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By J. H. Daniel

Dust-related respiratory disease remains the major health concern in mining, and health agencies are proposing more stringent standards. The U.S. Bureau of Mines (USBM) is investigating techniques to continuously monitor respirable dust in real-time during the coal or ore extraction process. Continuous monitoring will allow mine operators to evaluate hazardous dust concentrations and adjust the operations to produce less dust. Mine instrumentation applications include machine-mounted and hand-held monitors, personal monitors, and area/environmental monitors. Six dust detection methods have been considered to meet application requirements. These are: light-scattering instruments, a smoke-particle detection technique, correlation of pressure drop across the collection filter with amount of dust deposited, the Tapered-Element Oscillating Microbalance (TEOM) instrument, a method that relates the amount of dust collected on a filter with the vibration of the filter, and beta attenuation measurement of dust. Studies to date have identified the TEOM instrument and the technique of correlating the amount of dust collected with the vibration ofthe filter as having the most promise for success. Development of the machine-mounted monitor is the highest research priority. The application options and progress to date in developing continuous monitoring instrumentation are presented.

Jan 1, 1995

By J. Alatalo

Autogenous grinding is a process of reducing the particle size distribution of an extracted ore by using the ore itself as the grinding media. It is a process that is difficult to control and there is a lack of knowledge of the events occurring inside the mill. To find out more about how the mill behaves under different processing conditions, a full factorial test was performed with iron ore in a pilot-scale pebble mill at the LKAB R&D facility in Malmberget. To complement this work, a strain gauge detector was embedded in one of the mill?s rubber lifters, the Metso Minerals continuous charge measurement (CCM) system, and was used to get more information about the charge dynamics. The data from the experiments has been analyzed. For production purposes, an increase in the number of particles smaller than 45 µm can be regarded as a probable increase in the production rate. The analysis shows that there will be an increase in fines at 65% of critical speed, especially when the mill is 45% full. This setting will also increase the power consumption, but improves the grindability of the ore even more. The deflection of the lifters is smaller for lower critical speeds. A higher degree of filling also gives a smaller toe angle and a higher shoulder angle as expected.

Nov 1, 2011

By Deming Wang, R. A. Overfelt

"The oscillating cup viscometer has become a dominant technique to measure the viscosities of high temperature molten metals. Unfortunately, the viscosity estimation model from the observed logarithmic decrement and period of the oscillation is very complicated. There are still large discrepancies of viscosity estimation values between using different measurement facilities and using different viscosity estimation models for a same molten metal. The purpose of the paper is to evaluate the accuracy of an oscillating cup viscometer in Auburn University. Two well known viscosity estimation models, Roscoe's and Torklep's equations, are compared and discussed. The theoretical literature for the fluid flow inside an oscillating cup is reviewed and a more accurate working equation for the Auburn oscillating cup viscometer is developed. Some design parameters of the oscillating cup viscometer, which directly affect the accuracy of viscosity estimation by using the working equation, are discussed. In addition, applications and experimental measuring data are presented in the paper for several different commercial alloys, such as aluminum alloys: A319, A356 and A201, nickel-base super alloys: In713 and In718, and casting irons, C40 Gray Iron and Ductile Iron.1 IntroductionThe oscillating cup viscometer is the most important and has been most frequently used in viscosity measurement for high temperature liquids [1-4]. The principal advantages of this technique over others are its mechanical simplicity and the ability to measure the time period and amplitude decay with great precision. In the viscometer, a high temperature liquid (such as a molten metal) is contained within a crucible suspended by a wire to form a torsional pendulum, which induces torsional oscillation motion. This motion is damped primarily by viscous dissipation within the viscous liquid inside the cup. The viscosity of the liquid can be calculated by an analytical or numerical solution ofthe equations of motion of the oscillating cup system."

Jan 1, 2001

The original and most basic relationship between mining company and explosive supplier was a simple one of consumer and product supplier. The divide between the two was quite clear-cut with neither taking much interest in the activities of the other. The explosive supplier had little understanding or share in the outcome, efficient rock breakage and therefore impact on mining and milling. Likewise, the mining company did not encourage the improvement or development of products. The transactions were limited to product and funds. This environment does not encourage any form of knowledge sharing, trust or optimisation of the mining process.Conversely, there are now a variety of relationships to the point that the mining company may simply be an asset manager whereby all æoperationalÆ aspects are contracted out. For the drill and blast aspect this takes the form of a æRock-On-GroundÆ contract whereby the explosives company takes on design, drill, load and fire responsibilities and is paid a rate per volume of broken rock. This removes the majority of risk to the mining company derived from having to produce broken rock and guarantees the cost of a portion of the overall unit cost of mining. The onus is now on the explosives supplier to break rock to a specification as efficiently as possible.There exist a number of variations between the æbasic supplyÆ and æRock-On-GroundÆ. These contracts may also include value sharing to encourage the explosive supplier to optimise the mining operation to maximise profit.This paper looks at some of the drivers for the change in explosive supplierûconsumer relationships and examines the æprosÆ and æconsÆ of a few of the options.

Jan 1, 2004

By J. M. Shneerson

At Gipronickel Institute a technological flowsheet of pressure leaching of copper from rich copper concentrates (i.e. containing: Cu -59-75%; Ni -D.5-4.64%; Fe -D.2-J.3%; S -21.8-26.9%) was developed. As a result, the possibility of deep decomposition of copper-containing minerals with extraction of elemental sulphur (up to 90-95%) was established. The obtained sulphur concentrates contain 80-90% of elemental sulphur, which can be separated from sulphide residue through autoclave melting and settling. As a rule, sulphide concentrates remaining after extraction of sulphur contain up to 1-2% of noble metals. The sulphide concentrate can be purified to the level of rich concentrates or pure metals using the well-known methods as in the case of tankhouse slimes. The presented research specifies the parameters of main operations: pressure leaching and sulphur extraction. It was established that 98% of copper could be transferred into solution at temperatures of 108-1 10°C and oxygen partial pressure 0.4-0.6 MPa. Experiments were carried out in autoclaves of various volumes using the products of nickel matte processing.

Jan 1, 2003

By John Stubbles

Data are presented on the global warming issue to reinforce the decision by the U.S to reject the Kyoto protocol. The evidence that CO2 is a problem rather than a benefit is inconclusive and will be discussed in this paper. Nevertheless, for economic reasons alone, the US steel industry will continue to minimize CO2 emissions (and the release of real pollutants) per ton of steel through energy reduction programs. However, relative to inevitable increases in absolute CO2 emissions from the utility industry and the transportation sector, future reductions by the steel industry will be inconsequential in the "big picture."

Jan 1, 2004

By M. G. Lipsett

"Mining properties are becoming increasingly remote, a challenging situation for operating and maintaining equipment. Logistics of transporting workers and materials can be alleviated by having timely, accurate information of equipment location and operating condition, and by automating some activities. This paper discusses an infrastructure for remote operations, with strategies for communicating different types of data, and a design method so that systems can interact with either an operator or another system. A remotely operated excavator prototype is described, with on-board performance and diagnostic monitoring systems now used on production equipment. IntroductionSyncrude Canada Ltd. operates an openpit oil sands mine near Fort McMurray, Alberta. For twenty years, draglines and bucketwheel reclaimers have fed conveyors that transport dry oil sand to an extraction and upgrading plant. In converting to a truck and shovel operation, Syncrude has developed slurry pipelines and bitumen froth pumping to allow more remote leases to be mined more than 30 km from the base plant.There are organizational and resourcing challenges in operating and maintaining equipment in three nearby, but separate, mines. The logistics of transporting workers and materials to production and support equipment become more difficult, and operations and maintenance personnel and facilities become more distributed. Supervising mine operations will rely even more on having timely, accurate information about equipment location and operational status.Syncrude is typical of an open-pit operation. Voice communications are the preferred way to exchange information for making immediate decisions about operations and maintenance. A large number of narrowband FM broadcast radio channels keep teams of miners working together. Haul truck drivers, shovel operators, and dispatchers talk on one channel while maintainers coordinate activities with the control tower on another. Cellular phones have become popular for supervisors who have to talk with planners and engineers in offices without radios."

Jan 1, 2000

By Bora Okumusoglu, Devon K. V. Mothersille

"AnchorTest is an innovative software package, specifically developed for tablets, that permits ground anchor test data assessment and management in real time. The solution has two components: a front-end tablet app runs on the Apple iPad platform, and a back-end Cloudbased system running on Amazon Web Services with an online cross-platform website, which can be accessed from any PC, tablet or even mobile smartphone. This tool provides full data analysis and data management capabilities and portability to create greater efficiency in the anchor testing process. AnchorTest is programmed to accommodate the major international anchor testing codes and incorporates an intuitive user interface, which is revolutionary compared to conventional engineering software designs. The use of this tool creates an environment where the testing of ground anchors has effectively become a paperless exercise with greater efficiency and access to instantaneous feedback on the performance of anchors in relation to established acceptance criteria.Historically, project personnel record and analyze the results from anchor load tests using spreadsheets and a laptop computer and/or on predesigned paperbased test sheets (usually as a backup of the testing). In addition, the processing of the test results is not typically performed in real time as the testing progresses — the calculations and analysis are performed either afterward while still on site (if a field office is available) or after returning to the office. Undoubtedly, on larger projects containing numerous anchors where multiple anchor tests may be performed at the same time, processing, analyzing and accepting the load test data and results can be especially time consuming, which could cause delays to the construction schedule.DevelopmentThe need for a more automated and digitized approach to record, process and analyze the data from anchor load tests was highlighted at a deep basement project for a mixed-use development complex in Moscow, Russia. The diaphragm wall supporting the structure was approximately 1,970 ft (600 m) in perimeter length and about 148 ft (45 m) deep, with an excavated depth of about 82 ft (25 m), which required six levels of single bore multiple anchors (SBMAs). This project provided a challenge to recording, processing and signing off on the data generated from some 3,600 3-unit SBMAs. More specifically, for this project, three hydraulically synchronized stressing jacks were used to stress and proof test each 3-unit SBMA, which resulted in nearly 10,800 data plots of the load-extension tests being generated. This project served as the main impetus in the conceptual design and optimization of AnchorTest."

Jan 1, 2017

By J. R. Odekirk

The nature of mineral distributions and locking characteristics in mill products are important factors in understanding mill performance. Such data are obtained by microscopic point counting methods. Reduction 'of point-count data from volume to weight percentages, and reduction of data for each size fraction back to a head sample requires lengthy hand calculations. The use of computer processing for such data reduction results in obtaining information on a realistic time basis. An example of computer processed point-count data is presented.

Jan 1, 1981

By R Shaw, T T. Neidel, C Adams

Sampling equipment manufacturers endeavour to ensure that the mechanical equipment installed in sampling systems are designed and manufactured to adhere to the requirements of the International Organization for Standardization (ISO) or other standards relevant to the application. The mechanical parameters necessary to achieve these standards can be well controlled and requirements such as constant speed can be met through good mechanical design and engineering. However, when the equipment is installed and put into operation, the ISO compliance of the system is out of the hands of the equipment manufacturer and handed to the operator, who may be a generalist control system integrator.Making a sampling system perform according to standards, and being able to monitor and report on compliance require that the sampling system knowledge and the control integration is combined and applied in an integrated approach. Using a dedicated library of control routines developed for sampling can change a system from having compliant equipment to being a compliant system. The library has to include monitoring of relevant parameters and control and reporting on sampling parameters.CITATION:Neidel, T T, Adams, C and Shaw, R, 2014. Control and monitoring of International Organization for Standardization compliance for industrial sampling systems, in Proceedings Sampling 2014 , pp 121–126 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

The BHP Billiton Cannington Mine uses paste as the principal method of backfill. The paste consists of mine tailings and cement. The pastefill process at Cannington includes a surface plant where the thickened total tailings stream is filtered using two vacuum disc filters operating in parallel. The filter cake is mixed with Portland cement in a spiral mixer to produce a paste at a specified yield stress and cement content. The initial system design only required paste to be delivered under gravity. In July 2001, Cannington Mine expanded to 1.8 million tonnes per annum. In order to achieve this, production commenced on five new levels underground, 350 metres horizontally from the paste plant. Due to the high viscosity of paste, this distance was too far to transport by gravity. Traditionally, paste has been transported only short distances (50 m) using positive displacement pumps, with very limited success. At Cannington, a conveyor was installed which was designed to achieve zero spillage into the environment. This paper discusses the innovative design strategies used to attain zero harm on the environment whilst conveying a material, which is difficult to transport.

Jan 1, 2002

By K. Sakaguchi, T. Yokoyama

"In-situ rock stress measurement was carried out in the Kamaishi mine of Iwate Prefecture to quantify the variation of the shallow crustal stress field associated with the 2011 Tohoku-oki earthquake. Stress measurement was conducted by the Compact Conical ended Borehole Overcoring (CCBO) technique, which is one of the stress relief method. The CCBO technique is the one of the suggested method of ISRM. Measurement period is from 1991 to 2014. Main results obtained in this study can be summarized as follows.The direction of the maximum principal stress did not change much before and after the earthquake. However, the directions of the intermediate principal stress and the minimum principal stress of one year after the earthquake changed from those of before earthquake. Namely, the direction of intermediate principal stress was East-West horizontally, and the direction of minimum principal stress was vertically. This state of stress is reverse fault type and was maintained for three years after the earthquake.The magnitudes of principal stresses and the vertical stress of one year after the earthquake became more than the double before the earthquake. However, the magnitudes of the maximum principal of two year after the earthquake became smaller comparing with those of one year after the earthquake. Furthermore, the magnitudes of the intermediate principal stress and the minimum principal stress of two year after the earthquake became almost same as those before earthquake, and the vertical stress of two year after the earthquake became almost equal with the overburden pressure. And the magnitudes of three principal stresses of three year after the earthquake became the same level before the earthquake."

Jan 1, 2015

By Robert J. Uffen

YOU will likely recall the accomplishments of the International Geophysical Year of 1957, with its polar expeditions, the discovery of the Van Allen radiation belts and the spectacular launchings of the first artificial earth satellites. Our know ledge of the exterior of the earth was greatly increased by this international, friendly, cooperative scientific investigation. The Inter-national Union of Geodesy and Geo-physics has now been joined by the new International Union of Geological Sciences in sponsoring a similar study of the earth's interior. The program will extend from January, 1962 until December. 1964, and is known as the International Upper Mantle Project. During the T.G.Y studies of the interior of the earth were relatively neglected, even though the same international •Cooperation in obtaining simultaneous world-wide observations, by similar instruments, is required to locate and study earth-quakes, for example, as it is to study the earth's upper atmosphere. The upper mantle is 1•emote from man, as it extends from a depth of about 10 km. to perhaps 1000 km., but its practical importance is great.

Jan 1, 1962

By P. Schloth, H. van Swygenhoven, N. Chobaut, J-M. Drezet

"In the current trend toward thicker aluminium plates, a major concern is the stress build-up during quenching which causes distortions during machining. Indeed, cooling rates are not high enough, especially at the core of such thick plates, to prevent any precipitation and quench induced precipitates lower the hardening potential. Multi-scale modelling is required when predicting macro-scale stresses after quenching for thick heat treatable aluminium components. The reason is the instantaneous strong coupling between phase precipitation at the nano-scale and material hardening due to precipitation or softening owing to solute depletion at the microscale. For thick parts, quenching intensities decrease when going from the skin to the core of the component, thus introducing a gradient of nanostructure and consequently a gradient of mechanical properties. In addition, large thermally induced deformations lead to high macroscale residual stresses although part of them is relaxed by plastic deformation. These stresses have been measured in water quenched thick plates of 7040 and 7449 aluminium alloys using neutron diffraction and layer removal techniques and the results when compared with a thermomechanical finite element model of quenching highlight the influence of precipitation.IntroductionIn the processing route of heat-treatable aluminium alloys (AA), a critical step is quenching from the solutionizing temperature. High cooling rates are desired, as they avoid formation of coarse precipitates, which reduce mechanical properties. Fast quenching, however, cannot be achieved in the centre of thick components, where the quenching rate can be more than one order of magnitude lower than at the surface. The existence of a thermal gradient between core and surface leads to a differential thermal deformation which is accommodated by elastic and plastic deformation to comply with the compatibility of deformation. Whenever the material yields, especially at high temperature when the yield strength is low, residual stress remains after quenching due to the irreversibility of plastic deformation. After quenching, the plates are in a state of residual stress that causes unacceptable distortions during machining and may reduce service life drastically. Since stress relaxation is negligible during ageing treatments [1 ], agehardened aluminium parts are usually stress relieved prior to ageing. This is typically achieved by applying plastic deformation: stretching from 1.5 to 3 % in the rolling direction (L) can reduce the internal stresses by a factor of approximately 10 [2, 3]. However, complex geometries or thicker components like thick sheets require other approaches. Reducing the quenching rate by using boiling water for instance leads to lower residual stresses [1, 4]."

Jan 1, 2013

By Huw Williams

"Power companies are always looking to increase the carrying capacity of existing transmission lines, and the preferred method is to string heavier capacity conductor lines. However this results in higher wind loading and the potential for towers overturning, if the existing foundations do not have the tensile capacity. On older lines, there is often a lack of information on construction type and dimensions and in practice the as-built foundation can differ considerably from design drawings, due to unforeseen ground conditions along the line route, and no record of the resulting change in design being made.Following successful trials in New Zealand, integrity testing with Frequency Response and impedance profiling techniques is now being used in the region to check concrete foundation properties in-situ and are enabling power companies to get the most out of their assets. INTRODUCTIONIn most regions of the globe, the US included, there is generally a requirement to upgrade transmission line capacities, to cope with increasing power consumption. Problems with under capacity only come to light for the public when blackouts occur, even in developed countries.A large number of transmission line towers are designed with a certain capacity redundancy and will be able to carry greater loads than originally designed for. Power companies are therefore looking for ways to assess their assets and to minimize the costs of upgrade work.Re-assessment of tower foundation capacities using design drawings may not be valid , as constructed foundations may differ considerably from design drawings, to accommodate local difficulties and in some instanced, particularly with earlier lines, there is no information whatsoever. This complicates efforts to determine the capacity of foundations considerably."

Jan 1, 2005

By J. O?Shea

From the characteristics of the new (1976) electronic components and units that are being marketed, the author has tried to foresee the types and the performances of the near-future slope-monitoring equipment. Much-improved sensors, instruments and systems for pit use can now be developed - sun-powered telemetry remote stations are feasible, very sensitive as well as precise and drift-free liquid level inclinometers will be available, new techniques for distance measurement with lasers obviate the need for atmospheric corrections and the latest generation of desktop calculators have become easily programmed minicomputers. Thus, it is realistic to assume that fully automatic pit-slope monitoring systems will be operational in the foreseeable future.

Jan 1, 1978

By W. A. Gow

"In January of 1964, a group known as the Canadian Gold Metallurgists was formed with the backing of the managers of most Canadian gold mining operations. This organization is composed of about thirty mill superintendents of Canadian gold milling operations where the cyanidation process is in use, and one member from the staff of the Mines Branch, Department of Energy, Mines and Re-sources, Ottawa. The aim of this group is to bring together gold mill operators, and research and development people from both industry and government for the purpose of discus-sing common metallurgical problems, and deciding on what operational R and D efforts can be made to help solve these problems. Since the conception of this organization, this approach taken by the gold industry to the study of metallurgical problems has resulted in benefits to all operators, both by assisting them with problems peculiar to their own individual operations and by providing developments of general interest to the industry.This paper describes events leading up to the formation of the Canadian Gold Metallurgists, and how the group has operated since its formation. Examples of progress made toward the group's objectives are given, and possible future programs are discussed."

Jan 1, 1968

By Jr. Goller

You and I can visit cement plants, inspect the various rotary kiln systems and find some equipment or some burning techniques that waste energy--fuel and power. After we have made such a visit and studied a few ideas, we could recommend ways to eliminate much of this waste. Probably every idea would cost money to bring into action. For our discussion, let us arbitrarily set an upper limit of $1,000,000 on the recommendations that we are allowed to make. Call these "low-cost" or "short-term" measures. They are improvements that do not require more than say, three months to complete; they do not require a major revision to the process. Other recommendations are "high-cost" or "long-term"; they are outside the scope of this discussion. Some of our "low-cost" recommendations would offer a satisfactory return on the money that they cost; the remainder would not. Now, is there some way that we can rather quickly pick out the "low-cost" measures that will show a satisfactory return and spend our time making these improvements first? Can we separate these items from those where the return is less likely to be good? I feel that we can pick some of these items quickly if we have a kiln system that has consistently non-uniform day-to-day operation. If the operation is uniform we probably cannot pick them quickly.

Jan 1, 1977

By John D. Galloway

Mining is one of the important primary industries of Canada, with a gross production in 1927 estimated at $241,773,000- the highest in the history of the country-and an impressive dividend record. It is quite apparent, therefore, that mining is a business worthy of the careful attention of the people of Canada. Furthermore, with a vast undeveloped territory more or less mineralized, it is highly probable that our mining industry will continue to expand indefinitely, with a consequent increase in production and in the amounts of the yearly profits distributed. In recent years, the public has taken a larger interest than formerly in mining-an interest, moreover, that is not academic, but primarily from the viewpoint of profits. It is quite evident that mining is a profitable business, at least to some, and the average man on the street, hearing of these profits, is attracted thereto. I have no doubt that many of you have .read in promotion prospectuses, with figures to prove it, that mining is the most conservative, the safest, and the highest-yielding business in the world. Now, a lot of this information is best judged by the old saying that "While figures don't lie, liars figure". At the same time, mining, properly conducted, is a profitable business, even though speculative, and undoubtedly much profit will come from Canadian mines in the future. In this paper my conclusions regarding mining investments are based largely on British Columbia experience, together with some slight knowledge of mining conditions in the other Provinces. It is considered, however, that the inferences drawn are applicable to mining throughout Canada.

Jan 1, 1928

The U.S. Bureau of Mines (USBM) has developed a test procedure to compare the initiating strength of detonators by using adjustable-sensitivity liquid explosives. Various tests of detonator strength are currently used by the industry, but many of them do not quantify the ability of detonators to initiate detonation reactions in an explosive charge. The USBM used mixtures of nitromethane and ethylene diamine, the sensitivity being "fine-tuned" by 2-nitropropane. Military standard J-2, commercial No.6, and commercial No.8 detonators were evaluated using three test configurations: (1) axially immersed in the test explosive, (2) tip just touching surface of the explosive, and (3) immersed transversely in the explosive. Markedly different results were obtained for these three configurations, indicating that the directional effects are important. This explains why different detonator strength tests do not correlate well with each other. Some tests, such as the sand bomb and underwater, measure the total energy out-put, while other tests, such as the plate dent, test measure the energy in the axial direction. The USBM's test data indicate the importance of conducting the experimentation in the manner in which the detonator is actually intended to function.

Jan 1, 2010