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By G. T. Lapidus, J. Trejo-Gallardo

A phenomenological model is presented for leaching silver from silver sulfide contained in mineral particles with ammoniacal thiosulfate solutions of copper in stirred reactors. Experimental results were used to adjust the kinetic parameters of the model, such as the reaction order and velocity. The incorporation of the cuprous sulfide-silver sulfide equilibrium at the reaction interface allowed the prediction of the conversion limits for different reagent concentrations. The information obtained from the reactor model was later integrated into a heap leaching simulation, whose results adequately describe tendencies observed in column tests, with respect to variations in copper and thiosulfate concentrations. Comp

Jan 1, 2005

By D. M. Ward

"The uranium deposits upon which the Rabbit Lake project story is based are located at the eastern margin of the Athabasca Basin just west of Wollaston Lake in northern Saskatchewan. This paper provides a general review of the exploration history for the major deposits and the influence of an expanding geological data base, which served to guide the continuing exploration programs.A brief description of each of the deposits is provided in order of their discovery and with emphasis upon their relative geological and mineralogical characteristics.The Rabbit Lake and Eagle Point orebodies are monometallic uranium deposits localized by thrust faults within the Aphebian Wollaston Group. The Cof/ins Bay A-zone, B-zone, and D-zone are polymetaflic U, Ni, As, Co (Au , Ag) deposits located within the Helikian Athabasca Group at its unconformable contact with the underlying Wollaston Group. INTRODUCTIONThis paper demonstrates the importance of applying the accumulated geological knowledge, gained through the exploration, mining, and development process, to the ongoing success of exploration programs. To emphasize this point, the basic geology of each of the major Rabbit Lake area deposits will be presented in chronological order of their discovery and subsequent development. These depos its include Rabbit Lake, Collins Bay A-zone, B-zone, D-zone and Eagle Point. The geological descriptions are based primarily upon the detailed observations of many current and former geologist s employed by both Gulf Minerals Canada Limited and Eldorado Resources Limited. Much of the early historical data was obtained from Dr. E.E.N. Smith, formerly with Eldorado Resources Limited. Regional GeologyThe Rabbit Lake area which includes the Rabbit Lake, Collins Bay A-zone, B-zone, D-zone and Eagle Point deposit s, is located on the eastern edge of the Athabasca Basin close to the western shores of Wollaston Lake (Fig. I). The area is in the Churchill Province of the Canadian Shield within the Wollaston lithostructural domain, at the eastern edge of the Athabasca Group. The uranium deposits occur within both the Wollaston Group metasedimentary assemblage of probable early Aphebian age, and the diagenetic ally altered quartz sandstones and conglomerates of the Athabasca Group of Paleohelikian age. Both units unconformably overlie granitoid gneisses interlayered with metasediments and a graphitic iron formation all believed to be of Archean age. All uranium depo sits in the Rabbit Lake area occur in close proximity to the Paleohelikian - Aphebian or Paleohelikian - Archean unconformity."

Jan 1, 1989

By L. Chunpongtong

Compared to equipment used in hard rock mines, the lifespan of equipment deployed in oil sands operations tends to be shortened due to the abrasive nature of the material and soft ground conditions in which it operates. One of the challenges of oil sands mine planning is to determine the most cost-effective replacement time for aging equipment. For cost engineers dealing with aging equipment, the options become an economic trade-off between taking the chance of higher frame failure or buying new equipment. Therefore, the ultimate question is: “When is the best time to replace the equipment?”

Jan 1, 2012

By A. Ghasemi

An alumina-silica coating was deposited on a nickel substrate by sol-gel process, and the structures and composition were evaluated, The sols were made from aluminium and silicon alkoxide, and an acid catalyst including HCl, To produce adherent silica coatings on nickel, various additives such as surfactant, viscose additive and drying control chemical additives were introduced to the system, and appropriate drying and firing cycles were applied after dipping in solution. The hot corrosion and oxidation resistance of the coating at different temperatures were investigated, The structure and uniformity of the coatings were examined by scanning electron microscopy (SEM), The results indicate that a uniform coating of alumina silica can be produced on a nickel substrate by optimizing the composition and process variables of the sol. Coatings can protect substrates from oxidation and hot corrosion at different temperature up to 1000°C, but is not very effective for hot-corrosion resistance at 1000°C.

Jan 1, 2005

By Y. L. Mehta

The working experience of the Zinc Smelter, Debari, Udaipur with process modifications and iron control practices is described in detail in this paper. Most of the modifications were made at different times as part of capacity enhancement campaigns that led to distinct advantages, thereby increasing both zinc production and recoveries. This smelter came into existence in 1968 with a humble beginning of producing 18,000 metric tonnes (MT) of zinc per annum, using the conventional batch hydrometallurgical roast-leach-electrowinning technology. Zinc production capacity was increased stepwise to 45,000 MT, 49,000 MT and 59,000 MT, by making suitable process modifications and adopting new technologies, particularly in the leaching section. During these modifications, the process of iron separation as Moore cake was also changed to jarosite cake production. At present, jarosite is being disposed in a secured landfill at the Zinc Smelter, Debari (ZSD) and as Jarofix at the Chanderiya Lead Zinc Smelter (CLZS). As a result of subsequent in-house performance improvement and debottlenecking campaigns, this smelter could achieve further increases in production. Zinc production for the financial year 2005-06 was 81,000 MT.

Jan 1, 2006

By P. H. Willis

Since the 14th CMMI conference, held in Edinburgh in 1990, at which a paper was presented by the author (Willis, 1990) reviewing the role of integrating new technology as a survival strategy for South African gold mines, considerable change has occurred in the South African mining industry. This paper reviews the current state of the industry and provides an update on the technologies discussed ten years ago. It reviews available technology and provides a broad economic assessment of these technologies if they were to be introduced in an integrated mining system with a focus on deep level mining below 3000 m. It also reviews possible future technologies currently being researched and developed by CSIR: Division of Mining Technology (Miningtek).

Jan 1, 2000

By D. O. Tansey

This paper will describe the mechanisms involved in delay blasting and how they are applied with the use of D.S.B. It will examine the control of potential damage resulting from detonations, and show how good fragmentation and efficient recovery of this material blasted can be achieved.

Jan 1, 1979

By M. J. Lopatka

This paper presents the results of field test and theoretical analysis driving resistance articulated 4x4 tracked robot test-bed. Tests were made on four different grounds. Designated elastomeric tracks resistance coefficients are much higher than for steel tracks. This information was important for the proper estimation of energy consumption in the process of driving.

Aug 1, 2013

By K. Kawagishi, J. Ang, A. Sato, H. Harada

"We have recently proposed a new ""EQ Coating"" bond coat system to solve the problem of secondary reaction zone (SRZ) formation caused by bond coats applied on the hot section components of modem jet engines. A viable EQ coating alloy was previously found for a representative znd generation superalloy, TMS-82+. It would be ideal if the same could be done for a representative 5th generation superalloy, TMS-173. In this paper, we will show that the coating with the best oxidation resistance in the EQ system of TMS-173, although possessing considerably better resistance than TMS-173, did not have sufficient oxidation resistance. In order to improve the oxidation resistance of the EQ coating for TMS-173, we have ventured into ""Pseudo-EQ coatings"". A diffusion couple between the Pseudo-EQ coating and TMS-173, after 300hrs at 1100°C, had a 0-15µm IDZ, but no SRZ. A diffusion couple between a conventional coating and TMS-173 formed a 80-150 µm SRZ. After a 1 hr oxidation test at 1100°C, the PseudoEQ coating formed a thinner oxide layer than the EQ coating, but still contained NiO and spinel. Aerospace"

Jan 1, 2006

By S. Huang, K. Xia

"During crushing, rock particle is subjected to complicated loading and the particle shape influences the fragmentation outcome. Thus, a highly controlled laboratory test is desired to establish the relation between the loading and the fragmentation parameters for better understanding the rock crushing mechanism. In this work, a split Hopkinson pressure bar system in combination with high speed cameras is utilized to carry out a dynamic ball compression test, in which the spherical rock sample is adopted to avoid the shape effect. Using the elasticity theory, the history of the axial symmetric tensile stress perpendicular to the diametrical direction along the loading axis is determined, from which the loading rate and the dynamic indirect tensile strength are calculated. With the aid of the moment-trap technique, the total energy absorbed by samples is accurately determined from the one-dimensional wave analysis. Furthermore by considering the kinetic energy of the sample fragments using the high speed camera snapshots, the surface energy is determined for each sample. The relations between the loading rate and the fragmentation parameters, i.e., the number of fragments and the surface energy are established. The application of this method to a granitic rock shows that it is flexible and can be applied to the crushing study of generic brittle solids. INTRODUCTIONCrushers are widely used to break rocks to extract specific minerals in the mining industry, and to obtain rock fragments with desired size distribution in construction industry. During crushing, the breakage of particles can be in either the single-layer mode or the multi-layer mode. In the single-layer mode, the particle breakage can be assumed to be isolated, in which the interaction between particles can be ignored. It is thus suggested by many researchers that highly controlled single particle test should be performed to establish the relation between the input mechanical energy and size reduction for better understanding the crushing mechanism (Yashima et al., 1987; Tavares, 2007; Pitchumani et al., 2004)."

Jan 1, 2015

By S. J. Cook

Copper, a world commodity, and the first metal used by man, played a great part in the beginnings of modern civilization, which rests so dependently on the utilization of metals. Then, long after the close of the so-called 'bronze age,' when iron and steel had attained great prominence as the world's most important metals, the practical application of electricity to industry and commerce, for the improvement of every phase of man's multitudinous activities, gave a new impetus to the production of copper. Improved metallurgical practice made it possible to work low-grade properties at a profit. Research disclosed many new uses for copper. The metal, now produced from the mines of the world in the proportion of about one pound to every 50 tons of pig iron, has attained an importance which rivals that of iron and steel in the commerce and daily life of every nation. New fields of copper-bearing ore have been discovered in Canada in recent years. Established mines in the United States and Chile are producing on a great scale. Africa looms up as one of the great question marks in the future of copper. Whereas, a few years ago, the end of the world?s resources was predicted as being in sight, the evidence now available seems to show that the copper production of the world is likely not only to continue, but to increase for a long time yet to come. Canada's future in copper is a great subject; in the present paper only a few of the most outstanding factors affecting Canada's destiny in this large field may be noted, but if consideration of the points raised herein serves to focus attention on the magnificent possibilities of Canada as a producer of copper, the preparation of the paper will be more than justified.

Jan 1, 1928

By G. Avramovic-Cingara, H. J. McQueen

The microstructure of commercially pure aluminum was investigated by using polarized optical microscopy (POM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM) techniques. Specimens were deformed in torsion at 400°C and equivalent strain rate of 0.1 s-1, to various strains of 0.2, 0.5, 1, 4, and 6. The results indicate that POM can usefully reveal grain and subgrain structures over a large field in aluminum. TEM is most suitable to study dislocation substructure and evolution of subgrains. While TEM microscopy and OIM are capable of resolving individual subgrains, OIM can not reliably distinguish subgrains with small misorientations, particularly in samples with low strain. On the other hand, the OIM technique is very useful in the analysis of many regions surrounded by high, medium, and low angle boundaries (HAB, MAB, LAB). Various misorientation maps were studied using different data processing methods. The analysis revealed that the subgrain size is relatively insensitive to strain. The fraction of low LAB ( < 5°) decreased and HAB (>15°) increased conversely with increasing strain, whereas MAB (5-15°) remained stable. The development of an increasingly bimodal grain boundary misorientation distribution is consistent with the predominance of dynamic recovery (DRV) in the evolution of microstructure, combined with geometrical dynamic recrystallization (gDRX), now called grain-refining DRV.

Jan 1, 2006

Fault detection and identification are major challenges in process engineering and manufacturing and the key component of abnormal event management systems. Timely detection, diagnosis and rectification of abnormal or faulty process conditions can lead to savings of billions of dollars in equipment damage and lost productivity, not to mention the prevention of injury and loss of human life associated with industrial accidents. A major contributing factor to current losses in industry is the reliance on human operators to interpret high-frequency samples from hundreds or thousands of variables simultaneously. As a result, the automation of fault detection and diagnosis is seen as crucial to the successful implementation of abnormal event management, the need for which is becoming all the more urgent given the increased complexity associated with modem industrial plants. In this paper, a methodology for process monitoring that uses support vector methods to extract nonlinear features from data is discussed and applied in the diagnostic monitoring of an industrial liquid-liquid extraction column.

Jan 1, 2005

By David R. Ray, Arthur J. Pyron, William F. Thomann

"Proterozoic plutonic and volcanic rocks in the Franklin Mountains, west Texas, exhibit similar values in average concentrations of equivalent uranium (eU), equivalent thorium (eTh) and equivalent potassium (eK) when compared to Proterozoic igneous rocks of the southwestern United States. Variations of radioelement concentrations for all Proterozoic igneous rocks of the Franklin Mountains range from 1.1 to 357.1 ppm U, 2.1to 259.1 ppm Th and 2.5 to 10.2% K.Recent geologic mapping of the Proterozoic rocks in the Franklin Mountains revealed several types of granites previously unrecognized, and these warrant further exploration for U and Th resources. Fluorite-bearing granites and riebeckite pegmatites are likely targets for further investigation, as these have the highest U and Th concentrations compared to all other granites.IntroductionThis is a summary of the paper presented at the CIM Geology Division Uranium Symposium held in Saskatoon, Saskatchewan, September 8-13, 1981. The purpose of this study was to evaluate the distribution of uranium (U), thorium (Th) and potassium (K) in Proterozoic igneous rocks in the Franklin Mountains, and compare radioelement concentrations to Proterozoic igneous rocks elsewhere in the southwestern United States.General GeologyThe Franklin Mountains are located in west Texas and southcentral New Mexico, within the southeastern part of the Basin and Range Province o f the southwestern United States. The Franklins are a complex fault-block range trending northsouth with strata dipping toward the west. Ages of the rocks range from Proterozoic to Cretaceous. Harbour (1972, 1960) provides the most recent account of the general geology of the Franklin Mountains. Most recent accounts of the detailed Pro Proterozoic geology o f the Franklins are provided by Hoffer (1976), Thomann (1980, 1981), Pyron (1980), Ray (1982) and McCutcheon (1982)."

Jan 1, 1983

By G. Beckstead, L. Gormely, R. Zimmer, K. Hanneman, B. Nethery

As part of the EIS and permitting activities for the Pogo Mine in Alaska, a risk assessment study for the water management plan was carried out. The basis for the study was a site water volume and contaminant balance model. Probabilistic modeling was carried out using the @Risk Monte Carlo simulation package to investigate the frequency, quantity, and quality of discharges under varying assumptions. The results were used in discussions with regulatory officials as part of the permitting process for the project. The simulation allows probabilistic modeling of key environmental parameters based on input frequency distributions involving both quality and quantity of flow. When combined with predictions of water treatment plant capacities and removal efficiency, this was very useful for defining the likelihood of important regulatory outcomes. Based on the model, certain project modifications were made. Using the simulation as a basis, ongoing dialog with regulators led to consensus that all potential risks have been considered and mitigated for the Pogo Mine according to their likelihood and severity, and that regulatory requirements would be achieved. The paper describes the model and some of the applications for which it was used.

Jan 1, 2005

By A. Ockewitz, A. Trondl, D. -Z. Sun

"Numerical simulation of extrusion processes offers an efficient method for tool design and optimization of geometries and properties of extruded parts. However, until now there are few systematic investigations about influences of material model and different parameters e.g. for friction and thermal processes on calculated local and global responses. Since extrusion processes are essentially influenced by friction between billet and extrusion tools, new friction tests were performed in this work to develop a reliable friction model. Compression and torsion tests were performed at different temperatures and velocities to calibrate the material model for extrusion simulations. Extrusion processes for circular rods and U-profiles were conducted at TU Berlin with backward and forward extrusion for different extrusion ratios, billet temperatures, product velocities and cooling conditions. This work focuses on numerical simulations of the extrusion tests with the FE code HyperXtrude. Based on the calculated distributions of local strain, strain rate and temperature the recrystallized volume fraction and grain sizes were calculated with empirical models and compared with the experimental results from optical micrographs and EBSD scans. The calculated total and friction forces and temperatures were compared with the experimental results and the deviations between experiment and simulation were analyzed.INTRODUCTION Extruded aluminum components are widely used in vehicle constructions due to light weight and manufacturing consideration. Local mechanical properties in the components are inhomogeneous as a consequence of the spatial distribution of microstructure which is influenced by numerous factors like material composition, temperature, tool design, friction, extrusion ratio and speed during the extrusion process. For the optimization of the extrusion process with regard to all these factors numerical simulation can be an essential tool. Based on results of finite element simulations of the extrusion process the microstructure in the extruded components can be predicted and then the resulting mechanical properties can be numerically determined instead of by costly trial and error methods. The aim of the work presented in this paper is the development of a numerical method for the simulation of extrusion processes with modeling of microstructure."

Jan 1, 2018

By C. M. Acuna, M. Sherrington

In high temperature processes thermodynamic equilibrium is assumed and therefore chemical potential of elements, among the condensed phases, have to be the same. In such situation impurities distribute accordingly and their fractional distributions are affected by the masses of the coexisting phases. It has been claimed Teniente Converters perform quite well for smelting high impurity concentrates, especially in respect to volatilization and/or slagging. Production of high matte grade near white metal composition, requiring moderate oxygen enrichment in the process air, results in a huge mass of gas and therefore a high fraction of impurities report to it. Similarly, by recycling different sources of slag, flue dust or other materials, the mass of the final slag is increased and so do the masses of impurities reporting to the slag. Nevertheless, above a certain level the recycling of smelter byproducts is no longer feasible and the cycle has to be halted, unless higher impurity mattes are accepted. Although the process might be continued during converting and refining, lengthy and expensive measures have to be taken if suitable anode copper for electrolytic refining is to be achieved. In the present study samples of high arsenic matte grade and slag were obtained on a pilot scale. The matte samples, on the order 75%Cu, were equilibrated with slag at varying ratios in magnesia crucibles under CO/C02 atmospheres at 1523 K. After 24 hours equilibrium matte and slag were rapidly solidified and analyzed by copper, sulfur, iron and arsenic. Furthermore, industrial samples of matte and slag, in the order 75%Cu at 1523 K, were obtained via a special quenching sampling device to determine the association of copper and suspension of matte and copper in slag. Based on the results, the distribution coefficient of arsenic between slag and matte was evaluated along with copper species in slag and the fractional distribution of arsenic, in the coexisting phases, was determined as a function of the ratio mass of slag to mass of matte.

Jan 1, 2007

By D. A. Mackie, J. E. Rider

"Good belt conveyor design is the most often neglected detail in the engineering of a plant. This results in downtime from spills or jams and premature failure of equipment components. Careful layout and component selection will result in better operation, a cleaner plant and therefore lower maintenance costs.IntroductionDespite the availability of many excellent sources of data on conveyor design, such as the Conveyor Equipment Manufacturers&apos; Association (CEMA) Manual, ""Belt Convyors for Bulk Materials"" , there continues to be repetitive errors made in design. Why? Certainly, there is no substitute for experience, but largely, classical errors in belt conveyor design is rather elementary and so the temptation to have the work done by relatively inexperienced designers is great. What that does is develop "" experienced"" designers who become incompetent through no fault of their own. It is hoped that this paper will supplement available design data, help those who are "" put into"" a design situation to better cope with their predicament, and ease the lives of plant maintenance personnel."

Jan 1, 1990

By J. Peck, M. J. Scobie, M. D. Pollitt

"IntroductionOne aspect of current research in the Canadian Centre for Automation and Robotics in Mining (CCARM) involves the automatic identification of different rock types based on particular drill performance parameter responses. In this paper, the four drill performance parameters of torque, pulldown pressure, rotary speed and penetration rate, were measured from an instrumented rotary blasthole drill during field investigations undertaken at the Fording River Mine, Elkford, British Columbia. The variations in these parameters were subsequently correlated with the corresponding rock types using the results from gamma, neutron and core logs in the same or adjacent boreholes. Work to date has sought to understand the relationships between drilling performance parameter variation and rock properties. Using the results of these studies, the present research is aimed at developing techniques whereby classical statistical pattern recognition methods are applied to drill data to permit the discrimination of different rock units. A monitoring system incorporating such a capability would greatly enhance the quality and amount of geological information on a per borehole basis while drilling. This data in tum could be used economically and directly towards explosive loading, geological exploration and reserve estimation. Background and PhilosophyThis work is an extension of equipment monitoring studies at the Fording River Mine. At this site over a two-year period, 5180 m of data was acquired on an instrumented Bucyrus-Erie 60R drill during routine production blasthole drilling. Throughout these studies, a 311mm diameter S8M Security tungsten-carbide tricone bit was used. The mine, located in southeast British Columbia, is a large-scale, open pit coal operation. The means of excavation revolves around a drill-blast-muck cycle and employs a standard shovel-truck system of transport. Four main rock types are present: sandstone, siltstone, mudstone and coal, with average compressive strengths ranging from 10 MPa to 150MPa respectively (peck 1989). However, based on the field studies, very few differences in terms of strength and compositional properties were seen between the sandstones and siltstones at the site. Therefore, they are referred to as sandstone/siltstone in all further discussions."

Jan 1, 1991

By S. S. Rahman, A. Gholami, M. A. Aghighi

"This paper provides a foundation for studying the growth of fractures in presence of other discontinuities and different anisotropies of low permeable hydrocarbon formations and helps to improve the design strategies for multistage fracturing.The multistage fracturing technology has recently been used to exploit low permeable hydrocarbon reservoirs. However, the mechanism of hydraulic fractures interaction and the impact of local heterogeneities on ultimate trajectory of the growing hydraulic fractures are not yet understood in depth. A fully coupled poroelastic Finite Element based model is developed to investigate the mixed mode propagation behaviour of growing hydraulic fractures. This model takes advantage of an explicit representation of the fracture which enables us to take the effects of rock and fluid related parameters into account. Moreover, impact of fracture geometry and leak-off phenomenon is investigated. The refined mesh around the crack provides the added advantage of more detailed stress distribution, pore pressure change and back stress in the vicinity of the fracture and in particular at the fracture tip. The potential deviation propensity of the fractures is evaluated based on the fundamental rule that fractures propagate perpendicular to the direction of the minimum horizontal stress.This study shows that pressurization of transverse hydraulic fractures results in the reorientation of local principal stresses, particularly in vicinity of fracture tips. Variation of flow patterns clearly influences the evolution of shear stress around the fracture tips which will potentially lead to mixed-mode I and II fracturing and consequently, fracture deviation. The presence of local heterogeneities such as preexisting fissures and/or fractures is a main source of such pore pressure induced stress redistribution and reorientation and potential deviation of hydraulic fractures.Most existing models ignore or simplify the effect of pore pressure/stress coupling as well as the fracture geometry and fluid flow within the fracture. Also, the fluid leak-off from the hydraulic fracture into the formation, which is a controlling factor in fracture growth, is often considered using analytical models. Taking advantage of a fully coupled porelastic model along with an explicitly discretized fracture, this study provides a more realistic insight into the complex fracture propagation processes of multistage fracturing operations particularly in presence of reservoir geo-mechanical complexities."

Jan 1, 2015