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By D. D. Tannant

An experimental and numerical study was conducted on the geomechanical behaviour of oil sands during penetration tests in which a steel wedge with an apex angle of either 20 degrees or 30 degrees was forced into compacted oil sands. The boundary conditions simulated in the laboratory tests are similar to shovel penetration into oil sands. The objective of the laboratory tests was to measure the force required to push a steel wedge into compacted oil sands. A wedge penetration test differs from conventional triaxial tests in that much more shear is generated. The laboratory data was needed to improve calibration of micro-mechanical input parameters for a two-dimensional discrete element model of oil sands constructed with Particle Flow Code (PFC). Initial model calibration was performed with triaxial test data and then a PFC model of the wedge penetration test was constructed. The measured force-displacement behaviour of the steel wedge was compared with PFC modelling results. It was found that different combinations of PFC particle and bond parameters could equally well replicate the laboratory triaxial compression data for bitumen-rich oil sands. When the wedge model was run, it was found that the resulting force required to penetrate the wedge into the oil sands was about four to six times higher than that measured. This clearly indicates that further research is required to improve the predictive capability of PFC models of oil sands.

Jan 1, 2002

By A. K. Debnath

Coal is the mainstay of Indian energy supplies. The many-fold increase in demand for coal puts a huge pressure on augmenting production, primarily from opencast mines. The increase in production necessitates heavy blasting in overburden and coal benches of opencast mines, which poses numerous challenges in carrying out blasting operations techno-economically. Presently, the consumption of industrial explosives and accessories in Coal India Limited (CIL) has touched a whopping figure of $350 million USD per annum and CIL will be spending approximately $1 billion USD between 2012?2013 to 2014?2015 for procuring explosives and accessories. This paper discusses some of key challenges faced in various mines of CIL during blasting, where blast instrumentation at the mine level will prove to a harbinger for practicing blasting engineers. Presently, the problem of scattering in surface detonators and down-the-hole detonators affects the blast performance significantly by increased blast induced ground vibration and reduced fragmentation. The paper discusses a case study carried out at Umrer opencast project of CIL to investigate the effect of scattering by using blast simulation techniques (i.e., JKSimblast) and observing the actual blast results with the help of a high-speed camera and multi-channel high frequency data acquisition systems. The fragmentation assessment was carried out by adopting Digital Image Analysis techniques and using the granularity software viz. Wipfrag. The blast instrumentation in the case study mine resulted in improvement in fragmentation of 12.76% and a direct savings in explosives cost of 28%. Geophysical techniques such as the seismic survey method have been used at Umrer Project, CIL to characterize the rock mass using the Multi Channel Analysis of Surface Waves system for selecting the explosives technoeconomically. The minimum deck thickness for mines of CIL using drill cuttings as decking materials should be 10 D, where D is the drill diameter. The estimation of blast performance on the basis of prescribed Powder Factor (i.e., kg of explosives per m3 of rock) is technically unscientific as the criterion of a good blast depends on many factors (i.e., good heave, loose muck, muck profile angle, ease of digging, uniform fragmentation). The present paper proposes a new methodology for techno-economic evaluation of blast performance. The new methodology involves four significant factors viz. specific energy consumed by the loading equipment, charge factor, productive yield and diggability index for assessing blast performance. The use of user-friendly, accurate, reliable, rugged and handy instruments in blasting will significantly improve mine productivity, equipment efficiency and economics. The improvement in blast performance, even by 1%, will provide a significant savings of $3.5 million USD per annum to CIL. It may be concluded with high degree of confidence that blast instrumentation at the mine level will influence the mine productivity and economics.

Aug 1, 2013

By J. M. B. Scarborough

This paper deals with measures taken to maintain effective operation of heavy-duty equipment in open-pit mining. at Pine Point, N.W.T., during periods of extreme cold weather. The points covered include equipment modifications designed to improve cold-weather performance, effective lubrication of machinery that is vulnerable to extreme cold and operating procedures designed to prevent equipment damage.

Jan 1, 1966

By Norman A. Jull

"Factors which affect the separation achieved in a hydrocyclone are discussed and illustrated with graphs of some mathematical relationships.Definitions of separation and sharpness include comment on use of elutriation devices.A plea is made for better evaluation of field data prior to their reporting or use in calculations. Methods of evaluation are suggested, with samples of the relevant calculations.An example of the effect of percent solids errors is given, with computer printout and plotted corrected recoveries.INTRODUCTIONThe range of interest in cyclones runs from a simple demand for classification results to a detailed study of published equations defining cyclone characteristics. Probably this group covers as broad a range and, in an attempt to offer something for everyone, I will begin with general operating comments, then move on to more analytical topics. Ideally, an author would compose his paper after the discussion period, when he would have a better idea of the areas of special interest to his audience.Sor'1e of you may share our incurable fascination with classification, especially as performed in cyclones. It is amazing that such a simple device could be in use for more than 20 years and retain as much mystery as it does. Substantial parts of the mystery have been solved but some remains, to keep up our curiosity. There is at least one valid reason: the unusual compactness of this device, which makes internal observation very difficult. What other unit can you think of which performs such a complex separation between particle sizes, shapes and specific gravities at such high capacity? Retention time in a cyclone is typically 3 seconds!Mutual Agreement - In a cyclone, every parameter of geometry and of operation interacts with every other. In an orderly discussion of individual parameters it would be necessary to repeat, in every section, 11 if all other factors are equal"". Could we agree now, for our mutual convenience, that that phrase is clearly understood between us during the remainder of this paper?"

Jan 1, 1972

By Greg Baiden

Telerobotics focused on mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run? A new Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University. This chair will investigate these questions and many more through a series of experiments in a newly established telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian college?s eDome. The laboratory will support many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one/quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments and some preliminary results.

May 1, 2003

By G. Winkel

Safety conditions in industry have greatly improved over time. However, around the world, in Canada, and in each province or territory, people are still the victims of serious industrial accidents. The increasing safety of people at work then continues to be an imperative in industry today.<p> So how do we achieve a workplace where no one gets hurt? Well, in simple terms, folks need to be protected from unplanned exposures to equipment or energy sources that can do harm. If you think about it, all of our efforts in loss management and safety should then be directed toward avoiding these uncontrolled events. And it works! Our safety performance over the years has enjoyed tremendous improvement due to this support for loss management and safety. We now explore best practices toward achieving that next step in safety improvement.<p> As shown following, a large combination of loss management activities act together to support safety performance. Many of these activities are interrelated and some people have described them as the ?inputs? into an approach or program for achieving safety. Using this description, it follows that the ?outputs? of the program are some of the advertised measures of safety we see around us today, such as injury frequency rates. <p> It is asserted that a leadership focus to regularly measure safety and loss management activites (so-called ?inputs?), as a basis for taking supportive actions to ensure their effectiveness, is the basis for safety results (so-called ?outputs?) that consistently achieve high standards of excellence.<p> The concept of managing input activities, as enabled by effective measurements, can significantly act to transform our focus and priorities in the workplace. Supporting input activities like strategies, plans, or procedures with our best efforts will get us to our intended goals. Tracking outputs alone will not.<p> Safety and production have traditionally been cast as competing objectives. When both objectives are mutually supported and considered, however, people will invent ways of doing work that support both safety and production, and any other business parameter. When done right, innovation through meaningful involvement of affected people in the workplace will support safety excellence in a manner that in turn improves business efficiency overall.<p> For a workplace to be safe, it then requires everyone?s help and participation to make it happen, a collaborative effort by management, leaders, and frontline folks with the power and responsibility to take appropriate action at every level in the organization. In this way, everyone becomes a leader in safety.<p> The achievement of commitment to loss management input activities by folks in the workplace is the basis for attaining safety excellence. A workplace founded on commitment supports a safety culture with a vision for safe work performance at outstanding or world-class levels of achievement.<p> One may ask if injury incidents will be eliminated with this commitment and focus on workplace safety? Well, despite our best efforts in this area, there is never a guarantee that things can?t go wrong. We are simply not perfect. There remains in our workplace complexities and unanticipated risks that can have disastrous consequences if not managed at every moment. And when it goes wrong, we need to know we?ve truly tried our best, and now we have more to learn so we can get even better. <p> That?s the challenge represented by the safety imperative, a challenge to take safety performance that next step, a fulfillment of our commitment to the moral obligation we have to each other?s safety. It?s an effort that will continually raise the bar of world-class safety performance achievement for future generations. It?s a legacy we can be proud to be part of.

Sep 1, 2004

By H. Stutchbury

Alberta is labouring, and has laboured, under serious difficulties in the marketing of ?her coals, due to a number of conditions which now obtain, but all of which appear capable of solution, and their elimination would insure a very largely increased market for the vast coal resources of that province. It is perhaps necessary to again mention the fact that 15 per cent of the world&apos;s coal resources are to be found in Alberta; 21 per cent of that of North America; 72 per cent of that of the British Empire, and 87 per cent of that of all Canada. While we talk largely of the great wealth of Canada, the immensity of her vast natural resources, it is axiomatic that the mere presence of any natural product in a country does not in itself constitute wealth for that country, unless these raw materials can find a market, either in their raw state, or by the process of manufacture. There are many factors, however, which enter into the marketing of any commodity. The chief of these, in my opinion, is price competition. High costs of production materially reduce the radius in which any product can be marketed, and this applies particularly to coal. Mining costs in the province of Alberta are necessarily high at the present time, due in a large measure to the ease with which the &apos;gopher hole&apos; mine can be opened with small capital.

Jan 1, 1925

By Robert B. Wickham

"American Barrick has always balanced its aggressive operating approach with a conservative financial strategy. In fact, what enables their mining team to pursue such aggressive plans with confidence is the conservative financial strategy adhered to by the company. These policies are built on a prudent mix of gold linked financings, equity and gold price hedging.This paper outlines these policies and focusses in particular on American Barrick&apos;s gold price hedging program.IntroductionThe company&apos;s balance sheet at the end of 1990 clearly shows the wisdom of its conservative policies. Total assets have grown to over US$1 billion; cash has grown to US$312 million and shareholders&apos; equity to US$645 million. All amounts included in this paper are quoted in U.S. dollars. Increased gold production and an effective gold price hedging program also combined to produce record income from operations, earnings and cash flow in 1990.The first half of 1991 is also indicative of the benefits of the company&apos;s conservative financial policies. Increasing production, together with its comprehensive gold hedging program, has generated increased earnings, even in a period of falling gold prices.All year-over-year numbers for the first six months are up. Gold production was 36% higher; earnings of $40.2 million $ 0.30 per share - were 46% higher than 1990.Barricks revenue continued to increase despite gold prices remaining unchanged during 1990. Barrick&apos;s hedging policy protects the company from falling gold prices on the basis that the upside looks after itself. Their hedging program - including various goldlinked fmancings - enabled Barrick to realize an average price of $437 per ounce of gold sold in 1990, compared with the Comex average gold price for the year of $384 per ounce."

Jan 1, 1991

By R. F. Hochstein, A. J. Neale, B. C. Flintoff

"Process control technology holds very significant potential benefits for many mineral and coal processing plants. The impact can be expected in terms of performance improvements (e.g. increased throughput, better quality control, higher availability), through reduced operating costs (e.g. lower reagent consumptions, manpower reductions) and in the form of intangibles (e.g. reduced vulnerability to manpower turnover, increased productivity in the user group). However, the installation of a process control system will represent considerable capital expenditure and will generate an operating cost. No management team would approve the funding for such a project without some reasonable measure(s) of the profitability of a proposed system. This paper describes a methodology for addressing the justification problem. Of particular interest is the approach to quantifying performance improvements, frequently found to be the predominant benefit of process control.INTROPUCTIONProcess control has become widely recognized as an essential component of any processing operation. It has direct impact on productivity, process efficiency and product marketability. The reported pay backs associated with successful installations underscore this observation. As a consequence, many operators who have little in the way of process automation are looking to initiate control projects, while those who currently enjoy some level of automation are looking to upgrade existing control systems (= process + instrumentation + hardware + software + operators + support). While the emphasis here would appear to be on retrofit process control projects, new plants, or those currently in the design stage, will usually find themselves in one of these categories shortly after startup 1."

Jan 1, 1990

By E. P. Cadwell

"Throughout the years Cyanamid has been a supplier of cyanide and a supplier of information to the mining industry. In general, the knowledge of mineralogy is greatly overlooked. Mineral deposits in the Western hemisphere have been exceedingly rich in the past but now they are becoming poorer. In other words, we will have to use our talents to the utmost to extract the precious metals and base metals from these ores. Modifications of some of the mineralogical equipment displayed here belong in the mill.Cyanidation of copper has been one of the main projects in our labs in recent years. De-rimming or de-filming of copper in order to upgrade copper concentrate was the main aspect investigated. A study was made as to how wide spread was the filming of secondary copper on pyrite, and to what extent it affected the copper industry. It was very wide.Often there is no conception as to what the minerals are. One open pit copper producer with a chalcopyrite ore was producing a copper concentrate with a 5% copper value whereas chalcopyrite contains 35% copper. They used primary and secondary grinding and a regrinding section. The ore contained about 8 parts chalcopyrite to one part of other copper minerals. In tests, a 3 1/ 2% copper rougher concentrate, cleaned without regrinding but conditioned with cyanide for a low contact time of 30 seconds produced a 30% copper concentrate with 90% recovery by removal of the film. It was of utmost importance that some quantitative mineralogical analysis be made before flow sheet changes were made. Every man should be trained to do his own microscopic examination in order to get quick answers. The fundamental thing in all mineral dressing is to first of all know the minerals and the mineral associations."

Jan 1, 1964

By C. G. McLachlan

INTRODUCTION The work described in the following paper was under-taken with a view to determining, if possible, the relative importance of some of the phenomena on which flotation seems to depend, in the hope that, if this information could be obtained, it would be of value in dealing with the problem as a whole. At the outset, brief reference will be made to three papers which had a considerable bearing on the course followed in the present investigation. In 1919, Langmuir, in a paper on &apos;The Mechanism of the Surface Phenomena of Flotation&apos;, showed that mono-molecular films of very great stability could be produced on solid surfaces with oleic acid, but that pure paraffin oil, though spreading readily on a dean dry surface, was easily displaced by water.

Jan 1, 1926

By R. D. H. Wigmore

"The title of this paper probably sounds quite simple and self-explanatory. The problem, however, was not a simple one, and proved somewhat baffling and expensive over a period of years. After outlining the problem, and the methods which were used to overcome it, we will present our solution, or perhaps it would be more accurate to say the partial solution which we reached.We have in the cyanide circuit at Upper Canada two Dorr Single Tray Thickeners with 30 ft. diameter wood stave tanks 12 ft 4 1/ 2 in. deep. In the years prior to 1948, when the tonnage was 250 to 280 tons per day, two stage thickening was practised. As the tonnage was increased to 450, 500, and finally 560-600 the thickeners were used in parallel.Some settling problems were encountered, and in those days the means to combat these problems were very few. The only remedy was to dump in pounds and pounds of lime. Then along came a few reagents, and the writer remembers one in particular, - 11 Carboxel11 (carboxymethlycellulose). When water or solution was added to this reagent, the result was a gooey mass somewhat resembling tapioca. One drawback was that it stayed in this state, and didn't go anywhere. A method was finally developed of containing the mass (or mess) on a fine screen, and dissolving some of it was a fine spray of solution. The only thing the writer recalls was that it was not a very effective settling agent.Shortly after this time, along came the new flocculents, first a few, and then many, and our settling problems were over.But when the settling problem was solved at Upper Canada, some other problems were creeping up on us."

Jan 1, 1965

By B. E. Shaw

This paper describes the use of the Free Piston Valve, and a simple hoist brake control system, which has been developed over the last two years, greatly improving the performance of low-pressure brake engines. The basic control system is outlined, with sections devoted to emergency trips and differential braking, and the application of the system to deep shaft hoisting is discussed.

Jan 1, 1966

By M. Bavand-Vandchali, F. Golestani-Fard, S. Khalili, S. Rowshanfekr-Fallah

In the secondary metallurgy of steel, the availability of ladles plays an important role in decreasing the production cost. The refractory lining, therefore, should satisfy optimized quality to grant higher heats. This paper reports the results of an investigation carried out in Iranian Mobarakeh Steel Company in order to increase the lining life of ladles by employing different types of MgO C and Al203 - Mg° - C. The zoning concept was used in replacing the conventional refractories either in slag line or the lower parts of ladle. The number of heats could be improved to almost two times as before. The results are explained in terms of refractory quality as well as zoning approach. The economical impact of this improvement will also be analyzed.

Jan 1, 2004

By K. Kim

"All milling operations would like to achieve the best possible recovery in combination with the highest achievable throughput. Unfortunately, many operations have problems with low recovery, low throughput or both. In the majority of these cases investigated by the author, the solutions to improve recovery and throughput were simple. The solutions did not include implementation of new technology or major capital, but rather a return to fundamentals. In most cases, problems occurred because the operation was not following their own operating procedures, because the design of the circuit was changed without adequate change management or understanding of the implications of changes, or because basic metallurgical measurements and control were not taken or ignored. In this paper, examples of these problems and their solutions derived from long and varied experience will be discussed. The objective of this presentation is to provide the milling operator with practical and readily implementable solutions to common milling issues to improve throughput and recovery.INTRODUCTION Mill operations can be evaluated by many operating parameters, but the two best indicators are recovery and throughput. These two parameters summarize the wellbeing of an operation. The grade to the mill is also a good indicator, but this is usually controlled by the mine. The best recovery and throughput are achieved through a team work involving operators, maintenance workers and metallurgical staff. The milling operations include many unit operations, such as crushing, grinding, flotation, leaching, carbon in leach, Merrill Crowe, roaster, autoclave and refinery. The tools available to the operations are plant design, process measurements, assays, metallurgical balance, and operating strategy. Twelve real life examples of improvements of recovery and throughput are presented in this paper. EXAMPLE 1: CRUSHING CIRCUIT WITHOUT FINE ORE BIN At this operation plant throughput could not be maintained at a high rate because feed to the mill became coarse during the day. The cone crusher was feeding the ball mill directly. As the day wore on, the gap on the cone crusher would slowly increase, which would cause the product size to increase. This would increase the re-circulating load on the ball mill. The throughput would decrease accordingly. Furthermore, the throughput would decrease more with high frequency of maintenance on the cone crusher."

Jan 1, 2019

By E. R. Dixon

Copper SX/EW plants often bleed part of their electrowinning electrolyte to control impurities and maintain consistent cathode quality. Depending on the specific situation at each site, the bleed is either returned to raffinate, to an SX extraction stage, to an SX wash stage, or to the PLS pond, to avoid losing the copper in the bleed. This practice can have undesirable effects on the overall process. An alternative is to electrowin all or most of the copper in the bleed, thus avoiding the recirculation of the copper in the bleed. In this manner, the bleed is converted to metallic copper without interfering with the SX circuit. This in turn reduces the copper concentration in the raffinate, improving global copper recovery because of improved leaching conditions.

Jan 1, 2007

By Seunghoon Lee

The increase in the number of higher and larger buildings is expected to require the buildings&apos; outer wall maintenance process, which includes cleaning, painting and monitoring, still depends on manpower. In this study, we proposed the robotic building maintenance system and aimed to reduce the jerk effect through the motion control of the system, improve the performance of the maintenance task, and ensure longer life and safety by improving the stability of the building structure and robot system. Through the results of the motion control and field-test with the proposed system, in specific, horizontal sliding module (HSM) showed that the jerk oriented by impact force was significantly reduced, feasibility of the proposed method was verified, and the robotic challenges were explored.

Aug 1, 2013

By Claudia Gasparrini

"Factors affecting the extraction of gold are of a mineralogical nature. Knowledge of the mineralogy of the ore or metallurgical product to be treated, if appropriately combined with the metallurgical test work, may improve gold recoveries. .This paper outlines the mineralogical techniques f or the study of gold ores and metallurgical products and describes the gold mineralogy in relation to its metallurgy. An effective plan for studying refractory and other difficult ores, combining metallurgical test work, chemical analysis and mineralogy and capable of giving positive results over relatively short periods of time, is suggested.IntroductionFactors affecting gold recoveries are of a mineralogical nature and include (i) the gold-bearing minerals, (ii) their grain size and, particularly where the grain size is very fine (10 microns in diameter and less), (iii) their host minerals and (iv) the association these form with the gold-bearing minerals.Mineralogical studies of gold ores and metallurgical products containing gold in economic amounts (today down to 1/10 of one ounce per tonne or 2.84 ppm) are difficult and time consuming. Mostly because of such reason, metallurgical testing (test work) is usually done simply by trial and error without understanding the causes for failure or success.Mineralogical studies, if appropriately conducted and combined with the test work, provide an efficient mean s of improving recoveries through the understanding of gold losses derived from the use of the wrong technique for separation. The information they provide is therefore the first step in the development of recovery techniques, for those ores where the test work alone failed to produce positive results."

Jan 1, 1983

By W. Pietsch

For a number of reasons, solids entering and leaving facilities for the treatment of minerals are becoming increasingly finer. Such materials pose problems throughout processing. Solids featuring small particle sizes tend to dusting, result in losses and segregation, exhibit various storage, transportation, and metering problems, and fine particulate effluents can not be easily captured, used and/or recycled. Sustainable mineral processing must minimize the exploitation of natural resources and avoid the need for disposal of wastes. The first requires the use of lower quality raw materials and upgrading, which typically results in the production of fine grained concentrates, and the latter encourages the recycling of wastes and byproducts or efforts to investigate them as sources for secondary raw materials or other beneficial applications. To overcome the difficulties associated with fine particulate solids, size enlargement by agglomeration is necessary. The resulting products have free flow characteristics, do no longer dust or segregate, and are sized and shaped as required for optimum processing. In addition, agglomerated materials may be engineered to feature desirable structure, composition, and a number of related, improved properties. Such engineering may be applied for the modification of fine run-of-mine and up-graded minerals as well as the production of secondary raw materials from by-products or wastes. By the interdisciplinary application of size enlargement by agglomeration waste-free processing of minerals becomes feasible.

Jan 1, 2004

By Engin Burak Anil

Objective, accurate, and fast assessment of damage to buildings after an earthquake is crucial for timely remediation of material losses and safety of occupants of buildings. Laser scanners are promising sensors for collecting geometrical data regarding the damaged states of buildings, as they are able to provide high coverage and accuracy at long ranges. Yet, we have limited knowledge on the performance of laser scanners for detecting earthquake damage, and requirements of such data collection. This paper focuses on characterizing the performance of laser scanners for detecting thin cracks for damage assessment of reinforced concrete frames. We identified a series of crack parameters based on the state-of-the-art damage assessment codes and standards. Similarly, we identified parameters, which affect the performance of laser scanners for detecting cracks, based on prior research in this area. We studied the width, depth, and orientation of cracks; sampling interval of the scanner, and the range of the laser beam from the surface. Effects of these parameters on the detection of the minimum crack size were determined in an experimental setting. An automated algorithm was used to analyze the data. The results show that it is possible to detect as small as ~1mm cracks.

Aug 1, 2013