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By Christopher R. Davis

Resource modelling is the basis for any economic appraisal of a mining project and includes a number of steps from data acquisition and validation to resource reporting and classification. At each step in the modelling process it is necessary to define the specific objectives, the methodology proposed to achieve those objectives and to establish a set of checks and validation tools to assess the effectiveness of the proposed methodology. The data used has to be both reliable and relevant for the purpose of the modelling. QA/QC for database validation requires verification of sample location; including correct collar location, topographic modelling and down-hole surveying. Validation is also performed on assaying information such as checks for sampling bias and accuracy of core splits, proper use of pulp duplicates and standards, handling of calculated values, explicit/implicit absent data and data entry errors. The second step involves identifying the mineralized domains resulting from the mineralization process. This step requires a geometric interpretation of all relevant geological features that have influenced the spatial distribution of the mineralization including dykes, faults and alteration. In addition, a geologic reference system rather than a standard Cartesian system is established to measure distances between samples. Once the mineralized domains are established and the database has been validated, statistical and spatial description of the mineralized samples are examined in order to establish the histogram and the variogram of all variables of interest and their correlation. Results are also used to calibrate the global resource estimate within the mineralized domain and to establish the search strategy for grade interpolation. The mineral envelope is filled with polyhedral cells representing mining blocks. The average grade of these blocks is estimated using kriging techniques in order to eliminate global bias and to minimize the local error in the block grade estimate. Visual checks are made to validate the spatial trends in grade distribution while global bias and smoothing effect are assessed from the declustered sample statistics. When required, smoothing correction may be applied using ?change of support? techniques. Simulations are used to perform sensitivity analysis and the simulation models are used if severe smoothing of spatial variability makes the interpolated model inappropriate for mine planning. The keys to successful resource estimation are an integrated team of geologists, geophysicists, geostatisticians and mine engineers using the best available technology and reviews by independent auditors. The resource team is also responsible for performing a QA/QC program in order to measure the effectiveness of the methods in meeting the specific objectives at each step of the modelling process.

May 1, 2001

By P. Maltais

Over the last 10 years, Computer Aided Design, Finite Elements Analysis and field testing of prototypes have enabled the cycling industry to grow and to significantly improve its products. However, today's cyclists have become more and more demanding, making these classical design approaches almost obsolete. Devinci understood that problem four years ago and fully revisited its design approach; to offer bicycle frames better suited to real life riding, one must fully know those real life conditions. In partnership with the University de Sherbrooke, Quebec, Canada, Devinci then developed a bicycle enabling them to measure the actual load applied on a bicycle frame in real-time for real riding conditions: the instrumented bike. Today, Devinci uses its instrumented road and mountain bikes, combined with virtual prototyping and laboratory testing capabilities to develop better bicycles, faster.

Jan 1, 2006

By V. I. Lakshmanan

Rare earth elements and yttrium (REEs+Y) are being used in the making of hybrid electric cars, catalytic converters, wind power generators, LEDs, hard disc drives, flat panel displays, and portable electronics. Currently China produces more than 95% of REEs+Y, which has made REEs+Y a critical strategic resource. Process Research ORTECH Inc. (PRO) has developed the innovative mixed-chloride (HCl+MgCl2) solvent extraction processes for recovery of REEs+Y from their ores. The HCl leaching system provides the opportunity to regenerate the acid, while the presence of MgCl2 in the lixiviant enhances the activity of the hydrogen ion by orders of magnitude, making the lixiviant very aggressive and resulting in high recoveries of REEs+Y. Solvent extraction steps are used for separation and purification of REEs+Y from other value metals or impurities including iron, zirconium, hafnium, uranium, thorium, niobium, tantalum and titanium. Direct individual separation of REEs+Y in a mixed chloride system allows avoiding the additional process steps of precipitation and dissolution in HCl. The resulting process has a simplified flow sheet that is closed-loop and environmentally friendly.

Jan 1, 2014

By D. A. Beattie

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined using ex situ depletion techniques and in situ ATR-FTIR spectroscopy has been used to determine adsorption kinetics. Adsorbed layer thicknesses have been determined for the polymers on cleaved talc surfaces using the AFM. The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.

Jan 1, 2006

By M. Sukhram

This paper presents a technique to determine the direction of velocity in liquid aluminum (Al) by measuring the temperature distribution within a cylindrical rod while it is inserted into the flow. The heating pattern of the rod is a result of the interaction of the thermal fields of the rod with the liquid Al. This interaction freezes aluminum onto the cylinder in a characteristic pattern and as a result the temperature response within the rod also follows a distinctive heating pattern. Monitoring the temperature within the cylindrical rod as a function of spatial and temporal coordinates, the direction of velocity can be inferred. Experimental research work involving liquid Al was conducted at the University of Toronto using the Revolving Liquid Metal Tank (RLMT). The RLMT is a resistance furnace which can hold up to 50kg of liquid Al. In this RLMT tangential velocities up to 0.35m1s can be generated. Experimental data for different superheat and magnitude of velocity demonstrate that the sensor records different heating patterns under different fluid flow conditions. Using the transient temperature information, the direction of velocity of the molten Al flow field can be detected.

Jan 1, 2011

By Jose Alberto Gonzalez, Said Sharif Mahboob, Jeffrey L. Shepherd

"During the industrial electrowinning of zinc, uneven growth can cause short-circuits and make the deposits more sensitive to the presence of impurities that can significantly impact current efficiency. To produce levelled zinc deposits, additives such as glue, licorice and sodium silicate are often added to the electrolyte. Even in the presence of additives, uneven zinc growth still takes place because of the combination of hydrodynamic and electrolysis conditions in the cell house. Recent advancements in imaging spectroscopy and scaling analysis have opened an avenue to further study the effects of additives on zinc growth morphology. In this study, Atomic Force Microscopy (AFM) and scaling analysis have been used to monitor zinc growth characteristics including roughness, periodicity, aspect ratios and growth mechanisms as a function of electrolyte composition as well as deposition time. Zinc was electrodeposited from an industrial electrolyte containing a host of additives onto an aluminum cathode with a platinum wire serving as the anode. AFM images of the samples were collected to obtain 3D topographical information on which scaling analysis was performed to extract details on root-mean-squared (rms) roughness, periodicity (grain size), aspect ratio of surface features and growth mechanism. This analysis provided information on the mechanism by which the previously mentioned variables can impact short term growth and also provided a prediction of expected growth at long deposition times.INTRODUCTIONElectrowinning is one of the final stages in the industrial production of zinc metal. It is during this process where dissolved zinc ions undergo electro-reduction from an acidic electrolyte onto an aluminum cathode and are later recovered by stripping the zinc metal from the substrate. However, due to the nature of zinc growth as well as the various operating conditions, zinc deposition may occur unevenly, sometimes causing short-circuits that can cause electrode damage and reduced zinc production."

Jan 1, 2016

By Amir Karami, Derek Kinakin, Catherine Schmid

The Mathews Stability Graph Method (Mathews et al., 1981) has been used by geotechnical engineers and mining engineers for over 40 years to estimate the performance of longhole open stopes in underground mines. The method is widely used and accepted by practitioners because it is relatively simple to use and can be modified to account for observed performance at a given mining operation. While the simplicity of the method increases its accessibility and utilization, it does not intrinsically account for variability in the various inputs, including rockmass quality, structure, stress, or stope orientation. This paper presents a modified approach for the Stability Graph Method, whereby Python scripts are used to process available geotechnical datasets and combine them with actual or potential distributions of Q parameters, induced stress, structure, or stope orientation. The resulting Stability Numbers are then plotted as a contoured distribution on the Stability Graph.  This allows the practitioner to quickly incorporate large datasets into the analyses, while also developing an understanding of how variability in rockmass quality, induced stress, structure, or stope orientation could affect stope stability.  This paper presents the fundamental principles of the Stability Graph method, the Python script and workflow, and two case studies to demonstrate the utility of the tool.

Oct 1, 2024

The control of carbon concentration in a counter current carbon absorption circuit is critical to optimise gold recovery. MINTEK has developed a carbon movement controller to address this potentially problematic area in gold extraction. This controller reduces operator interaction by automating carbon movement. Elution schedules are entered into the control system, which then moves the carbon through the circuit into the first adsorption tank until enough carbon is available for elution. This is done while maintaining the specified carbon profile within the circuit. MINTEK has also developed an online-carbonconcentration- meter to measure carbon concentration in pulp. The meter uses an ultrasonic measurement technique. Long term testing has shown the measurement to be robust and require minimal maintenance. Results from a gold mine in South Africa’s well known Witwatersrand gold producing area has shown a decrease in soluble gold loss between 30 - 50% when the controller was used.

Jan 1, 2014

By T. B. Williams

Most geologists have felt the need of a longer base than is ordinarily available when using a Brunton compass or other convenient instrument for taking strikes and dips in the field. To overcome this difficulty a lath or stick with straight parallel sides is frequently used. This accessory adds to the accuracy of the work, but it is a decidedly inconvenient one for the geologist to carry, especially if he be heavily loaded or is travelling on horse-back or through thick brush on foot. The writer has abandoned its use in favour of a sturdy two-foot carpenter's rule. The rule preferred is manufactured by J. Rabone and Sons, Birmingham, England. It is provided with a good level-bubble set in one of the limbs, and a scale, of the protractor type, graduated to five degrees through 180 degrees, attached to the main joint at the middle of the rule. (See Figure 1). For an instrument of its kind it is very accurate, and, in addition to the uses mentioned below, it 'is a handy thing to have around any camp. It is frequently used when plotting roughly in the field and for a protractor when one is not available. When not in use it may readily be carried in the top of the high-boot or legging. Ordinary strikes are measured as illustrated in Figure 1, the compass being held against the rule, which is in a horizontal position. Dips may be measured in a corresponding way by holding the Brunton compass against the extended rule, which is thus used merely as a straight edge. It is usually much more convenient, however, to ? use the rule only for this purpose, in which case one foot of the length rests as a straight-edge against the rock surface. This adaption is shown in Figure 2.

Jan 1, 1929

By M. A. N. Rosa, L. C. R. Machado, R. A. Fonseca, A. M. Mendonça

"Sossego Mine was the first Vale SAG mill operation to process copper-gold ore. It is located in the state of Para, in the south-eastern Amazon region of Brazil. In the first six years of continuous operation, Vale investigated different alternatives for improving circuit performance by investigating operating conditions, mainly focusing on the SAG mill.Today, after a steady increase over five years the annual production rate seems to have stabilized. It is hoped this work will show how the SAG operating practice have been perfected with time and as new data are collected. Historical data of mill grind-outs and crash stops helped create operation curves depending on the ball charge volume and total charge volume. Also noted were impacts on throughput due to the effect of reducing liner weight and the ore type characteristics."

Jan 1, 2012

By D. Larouche, M. Mardan

Hot tearing is a complex defect in aluminium castings which is produced during solidification when a certain amount of liquid phase remains and weakens tensile resistance of the alloy. In direct chill casting of aluminium alloys, hot tears initiate at the surface of sheet ingots just after the primary cooling zone, where the microstructure is particularly vulnerable. In order to study the hot tearing susceptibility of these alloys, and the effect of grain refiners on their thermo-mechanical behavior , tensile tests were carried out in the semi-solid state ( ~95% solid) and at low strain rates using an apparatus called DCSS, for Direct Chill Surface Simulator. This apparatus, originally developed at Alcan Arvida R&D Centre (ARDC), is an instrumented rig test reproducing the conditions prevailing during the primary cooling stage of the DC casting process. The mechanical behavior of solidifying shells and the hot tear formation under applied tensile loads were measured and the occurrence of hot tearing was observed. Temperature in different locations of the casting, applied load and surface strain were monitored during the tensile tests conducted on aluminum alloys AA5182, AA6111 and AA3104. The microstructure of the tested samples was examined using the optical microscope to evaluate their columnar or equiaxed aspect and their effect on the mechanical response of the alloy. A special emphasis has been given to the evaluation of fractions solid existing in the castings at the start of the tensile tests, taking into account the local temperature, thermal gradient and cooling rates experienced. It was found that excessive grain refiner additions decreased the strength of solidifying shells because of the increased level of porosity induced by easier nucleation of new phases (gas included). It was also observed that cooling rates increased with the level of grain refiner, a phenomenon that was associated to the higher number of contact points obtained with small equiaxed grains. Finally, the concept of a stress based criterion for hot tearing was reinforced by the strengths obtained on not grain refined AA5182 and AA6111 showing similar fraction solid near the surface, but significantly different grain sizes.

Jan 1, 2006

By G. Szilvay, P. Kinnunen, J. Salminen, V. Miettinen, O. Salmi, J. Mäkinen

This paper demonstrates experimental studies on bioprocessing of different waste streams. In Part I of this paper three tailings from mining industry were bioleached with mixed acidophilic culture in order to solubilize valuable metals, like copper, nickel, zinc and manganese to leaching liquor. Bioleaching resulted in > 70 %, > 85 %, 100 % and > 70 % leaching yields for Cu, Ni, Zn and Mn, respectively. However, contaminants like arsenic and chromium were not leached efficiently and they will cause challenges in residual solids and sometimes also in metal recovery from leaching liquor. Bioleaching resulted in 99 % leaching yield for copper. Part II demonstrates mine water treatment and also gold recovery from process liquids with biosorption method. The novelty of biosorption was finding that certain fungal species were able to be cultivated to self-immobilized systems, which are easier to operate than traditional suspended biomass methods. Biosorption resulted in more than 90 % removal for all contaminants, but was also seen to be gold selective.

Jan 1, 2014

By M. Abdollahi, M. R. Khalesi, Y. Kianinia, A. Khodadadi Darban

High cyanide consumption during the processing of gold ores with high sulphide minerals can make the typical cyanidation uneconomic. Also cyanide is a toxic material and environmental concerns of cyanide compounds are serious. Optimization of cyanide consumption requires a methodology to estimate the amount of exposed cyanicides, the kinetic of their dissolution and estimation of formation of cyanide complexes which consume the free cyanide. In this paper, a methodology to estimate cyanide consumption by modeling the minerals and gold leaching kinetic based on a liberation model and speciation of all possible cyanide related species in the solution is presented. The results showed that this methodology could successfully estimate the cyanide consumption based on mineralogical data with very lower number of parameters compared to empirical models present in the literature, while it offers the prediction of formation of all cyanide complexes which could be used for optimization purposes.

Jan 1, 2017

By K. Johanson, M. Hubert, C. Eckert, D. Ghose

The mining industry routinely processes material with different particle sizes. Coal, nickel ore, copper ore, lignite, shale, and phosphate ore are all examples of materials with wide particle size distributions. It is often assumed that these materials are homogenous and that any particle size distribution has the same chemical activity and composition. It is entirely possible, and quite likely, that chemical composition is a function of particle size distribution. In addition, particle size distributions in ore materials are often responsible for the difference in flow behavior in process equipment. This is evident in coal electrical production facilities. Fine coal may have the same ash content, sulfur content, and BTU value as coarse coal. However, all electrical production facilities know the extreme flow problems that result when attempting to handle wet fine coal. Segregation of these bulk materials is an important issue that must be understood to prevent these cohesive flow problems. Additionally, fertilizers are mixtures of particles with different shape and sizes. These mixtures must remain homogenous to optimize fertilizer performance. Segregation leads to poor product quality. This paper presents a method of measuring the magnitude of sifting segregation occurring in bulk material and the relationship between the strength of the bulk material and the separation tendency. It shows an inverse relationship between the yield strength of the material and the bulk segregation.

Jan 1, 2004

By Jean-Pierre Birat, François Hanrot, Gérard Danloy

Global warming presents an enormous challenge to the steel industry, which is both carbon-intensive and energy efficient. Lean production can provide some short-term emission mitigation, at the level of the Kyoto requirements. In the middle term, more use of scrap will also help alleviate emissions. But to reach much larger reductions in GHG emissions, on a par with the likely targets that will be set after the Kyoto period, the steel industry will have to imagine new production paradigms, which constitutes its most formidable challenge for the years to come. Carbon capture and sequestration, processes leaner in carbon use, electricity and hydrogen from green sources will have to be added together in a patchwork of process routes, which will have to be developed at great risk in the next decade, hopefully through broad international cooperation.

Jan 1, 2004

By C. O. Staples, J. G. Morrow

The application of cationic flotation to the upgrading of magnetic concentrates was investigated in the laboratory by both batch and continuous test procedures. It was found that the collection of coarse gangue particles with amine, heretofore considered a serious obstacle to this particular application of cationic flotation, is greatly enhanced by a drastic reduction in what might otherwise be considered normal impeller speed. Gangue flotation is in-dependent of variations in the rate of aeration. The collector and Crother additions and the impeller speed which favour the formation of a matte froth yield optimum results.

Jan 1, 1966

By R. K. Singhal

"On the mining side the Canadian oil sands industry has become proficient in excavation and disposal of ore and overburden. Nearly twenty years of mining experience is now behind this industry. While local improvements to existing mining systems and practices will continue, it is believed that some further gains in productivity can be achieved by selectively introducing new ideas from other mining and non-mining industries. This type of technology transfer is vital for over-all cost-effective technology enhancement of oil sands mining operations.Discussed in this paper are the issues of mining equipment, equipment sizing, microprocessor and computer based technol¬ogy as applied to mine-wide data management, automation and remote control and a projection of likely mining systems in the year 2000!This paper reviews the ""state-of-the-art"" in selected surface mining systems and attempts to evaluate the forthcoming technology and its application."

Jan 1, 1989

By Rebecca L. Jones

The paper addresses the application of XPAC AutoScheduler at the Fort Hills Energy Oil Sands Project to complete fast turn around ?what if? scenario testing of different mine schedules. Traditional scheduling approaches involve engineers making a ?best guess? at the required mining sequence, loading this sequence into a scheduling package and testing the results to determine if the schedule meets corporate objectives. This process is iterative and can be very time consuming. Autoscheduling techniques, on the other hand, are based on the engineer pre defining the mining rules and constraints of the deposit. The software then automatically selects a sequence of mining which the schedule should try and achieve, based off specified corporate objectives. Under this system the engineer is able to adjust the objectives and rules to evaluate numerous scheduling scenarios quickly and easily. An XPAC AutoScheduler model was built, documented, and implemented by Runge and Petro-Canada Oil Sands Inc. personnel in a month. It is currently being used by Petro-Canada Oil Sands Inc. to run multiple schedule scenarios, most taking less than ten minutes configure and ten minutes to schedule. The results of each schedule are tabulated with supporting graphs on; the bitumen grade profile, strip ratio, ore inventories and mined tonnage. In addition to this, the block model may be animated to show the progression of the resources mining the schedules.

May 1, 2008

By C. Bernier

This paper deals with three major problems associated with mining operations during the winter. These are the maintenance of the cooling systems of diesel engines, the high incidence of hydraulic dump failures on packaging machines, and the build-up of frozen fines on wet-ore conveyor belts.

Jan 1, 1966

By The Staff

"SummaryDetermination of uranium in ores may be made by measurement of their radioactivity.The method most commonly used is that of measuring beta radiations with the tray-type beta counter. This will give an accurate uranium determination provided the sample does not contain thurium and that the beta and gamma activities have not been disturbed from their natural state of equilibrium. Such a loss of equilibrium will result from mining the ore or from the weathering of the surface rock.A method is described which eliminates errors due to loss of equilibrium. The beta and gamma activities are measured simultaneously in one simple operation. This method is recommended for assaying samples of products from milling operations and its use is limited only by the presence of thorium in a ratio greater than one part of thorium to twenty parts of uranium.A third method is recommended for the analysis of exploration samples and diamond drill cores, which may be assayed in the uncrushed state.Rapid determinations of a large number of samples is possible with the pressure ionization chamber, which is sensitive to gamma activity."

Jan 1, 1950