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By Nicolas Gatelier, Sophie Laurent, Thierry You

Hard-rock caverns for hydrocarbon storage are a very particular type of underground facility controlled not only by local administrative and regulatory constraints that can be very specific, but also by the possible risks of geotechnical or geomechanical failure. Each such facility throughout the world is a prototype that needs to be adapted to very different site conditions. The straight forward application of design methodologies from relatively similar fields (mines, tunnels) can be very useful, but risks holding back the scientific and technical improvements needed by an engineering industry in full development. Here we look at various case histories and at problems that have been raised where recent attempts at standardization would appear to have been ill adapted, and where storage designers, through experience and judgment, may still provide innovative engineering solutions.

Jan 1, 2015

By Robert R. MacLachlan

New underground mining technology is evolving through the use of large-diameter bore holes containing individually restricted charge weights. This article presents summary observations on cube-root scaling trials using single and rows of charge blasting in sand and in frozen ground. These observations have some bearing on the evolving underground practice, especially where charges of appropriate geometry are used.

Jan 1, 1978

By Richard Howie

Avian Diversity ?? Pre-mining ?? 110 - 125 species would have occurred ?? Dominated by forest species ?? Wetland productivity unknown ?? Post mining ?? 192 documented ?? Forested species in reduced numbers ?? Increase in wetland species ?? Increase in open country/grassland species

May 1, 2008

By T. R. Eger

Miners can be exposed to whole-body vibration (WBV), when sitting or standing to operate mobile equipment. In order to prevent vibration-induced injury it is important to understand how miners can be exposed to vibration, the health risks associated with vibration exposure, methods to evaluate vibration exposure, and strategies to reduce vibration exposure. WBV exposure typically occurs when operating mobile equipment, such as a load-haul-dump vehicle, haulage truck, or dozer. The probability of health effects such as low back pain, neck pain, headaches, and gastrointestinal track problems occurring from daily vibration exposure can be determined based on criterion values published in ISO 2631-1 and EU Directive 2002/44/EC. A special case of WBV termed foot-transmitted vibration (FTV) occurs when a miner is exposed to vibration that travels through the feet. FTV typically occurs when standing on vibrating surfaces associated with the operation of locomotives, jumbo drills, bolters, or raise platforms; however, there is no set standard to evaluate health effects associated with FTV. Recent medical evidence confirms workers exposed to FTV can develop cold induced blanching of the toes, in addition to numbness and tingling in the feet and toes. In order to reduce the risk of adverse health effects from exposure to vibration, the hierarchy of controls (elimination; substitution; engineering; administration; and personal protective equipment) should be followed. Best practices should be used to minimize vibration exposure through equipment purchases (i.e. vehicles with lower vibration emissions and seats that attenuate vibration), reduced driving speeds, and improved road maintenance for example. The elimination of other risk factors, which increase injury risk when combined with WBV exposure, such as awkward working postures, should also be eliminated. Very little is known about FTV exposure therefore further research is required in order to develop exposure standards and identify prevention strategies.

Aug 1, 2013

By Gary M. Bone

The autonomous control of vehicles interacting forcibly with their environment, such as dozers and tractors, is an unsolved and challenging problem. Forces and motions are inherently coupled between the tool and the means of vehicle propulsion. Furthermore, they are often operated within uncertain and unstructured environments, such as those encountered in underground mining. There is a growing industrial interest in the development of robotic vehicles to improve productivity, efficiency and safety in mining and construction. This paper focuses on the modeling and control of autonomous robotic dozing for a material removal operation. A dozing process model has been developed based on observations of both a fullscale dozer and a scaled-down version. The model characterizes the dynamic interactions between the blade position, material accumulation on the blade, material distribution in the environment, and the motions of the dozer. The dozing control objective is to remove the loose material as rapidly as possible by driving forwards at full power while automatically raising/lowering the blade in response to sensor measurements. Two different controllers were developed to meet this objective. The first controller is based on a set of heuristic rules, and the second is an optimal controller based on the dynamic model. An instrumented scaled-down robotic dozer and dozing environment, designed to emulate the full-scale operation, are used to implement the controllers and compare their performances over multiple dozing passes. Experimental results are presented showing that the model-based controller increased the material removal rate by 33% compared to the rule-based controller. Lastly, technologies for full-scale implementation are discussed, followed by proposed future work and conclusions.

Aug 1, 2013

By Roger Potvin

Abstract The demand for pure zirconium and titanium metals in Germany increased considerably during the war. Pure zirconium was used in flash bulbs, in vacuum tubes, and in time fuses for bombs, where it has a decided advantage because it gives no gas in burning. Under the form of alloy, it was used with other rare elements for making substitutes for platinum; it was also used as a scavenging agent in high-grade steels. Metallic titanium was mainly used in connection with the manufacturing of special alloys. The authors were sent to Germany by the Department of Reconstruction and have investigated the German process developed for producing these rare metals. They describe the procedure and special equipment used for their commercial production in Germany during the war. General Metallic zirconium and titanium were .produced on a commercial scale in Germany by the thermal reduction, with metallic sodium, of potassium fluozirconate and titanium chloride, respectively, using a mixed potassium and sodium chloride flux. According to the information gathered, the sole German producer of these rare metals in pure form was the Deutsche Gold und Silber Scheideanstalt (commonly called Degussa), at their Werk II, 215 Gutleutstrasse, Frankfurt/Main, which was visited by the authors on September 18th, 1945. As far back as 1934, Degussa was carrying on active research on the manufacture of zirconium, and nearly one ton of the pure metal had been produced before September, 1939. Concurrently, a quite similar process was worked out for the recovery of titanium and it was in commercial operation in the year 1938, during which the production totalled about half a ton (metric). The demand, especially for pure zirconium, increased considerably during the war, attaining a total of about 48 tons during the period October, 1939, to the end of 1944, and reaching a peak of more than 15 tons in 1943. In 1944, the plant was slowed down due to the frequent and disastrous bombing by the Allies, especially in March and September.

Jan 1, 1946

By D. Racicot, T. Hanel, E. H. Chown

Over thirty plutons in the Chibougamau-Desmaraisville belt were examined briefly in the field and sampled, in addition to the few masses that have been studied in detail. The survey indicates that the intrusions may be conveniently grouped in four main categories, based on their time of intrusion. These are; remobilized basement domes, pre-kinematic intrusions, syn-kinematic intrusions and postkinematic intrusions. Basement domes, as exemplified by the Lappa rent Massif, are composed of migmatized tonalite-diorite gneiss that has undergone at least two periods of mafic dyke intrusion and at least three major deformational periods. The rise of the basement domes was accompanied by extensive mylonitization and the intrusion of syn-tectonic plutons. Pre-kinematic plutons, such the Chibougamau pluton, are diori te-tonalite in composition, and were intruded into the supracrustal pile and partly eroded before the main deformation of the belt. Syn-kinematic plutons occur principally as marginal intrusions bordering the belt (Barlow), or as discrete intrusions along structural highs (La Dauversiere), and are either hornblende monzodiorite or tonalite in composition. Post-kinematic plutons, such as Muscocho, are principally granodiorite and often porphyritic intrusions locally deforming the enclosing rocks. The close relationship between mineralization and high-level intrusions such as the pre-kinematic and some of the post-kinematic plutons is discussed.

Jan 1, 1984

By Edgar Dernedde

Cryolitic melts at a temperature of about 960 °C are used in reduction cells to dissolve alumina and to produce primary aluminium. At these temperatures cryolitic melts with an acidic composition have a significant vapour pressure, which contributes substantially to the evolution of fluorides from these cells, The Antoine equation is commonly used for relating vapour pressure data of liquids at different temperatures, It is also applicable to cryolitic melts, Published equations have at least 20 numerical constants, in order to allow for the effects of melt composition. In the present work a simplified equation with only 12 numerical constants was developed and is applicable for multiple additions to molten cryolite up to 30 wt %, The simplified equation was compared with the published equations of Haupin & Kvande and Gustaysen & Ostvold using 472 vapour pressure data of cryolitic melts. Results showed that the simplified equation has the same accuracy as the published equations in the composition range of interest to industry.

Jan 1, 2004

By The Hollinger Mill Staff

ALTHOUGH cylindrical grinding mills have long been used, there is wide divergence of opinion as to what constitute best operating conditions. Questions such as mill diameter, diameter-length ratio, revolutions per minute, type and size of grinding media, volume of charge, circulating load, pulp level, pulp consistency, liner design, and size of feed, have all been given serious consideration by competent scientific investigators as well as by operators. While many laboratory and plant tests have been made that would seem to justify certain definite conclusions, there is a dearth of definite data giving actual results obtained when a grinding mill working between fixed limits is operated at its maximum capacity under varying conditions as to ball load, circulating load, speed, etc. In tests conducted recently at the Hollinger, extending over a period of thirteen months, to determine the best operating conditions for a ball-mill 6 ft. 6 in. diameter inside the liners, some very interesting facts have been ascertained. This paper is presented in the desire to make public the results of these tests and not with the idea that the last word has been spoken in regard to grinding. We feel, however, that these facts justify certain definite conclusions and hope that, by the fullest and frankest criticism and discussion, the essentials necessary for the correct design and operation of grinding mills will become better known.

Jan 1, 1937

By M. Savich

A graphical method has been developed for the evaluation of the U.S. Occupational Safety and Health Act Noise Exposure Index and the Equivalent Continuous Sound Level. The method makes use of a noise survey form and a mechanical integrator with two sliders, and is less tedious and susceptible to error than alternative methods. The graphical method is adaptable to various codes for noise exposure and may be used with any instrument that measures noise level. One example of its application to a practical situation in a Canadian mine is given to demonstrate the procedure .

Jan 1, 1978

By A. W. Jacob

THE shatter cut, or burn cut as it is often called, is one in which the centre of the round is almost reamed out by drilling holes so close together that the blasting of a few holes shatters the rock embraced by all of them. The idea of shattering the centre of a face by shooting holes drilled parallel to one another is not new. Some miners have used this method for years past, when drilling quartz or a face near timber. But, they followed the age-old practice of first blasting the cut, then the square-up. It was not thought possible to shoot both together. In the case of machine men, the two largest contributors to silicosis are dust from drilling and dust from blasting. It follows, then, that material reduction of exposure to either constitutes an important step in lessening the incidence o silicosis. It was? the hope of being able to do away with the necessity of the men having to return early to a face, through dust concentrations of 60,000 to 80,000 particles per cubic centimeter, that aroused interest "in the shatter cut at McIntyre. Efforts to this end were successful. Now, with this kind of cut, all holes of a round are shot simultaneously.

Jan 1, 1942

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986

By R. A. Walker, G. Scheltgen, T. Javorsky, G. Blackwell

"Recent engineering advances in open pit rock mechanics have resulted in improved pit wall slope design and improved operating procedures in the event of a major wall instability. At the other end of the spectrum, on the scale of single bench failures, considerable discretion is left to the mine operators as to how potential problems are handled. The usual alternatives are either to operate with caution beneath potential hazards, or try to bring the unstable rock down. In specific cases it may be advantageous to attempt to stabilize rock structures for reasons of access and operating safety.A t the Brenda Mines open pit a prominent structure on the north wall had caused recurring bench-scale wedge failures when exposed on each mining level. In spite of operating precautions a shovel was hit by a rockfall causing significant damage. The first section of this paper describes the investigative, design, and stabilization methods which permitted subsequent mining beneath the structure to proceed without incident. Emphasis is placed on the personnel and equipment resources available at the mine site which were used to minimize costs and which would be available at most operating mines.The second section describes an ongoing research project that utilizes radio telemetry to transmit slope monitoring data. As part of this project the wedge structure was instrumented so that it could be continuously monitored with the aid of a computer. The application demonstrated the potential of 'micro- chip' technology to remote data collection and processing as related to rock structure monitoring, slope stability and safety."

Jan 1, 1989

By K. Meshinchi Asl

In this study the effects of T4 and T6 heat treatments on microstructural characteristics of AZ91 alloy containing Rare Earth elements have been investigated. Formation of intermetallic Al1 1RE3 needle shape particles which have a good thermal stability reduces both formation of ß(Mg17A112) and discontinues precipitation in AZ91 alloy which are dominated at the grain boundaries and are responsible for poor mechanical properties specially in elevated temperatures. For AZ91-RE samples both T4 and T6 heat treatments led to a continuous precipitation of ß particles at the grain boundaries after aging. However, in AZ91 samples (with no Rare Earths) precipitation was discontinuous at grain boundary areas. This type of precipitation is one of the main reasons of poor mechanical properties of this alloy at elevated temperatures.

Jan 1, 2007

By J. Zhang, T. Oleniuk

It is well-known that Saskatchewan has the world’s richest uranium deposits and advanced processing technologies. Unlike the Saskatchewan deposits, complicated mineralogy is common for other places in the world. Mineralogy dictates the process. Mineral Processing at the Saskatchewan Research Council has been working with the uranium industry worldwide since its inception to develop effective processing technologies to suit the unique mineralogy of each deposit. This paper reviews the research and development of uranium processing technologies in the current major uranium production areas such as Canada, as well as the potential development regions like Argentina and Sweden. Acidic and alkaline leaching processes, as well as by-product recovery technologies are discussed based on mineralogy.

Jan 1, 2020

By Les F. Sawatsky

Surface drainage, particularly mine closure drainage, must be properly considered during all stages of mine planning because it presents constraints that are critical to economic mine operation, minimizing environmental impacts and ensuring compliance with government regulations. Deficient mine site drainage increases costs of operation, causes unnecessary environmental impacts and may result in regulatory violations. The scope of this paper includes stream diversions around mine areas, drainage systems within the mine disturbed footprint, and closure drainage works to control surface water, ground water, erosion, sedimentation, and seepage discharges following mine operations. Developing selfsustaining drainage facilities upon mine closure, requires a mine plan that develops appropriate topography and constructed drainage courses that replace the function of pre-disturbance drainage systems without aggravated erosion and deterioration. Drainage criteria, particularly closure drainage criteria, represent important constraints on mine planning and are best considered by integrating drainage features into the mine plan well in advance of mining activities. Integrated mine planning by a multi-disciplinary team is recommended to achieve closure objectives at minimum cost and maximum effectiveness The geomorphic approach to channel design is an effective means of providing a drainage system that has the appearance, function and longevity of natural systems. By incorporating this technique into closure drainage planning, mine operators can construct sustainable (walk-away) drainage systems that require little or no maintenance in the long-term. This paper presents a process by which drainage criteria and associated mine plan constraints can be integrated into the mine planning process. This paper outlines the process for detailed design of drainage facilities, particularly closure drainage systems that are designed by the geomorphic approach.

May 1, 2009

By L. D. Smith

"The economic evaluation of a mineral project requires a great deal of diverse information to be brought together in one place. The greatest concern is that there will be an error by omission, so it is useful to have a detailed list of what one needs to know in order to make a thorough evaluation. The list that is presented below is intended to act as a checklist for the person who develops and reviews an evaluation, and as a shopping list for the persons gathering data at the project site.There are varying degrees of detail required at the different stages of evaluation in a project, from the ""quick and dirty"" overview, to the pre-feasibility study, to a full detailed feasibility study, to a due diligence review. This list addresses most of the economic variables in a project and can be used for all levels of studies. Its purpose is to identify a variable or issue and to raise a question, which the reviewer can then pursue in more detail using increasingly more comprehensive checklists for each topic. While developed from the point of view of a new project, this list is equally valid for an ongoing operation."

Jan 1, 1994

By W. McCombe, G. Remple, L. Zunti, M. Bernardin, L. Nightingale-Mercer

"The McClean Lake Mill is located approximately 700 kilometres north of Saskatoon, Saskatchewan, Canada and is operated by AREVA Resources Canada Inc. (AREVA). The mill was designed to process high grade uranium ores, and has been undergoing a multiyear expansion to increase its production capacity to 24 Mlbs U3O8 per annum, while also undergoing upgrades to allow it to safely transition to processing high grade ores from the Cigar Lake Mine. During the metallurgical test work on the Cigar Lake ores, it was identified that some ore zones in the Cigar Lake deposit have a propensity to generate hydrogen gas during acid leaching. Hydrogen is a volatile and explosive gas, which poses obvious safety concerns in the leaching circuit. Uranium processing is further complicated by the fact that an oxidant in the form of oxygen gas or hydrogen peroxide is required to regenerate iron in the leach, which further increases the risk from hydrogen gas. During 2013 Hatch and AREVA designed and engineered a number of novel upgrades for the leaching circuit to mitigate the risk of hydrogen gas evolution in the process. Best in class technology was utilized in addition to control and operating strategy changes to ensure the leaching circuit can be safely operated with ores that can evolve hydrogen gas. This paper reviews the design concepts and modifications implemented on this unique and challenging project.INTRODUCTION The McClean Lake mill was originally designed to process high grade uranium ores, however until 2014 the average ore grade processed was 1%. The facility has been undergoing a multiyear upgrade and expansion to increase its production capacity from 12 to 24 Mlbs U3O8 per annum, while also undergoing upgrades to allow it to safely transition to new high grade ores, averaging 18% U, from the Cigar Lake Mine. During the last round of metallurgical test work on the Cigar Lake ores, it was identified that some ore zones in the Cigar Lake deposit had a higher propensity to generate hydrogen gas during acid leaching than previous test work had indicated. Hydrogen gas is a volatile and explosive gas, which poses obvious safety concerns in the leaching circuit."

Jan 1, 2017

By A. S. Nortjé

At South Deep Gold Mine longhole stopes are backfilled using a cemented Cyclone Classified Tailings in its hydraulic state. The need to contain the hydraulic fill until cured requires a barricade. Due to the massive size of the stopes, the tailings can exert enormous forces on any such barricade. Barricades have long been in use, but recent failures in Australia and the large rate of filling required at South Deep solicited a robust design. A robust design must examine all foreseeable failures and the barricade must be able to resist all expected and, within limits, unexpected loads. The design should also be simple to construct and cost effective, limiting the impact of construction errors and unnecessary delays to production.

May 1, 2007

By A. Putz, F. Vincent, A. R. Laplante

"This paper briefly reviews some of the gravity research done at McGill University and current Canadian operating practices, with emphasis on results of interest for operators. The following topics are addressed: security, economics, predicting recovery, circuit optimization, unit selection and final upgrading. Emphasis is placed on the Knelson Concentrator.The topic of security and economics are addressed jointly, in terms of the place of the gravity circuit in the mill flowsheet. Actual plant experience is drawn upon to identify potential problems and actual solutions.Predicting primary recovery is linked with a characterization of the ore, the choice of a circuit, and the fraction of the bleed used. Factors such as feed preparation, preliminary upgrading, fraction of recycle treated, ability to recover fines and location of the bleed are discussed.Final upgrading is achieved almost only by tabling and smelting. This can lead to fine gold recovery problems when more effective units are used upstream. Alternatives are discussed.IntroductionResearch on gold recovery by gravity over the past eight years has associated McGill University with a number of gold producers. This paper attempts to review the information gathered from a practical perspective. Some of the information was generated in McGill University's labs, some gathered at plant site, and some was shared by operators."

Jan 1, 1994