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By J. Abrahams, A. Nesbitt

Over the past half-century, researchers have commented on the complexities of ion-exchange processes, but have been forced to use gross assumptions to simplify the associated mathematics sufficiently for mathematical models to be of practical use, given the available computational power. This paper reviews the development of increasingly complex models as computational power has increased over the past half-century, from the direct application of Fick's Law in 1947, through to today's models requiring finiteelement methods. The assumptions required for and the associated limitations of the various models are presented and the associated computational complexities are discussed. A case study is presented in which a continuous loss of capacity in an acid resin was observed over about sixty cycles of loading and elution. Resin poisoning does not explain this observation. This paper presents the capacity loss data, speculates on possible causes of the phenomenon, discusses why conventional kinetic and equilibrium mechanisms cannot explain it and concludes that the need to develop a more rigorous model is apparent. The significance of this observation is that standard tests done for a new resin application could significantly overestimate the commercial performance of the resin concerned, highlighting the importance of computer simulation in this field of process engineering.

Jan 1, 2005

By J. L. Collins

"Une recherche debutee en 1987 tente de cerner divers éléments ayant un impact sur la productivite miniére, de facon à améliorer la planification des operations souterraines. II a été possible de recueillir jusqu'à trente variables dans sept opérations minières differentes du Nord-Ouest québécois. Cette présentation rend compte de quelques résultats préliminaires obtenus à l’une d'entre elle. Entre autres, elle montre comment une association entre une analyse de régression multiple et un logiciel d'optimisation (OPTIMUL) peut servir à une application particulière de la planification d'une opération minière du Québec. Plus spécifiquement, la présentation montre comment une quantité appropriée de ANFO et de TOVEX peut maximiser la quantilé de minerai cassé, minimiser les couts de sautage ou encore minimiser les coûts d'explosifs par tonne de roche cassée, en se basant sur une série de contraintes réalistes provenant de la mine.ABSTRACTA study, underway since 1987, tries to evaluate factors affecting mines' productivity. Information has been collected from seven underground mines in Quebec and this paper shows preliminary results from one. In particular, it shows how a combination of multiple regression analysis, mathematical programming and a set of realistic mine constraints can be used for a particular application of mine planning. More specifically, the paper shows a parallel between maximizing production of tons of broken are, minimizing explosives costs or minimizing the costs of explosives per ton of broken are by an appropriate selection of ANFO and TOVEX quantity of explosives. Finally, the paper shows that minimizing the costs of explosives per ton of broken are is the best alternative to follow providing a special optimization program can be set up."

Jan 1, 1990

By Robert Hopler

Some few years ago, when the cruiser “Brooklyn” was passing through the fairway to the southwest of the Battery, the ship being fully equipped with stores, etc., and therefore at her maximum draft, she grounded quite heavily upon some obstruction, and received injuries which necessitated her docking at the Brooklyn navy yard, where extensive repairs had to be made on her damaged bottom.

Jan 1, 2007

By J. Hollow, D. Walsh

The Fort Knox Mine is located in Alaska’s interior, where the average ambient air temperatures range from -24oC in January to 16oC in July. The mill processes a free milling gold ore utilizing both a gravity recovery circuit and a conventional cyanide leach/carbon-in-pulp circuits. Mathematical models have been developed to accurately predict the impact of leach circuit slurry temperature on gold leach, carbon adsorption and cyanide destruction kinetics. Additionally, an energy balance approach has been used to model the seasonal variations in slurry temperatures throughout the Fort Knox mill. The energy balance model, combined with the kinetics models previously developed to predict plant performance, was used to justify a tailing thickener installation at the Fort Knox Mine. This paper describes the development of the energy balance model and its prediction of plant performance assuming a tailings wash thickener to reduce heat loss from the mill. Also presented is an analysis of the post project plant performance that validates the model and shows the mine produced an additional 596 kg (19,155 ounces) of gold, while reducing mill reagent costs by $6,302,000 during the first 38 months of operation.

Jan 1, 2007

By C. Pattenden

The viability, self-reliance and resilience of small communities are perennial challenges in regional Australia. Recent developments in Australian mining regions seek to govern the minerals industry in a more holistic way that contributes to sustainable futures for affected communities in different contexts. In some areas of the State of Queensland land use conflicts and the cumulative impacts of multiple projects and activities across time and space have come to the fore. In more isolated regions of Western Australia the dominant issues relate to overstretching people, infrastructure and services in predominantly mining towns. In both cases, there is an ambition for regional towns with a strong extractive industry presence to transition into desirable, liveable and affordable cities with a diversified economy. The paper analyses two strategies - the Pilbara Plan in Western Australia, and the Sustainable Resource Communities Policy in Queensland - to identify how these governance instruments are contributing to sustainable development.

Jan 1, 2011

By Serge V. Krasavin

The behavior of rocks subjected to dynamic loading conditions under explosion includes sufficient information about hydrodynamic variables such as pressure P, mass velocity U, internal energy E, specific volume V and density p as functions of time. Measurement of dynamic characteristics in compressed media with manganin wire sensors has become common in the past few years, but the experimental data for certain media, such as rock, do not provide an exhaustive description of rock's behavior in the near zone of an explosion, which is highly responsible for the transformation of energy of explosives.

Jan 1, 1992

By R. Bruce Patterson

The New Tacoma Narrows Bridge is a classic suspension bridge founded on concrete caissons. Caisson construction was complicated by the proximity of the existing bridge piers, only sixty feet away. High capacity plate anchors were used successfully to moor the new caissons in currents as strong as seven knots during construction.

Jan 1, 2004

By T. MacKinnon, M. C. Bétournay, D. Eastick, F. C. Delabbio, C. Graves

"The successful implementation of a new technology in an underground production mine requires many challenges to be overcome. These challenges include mine hardening of new technology, mitigation of safety risks and hazards, mine operation support, and technology transfer to mine staff. In the end, the majority of these challenges relate to the human aspects of implementation. The approach selected to overcome these challenges must be customized and appropriate for each unique situation.This paper outlines the approach used to address these challenges as part of successful implementation and resulting demonstration of the hydrogen fuel cell locomotive at the Placer Dome (CLA) Limited Campbell Mine. This technology demonstration at Campbell Mine is critical for determining technical, regulatory, and implementation aspects to be incorporated into future fuel cell prototypes such as the LHD project."

Jan 1, 2005

By J Boshoff, D Reid

It has been recognised worldwide that the liquefaction risk of unconstrained tailings stacks or cyclone underflow embankments requires careful consideration. The stability of a tailings deposit where the perimeter embankments are made up of hydraulic fill is often governed by post-liquefaction stability.Cyclones are frequently used around the world to classify tailings into a coarse underflow for building a tailings impoundment wall and a finer fraction that is disposed of into the basin. The shear strength of the tailings that form the outer embankment of a tailings storage facility (TSF) and the location of the phreatic surface are the two most significant factors influencing the structural integrity of the facility. The coarse underflow is placed in such a way as to contain the overflow, which is finer, has low strength and is often poorly consolidated.A cyclone field trial was undertaken at a gold mine in Western Australia to assess the feasibility of using the cyclone deposition method to optimise and increase the capacity of an existing tailings cell. The aim of the cyclone trial was to collect information to demonstrate to the client and the regulators that cyclone deposition was a feasible option for raising TSF embankments. The cyclone trial provided an opportunity to assess the cyclone under field conditions and the quantity and quality of the underflow fraction produced on-site. A variety of methods were used to assess the flow liquefaction susceptibility of the tailings underflow sample produced during the cyclone field trial.The field trial, laboratory testing and analysis will be discussed in this paper.CITATION:Boshoff, J and Reid, D, 2015. The resistance of cyclone underflow material to flow liquefaction, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 151–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By John Meuth, Brandon Fryman, P. E. Hoffman, Joshua Ph. D., P. E. Calnan, Josh Ph. D.

Quantitative Risk Assessment (QRA) can be specifically tailored for use by the commercial explosives industry to calculate risk to employees and the public from commercial explosives facilities and operations. This methodology has several advantages over the American Table of Distances (ATD) which is solely a Quantity Distance (Q/D) analysis. While the ATD has remained essentially the same for 100 years, the safety of commercial explosives in storage has increased immensely. However, the concepts behind QRA calculations are not as intuitive and even at the end of the calculations the values of risk must be compared to something. A few regimes for assessing an acceptable level of risk are discussed in this paper. Risk levels for various United States Federal entities and international agencies are highlighted and suggestions for acceptable risk criteria for individuals and groups are provided. Referencing risk levels from normal daily activities is also done in this paper to make relative the accepted risk criteria. This paper presents some relevant individual risks for everyday activities and some scenarios for group risk for comparison. Individual risk is a straightforward concept however group risk is more complicated. This paper aims to clarify these concepts and provide means to communicate them to the public.

Jan 1, 2019

By Michael Cruickshank

Bob Woolsey was born in 1936 in the state of Georgia and grew up to be a man of great integrity, vitality, wisdom and charm, totally neutral on matters of race, gender, and religion. A true Southern Gentleman in every sense of the word. His passing on July 9, 2008, the victim of an automobile collision, left an empty space in the hearts of his family, and his many friends and colleagues throughout the globe. The posthumous award of the Moore Medal of the International Marine Minerals Society, to Dr. J. Robert Woolsey for Excellence in the Development of Marine Minerals, is a well deserved tribute to this man who spent the last 30 years of his professional career heavily involved in research and development of marine minerals on an international basis. He first came to my attention in Burma in 1979 where, as a newly appointed technical advisor to the United Nations Development Program Offshore Exploration for Tin, I had to fill the shoes of an almost legendary figure "Dr. Bob", who accompanied by his wife Maxine had spent the previous two years initiating the program. Bob had planned to completion the construction in Singapore of a unique drilling vessel the RV Sea Drill, a spud anchored, twin-hulled barge, mounted with a Becker Drill, and designed for sampling alluvial tin deposits in the coastal waters of the Mergui Archipelago in the Andaman Sea, off Tenasserim. He had also designed and built, with the help of his side -kick Bruce Jernigan, a barge mounted dressing plant for reducing and concentrating the drill samples. The adventures of Dr. Bob in transporting the equipment to the drilling site in monsoon weather and the transfer of the drill barge from the Malaysian port of Ranong across the strait to Victoria Point in Burma with a mutinous crew will remain in the hearts and minds of his Burmese colleagues for many a long year. On his return to the States he joined, in 1980, the faculty of the University of Mississippi (UM) as assistant Professor of Geology and Geological Engineering. His prior experience in private industry and the United Nations had focused on marine mineral resources and related environmental engineering projects in Africa, South America, the Mediterranean, the South Pacific as well as south east Asia, working with dredges, mining for alluvial tin, gold, diamonds and industrial minerals. He continued to work in the area of marine minerals at UM, making a name for himself as Director of the Mississippi Mineral Resources Institute (MMRI).

Jan 1, 2008

By K. Wenrich

The uranium industry has made a dramatic turnaround in the past three years that even the most optimistic economist was not willing to predict during the uranium downswing of the 1990s. Uranium reached a 30-year low in February 2001 of $6.50/lb. By the end of February 2006 it had soared to $38.50/pound. This nearly 600% increase in the uranium spot price within 4 years dwarfed the increase in gold price that has barely mustered a 100% increase. The initial slow rise from $6.50 in February 2001 to $10.75 in April 2003 (fig. 1) was primarily driven by the decrease in the value of the dollar. Since then several factors have contributed to the soaring price: (1) The awakening of many to the simple fact that uranium supply has not met demand for several years and that the world’s stockpiles are being drawn down, (2) How sharply this fragile supply can be impacted by disasters at the world’s major uranium production facilities, such as a) the flooding of the McArthur River Mine in the spring of 2003, b) fires at Olympic Dam, c) the potential that Rossing, with an annual capacity of 4000 tonnes uranium might close by 2007, (3) the withdrawal of Tenex from the HEU (highly enriched uranium) feed agreement, and (4) the announcement by the Chinese of their intent to build 30 new nuclear reactors.

Jan 1, 2007

By N. Ripepi

"The Langmuir model has been widely used for the coal-methane sorption process via an isothermal test. However, even though the temperature-dependent Langmuir model were recognized theoretically and experimentally, the quantitative relationship between the Langmuir’s constants (a & b) and temperature have not been clarified and confirmed by lab test data. This paper collects 158 methane-coal sorption data under different temperatures, which apply the Langmuir model to consider the relationship between Langmuir’s constants (a & b) and temperature (see APPENDIX I). Even though the Langmuir model cannot be used to show the physical state of methane adsorption on coal, it is widely used because of its simplicity and the reasonable explanation of its parameters (a & b). The results from these published isothermal tests confirm that 1) there is no consistent relationship between Langmuir’s constant-a and temperature; 2) the Langmuir model is a temperature-dependent model, and the temperature-dependent feature is mainly shown by the relationship between Langmuir’s constant-b and temperature; 3) The relationship between Langmuir’s constant-b and temperature can be described by both the exponential and linear relationship with dried coal. This paper provides a database for temperature-dependent Langmuir’s model, which can be used for reservoir simulation of coalbed methane reservoir, coal seam degasification modeling for underground coal mines considering the heating effect induced by geotherm and heat injection (via hot water, hot steam, ultrasonic, etc.). INTRODUCTION The isothermal test for gas sorption on coal is one of the fundamental tests in Coalbed Methane (CBM) recovery fields, such as underground coal mine methane degasification, CBM gas-in-place estimation, and carbon dioxide sequestration in un-minable coal seams. Generally, two methods, volumetric and gravimetric, are employed to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012). Based on these two approaches, a series of commercial and self-assembled instruments are built and several calculation methods are used to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012, Gasparik, K., 2014; Goodman, A. L., et al, 2004; Zhang, L., et al, 2013). In the post-processing stage, many models are provided to analyze isothermal data in order to understand the storage mechanism of gas in coal. Common models include the Langmuir model (and its extended forms), the pore-filling model, multilayer adsorption model (BET), and the Gibbs’ model. Among these models, the Langmuir model is the most widely used for its simplicity and functionality. The Langmuir model is expressed as follows:"

Jan 1, 2016

By T. J. Batchler

Deformable materials are sometimes added to ventilation stopping constructions to prevent damage caused by convergence in coal mines. However, adding deformable materials can significantly reduce the capacity of a stopping to resist transverse loading. As part of its mining health and safety program, the National Institute for Occupational Safety and Health (NIOSH) has conducted research on the effect of various materials with different deformation properties on the transverse loading capability of a stopping wall. Based on a three-point hinge method of failure, a half-wall method of testing in the NIOSH Mine Roof Simulator was used to simulate full-scale wall behavior. This simulated the fracture initiation and eventual failure of the stoppings from transverse loading. The impact of the modulus of elasticity of various deformable materials was examined in this study. A polystyrene foam block with a low modulus of elasticity, which is commonly used as a deformable material, was shown to degrade the transverse load capacity of the stopping by as much 95%. Other materials with higher modulus of elasticity preserved more of the transverse load capacity of the stopping, but were not able to absorb as much convergence. This paper presents the results of a parametric study that quantifies the impact of various deformable materials in block stopping construction under transverse load conditions. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By A. F. Banks

"Potash processing has much in common in terms of unit operations and plant operating strategy with other mineral processing plants. As it is a rather large topic the processes will be broad brushed to give you some background and then I will go into a little detail on the things we do in the Cominco plant that may be of interest to the group as a whole. In particular the centrallized computer control system and associated instrumentation and the operator training programs will be covered as well as the mill fire, something that could happen in any plant. THE ORE AND PRODUCTSThere are differences in potash ores as you would expect. It is my intention to deal with the ores processed in the Saskatoon area. These are mined from the beds in the Patience Lake Member and have a mineralogical description as follows:Sylvite (Potassium Chloride) 40%Halite (Sodium Chloride) 55%Insolubles (Slimes) 5%A number of products are made from this ore. It is characteristic of a potash plant that you put as much effort into grading and converting the sylvite to meet market requirements as you do in recovering it."

Jan 1, 1976

By Steve Tadolini

Underground roof falls can have devastating effects on the safety of operations personnel, and equipment, and seriously impact production. Immediate steps are usually taken to danger off and secure the area while clean-up efforts are designed and implemented. A critical step, often overlooked due to production demand, is the determination of - why the roof fall occurred so that additional occurrences can be avoided in future developments or what measures can be taken to identify areas that have similar ?symptoms?? Forensic engineering includes the investigation of materials, products, structures or components that fail or do not operate/function as intended. The authors define forensics in ground control engineering as the study of evidence discovered while examining underground roof falls by applying expert observational techniques and established mining engineering principles to determine the probable cause, hypothesize solutions, and design engineering safeguards to prevent reoccurrences. Simply stated, the primary steps in the forensics of underground roof fall techniques are: ? Assess regional and local conditions prior to the event. ? Assess post-event conditions. ? Hypothesize plausible ways in which the pre-event conditions ? became the post-event conditions.Search for evidence that either denies or supports the various ? hypotheses.Apply engineering skill to relate the various facts and evidence into a cohesive scenario of how the event may have occurred. This paper details the proposed technique by utilizing a roof fall case study that required the examination of five primary factors: mine design parameters, excavation geology, method of excavation, method of support, and mining cycle times.

Jan 1, 2009

By Pierre Lacombe

"The operation of the Louvicourt Mine will have to rely on stringent grade control and on the optimization of the amount of blocked ore made available per given development effort. All of the above being necessary to obtain the highest throughput at the lowest mining cost.To assist in achieving these objectives, the need for production of a competent fill with short curing time was recognized early by the project partners. As well, operating costs associated with the selected method should be as low as possible while meeting the technical criteria.A feasibility study comparing filling methods showed potential benefits in all aspects of the paste fill use, except for its higher capital costs and increased operational complexity. This last consideration was tackled by the conservative design approach adopted in the flowsheet development of the paste fill plant.Since commissioning of the plant has just been completed at this time, the paper will focus on the feasibility study and its background, the design of the plant and testwork results at pilot plant and plant scale.RésuméLe succès de l 'opération de Louvicourt Mine dépendra d' un contrôle serré des teneurs du minerai et de la maximisation de la quantité de minerai développée par effort uni ta ire. Ces critères devant etre respectés afin d'obtenir le taux de production le plus élevé au coût le plus bas.De façon à satisfaire ces contraintes, les partenaires du projet ont reconnu tôt la nécessité de produire un remblai de qualité tout en maintenant un temps de curage court. De plus, les coût d'opération associés a cette opération se devaient d'être des plus avantageux sans sacrifier l'atteinte des objectifs techniques.Une étude de faisabilité comparant différentes méthodes de remblayage a démontré que le remblai en pâte offre des aspects positifs sous taus les angles, si ce n'est de son coût en capital initial élevé et de sa complexité relative d'opération. Ce dernier point fut considéré de près par l'adoption d' une approche conservatrice lors de la conception de l'usine de rernblai.Puisque la mise en service de l'usine n'a été faite que les détails de l 'étude de faisabilité et ses fondements, 1 'usine et des résultats d' essais obtenus a l'échelle de l'usine seront discutés."

Jan 1, 1995

By Brian Hart, Roger St. C. Smart, James Francis, Mark Biesinger

"There are a number of challenges involved with the surface analyses of different mineral phases from process streams in a flotation facility. The first of course is to collect samples that are representative of the process and to ensure that they remain in a pristine condition prior to introduction into the instrument. In mineral processing, sample collection from the different streams is done on site and preservation involves simply removing oxygen from the sample by bubbling nitrogen or argon gas through the sample and snap freezing with dry ice.The second challenge in studying the surface chemistry of specific minerals is to find reliable methods of mineral phase recognition. In surface analysis of mineral particles confident mineral selection can be difficult with many multi-metal minerals (e.g. chalcopyrite, pyrite, sphalerite) and with precipitated, adsorbed, reacted and contaminant species in the outermost molecular layers.In this paper we show that principal components analysis (PCA) of ToF-SIMS data provides improvement in phase recognition, particle selection and associated variations in surface species. We will demonstrate, with specific examples, that this technique can be utilized to differentiate surface chemical factors promoting (hydrophobic species) or inhibiting (hydrophilic species) flotation.Species recognition based on the PCA method in a study of Cu transfer between chalcopyrite, pyrite and sphalerite mineral mixture clearly identified a statistical difference in copper intensities between the sphalerite and pyrite phases. A similar ToF-SIMS/PCA based study applied to concentrate and tails samples collected from the Inco Matte Concentrator demonstrated extensive CuOH and NiOH transfer between the chalcocite and heazlewoodite minerals. The statistical analysis has been able to confirm some mechanisms and deny others proposed to control recovery and selectivity giving more focus on the control factors.The ToF-SIMS PCA statistical analysis has elucidated differences in surface chemistries which illustrate the discriminating depressant action of adherent aluminosilicate (gangue) fine particles and adsorbed ions on the surface of sphalerite grains. In the flotation test concentrates, HIC conditioning resulted in the removal of these gangue fines thereby improving surface collector attachment efficiency, promoting a greater recovery of sphalerite."

Jan 1, 2007

By D Craw

Previous studies of alluvial gold in Otago and Southland placer deposits have suggested a gold-mercury association for some deposits derived from Caples Terrane schist, whereas alluvial deposits on Torlesse Terrane basement typically have no mercury. A regional study of gold from Otago Schist vein deposits from both Caples and Torlesse Terranes has revealed the presence of both Au-Ag and Au-Ag-Hg alloys in both terranes. Au-Ag alloy (3 - 4 wt per cent Ag) is typical for gold found in most Torlesse vein deposits, and Au-Ag-Hg alloy (3 - 8 wt per cent Ag, 2 - 8 wt per cent Hg) is found in many Caples vein deposits. Au-Ag-Hg alloys are not exclusive to the Caples Terrane, however, as Au-Ag-Hg alloys with up to 4 wt per cent Hg are found in vein material from the Torlesse-hosted, HydeMacraes Shear Zone. In addition, not all Caples-hosted deposits have a gold-mercury association; gold grains from the Carrick and Invincible gold fields have no detectable mercury. The present study characterises gold compositions from various hard-rock vein deposits and has potential for determining placer-source relationships.

Jan 1, 2003

By Thomas R. Scotese

A rock mechanics instrumentation and monitoring program was implemented during pillar extraction at Gulf Mineral Resources' Mt. Taylor Mine, the deepest uranium mine in the U.S. Three types of monitoring were employed: (1) drift convergence around stopes (using a portable tube extensometer), (2) stress changes in pillars (using vibrating wire stressmeters in horizontal boreholes), and (3) load changes in haulage ways under stopes (using vibrating wire load cells in jack stands). Results include convergence-time graphs, convergence contour maps, stress-time graphs, a stress increase contour map, load-time graphs, and abutment load limit maps. Major factors influencing results include (1) size of pillars around the extraction area, and (2) presence and orientation of a major fault adjacent to one extraction area. These factors, combined with pillar extraction, produced evidence of load transfer over 120 m from a stope measuring only 55 m x 45 m. Vertical stress increases of 7 to 17 MPa (1000 to 2500 psi) within 60 m of the stope were obtained using the stress- meter manufacturer's method. The fault apparently prevented load transfer in the down-dip direction but increased load transfer in the up-dip direction. Convergence rates of up to 1.3 cm/day (0.5 in/day) were measured at two stations. Instruments were generally reliable despite adverse underground conditions. The instrumentation and monitoring program at Mt. Taylor provided a warning system against ground control problems and a characterization of ground behavior for future development and extraction of pillars. Recommendations are made for future mining and instrumentation practices.

Jan 1, 1984