximately 50 ft below multiple perched water tables in an urban setting, creates a very unique and challenging situation. The ground is being managed with various types of ground improvements such as jet grouting and vacuum assisted deep dewatering wells from the surface, and from underground by use of “SEM Tool-box Items” such as barrel vault canopy, grouted pipe and rebar spiling, chemical grout,

Jan 1, 2007

By J Cahill, D Holden, R Stuart, G Cryan, W Power, W Stratford, S Garwin

The combination of Stage 1 Geoinformatics legacy data intervention processes with the Stage 2 ultra-detailed airborne geophysical prospecting demonstrates a new approach to converting data to information to knowledge, and converting that knowledge into exploration results.   The Coromandel region of the North Island of New Zealand has long been know to host gold deposits of economic viability (Hauraki Gold Fields). To the SE of this area lies the Taupo Volcanic Region (TVR) where the geology and structural setting mirror the Hauraki Gold Fields, however mineral exploration in the past has been hindered by the blanketing volcanic ash deposits. Glass Earth Limited recognised that this whole potential epithermal gold province could be effectively explored utilising rapid, risk orientated processing to review legacy geoscience data: The Geoinformatics Data Intervention Process; which in turn directed ultra detailed airborne geophysical surveys over the TVR. Results have outlined 21 new drillable potential epithermal gold targets; and a plethora of other targets with high prospectivity.

Jan 1, 2005

By M. Abdellatif

Keywords: Magnesium, pyrometallurgy, Mintek Samples of crude magnesium produced by the Mintek Thermal Magnesium Process were refined in two stages. The first stage consisted of co-melting of batches of the crude metal and MgCl2-KCl flux (cleaning), followed by stirring at 30 rpm for 30 minutes and settling of the sludge (mixture of molten salt and solid impurities) from the magnesium melt. The operating temperature was 680?730°C. Most of the contained calcium and significant proportions of iron and silicon were transferred into the sludge phase, which left a metal containing, on average, 950 ppm Si, 470 ppm Fe, and 230 ppm Ca. In the second stage, small-scale refining tests were conducted on cleaned samples from the first stage, as well as on crude magnesium. FeCl3 was used as the refining agent. These tests were carried out at 715?760°C with various amounts of the refining agent. The refined metal was suitable for the production of various magnesium alloys, particularly AZ91D.

Jan 1, 2006

By Soner Top

In this study, a process to separate manganese and iron from manganiferous iron ores by reductive acid leaching followed by magnetic separation was conceived and experimentally tested. In the leaching process, sulfuric acid was used as lixiviant and oxalic acid was used as reductant. The experimental results showed that the manganese and iron separation was optimum when the concentration of the sulfuric acid and oxalic acid were 0.75 M and 30 g/L, respectively, at a temperature of 80 °C, a solid/ liquid ratio of 67 g/L, stirring speed of 400 rpm, and leaching duration of 60 min. Under this condition, 90.49% and 6.78% of Mn and Fe were dissolved, respectively, from the ore sample with a size fraction of − 106 μm. It was determined that the leaching of manganese from the ores was a second-order reaction with an activation energy (Ea) of 53.38 kJ/mol. The leaching residues obtained under the optimum condition were subjected to high-intensity wet magnetic separation tests to recover the remaining iron content. This separation process produced a concentrate containing 56.20% Fe and 1.79% Mn with iron and manganese recoveries of 56.83% and 66.73%, respectively. A magnetic separation test from an unleached ore sample was also carried out as a benchmark. To the best of our knowledge, this is the first time that a magnetic separation process was used to a residue obtained from reductive acid leaching of manganiferous iron ores to recover iron.