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By J. W. M. Porritt, K. C. Cheng

Knowledge of radon emanation rates from uranium-bearing rocks is essential to the design of mine ventilation systems for uranium mines. Measurements of equilibrium ratio between radon and its daughters in mine air are important for a better control of mine radiation conditions. The concentrations of radon and daughters were monitored at cut-and-fill stopes in the Beaverlodge Mine of Eldorado Nuclear Ltd. during all phases of the mining cycle. The radon emanation rates of ore and rock samples were measured at the laboratory and the results were compared with in-situ emanation tests in an isolated ore drift. Samples of backfill solution, backfill drainage and ground seepage water were measured [or radon and analyzed for radium and uranium. The results showed that discharges of backfill solution and daily shift-end blasts were the two major sources for a rapid release of radon gas in the ventilation air. Other mining operations, such as drilling, mucking, etc., contributed little effect on radon release to the mining environment. Radon emanation rates of the Beaverlodge are samples ranged from 13 x 10-18 to 600 X 10-18 Ci/cm2/ sec and that of waste rock samples from 0.54 x 10-18 to 13.4 X 10-18 Ci/cm2/sec. The in-situ emanation rate of mine walls with ore-to-rock ratios of 1 to 7 was 60 x 10-18 Ci/cm2/sec. The average equilibrium ratio of radon and its daughters in stapes was 32.6%. Under a normal ventilation condition, the average background levels of radon concentration in cut-and-fill stopes ranged from 13 to 80 pCi/L. The discharges of backfill solution during backfill operations at 100 tons solids per hour released approximately 1.8 x 106 pCi/min of radon and elevated radon concentration in stapes 2 to 5 times above the background levels.

Jan 1, 1981

By G. J. Hutchins

Precision surface mining is gaining traction in the iron ore, copper, iodine, limestone, bauxite, coal and gypsum markets. In this paper, we first address the possible improvements of a surface miner control using GPS techniques. An application in an iron ore mine in Western Australia is presented. The second item addressed is improvements of a new drum driving technique for a 100 ton surface miner. This technique involves installing a slow speed hydrostatic motor directly on the cutting drum rather than driving the drum through chain and sprockets. Details of the performance of this direct-drive versus the chain-drive are detailed. In addition to the 100 ton machine, we also present a 200 ton surface miner. This larger machine has 1600 hp (894.8 kg), and has been successfully introduced into a large iron ore mine in Western Australia. Performance of the 200 ton surface mining machine in various rock hardnesses is detailed. Some comments on the cost effectiveness of using a built-in loader versus loading with wheel loaders are included.

Aug 1, 2013

By K. Soucek, J. Ptácek, A. Hastíková, R. Kukutsch, P. Konícek, P. Waclawik

"Cable bolts are used frequently as a secondary support system (with steel arch support) in difficult stress-strain conditions of deep coal mines. The load transfer mechanism of cable bolts depends on several factors, such as the strength, deformation and geometric properties of the bolts, resin and the surrounding rock mass so-called cable-resin-rock system (CRR system). The bonding length and bolt/borehole diameter ratio strongly influence the final bearing capacity of the CRR system.The study presents the behaviour of CRR system during a pull-out test which is usually used in the carboniferous rock mass in the Czech part of the Upper Silesian Coal Basin. A series of 28 pull out tests were performed on 3-m-long cable bolts, with various combinations of borehole diameters and bonding lengths, to understand this behaviour. Boreholes were drilled into a solid rock mass consisting of fine-grained sandstone to guarantee similar conditions during the pull-out tests. Video inspection and measurement of borehole diameters were performed to determine their quality and real diameters. Three characteristics were observed from pull-out test results: ultimate pull-out load; displacement of the end of bolt and system stiffness. Numerical modelling by FEM (Finite Element Method) was used to determine the stiffness of the CRR system for variable bolt/borehole ratios and bonding lengths each under constant load. A linear elasto-plastic model and a mohr-coulomb model were used for cable and resin-rock respectively. The results of the experiment may contribute significantly to improving of the methodology of cable bolts installation as well as the design of used cable bolts."

Jan 1, 2015

By B. S. A. Tatone

The surface roughness of unfilled rock discontinuities has a major influence on the deformational and hydraulic behaviour of discontinuous rock masses. Although it is widely recognized that surface roughness is comprised of a large-scale (waviness) and small-scale (unevenness) components, most investigations of surface roughness have been restricted to small fracture surfaces (< 1m2). Hence, the influences of the large-scale components of roughness are often neglected. Furthermore, these investigations typically focus on analyzing roughness in terms of two-dimensional profiles rather than the complete three-dimensional geometry, which can lead to potentially biased estimates of roughness. This contribution demonstrates the use of a new optical digital measurement system, based on the principle of triangulation, to digitize a large-scale natural rock discontinuity surface at both outcrop-scale (~6m x 2m) and lab-scale (~100mm x 100mm). Subsequently, the digitized surfaces are systematically analyzed using the three-dimensional roughness methodology proposed by Grasselli to investigate the dependency of roughness on sample window size and measurement resolution.

May 1, 2009

Arguably the SMC Test® has become the most popular laboratory hardness test in the world with over 17,000 tests having been completed to date, covering over 650 different ore bodies. It is now routinely used in design, optimisation and orebody profiling projects. The test is unique in that from relatively small amounts of drill core it simultaneously provides parameters that are used in simulation modelling of AG/SAG and crushing circuits as well as work indices that are used in power-based equations for predicting the specific energies of AG/SAG/Crushing and HPGR circuits. The very large data base that has been accumulated has provided the opportunity to study the differences in variability from deposit to deposit. This paper describes and discusses the trends that have become apparent from the study of this data base. Recommendations for appropriate selection of sample numbers are also made which are based on these trends.

Jan 1, 2012

By S. Esfahani, M. Barati, Y. Kauwachi

"Heat recovery from slag has gained attention due to its high potential in lowering energy intensity of metal extraction processes. A direct method to recover the thermal energy of slag is to use countercurrent air flow that extracts the heat from falling droplets. Often, the solidified slag is aimed to be used as a substitute for Portland cement, thus high cooling rates are required to form an amorphous slag with sufficiently strong hydaulicity. Rapid cooling however involves using large gas flow rates that in turn lower the thermal efficiency of the process. This article presents a mathematical model that was developed to determine the optimum conditions in the heat recovery process and to investigate the effect of the air flow and granule diameter on the cooling rate of the droplets as well as the thermal efficiency of the heat recovery system. INTRODUCTIONMetallurgical slags are the largest by-product of high temperature materials refining and extraction processes. The total amount of metallurgical slag produced in the year 2008 has been estimated at up to 422 million tonnes containing up to 222 TWh/y (Barati and Esfahani, 2011) of thermal energy. Over the past four decades attempts have been made to recover this substantial amount of energy as heat, electricity, or fuel, while none of the proposed method has been commercialized yet.During slow cooling the slag tends to crystallize the constituents (CaO, SiO2, Al2O3, etc.) into a hard, heavy solid. In the past, over 90% (Bengt, 1983) of the molten waste was discharged onto heaps and allowed to cool slowly, then crushed and used in road construction or land filling or as coarse aggregate for concrete. However, later it was found if cooled rapidly, the slag can be used as a substitute for Portland cement. As a result, processes such as wet granulation were created in which molten slag is fragmented with water, forming amorphous (glassy) phases. Despite its effectiveness in producing a suitable material, heat would not be recovered through this process. Thus, dry granulation was introduced in 1930’s and was developed further in 1970 – 1980’s."

Jan 1, 2012

By Lar Liljeblad

"As demands upon the earth&apos;s natural resources continue to grow, exploration companies, mining organizations and others face the problem of the need to tackle increasingly more difficult strata to open up new reserves. Innovations in materials technology and tool design have steadily improved this capability, but none perhaps so drastically as a recently introduced cemented carbide in which tool wear resistance and/or toughness can be tailored precisely to the user&apos;s drilling needs.Introduction Until about forty years ago, the bulk of rock-drilling operations had to be carried out with hardened steels. Short life between re-grinds was common especially in abrasive rock formations. Shortly after World War II, Sandvik, Sweden, pioneered the development of sintered (cemented) carbide-tipped steel tools as a means of improving drill tool life. The new material was a composite of tungsten carbide and cobalt, the latter acting as a &apos;cement&apos; to bind the wear-resistant carbide grains together, and the composite, in turn, was brazed to the steel. The immediate effect was a 100-fold increase in the service life of the tool.Intractable ProblemsWhile the carbide-tipped tools served the mining and quarrying industries admirably there were, nonetheless, some seemingly intractable limitations. The greater the wear resistance of the material - the quality for which it is selected - the more brittle it is. Also, rocks vary widely in hardness and abrasiveness and no single tool, either in terms of material or shape, meets every need. Specifically, for fast penetration of non-abrasive rock, toughness must be combined with a relatively sharp tool prome. Highly abrasive rock, on the other hand, demands a substantially broad area of extremely wear-resistant material on the tool if long bit life is to be assured. Between these extremes there are innumerable variations in rock"

Jan 1, 1991

By A. J. Harrison

"The introduction of an amendment to the Mines Regulation Act in the Province of British Columbia, passed in July 1974, and similar amendments since enacted by other provinces introduced the Canadian underground mining industry to the use of fire-resistant hydraulic fluids.Few, if any, of the hydraulic circuits in use in underground mining at that time were specifically designed for use with fire-resistant fluids, compared with the increasing number of such circuits conceived and in production today. The technology required in designing equipment for use with fire-resistant fluids may be likened to that associated with conventional mineral oils, but, in many respects, a variety of additional and / or alternative considerations must be taken into account. The fast-increasing use and development of fire-resistant fluids throughout all facets of industry, world wide, during the past 20 years has led to a whole new technology in system construction and component design, whereby acceptable performance can be achieved . However , the transition from conventional mineral hydraulic oils has not been without its problems, particularly when retro-fit of existing units was involved."

Jan 1, 1981

By Robert B. Parsons

"There is a widespread concern that certain of Finance Minister Michael Wilson&apos;s Tax Reform proposals will likely lead to a significant decline in flow through funding after 1988. This does not bode well for the junior exploration sector, which relies heavily on flow-through to finance exploration programs. The exploration industry is actively pursuing various solutions to the problems posed by Tax Reform, in order to ensure that flow-through has a future.IntroductionWhile the proposals contained in Finance Minister Michael Wilson&apos;s Tax Reform White Paper may not be as far-reaching as some people had expected, nevertheless the combination of the existing tax rules and proposed new rules offers sufficient complexity to keep pencils sharpened for many months. After having had an opportunity to study Tax Reform since June 18, 1987, the sharpened pencils are suggesting that the White Paper is not without its shortcomings and pitfalls. Insofar as the mineral exploration industry is affected, there is widespread concern that adoption of certain Tax Reform proposals could spell near disaster for mineral exploration in Canada. More specifically, there seems to be a consensus among the industry, as well as some federal and provincial government officials, that the announced phase-out of the ""mining exploration depletion allowance"" (MEDA) would reduce the appeal of flow-through shares to the point where only a fraction of exploration funding would be financed in the future by flow-through."

Jan 1, 1987

By A. W. Chan

"An interactive computer simulation model of conveyor systems used in oil sands mining has been developed to aid in the selection of mining equipment and the evaluation of operating policies. The materials handling links between supply points, such as bucket-wheel excavators and draglines, and demand points such as bins and extraction plants are modelled in such a way that the conveyor model can be interfaced with any combination of these equipment submodels. Detailed calculations of the power demand of each conveyor section based on operating characteristics and conveyor design parameters are included to permit the close monitoring of energy requirements. Various interactive features are incorporated so that an operator can not only monitor, but also control, the mining operations in the model and experiment with different operating strategies.IntroductionThe interactive simulation model of conveyor systems described in this paper is one of a number of detailed computer models being jointly developed by the National Research Council and Canstar Oil Sands Ltd. on the mining equipment and operations used in oil sands mining. Reference I presents an overview of this whole series of models, their interrelationships and the underlying motivation for their development.A network of conveyors constitutes one of the practical ways for transporting mined material in an oil sands plant. The materials handling links between supply points, such as bucket-wheel excavators, bucket-wheel reclaimers and bins, and demand points such as dumps, bins and extraction plants can be represented by a series of interconnected conveyor sections. For example, the fluctuations of the feed rate at the bucket-wheel excavator, the flow of ore material through the conveyor network and the arrival of this material at the extraction plant can be simulated."

Jan 1, 1982

By J. E. Udd, L. B. Geller

"Mine-shaft wire-rope discard regulations include, among other criteria, a limited amount of permissible loss-of-breaking-strength (LBS). Currently, this parameter is estimated on the basis of non-destrutive-testing (NDT) with electro-magnetic (EM) type instruments. This paper analyses the accuracy with which these estimates have, so far, been obtained in practice.It concludes that while certain types of testers have produced better results than others, the desired accuracy level has not been attained. Also discussed are the putative reasons for this situation, and appropriate actions that the mining industry might wish to take."

Jan 1, 1990

By Patrick S. Hudd

Traditionally in hard rock mining, large diameter raise boring was thought of as 3.04 metre or 3.66 metre diameter holes 300 metres deep. Mine and ventilation engineers were challenged to design systems either incorporating such holes, or slashing and modifying to suit. Now, 5.49 metre diameter holes up to 1,000 metres deep are being excavated. The ability to pilot and ream such holes not only creates new options for mine engineers in mine ventilation system design, but also creates new opportunities in mine access. By combining holes of this diameter with the ability to accurately drill long pilot holes within the diameter of the pilot hole through the entire length of the hole, borehole hoisting systems are now fully capable of being main production or service accesses for mines. This paper will review the present day capabilities of large diameter raise boring, potential applications for such excavations and some considerations for companies contemplating using large diameter raise boring in their operations

Oct 1, 2010

By Lisa L. Van Loon, Neil R. Banerjee

Canada is a world leader in uranium exploration, but many deposits are located in remote regions making exploration targeting challenging. Novel approaches are needed to detect the presence of large-scale ore-forming systems and to vector toward mineralization. Boron is commonly used as a key pathfinder element associated with sandstone/unconformity-hosted and basement-hosted uranium deposits in the Athabasca Basin, but the genetic relationship remains uncertain. Alteration assemblages containing boron geochemical anomalies are commonly spatially-associated with – and possibly coeval with – uranium mineralization. Boron is commonly found in tourmaline minerals but in some portions of ore deposits the host mineral for the anomalous boron remains cryptic. Boron coordination chemistry within alteration haloes can better constrain boron host mineralogy, provide insight into the nature of the boron-uranium relationship, and thus has the potential to better constrain targets for exploration. Synchrotron-source X-ray absorption near-edge structure (XANES) spectroscopy is a direct, element-specific analysis that identifies boron coordinated in both trigonally- (BO3) and tetrahedrally-coordinated (BO4) forms. This makes XANES uniquely suited for identifying the geochemical hosts for boron that may be related to hydrothermal ore forming processes. XANES spectroscopy was conducted on whole-rock assay powders from uranium deposits across the Athabasca basin containing boron concentrations ranging from <10 ppm to >10,000 ppm. XANES directly identifies the relative amount of trigonally- (BO3) and tetrahedrally-coordinated (BO4) boron in these complex mineralogical mixtures. Our work suggests a link between boron and uranium that is likely related to the unique physiochemical characteristics of ore bearing fluids that may provide a unique vector to mineralization.

Jan 1, 2020

By H. Jung

The microstructures and grain sizes of nanocrystalline Co and Co-1.1 wt % P alloys were characterized by X-ray diffraction. The corrosion properties of as-deposited and annealed Co-l.l wt % P alloys and pure nanocrystalline Co were studied in a deaerated 0.1M H2SO4 solution using electrochemical measurements and XPS surface analysis. Potentiodynamic polarization testing and impedance measurements revealed that an addition of P to pure nanocrystalline Co improved the anodic-corrosion resistance, however, this enhanced corrosion resistance was compromised by the heat treatment process at 350 and 800°C. The corroded surface of annealed nanocrystalline Co-1.1 wt % P at 350°C exhibited a more porous P-enriched layer compared with the as-deposited case. A sample annealed at 800°C corroded uniformly showing second-phase precipitates. The enhanced corrosion resistance of as-deposited nanocrystalline Co-1.1 wt % P was attributed to the elemental P on the surface that acted to hinder the anodic dissolution kinetics of surface Co following an initial selective dissolution of Co. However, at a higher anodic overpotential region, the superior corrosion resistance of Co-l.l wt% P alloys did not last because of the formation of a non-protective surface film consisting of mainly hypophosphite and phosphate as well as elemental P.

Jan 1, 2005

By K. K. Feng

"Spontaneous combustion has always been a problem in coal mines and is identified mainly with the mining of low-rank coals. The liability of coals to spontaneous heating is only one of the factors in determining whether spontaneous combustion will occur. However, knowledge of the relative oxidizability of the coal is a useful factor to take into consideration when selecting new coal seams and mining methods for future mine development.Four methods (static isothermal, ignitability, adiabatic and dynamic) have been used to compare the relative liability of Canadian coal to spontaneous combustion and to investigate the mechanism of spontaneous combustion of these coals. Among these f our methods, the static isothermal method is considered to be the best indicator of the susceptibility of various coals to spontaneous combustion. Western mountain coal adsorbs more oxygen and has a higher tendency to undergo spontaneous combustion than the Harbour seam coal of Nova Scotia. It has also been observed that a higher methane content in coal will indicate a lower liability to spontaneous heating."

Jan 1, 1985

By D. E. Salman, R. R. Maclachlan, R. J. Barclay

"There is a considerable resource of data for spherical charge cratering, both as single charges and in row-of-charge geometr(1). The data are. however, based on cratering performance to a single free planar surface.In practice. the more common circumstance involves an angular surf ace geometry. such as occurs at the toe of a bench or the wall of a stope. It is for the purpose of investigating this circumstance that the described test work was conducted.The test objectives were: (1) to observe the change in single-charge cratering performance between planesurface and angle geometry; (2) to identify the optimum performance of single charges cratering to a plane surface. cratering from a bench sub-grade position and cratering from a condition of zero sub-grade or stope wall geometry; and (3) to observe the performance of row-of-charges cratering to an angular surface at various row burials and spacing. The row charge burial and spacing dimensions were to be expressed in simple numerical multiples of single-charge depth-of-burial data."

Jan 1, 1981

By Robert B. Parsons

"The budget that was tabled by Finance Minister MacEachen on November 12, 1981 will result in a major tax reform of Canada&apos;s income and sales tax systems, the likes of which have not been witnessed by taxpayers since 1971. All segments of the economy will be affected one way or another by the far-reaching budget proposals; the mining industry did not escape untouched.Important changes will be introduced which will alter some of the fundamentals of structuring mineral resource ventures in Canada. This month, Tax Notes examines these changes, and also summarizes the other highlights of this key federal budget.IntroductionFinance Minister MacEachen&apos;s budget, with its lower personal tax rates, loophole plugging and tax shelter bashing, represents the biggest shakeup in our tax system since tax reform in 1971. In his budget, presented in the House of Commons on November 12, Mr. MacEachen proposed substantially lower tax rates for middle and upper income individuals, with the top federal and provincial tax rate dropping to about 50%, but in return he eliminated most of the opportunities for individuals, and corporations, to reduce or defer taxes through a wide variety of tax shelter and tax planning mechanisms.Although many of those budget proposals that dealt with the resource industries focused on the implementation of the September 1, 1981 agreement reached by the federal and Alberta governments concerning the National Energy Program (see Tax Notes in the December 1981 issue of the Bulletin), the budget also contained some proposed amendments that would have significant implications for investment in the mining industry.This month, Tax Notes examines these latter proposals, and also summarizes very briefly those budget proposals which are not unique to the resource sector."

Jan 1, 1982

By F. Goodarzi

"The nature and distribution of the inorganic components and the concentration of certain environmentally sensitive elements, such as, As, Sb, B, Hr, Cd, CI, F, Mo, Pb, S, and Se, or elements detrimental to the utilization by industry such as B, Na, P and S are very important in determining coal quality. The concentration of elements in coal is controlled by the following factors: (1) frequency of occurrence of partings; (2) nature and habit of occurrence of minerals in coal; (3) environment of coal deposition; (4)rank; (5) geological setting; and (6) weathering.Selective mining of coal can reduce the input of undesirable elements such as As and S by eliminating the part of the seam which is enriched in these elements. IntroductionCoal is a sedimentary rock of plant origin and consists of two components: an inorganic component (minerals) which is formed by influx of clastic sediments into the coal-forming environment and also by activities of groundwater, and an organic component (macerals) which is formed from plant debris deposited in the original coal-forming environment. However, coal is a generic term with a broad range of utilization characteristics. A coal that is attractive for use in one market - such as generation of electricity (combustion) - may not necessarily be acceptable for use in another, such as for production of coke (Davis, 1978).The elements in coal are associated with both macerals and minerals. The elements associated with coal macerals, such as C, H and N are termed elements with organic affInities. The concentration of elements with organic affmities (including B, Br, CI, F, I, S, and Mg) often decrease with increasing ash content of coal (Nicholls, 1968; and Finkehnan,1982). FIgure 1 shows such a trend for chlorine. Some of these elements may also be incorporated in coal maceral as very fine mineral grains (Finkelman, 1982). The elements with organic affmities are often volatilized during combustion and carbonization of coal and emitted in the vapour phase. Emission of some of these elements (C, 0, Br, N and S) is of major environmental concern (Lim, 1979)."

Jan 1, 1994

By C. Desmeules

"Carbon addition in the oxide pelletizing process is a big concern at the Sidbec-Normines pelletizing plant since 1976.Laboratory pot-grate testing carried out before the initial start-up of the Port-Cartier plant indicated that the nominal pelletizing grate capacity could be increased by fifteen per cent with a suitable carbon addition. Also an improved induration cycle offered the possibility of a significant energy reduction within the process with no adverse effect on pellet quality. A one-month plant scale program duplicated the lab test results and confirmed the anticipated cost saving by using these techniques. Since March 1980, Sidbec-Normines used coke addition as a current operation.This paper reviews briefly earlier laboratory and in-plant test work carried out to investigate the effects of adding carbon materials to the Fire Lake hematite concentrate, and presents operation techniques and plant results of carbon addition in the Port -Cattier pellet plant.IntroductionThe Sidbec-Normines pelletizing plant at Port-Cartier, Quebec, is designed to produce six million ton s per year of oxide pellet s. It is a Dravo-built two-line plant; one line to produce three million s tons per year of blast furnace grade pellets averaging 5.5 per cent silica, and another line of three million ton s to produce direct reduction grade pellets of about 2.0 percent silica.The laboratory pot-grate test program was conducted in 1977 at the British Steel Corporation Research Laboratories in England, with the assistance of J .E. Appleby, consultant to British Steel Corporation (overseas services) Limited.The purpose of that test program was to determine the optimum energy saving cycle and to study the physical and metallurgical effects on blast furnace and direct reduction pellets."

Jan 1, 1983

By A. David MacPhail

"Highland Valley Copper is a large volume producer of copper and molybdenum concentrates. Production is by conventional truck and shovel operation combined with an extensive ore handling in-pit crushing and conveying system.Grade of the two orebodies is low at 0.4% copper and 0.007% molybdenum and this demands a production rate in excess of 260 000 tpd at a stripping ratio of 1: 1. Mining cost has to be kept at minimum levels to keep the mine profitable and thus, it is necessary to keep in the forefront: of technology. As well as the in-pit crushing system, the mine has pioneered the use of shovel weighing coupled with a state-of-the-art dispatch system.Maintenance of the equipment is carried out at the on-site mine maintenance shop with assistance from local shops for engine and wheel motor rebuilds and other large jobs such as those requiring stress relieving. Shovel and truck rebuilds are undertaken by mine crews. Both long- and short-term planning is designed and scheduled in the mine engineering section. Outside consultants are used to assist in slope design, reclamation and blasting technology."

Jan 1, 1992