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By R. J. Mitchell

"Centrifuge modelling of earth structures is a well-proven technique for evaluating the performance of prototype structures using physical models. The applications of this technique have increased dramatically during the last decade such that even the modelling of dynamic responses in structures has been accomplished.This paper presents the first model test results used to design a mine backfill. The models were tested using a 3 m radius 30 g-tonne geotechnical centrifuge which was constructed at Queen's University specifically for model studies on mine backfill stability and subsidence. The models represent the first production blast-hole stope to be mined at Westmin Resources Ltd. 's H. ~ Mine on Vancouver Island. This paper includes photographs of:model failures in the centrifuge and correlations of model test results with analyses based on unconfined and triaxial test data.IntroductionDuring the feasibility study and development stages for the H.W. Mine, Westmin Resources Ltd. conducted a comprehensive rock mechanics and backfill engineering program. The results of these studies indicated the need for assurance of backfill stability during pillar recovery on the initial blast-hole mining block. The cemented tailings backfill had to be free standing for heights up to 25 m and the potential for surcharge loading from a weak hanging wall zone, the potential for fill block sliding down-dip and the potential for seismic loading had to be considered in the design of the fill strength. The basic questions to be answered were: what cement content is required and will the resulting backfill costs be economic relative to the proposed mining method and sequence? Figure I shows a typical cross-section through the first mining block . The up-dip stope is to be mined first and backfilled with cemented tailings . The down-dip stope would then be mined and filled. Depending on ground conditions encountered, the complete intervening pillar could be recovered and the void backfilled with uncemented tailings or it could be recovered in small sections by exposing limited back and wall areas, backfilling with waste rock and I or cemented tailings . This latter method is commonly referred to as the Avoca method"

Jan 1, 1987

By Dave Ecobichon, Éric Côté, Simon Nickson, Michel Leclerc

The feasibility assessment of a mineral deposit requires the construction of a geo mechanical model of rock mass properties, for the purpose of preliminary mine design. The Noranda Technology Centre has been involved in the development of geomechanical models for several mineral deposits at the feasibility stage. Each model is constructed through intact rock testing, geotechnical core logging, geotechnical mapping and rock mass classification. Rock mechanics principles are used to develop conceptual stope designs and propose possible mining sequences. This methodology is applicable to both new mining projects and to the development of new areas within anoperating mine. This paper explains how the geomechanical model is developed and reviews its application to several case studies.

Jan 1, 1996

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The major importance of liners in grinding is their role in providing an appropriate trajectory for the charge. Since it is not possible to study the charge movement by direct observation in operating industrial mills, this task is accomplished by physical (laboratory), and/or, mathematical (software) methods. Because of the high cost and a longer time required for a physical analysis, mathematical simulations have become more common. Simulation of the effect of liner shape on the charge movement has provided a means to select a proper design based on the operational objectives and conditions. Furthermore, the liner shape changes due to wear and impact during operation, which will influence the charge trajectory. This adds more of an incentive to use simulation. These changes in liner could be predicted through liner profile measurements during operation and/or simulation. In this research, an inhouse developed DEM software called KMPCDEM © was used to simulate the charge movement in industrial plant SAG mills. A geometrical method of implementing the shell liners on SAG mills at the Sarcheshmeh (9.75×4.87 m) and the Gole-E-Ghohar (9×2.05 m) operations facilitated the software simulation. Point by point implementation of the measurements of liner profiles of these mills enabled the study to trend the change in the charge movement as the liners wear. Comparison of the simulation to a laboratory mill (1 m diameter) showed that the difference between the measured and predicted charge impact point, shoulder angle and toe angle were 6, 4 and 3°, respectively. INTRODUCTIONComminution is the most energy intensive operation constituting the major portion of operating and capital costs of a mineral processing plant. In the last decade, a vast number of research was aimed at studying various aspects of grinding with the aim of performance improvements (Davis, 1919; Mishra & Rajamani, 1990; kalala, Breetzke, & Moys, 2008). Mill liners transfer the input power to the charge and play a significant role in affecting the motion of the charge (Mclvor, 1983; Mishra & Rajamani, 1990; Radziszewski, 1997; Van Nierop, Glover, Hinde, & Moys, 2001; kalala et al., 2008). Lifters are usually used with mill liners to extend their life and to enhance the grinding and impact breakage efficiency. Mill lifters are used to raise the grinding media and ore to transfer the energy from the mill to the load (Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010)."

Jan 1, 2016

By Gerhard Melcher, Hermann Hilbrans, Michael Gamroth

"IntroductionSeveral new smelting processes have been proposed and developed during the last 20 years. This has been true, in particular, for copper smelting technology. The important impulses for the advances in this field have been the recent demands regarding the environmental protection, energy saving and improved utilization of the metals contents of deposits, in particular that of complex raw materials.The methods developed more recently for pursuing these objectives have been outlined in several papers. In some of them the advantages and drawbacks of certain developments have been stressed. These documents are of great importance for assessing the different processes. The following paper tries to explain some details of the cyclone smelting process taking into consideration a few of these well-known presentations. The effectiveness of operation of the cyclone smelting process indicates that this process presents a significant achievement when compared with other conventional methods.The application of the CONTOP smelting cyclone range s beyond the field of copper metallurgy or the smelting of sulphide concentrates with the aid of oxygen. The research work carried out in the pilot plant of KHD Humboldt Wedag AG in Cologne-Porz also includes the recovery of the metal contents of intermediate products and processing of smelter residues which have to be converted in a disposable stat e, free of environmental pollution. This paper explains a few examples in this regard."

Jan 1, 1987

By G. L. Palmer

"Abstract- ln 1986, anomalous sampling results for heavy minerals were obtained at various sites in Namaqualand on the west coast of the Cape Province. Drilling in 1987 at Graauwduinen penetrated up to 35 meters of heavy mineral-bearing Tertiary sands which extend several kilometers inland from the coast. The heavy mineral suite includes ilmenite, rutile, leucoxene, zircon and monazite, along with garnet, pyroxene and amphibole. Three deposits are recognized, two of which comprise the resource to be mined by Namakwa Sands Limited, a recently formed Anglo American Corporation subsidiary company.Mineable reserves in excess of 500 million tonnes have been delineated, sufficient to sustain mining for over 35 years at projected production rates. During the feasibility study, on-site investigations included test mining at various sites to assess mineability and to provide material for metallurgical testing in a pilot plant located at the site. Ilmenite produced at the mine will be smelted at a new facility to be built at Saldanha Bay . Saleable products comprise titania-rich slag, pig iron, zircon and rutile.During the exploration phase, company environmental guidelines were established and monitored. The feasibility study incorporated a Class 1 Environmental Impact Report, the contents of which were made public following the principles of the Integrated Environmental Management legislation."

Jan 1, 1994

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

By Jason Palmer

"Water in mining is the commodity that has driven the mining industry for decades. Often used frivolously, modern economic and social pressures are forcing change to use less water and to improve the quality of water and effluents. Used in many processes, water is ultimately consumed in tailings disposal and technologies which can increase the recovery of water are constantly being developed. Filtration and thickening are often seen as competing technologies for water recovery however new cases are developing that show significant advantages can be achieved by combining the two technologies to develop the most effective solution. Supported by case studies this paper investigates the merits of each of the technologies and which strategies of combining the two produce the best outcomes.INTRODUCTIONMineral processing applications generally require water for the processing of ores, whether utilising physical or chemical methods. Water is first added in the milling stage and additional water added as required throughout the circuit. Water losses from the circuit are principally associated with the tailings stream. Optimised water recovery is necessary both because it is a scarce commodity and to minimise the environmental impact.Water recovery is usually accomplished through a sedimentation or filtration processes. Water can be removed from the tailings impoundment by evaporation but this does not improve the mine’s water consumption. The water recovery methodology also determines the water quality; increasing water recovery concentrates solutes in the process water and may create recirculating loads of fine solids."

Jan 1, 2016

By Ajit K. Sinha

"Abstract - Electromagnetic surveys were conducted over the Yava sandstone-hosted lead deposit in Nova Scotia to evaluate the usefulness of such surveys for detecting and mapping sedimentary­ hosted metallic ore deposits. Both transient and multifrequency systems were used for that purpose. The deposit consists of three zones of disseminated galena which also contain minor amounts of pyrite and sphalerite filling the interstices of the sandstone grains. Each zone overlies a basement depression and is separated from the adjacent zone by an intervening basement high. A conductive shale layer underlies the galena-rich sandstone formation at all three zones.Because the concentration of galena (3% to 4% ) and other sulfides is too low to affect the resistivity of the sandstone formations for detection by ground electromagnetic (EM) methods, the strategy for our survey was to look for areas of basement depressions and the presence of conductive shale in those depressions by EM depth soundings. The presence of the galena-rich sandstone formations could be inferred because of the close association of these two features with the deposits in the Yava area. Both transient and multifrequency EM systems were successful in mapping the basement depressions and detecting conductive shale at the three known mineralized zones. The technique, therefore, seems to offer good prospects for mapping similar stratabound sedimentary-hosted sulfide deposits."

Jan 1, 1993

By K. Bowes, M. D. Maley, R. J. Ring

The Honeymoon Uranium Project is an acid In-Situ Recovery (ISR) mine in South Australia. It was previously operated for approximately 18 months before being placed on care and maintenance in 2014, it was then acquired by Boss Resources in 2015. Boss has been performing a number of studies to plan for reopening of the mine, including a successful field leach trial (FLT) in 2017. The current configuration for uranium precipitation at Honeymoon is a batch process. Whilst this achieves effective uranium recovery, the precipitates produced are often very fine, with poor settling and solid/liquid separation characteristics. Continuous precipitation, involving recycling of solids, has reportedly been successfully utilised in other operations to increase the particle size and density of the product, leading to solids that can be more readily dewatered, dried and drummed, with less fines and dust generation. However, no operational data are available from such operations.

Jan 1, 2020

By C. G. Bruce

"ON NOVEMBER 15th, 1950, the Department of Mines and Technical Surveys announced the discovery of vermiculite near Perth, Ontario. The announcement followed nearly a month of study to determine so far as possible the potentialities of the deposit and quality of the material from surface indications. The mineral was identified by the writer in the field among samples submitted by Mr. Arthur Powers of Stanleyville or, September 22nd, 1950. Within a week of the announcement, mining rights to properties covering a major portion of the deposit had been acquired by commercial interests.Hitherto, Canada has had to import her entire requirements of vermiculite. Prospects of .a domestic supply gave promise of considerable benefit to many industries, particularly the building industry, and to the consumer public. Should the deposit •prove large enough there was also the possibility of exporting to centres in the United States.Field and laboratory studies were continued at the Mines Branch during the winter of 1950-51 as opportunity occurred. It is the purpose of this paper to describe the results of these •preliminary investigations, to attempt to present the Stanleyville occurrence in its proper perspective with regard to similar occurrences elsewhere, and to review the salient features of the vermiculite industry.Properties and UsesVermiculite is a hydrated magnesium aluminum silicate. In appearance it resembles mica, having the same micaceous cleavage, but it differs from that mineral in being very soft, pliable, and inelastic. Colours range from black through dark olive-green and brown to almost colourless."

Jan 1, 1952

By K. A. Mackinnon

The choice of fan type (axial flow, centrifugal or mixed flow) most suited for a mine ventilation application depends on a number of technical and economic factors. For each project, the relative importance of these factors will vary. It is worthwhile to carry out an assessment on a case by case basis. The paper, by discussing a number of technical and economic factors and their interactions, will provide the ventilation official a methodology to easily and methodically undertake such an assessment.

Aug 1, 2013

By J. A. Finch

The metallurgical performance of a flotation cell is strongly influenced by the features of the bubble population, characterized by the gas dispersion properties, a collective term including bubble size, superficial gas velocity and gas holdup. It is required that gas be well distributed throughout the cell. Gas distribution is estimated here by simultaneous measurement of gas velocity (Jg) at different distances from the center (radial Jg mapping). This communication describes a technique to perform radial Jg mapping together with fundamentals for the interpretation of the data.

Jan 1, 2009

By J. Seo

We propose a dynamic biomechanical simulation method that uses motion capture to evaluate the risk of Work-related Musculoskeletal Disorders (WMSDs). Statistics show that WMSDs accounted for 33% of all non-fatal occupational injuries and illness in construction in 2009, and were a leading cause of temporary and permanent disability. Present methods rely largely on self-reports from workers, observational techniques, and direct measurements of motion and muscle activity to assess awkward postures, physical loads, repetitiveness, and the duration of exposure. While these methods have helped to prevent WMSDs in construction work, they may not be suitable for estimating the internal tissue loads associated with WMSDs. We propose a dynamic biomechanical simulation method to estimate internal forces and moments at each body joint of construction workers with motion capture data. Particularly, we explore the biomechanical loads by simulating active 3D musculoskeletal models based on measured postures and movements. To demonstrate the feasibility of this approach, we studied a ladder climbing task using a portable ladder under controlled laboratory conditions. Postures and motions were determined with a commercial motion capture system (e.g., VICON). The results were analyzed to investigate the feasibility of identifying risk factors based on biomechanical simulation. The results show that the proposed approach allows us to determine the biomechanical basis for WMSDs, and to identify postures and movements associated with excessive physical demands on each body joint. When combined with marker-less motion capture which is our ongoing work, the proposed approach has the potential to assess an individual?s motions and to provide personalized feedback for the purpose of reducing biomechanical loads and WMSD risk in real workplaces.

Aug 1, 2013

By S. G. Hardcastle

The effects of air velocity in promoting cooling through the evaporation of sweat generated when working at a high metabolic rate and/or in hot environments is well known. Many of the environmental heat stress indices consider the effect of air movement directly or indirectly within their determination, be it through the use of a specific instrument i.e. a wet-bulb globe temperature meter or Kata thermometer, or inclusion of in the calculation of a stress index, including the effective temperature, air cooling power, thermal working limit, ISO 7933?s predicted heat strain model. Within these models, ambient air temperature, relative humidity and barometric pressure are also considered in varying degrees to quantify an airstream?s capacity to evaporate sweat. Deep mine studies have shown cumulative increases in heat exhaustion rates with both decreasing air velocity and decreasing air cooling powers. However, despite a capacity to cool, the resultant cooling is very dependant on sweat production and its availability for evaporation; these are included where sweat rates and skin wettedness are considered. The first depends on hydration and physiological factors whereas the second is more an engineering factor related to the degree of clothing required. As sweat rates deteriorate with aging, the benefits of evaporative cooling potential can similarly be expected to be diminished. This paper continues to report upon on-going physiological studies exploring the potential for heat stress in deep underground mines through the simulation of mining activities in environmental chambers and a human calorimeter facility. The focus of this paper is to introduce preliminary data suggesting that increasing air velocity (0.5, 1.5 & 3.0 m/s) is beneficial for young subjects (22 ± 1 yrs), as indicated by lower core and skin temperature measures and heart rate during an intermittent work protocol, and then show a lesser benefit for older subjects (62 ± 2 yrs). Both subject groups performed the same task under the same environmental condition (35°C, 60% RH) wearing a standard mining ensemble. The study similar to others being performed under the Deep Mining Research Consortium funded research continues to provide evidence that a greater understanding of heat management processes is required and that worker education is critical as environmental measures and health and safety regulations may not be expected to include all demographic factors such as age, sex and health which are known to affect human thermoregulatory response.

Aug 1, 2013

By Jean-Yve Tremblay, Michel Prud'homme

"IntroductionIndustrial minerals include a group of more than fifty minerals which are marketed into almost all the sectors of industry; they are the backbone of many manufacturing industries. Table I shows major end-uses for industrial minerals in manufacturing sectors.At Energy, Mines and Resources, industrial minerals are divided in three major categories: (I) agro chemicals and chemicals, (2) construction mineral s, and (3) ceramics and specialty minerals. A listing of the major groups of minerals is shown in Table 2.Agro-chemicals and chemicals are sold on the basis of their chemical content and purity. Construction minerals or structural minerals are distinguished by their performance as low cost and bulky commodities. Ceramics and specialty minerals are performance-specific and are sold for their property on imparting functions on end-products. Industrial minerals have unique characteristics that are useful in many stages of processing; from crushed size to micronized fillers a single mineral ca n serve a broad range of industries because of its intrinsic properties.The Industrial Minerals Industry in CanadaCanada has a large industrial minerals base and is a world leader in the production of some of them. The total value of product ion of these minerals has grown by 115% over the last 10 years despite the misfortune of asbestos.Industrial minerals have shown remarkable growth in the past 20 years at an average annual rate of 9.2%, compared to 7.8% for metallic minerals. In 1986, the value of industrial minerals rose to $4.9 billion, or 14% share of the Canadian mineral production. Figure I shows the value of production of the mineral industry for the period 1966-1986.The leading segment in industrial minerals segment since 1976 is the chemicals and agro-chemicals sector which has an average annual growth rate of 5.75 % in terms of value of production. During the same period, the growth rate for the whole Canadian mining industry was 1.37% per annum. The chemicals and agro-chemical s sector increased its contribution to the total value of production of 2% to 6070 despite the growing share of fuel minerals with 59%."

Jan 1, 1988

By Erik Q. Dahl

The strength of green and sintered pellets during reduction under various conditions in a laboratory kiln has been investigated. Equipment and test methods are described, together with the results obtained. The strength of sintered pellets drops sharply when the reduction starts, and goes through a minimum at the 70 per cent oxidation level. At more advanced reduction, the strength increases with increasing metallization. Successful use of green pellets as kiln feed requires that more attention be paid to the pellet preparation than is necessary when producing pellets for separate sintering. In particular, the ores have to be ground to a greater fineness. The initial strength of green pellets is low. Below the 70 per cent oxidation level, however, the strength of these pellets is about the same as the strength of sintered ones. Additions of such materials as silica, limestone and anthracite coal; within reasonable limits, affect the strength only slightly.

Jan 1, 1966

MR. J. F. MYERS, Consulting J3eneficiation Engineer, Greenwich, Conn.: In the written discussion contributed by Mr. F. C. Bond in item ( 2) (page 515), speaiking about the significance of the ratio of mill diameter to the make-up ball diameter, he states: "When this ratio exceeds 100 the power and capacity of the mill are de-creased"; and the paragraph ends with a reference to the 30 per cent ball volume "with some de-crease in mill capacity". I believe this broad statement is incorrect. When we are dealing with a non-cataracting mill, pre-ceded by a good rod mill, there is a slight increase in capacity, but the power does drop. The second point that I consider needs consideration is Mr. Bond's item (8), Proper Mill Speed (page 516). This paragraph should be qualified to cover single-stage mills only. It does not apply where a rod mill is followed by a non-cataracting ball mill. The statement as is, with no qualification, gives an erroneous idea of proper mill speeds.

Jan 1, 1957

By Jaime V. Ongpin

"The author will give a capsule history of Benguet Corporation and attempt to identify its operating environment and underlying ""strategy"" until 1974, when the company's management assumed office. The company's operating environment and ""interim strategy"" from 1975 to 1980 will be described. The discussion will cover an environmental forecast and define the company's"" strategy for survival"" for the balance of this century.IntroductionIn December last year, I was asked to deliver a pa per for the management lecture series a t the Asian Institute of Management in Manila. The paper was entitled "" The 1970's: A Decade of Disaster For New Mining Projects"" . In that paper, it was my task to review the results of new mining projects in the Philippines during the previous decade. The task was not a happy one, for the results themselves were not only unhappy, but disastrous on a scale unprecedented in Philippine history. Out of a total of 17 major mining project s involving an aggregate capital investment in excess o f US $2 billion during the 1970s, only three project s have been profitable, and all the rest have either gone "" belly up"" or are teetering on the very edge of financial disaster.It is in the context of this shocking record of widespread financial dislocation in the Philippine mining industry, (which in varying degrees appears to have been paralleled in virtually every other country in the world where mining is an important sector of the economy) that I address myself tonight to the theme of this symposium. My paper is entitled ""Risk Management Strategy in Mining"" and it is sub titled ""Can Benguet Corporation Survive to Celebrate its Centennial in 2003?"". I have inserted the word ""Strategy"" and added the subtitle, because I wish to make it clear first, that my presentation to you tonight will be focused exclusively on the strategic aspect s of risk management, and second that I will limit myself to Benguet's own ""in-house"" experience and perspectives on this subject. I would caution you therefore, to consider my views within this restricted framework, and in light of the particular and sometimes peculiar circumstances within which Benguet Corporation operates."

Jan 1, 1983

By A. Zhecheva

A commercial titanium alloy Ti-6Al-2Sn-4Zr-2Mo has been gas nitrided in this work, in pure nitrogen atmosphere in order to improve its surface properties. The nitriding was performed at two different temperatures, 950 and 1050°C, and for different periods of time. The influence of the initial surface roughness on the diffusion process and on the surface properties of this material was studied. The influence of the processing parameters of gas nitriding on the surface roughness, phase modifications and the microstructure of the nitrided layers has been analyzed using atomic force microscopy (AFM), X-ray diffraction and optical microscopy. Microhardness profiles were obtained on cross-sections of the samples after gas nitriding applying a Knoop indenter.

Jan 1, 2004

By Hang Zhao, Xinping Li, Pingan Wu, Yi Luo

"The deep-buried rock surrounding the Jinping II Hydro-power Station was taken as the engineering background. Using model specimens of classified rock materials to simulate fractured rock mass under high in-situ stress conditions, the test about acoustic propagation law on single fracture model of specimen under different pressures and different angles were carried out. The variation of p-wave velocity in fractured rock mass and axial stress-strain relationship in the whole test procedure was also studied. Based on damage mechanics principle and the acoustic wave propagation in cracked rock mass, comparative study on damage constitutive relation of fractured rock mass under high in-situ stress in consideration of equivalent strain and equivalent energy was performed. As the results showed, with the change of axial stress level under constant confining pressure, the change in wave velocity can be divided into three stages: slow increase (small variation in amplitude), rapid reduce (large variation in amplitude ) and accelerate reduction. When the confining pressure is constant, the maximum p-wave velocity and the peak strength of specimens increases with the decrease of the crack angle.When the crack angle is constant, the maximum p-wave velocity and the peak strength of specimens increases with the increase of confining pressure.It is identified that the theoretical calculation results of constitutive relation about elasto-plastic damage model containing variable wave velocity in the fractured rock mass is consistent with the model test results.Therefore,the constitutive relation can provide reasonable suggestions for engineering practice. INTRODUCTIONThere are a lot of joints and fractures in surrounding rock mass of deep-lying in the Jinping-II hydropower station, which has a great influence on the physical and mechanical properties of rocks and effects the acoustic wave propagation and attenuation law in rock. Many previous research and project examples has proved that sound propagation parameters are closely related to crack and stress condition. Thus, it has certain theoretical significance and practical application value to carry out researches on sound propagation characteristics and establish damage constitutive model of fractured rock mass which is related to sound propagation parameters."

Jan 1, 2015