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By W. L. Strand, D. N. Madge

"Experimental and pilot operations in bituminous sand processing require due care and attention in the design and analysis of measurement programs. This paper deals with a case study in experimental design and data analysis for a series of experimental campaigns that have been conducted over the past five years by Kilborn Western Inc., acting on behalf of Bitmin Resources. Beginning with the design of the experiment and following into the use of linear and nonlinear regression models, the phenomenology of bitumen extraction is illustrated. The final testing program tested 13 oil sand types as well as a wide range of process variables for all the unit operations of the complete process.The program was successful in developing process fundamentals and scale-up criteria. Several phenomenological models were proposed and tested. Their range of applicability was explored. This paper illustrates the range of applicability of these models and discusses the development of alternative models.IntroductionOver the past five years Kilborn has conducted a series of bench scale and pilot scale experiments designed to explore the phenomenolgy of a new concept in medium temperature processing of bituminous ores. These experiments at feed rates ranging from .1 to 24 t/h were conducted on water wet sands from the .Athabasca region near Fort McMurray. They were based on experimental designs chosen to provide a systematic means of identifying the response surfaces of the process over a range of conceptual designs. The following diagram shows the experimental arrangement:"

Jan 1, 1998

By O. Laitinen, M. Rudolph, J. A. Sirviö, H. Liimatainen, R. Hartmann, University of Oulu

The increasing complexity of the ores composition worldwide calls for suitable collectors with specific properties, such as selectivity, wettability, and in regard to current regulations, environmental sustainability. Therefore, collectors have to satisfy many features to improve the efficiency of flotation processes. Cellulose nanocrystals gain more and more interest due to the versatile synthesis routes which enable the integration of specific functional groups and components with different degrees of hydrophobicity within the molecular structure. Consequently, cellulose nanocrystals can be employed in flotation processes as depressant or collector molecules, respectively. Nonetheless, the usage of cellulose nanocrystals is still limited due to a lack of the characterization of nanocrystal-mineral interactions and the change of the surface wetting properties of minerals after adsorption phenomena between nanocrystals and minerals. In these studies, butyl-amine cellulose nanocrystal (BAC) and quartz are used as model system to investigate physicochemical properties of both, BAC and quartz, and examine the applicability of BAC in flotation processes. Therefore, the surface charge distribution and electrophoretic mobility of BAC and quartz are investigated and compared to understand the effect of electrostatic interactions between BACs, and BAC and quartz. Based on this, the adsorption of BAC on quartz is examined. Finally, microflotation experiments test the efficiency of BAC to be used in flotation processes. The flotation response is correlated to the specific surface charge of BAC revealing the dominant effect of surface charges on effective particle-bubble adhesions.

Jan 1, 2016

By A. L. Valdivieso

"The correlation obtained by plotting pH of maximum adsorption of dextrin versus the isoelectric point of involved metal hydroxides can be used to predict the depressing effect of dextrin on flotation in ""pure"" sulfide mineral systems. Sulfides are strongly depressed by dextrin whenever their surfaces are coated by the corresponding metal hydroxide. The efficiency of dextrin as a depressant is affected by the adsorption of the sulfhydryl collector. Hydrolyzable cations modify this relationship in flotation of sulfide ores. This type of deviation of the real-life systems from the predictions based on the behavior of the pure systems shows the possible ways that could be followed to further improve the obtained correlations. Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by"

Jan 1, 2009

By R. S. Forgan

The synthesis and study of a systematic series of phenolic oximes have shown that substitution in the 3-position can greatly affect extractive efficacy. Solid state, solution and gas phase analytical techniques, including X-ray crystallography, EPR and IR spectroscopy and collision induced dissociation mass spectrometry have been assessed for their applicability in interpreting the origins of differences in extractant strength. The dominant substituent effect on pH0.5 is the change in ligand pKa, with the more acidic ligands being stronger extractants. The influence of the 3-substituent on the stabilising intracomplex H-bonding of their copper(II) complexes also affects extractant strength. The 3-NO2 substituted ligand shows the lowest pH0.5 value, due to a combination of its low pKa and a stabilising bifurcated H-bond assembly around the copper(II) centre. Appending an aminomethyl group to the 3-position gives a ligand capable of binding a metal and its attendant anion. These metal salt reagents show potential to open up new flowsheets for the processing of high tenor copper feeds.

Jan 1, 2007

By E. Quaquero

This article reports on the current state of an ongoing research project which is aimed at implementing intelligent models for hardly predictable hazard scenarios identification in construction sites. As past evidences showed that no programmatic action can deal with the unpredictable nature of many risk dynamics, we tried to survey on how the current approach for safety management in the construction industry could be improved. In our previous research the use of Bayesian networks elicited from subjective knowledge were preliminarily tested. Those networks might be meant as a reliable knowledge map about accident dynamics and they showed that a relevant ratio of occurrences fall in ?hardly predictable hazards? class, which cannot be warded off by programmatic safety measures. This paper reports the second outcome of our research project, which focused on the development of first elementary fragments, regarding the occurrence of a possible ?hardly predictable scenario?. Instead of experts? contributions (who, over their carrier, seldom incurred in accidents), we used ?legal cases? as an accurate source of information. They suggested which categories of ?hidden hazard scenarios? are more likely to happen. We found that the most frequent hidden hazard scenarios are linked to operator?s negligence and abnormal behavior, e.g. irregular removal of scaffolding?s components, unprotected openings, improper use of PPE, etc. Every pattern determined by legal cases has been formalized by a fragment (i.e. elementary network) of the overall Bayesian network. Finally, all the elementary networks were integrated into a comprehensive intelligent tool for realtime hardly predictable hazards prevention. The final setup, asked for interfacing these intelligent models to a low-level sensor network and used to feed them with inputs about the current state of the context, is discussed too.

Aug 1, 2013

Delivering Our Products On any given day in North America, 80 kilometers of rail cars are engaged in moving our product. Global Customer Base Our business accounts for more than 30% of all bulk goods moved through the Port of Vancouver

May 1, 2006

By John D. Carriere, Jean Leung, Daniel. Laguitton, Michael .. J. Burrows

"The objective of this expert system application in a copper-zinc concentrator, is to increase the availability of assay data through substitution for erroneous data. The assay data is used by the Operations personnel and automatic process control strategies to control flotation circuit performance. Two online X-ray fluorescence analysis systems analyze 24 streams across four divisions to provide the required data. Data availability of individual streams average 90% while the resulting circuit availabilities are 70%. The unavailability of correct data results from mechanical, X-ray or process problems. The erroneous data can be identified by process experts using knowledge relating stream interdependencies and historical process behaviour. An expert system was devised to provide real time identification of erroneous data and substitute for that data with the ultimate aim of improving metallurgical response by both the operator and automatic control systems.The paper discusses the early development work and architecture of the knowledge base designed using Neuron Data's expert shell NEXPERT.INTRODUCTIONThis paper describes the early development of an expert system (ES) prototype at the Kidd Creek concentrator. The project is a joint undertaking of the Kidd Creek Division of Falconbridge Limited and CANMET. Kidd Creek entered into the project to apply heuristic rules to the XRF assay data to improve the metallurgical control of the flotation process by increasing availability of analysis data. This project provided a problem of suitable size and future expandability while making use of a wide base of in-house expertise and experience. Another important benefit is the introduction of expert system technology to the site providing tools and experience for future system selection and technology application. CANMET has an on-going interest in assessing various aspects of ES technology (hardware, software, knowledge engineering, integration) while addressing problems in process operations that could most readily benefit from the technique. CANMET's role in the project was to provide project assistance, financial support, substitution algorithm assistance and software for data substitution. The knowledge bases (rules) have now been completed and are to be tested in the online environment."

Jan 1, 1989

By J. Bouchard, R. del Villar, A. Vazirizadeh

"Industrial flotation is a continuous and often multistage process, where particles of a given mineral species (usually the targeted one), present in different sizes, encounter a large amount of gas bubbles (normally air) to produce mineral–bubble aggregates, which are removed from the flotation device (cell or column) as a valuable product (concentrate). The bubble content inside the cell is characterized by the prevailing hydrodynamic conditions (known as gas dispersion variables), which in turn are known to influence the flotation performance. Although most researchers and practitioners agree that the relationship between the hydrodynamic variables and flotation performance exists, the lack of an adequate method foronline measuring the average bubble diameter has prevented such studies.The aim of this study is to apply appropriate hydrodynamic variables for flotation kinetic modeling (as a key feature of flotation performance) for a given introduced particle size distribution (PSD). In this regard, experiments were conducted in a laboratory flotation column (5.6 cm internal diameter for a total height of 650 cm), and mixtures of quartz (hydrophilic gangue) and talc (naturally hydrophobic mineral), classified in four different size fractions. The correlation between the flotation rate constant and given hydrodynamic variables were analyzed. Results suggest that the relative importance of hydrodynamic variables for flotation rate modeling depends on the PSD. Finally the suggested hydrodynamic variables for each of the various particle size-classes considered were used to produce single variable models for the flotation rate constant. INTRODUCTIONIndependently of the prevailing flotation conditions, the mechanisms for bubble-particle aggregation and the residence time of the phases inside the device must also be considered. In this regard, one of the most used approaches to represent the overall flotation process is as a pseudo-chemical reaction between a particle and a bubble, whose rate (at a given time) is proportional to the amount of remaining floatable species. The proportionating constant is called the kinetic constant or the flotation rate constant."

Jan 1, 2016

By Don Ritz

Smart leaders focus on safety even in tough times. Businesses that retreat into survival mode and ignore safety do so at their peril, risking loss of employee and stakeholder confidence and exposing themselves to financial and reputational loss they can ill afford. It?s a moment of truth when employees and stakeholders learn whether safety is truly your priority or just a convenient cliché for good times. Visionary leaders who build safety culture even in a downturn maintain people?s trust, prevent loss, and position the organization for enhanced success as times improve. Safety is the right business focus in good times and bad.

May 1, 2009

By S. Orr

In situ leaching is a complex, multidisciplinary process, which requires both mastering and integration of the different disciplines involved. Particularly, in-situ leaching is the intersection between geology (geochemistry, mineralogy, structural geology), hydrology (hydrogeology, well hydraulics), metallurgy (hydrometallurgy, electrochemistry, aqueous chemistry), and economics (mineable ore, cost of operations, market). The management of such a complex system requires all relevant knowledge base, integration, and continual optimization. Our presentation starts with a description of the "expert system" ? from data acquisition to information and knowledge, including determination of essential in-situ parameters, analyses, and modeling, which ultimately leads to an integrated, real-time, hierarchical management/control system.

Jan 1, 2007

By W. M. Silva, PAP. Miotto, M. A. P. Silva, V. P. Ramos, L. R. M. Bittencourt

The major cause of breakdown of anode baking furnace fluewalls is chemical corrosion, which leads to deterioration of the properties of the bricks. Subsequent deformation of the fluewalls occurs, and also extensive cracking of the lining is observed. The present work studies the major changes of the brick during the operation of the furnace, after 22, 60 and 90 cycles of baking; in two different regions: upper and lower. Due to excellent cleaning conditions of the butts, negligible amounts of fluorine were found in the bricks. The major contaminants found were carbon, sulfur and alkali compounds, all of them present in the anode baked during the process.

Jan 1, 2004

By Simon Weixiao Sun

Conventionally, carbon steel has been the primary material for salt mine headframe construction, protected by specialty paint layers to prevent corrosion. These layers require meticulous QA/QC during fabrication and erection, and the top UV protection layer typically loses effectiveness after an average of 10 years, necessitating ongoing maintenance. As headframes age, significant structural repairs are often required. Alternatively, stainless steel can eliminate corrosion concerns, though its high initial cost has limited its use in headframe design. However, when factoring in long-term maintenance costs, a 'maintenance-free' stainless steel headframe can be an attractive option for stakeholders. This paper compares the structural performance and economic considerations of painted carbon steel and stainless steel headframes, including initial capital and long-term maintenance costs. Additionally, it explores a hybrid approach, strategically using carbon steel in low-contamination areas to reduce initial costs and significantly minimize future maintenance efforts.

May 4, 2025

By F. Sheykh-Jaberi, S. L. Cockcroft, A. B. Phillion

A coupled fluid/structure model has been developed to simulate semi-solid deformation in an industrial aluminum casting alloy, A356. Although this alloy has a significant eutectic fraction, nearly 50%, it still shows susceptibility to hot tearing. The model geometry consists of solid grains, created from a Voronoi tessellation of the domain, surrounded by liquid. The simulation is performed using the commercial codes, Abaqus Standard and Abaqus CFD. The solid model calculates the velocity, stresses and distortions in response to an applied uniaxial strain, and transmits them to the fluid-flow model, which computes the velocity and pressure fields in the liquid. It was shown that grain size and configuration, fraction solid and fluid properties all affect the semi-solid deformation behaviour.

Jan 1, 2014

By O. G. Olvera, D. G. Dixon, E. Asselin, L. S. Quiroz

Dissolution rates of chalcopyrite (CuFeS2) were calculated using electrochemical impedance spectroscopy (EIS). The calculated dissolution rate decreased by a factor of 3.2 after the electrode was passivated. The results presented in this work indicate that the reduction of Fe3+ was the rate-controlling step for fresh CuFeS2 electrodes while the transport of cations within the passive film limited the dissolution rate for the passivated electrode. The transfer of cations at the electrode/electrolyte and passive film/electrolyte interfaces did not affect the dissolution rates of the fresh and passivated CuFeS2 electrodes, respectively. The catalytic effect of pyrite (FeS2) on the dissolution of CuFeS2 continued after the passivating treatment. The contact of fresh and passivated CuFeS2 electrodes with different FeS2 particles resulted in increased dissolution rates, due to an increase in the reduction rate of Fe3+.

Jan 1, 2014

By R. Chen, K. Xia

In deep mining activities, blasting induced compressive stress wave would be reflected as tensile wave at a free surface around the openings, which would facilitate the tensile failure of the deep rock since it is much weaker in tension than in compression. It is thus critical to understand the dynamic tensile failure of rocks subjected to static tension for deep rock engineering applications. A modified split Hopkinson pressure bar (SHPB) system is adopted to load Brazilian disc (BD) samples statically, and then exert dynamic load to the sample through stress wave generated by impact. The pulse shaper technique is used to generate a slowly rising stress wave and thus to facilitate the stress equilibrium of samples during each test. Five groups of Laurentian granite (with tensile strength of 12.8 MPa) BD samples under the pretension stress of 0 MPa, 2 MPa, 4 MPa, 8 MPa, and 10 MPa are tested under different loading rates. The result shows that the dynamic tensile strength of the rock decreases with the increase of pre-tension stress, which is easy to understand because pre-tension stress weakens the rock sample. It is also observed that under the same pre-tension stress, the dynamic tensile strength increases with the loading rate, revealing the so-called rate dependency that is common for engineering materials. Furthermore, it is found that the loading rate sensitivity of the rock increases with the increase of pre-tension stress. A qualitative explanation for this phenomenon is that more microcracks are generated and activated under higher pretension stress, resulting in a more viscous material. Based on the results, an empirical equation is proposed to fit the data and explain the dynamic tensile behaviour of rock under pre-tension stress. A physical model is used to simulate the dependency of the dynamic tensile strength of rock on the pre-tension stress and the loading rate, which is shown to be in good agreement with the experimental results.

Jan 1, 2015

By J. Paraszczak

Application of teleoperated and automated (or ?autonomous?) mobile equipment in underground metal mines represents a promising avenue for overcoming some of the challenges facing the industry. This paper addresses the overall effectiveness of autonomous loading and haulage equipment compared with conventional human-operated machines. Factors affecting availability, utilization, and production rate are explored, and an emphasis is placed on some problems and risks not present in conventional human-operated systems, as well as on the character and criticality of autonomous equipment. The need for a more in-depth analysis of factors affecting overall autonomous equipment effectiveness is stressed; these factors should be taken into consideration at the stage of feasibility studies. The paper concludes with recommendations and directions for future research.

Aug 1, 2010

By G. Kipouros, M. Dadvand, A. Dadvand

"A novel methodology was developed to obtain a 3D porous layer with a high aspect ratio of porosity on a titanium electrode. The porous structure allowed more active material such as hydrous ruthenium oxide to be accommodated during the fabrication of the supercapacitor, resulting in an exceptionally high capacitance per surface area. The electrode demonstrated a remarkably high capacitance of 4,800 mF/cm2. The porous layer was composed of functionalized nanoparticles of TiO2 organized in a perfect 3D hexagonal close-packed array that resulted in a highly porous 3D structure. The layer was used as a template to electrolessly deposit a thin layer of silver prior to the electrodeposition of active material. KEYWORDS Capacitance, Porous, Ruthenium, Silver, Supercapacitor, Titanium RÉSUMÉ Une méthodologie innovante a été mise au point afin d’obtenir une couche poreuse tridimensionnelle (3D) affichant un rapport d’aspect élevé en termes de porosité sur une électrode en titane. La structure poreuse permet d’utiliser une matière plus active telle que l’oxyde de ruthénium hydraté durant la fabrication du supercondensateur, ce qui se traduit par une capacité exceptionnellement élevée par surface active. L’électrode affichait une capacité remarquablement élevée de 4 800 mF/cm2. La couche poreuse était composée de nanoparticules fonctionnalisées de dioxyde de titane (TiO2) organisées dans un arrangement regroupé parfaitement hexagonal en 3D, qui a engendré une structure en 3D hautement poreuse. Cette couche a servi de modèle pour le dépôt autocatalytique d’une fine couche d’argent avant l’électrodéposition de la matière active. MOTS CLÉS argent, capacité, poreux, ruthénium, supercondensateur, titaneINTRODUCTION There is a growing demand for integrating compact energy storage elements into electronic circuits due to the miniaturization of electronic circuits, sensors, and actuators, and the increasing importance of portable and wear-able devices incorporating more advanced electronic technologies that operate in controlled or uncontrolled environments to gather, process, store, and communicate information (Deng, Ji, Chen, & Banks, 2011; Beidaghi & Wang, 2012; Chen, Ramachandran, Mani, & Saraswathi, 2014). The manufacturing of compact energy storage elements needs to be compatible with the electronic circuit microfabrication processes. Recently, interest in integrating miniaturized supercapacitors into electronic circuits has increased due to their high charge–discharge rate and long operating life; however, ultra-high power miniaturized supercapacitors suffer from low energy density, hence requiring significant enhancement in their energy density for various applications (Deng et al., 2011; Beidaghi & Wang, 2012; Chen et al., 2014)."

Jan 1, 2019

By D. H. Ryan, J. T. Graham, A. Navarra, J. A. Finch, S. Somot

Pyrrhotite (Po) is widely considered to be the most significant mineral in the self-heating of sulphides. It is therefore desirable to determine the amount of Po in mineral samples. This is commonly accomplished through x-ray diffraction (XRD) or quantitative evaluation of materials by scanning electron microscopy (QEM-SEM). This paper introduces another quantitative method based on Mossbauer analysis that requires limited sample preparation and has the additional potential to detect the sulphur/iron ratio within Po. The technique is explored using pentlandite/pyrrhotite mixtures.

Jan 1, 2009

By V. Schenk

Dust exposure resulting from the exploitation and winning of natural resources below ground has presented a serious health problem since the beginning of mining. The boom phase of the German hard coal mining industry after World War II with at times up to 500,000 employees saw an increase of dust exposure of miners below ground as the mechanization of road heading and mining increased significantly. More and more miners were diagnosed with coal-workers-pneumoconiosis (CWP), a chronic and irreversible lung disease resulting in a significant impairment of pulmonary function. This realization led to a reduction of CWP in the German hard coal mining industry in the 1960s. The successful fight against CWP began with the introduction of technical dust prevention measures. By infusing the coal seam with water before mining, sprinkling and spraying of heading and mining machines as well as canopies with water, aspiration in places with high amounts of dust and the suppression of dust with chemical substances it is possible to significantly reduce the miners? dust exposure. All operating points below ground are checked and measured regularly with regard to dust exposure. Through the combination of these values together with the individual shift data a relatively precise profile of individual dust exposure can be obtained. This profile allows the targeted work assignment when certain predetermined limits have been reached, moving the miner to a work place with less dust exposure and thus reducing the chronic dust exposure. The state of health of the individual is known because since about 60 years ago extensive occupational health checks have been carried out regularly at least every two years which means that work restrictions can be imposed depending on the findings. Since the beginning of the 1980s more value has been attached to not only situational but also behavioral prevention. Given the comprehensive provision of protective masks, having a protective effect as well as the required comfort when being worn, each miner has the opportunity to protect his respiratory organs depending on the specific dust exposure. Through a combination of all these measures the German hard coal mining industry has succeeded in beating the classic coal miner?s disease CWP. For mines in the Ruhr valley this means that a miner who started work after 1978 will no longer develop CWP.

Aug 1, 2013

Applications of proven real time, through-conveyor elemental analysis technology and benefits achieved will be discussed using case studies in base metals, iron ore and phosphate operations. PGNAA (Prompt Gamma Neutron Activation Analysis) technology and its background in minerals applications and applications which are expected to further improve its utilization will be reviewed. Short payback through operational benefits such as removal of waste from feed, increased feed grade and overall improved productivity will be demonstrated based on results achieved at several processing operations. PGNAA technology is most applicable to conveyed flows as it is unaffected by belt speed, particle size, segregation/layering, mineralogy or dust. As a transmission method able to penetrate in excess of 500mm of rock it provides extremely representative results continuously measuring through the full conveyed cross section and reporting results typically on one to five minute accumulated increments to the control room. Multi-elemental results and moisture content are used for active process control: diverting conveyed flow increments(bulk sorting), blending ore types in plant feed, and providing advance warning of significant quality changes to the downstream plant operators (e.g. flotation). Elements of interest may include deleterious components as well as target metals. Ore feed quality measurements are also useful in metal accounting, ore reconciliation and real time feedback to mining operations. Further benefits can result when combined with other technologies such as particle sorters, to upgrade diverted increments of subeconomic material to achieve higher feed grades and lower deleterious content to the main process. Measurement of elements (e.g. silica) which correlate with ore hardness or grinding characteristics can be used to moderate feed rate to grinding mills to prevent overload, hence optimizing grinding performance and reducing energy and grinding media consumption. Pebble flows can be analysed and uneconomic increments diverted to prevent recirculating flows consuming mill capacity unnecessarily. This also increases average feed grade.

Jan 1, 2016