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By V. P. Mehrotra, D. W. Fuerstenau, A. -Z. M. Abouzeid

The use of pulverized coal for electric power generation results in the production of vast amounts of fly ash. One potential use for waste fly ash is the production of pellets for lightweight aggregates. This paper is concerned with the role of the physical and chemical characteristics of two different fly ashes in governing their agglomeration or pelletization behavior and their strength characteristics. In batch balling experiments, fly ash pellet growth was found to be extremely sensitive to the amount of moisture added. One ash (Mohave) exhibits marked pozzolanic activity whereas the other (Jim Bridger) does not. The pozzolanic activity has a very pronounced effect on pellet growth kinetics, moisture requirements, and the effect of various additives on growth kinetics. Slow drying under ambient conditions produces strong pellets from Mohave ash whereas Jim Bridger ash pellets lacking in pozzolanic activity are weak. Rapid drying at high temperatures results in weak pellets because water necessary for hardening is driven out of the pellet. Steam curing enhances pellet strength. Locked-cycle pelletizing experiments exhibit expected oscillation in pellet production rates and attendant fluctuations in pellet green strength.

Jan 1, 2004

By C. G. Williams

This paper describes the planning, development and operation of the Highvale Mine to supply coal to both the existing Sundance and the approved Keephills thermal power plants of Calgary Power Ltd. Reference is also made to the company 's Whitewood Mine, which feeds the Wabamun thermal plant .

Jan 1, 1979

By J. Edwin Van Buskirk

For a country that is as important a gold producer as Canada, the return to the gold standard of the major commercial countries of the world during the past five years is of particular significance. To the Canadian gold mining industry, the advantages of the gold standard are a matter of more than theoretical importance. According to economic theory, prices are determined by the relation between the demand for, and the supply of, money. The demand consists of the offering of goods for money; the more goods offered, the greater the demand. The supply consists of the total money available for the purchase of goods. The total supply of goods to be exchanged through the instrumentality of money remaining the same, an increase in the supply of money will, according to this theory, raise prices; conversely, a decrease in the supply of money will lower prices. Let us imagine that everyone in the world suddenly had twice as much money, and that the sum total of all goods remained the same. Is it not obvious that we would pay just double the price for these goods? In Canada today, most people have approximately 50 per cent grea.ter income than in 1913, and the average price for all articles sold in Canada is 50 per cent above those in 1913.

Jan 1, 1928

Vast quantities of cosmic material, ranging in size from fine dust to large meteorites and planetoids, have been colliding with and accumulating on the earth since its origin 4.5 billion years ago. There are less than twenty well preserved meteorite craters and Jess than thirty fossil craters or astroblemes on the present face of the earth. On the moon, there are approximately 200,000 craters on the visible face alone -the largest crater being 132 miles in diameter and attaining a depth of 16,000 feet. Making allowances for the different physical conditions on the moon and assuming that these lunar features are of impact origin, the indifference is that, since primeval time, large numbers of celestial objects have also encountered the earth, but that both the topographic expression of the impact and the objects themselves have been destroyed by weathering and erosion. It may be reasonable to suggest that additions of cos-mic bodies have materially altered the chemistry of the earth's crust from place to place and that the impact of large meteorites and asteroids has created zones of weak-ness in the crust that could be the center of magmatic intrusion and mineralization.

Jan 1, 1965

By R. Stratton-Crawley, S. W. Wilson

"Inco's Matte Separation Plant is a unique mineral processing facility having no process tailings stream. Each product is a high-grade concentrate with strict assay specifications which are defined by the downstream refining route. The most recent column application in the flowsheet, copper scavenging in the production of a high quality nickel concentrate, is described in detail. Testwork in pilot-scale columns (0.038 m, 0.051 m and 0.10 m in diameter) was used to develop a model of the copper scavenging system. This data was then used to simulate the performance of plant-scale equipment. The relationships thus established were confirmed by a series of plant tests in a 1.8 m diameter column. Column results consistently exceeded conventional cell performance. The modelling was extended to assess full plant production requirements and, as a result, a 2.1 m diameter column was specified for this application. Engineering design for this column is currently underway and the column is scheduled to be commissioned later in 1991.INTRODUCTIONMatte SeparationINCO's Matte Separation Plant is a part of the Copper Cliff Smelter complex near Sudbury Ontario. The flowsheet and the development of column flotation within it have been described previously (Feeley et al., 1987, Wilson et al., 1989). The plant feed is a synthetic Bessemer Matte from the Nickel smelter. This matte is slow cooled to promote grain growth and typically assays 46-52% Ni, 23-27% Cu. These elements are present primarily in sulphide form (Ni3S2 and Cu2S respectively) with some metallic alloy also precipitating from the sulphur deficient matte. Minor amounts of iron, precious metals, and nuisance elements are also present.The matte separation process is, in concept, relatively simple. Following magnetic removal of the metallic alloy from the feed, the flowsheet is designed to float a high grade copper concentrate from the nickel sulphide matrix. A simplified flowsheet of the process is shown in figure 1."

Jan 1, 1991

By T. Sugawara, S. Hara, Y. Mitsui

Surfaces of rock slopes in cold regions often become frozen in winter. Therefore, understanding time-dependent behavior of frozen rock, as well as that of unfrozen rock, is important for long-term stability assessment of rock slopes. In this study, a series of uniaxial compression tests and creep tests were carried out on Shikotsu welded tuff under dry and water-saturated conditions at -20 °C to clarify timedependent strength and deformation of the frozen rock. The influence of water content on them also was investigated. It was found that the amount of deformation of the water-saturated specimen was much greater than that of the dry specimen. It also was found that the creep behavior of the water-saturated specimen was similar to that of polycrystalline ice. These show that deformation of the water-saturated specimen is strongly affected by pore ice. The UCS of the water-saturated specimen was approximately equal to that of the dry specimen at a strain rate below 4.2×10-6/s, and its value was about 17 MPa. However, the former increased up to 26 MPa at 4.2×10-4/s with loading rate, whereas there was little increase in the latter. This means that the UCS of the water-saturated specimen was always greater than that of the dry specimen at higher strain rates. The creep life of water-saturated specimens was longer than that of the dry specimens at stress level greater than 15 MPa. These results of UCS and creep life show that inclusion effect due to presence of pore ice plays an important role on strength of the water-saturated specimen. Creep life of the non-failure specimen that was loaded for more than three days was estimated by the relationship between creep life and axial strain rate at 10 s on failure specimens. It was found that creep life of the water-saturated specimens was shorter than that of the dry specimen at stress levels less than 14 MPa. This suggests that estimation of creep life of frozen rock under water-saturated condition is important for the stability assessment of frozen rock slopes. It was clear that the loading-rate dependency of UCS was related to the stress-level dependency of creep life in both dry and wet conditions. This indicates that there are common fracture mechanism in creep and uniaxial compression tests. It also indicates that the creep life can be estimated by the relationship between the UCS and the loading rate. The time dependencies of the water-saturated specimen were in good agreement with those of polycrystalline ice. This confirms that pore ice strongly affects the strength of the water-saturated specimens as, well as the deformation behavior.

Jan 1, 2015

ABSTRACT The inevitable uncertainty in modelling spatial variables decreases as more data become available. This reduction depends on the properties of the variable being modelled. Spatially continuous variables show less uncertainty for a given spacing than erratic variables. A geostatistical simulation based approach is developed to quantify the relationship between uncertainty and data spacing. Reference realizations are sampled to condition additional realizations and quantify uncertainty. The procedure is automated, making it straightforward to consider sensitivity and different geological domains. A case study of the relationship between uncertainty and data spacing for net oil sands thickness data from northern Alberta is presented. _ KEYWORDS Simulation, Sampling,

Jan 1, 2013

By P. Abachi

Cemented carbides or hard metals that generally consist of hard tungsten carbide and a tough metal binder such as cobalt are important in many segments of the world economy, ranging from automobile related components to machining, cutting, and drilling tools. For metal cutting operations such as turning and milling, replaceable cemented carbide inserts are frequently used. The exposure of inserts to very severe conditions (e.g. temperatures as high as 1000°C) in combination with very high loads, limits their lifetime. When the tools and components are scrapped, they are collected with a view to recovering the tungsten carbide and cobalt due to both their environmental aspects and their strategic importance. In this work, a selective electrolysis process was used for recovery of WC powder particles from cemented carbide scraps. The WC-10Co and WC-10Co-VC up to 3 wt.% VC was produced using powder metallurgy route. The mean particle size of WC, Co and VC were selected as 2.5, l.5 and 2.2 µm respectively. Referring to electrochemical curves of WC-10Co cemented carbides in hydrochloric acid solutions with different concentrations, the recovery rate was enhanced in IN acid. Therefore, this solution was selected for recycling of all samples. The surfaces of as-produced and corroded specimens were investigated using a scanning electron microscopy (SEM). Detection of corrosion products was provided by energy dispersive spectrometry (EDS). According to results, the selective electrolysis process could be useful in the recycling of scrap carbide materials, although more studies should be undertaken on economical aspects of the process and the quality of samples produced using recovered powders.

Jan 1, 2005

By H. J. McQueen

Before 1950, hot working was simply deforming above the recrystallization point and gave a soft product compared to cold working. From 1960 onwards, improved testing in compression and torsion (stress, strain rate, temperature, quenching) provided valid specimens for microstructural analysis by polarized optical and transmission electron microscopy (TEM). Indeed, TEM was essential to uncovering the hot working mechanisms because it could distinguish between cold and hot substructures (dynamic recovery) in either initial or new grains (dynamic recrystallization). Over the years, teams at Concordia, McGill and UBC obtained NSERC support for students and equipment. CANMET built up a hot forming group having capabilities from high-rate cam-plastometer compression to rolling of experimental alloy billets; this was combined with latest metallographic instruments for fundamental research. Al alloys of every class (2000, 3000, 5000, 7000, 8000) were studied to understand the effects of solutes, precipitates, dispersoids and composites. The complex flow patterns in extrusion were clarified and modeled by finite element methods. Physical simulations of rolling schedules (up to 20 passes and reductions of 98%) by torsion provided evidence of microstructure development during both the passes and the softening intervals, thus clarifying development of texture in different alloys. The results frequently appeared in proceedings of Light Metals symposia and Canadian Metallurgical Quarterly

Jan 1, 2011

By Atsuki Sado, Akira Ueno, Kazuaki Takebayashi, Kunio Watanabe

The Saganoseki Refinery of Pan Pacific Copper Co., Ltd., Japan, introduced the ISA 2000® process in 2006 to improve product quality and productivity. After resolving various technical difficulties associated with the process, a current density of 325 A/m2 and electrolytic copper production of 234 000 tons per year were realized in 2018. In recent years, Saganoseki Smelter & Refinery has promoted treatment of recycled materials in addition to copper concentrates. Accordingly, the amount and type of impurities charged to the smelting process have tended to increase. In the electrorefining process, impurities such as nickel and antimony cause anodic passivation and formation of suspended solids, respectively. Although these undesirable phenomena can be avoided by controlling impurity concentrations in the anode and electrolyte to appropriate ranges, this also limits the choice of recycled materials that can be processed by the smelter. To achieve both stable operation of the electrorefining process and flexibility in treatment of recycled materials in the smelting process, Saganoseki Refinery improved the capacity of the impurity recovery processes during 2016 to 2018. This paper describes the expansion of the purification plant to remove and recover nickel and antimony. INTRODUCTION The Saganoseki Refinery of Pan Pacific Copper Co., Ltd., Japan, introduced the ISA 2000® (wax- less permanent cathode method) in 2006 to improve product quality and productivity. Since then, the refinery has gradually increased current density, and has been committed to establishing stable operation and high productivity via various improvements related to the electrolyte filtration and additive management systems. Figure 1 shows the trends of current density and current efficiency at the refinery. Although the current efficiency temporarily dropped when the current density was raised to 322 A/m2, it consistently exceeded 97% thereafter. At present, stable operation at 325 A/m2 has been achieved and continues.

Jan 1, 2019

By E. C. Sanford

A laboratory-scale batch extraction unit and operating procedure for studying the hot-water separation of bitumen from Athabasca tar sands are described. The extractor evolved from earlier units and has been in use by Syncrude Research for the past 10 years. By using a unit such as this, it is possible to study tar sand feed quality and the effects of chemicals on the hot-water extraction process, while process variables are held constant. Data are presented to demonstrate the importance of surfactants to the process and the interrelated role of inorganic bases and surfactants.

Jan 1, 1979

By R. W. Davis

INTRODUCTION CHURCHILL river was named for John Churchill, first Duke of Marl-borough and third Governor of the Hudson's Bay Company, in the latter part of the 17th century, some fifty years after the ill-fated Danish expedition, led by Munck, had abandoned the site of the now famous seaport of Churchill, as a worthless, cold, disease-ridden country. No other attempts were made to explore the interior until the river basin became a part of the grant to the Hudson's Bay Company and began to play its part in furnishing the luxury of fine furs to civilized people as it had furnished the necessities of food and dress for untold centuries to uncivilized natives. This was the sole contribution of the region to the economic life of the country for some two hundred and fifty years, until 1926, when the power site at Island Falls was discovered by engineers seeking a cheap power source to make possible the development of the great ore-body at Flin Flon. DRAINAGE BASIN OF CHURCHILL RIVER The river is some 1,325 miles long. Rising in the headwaters of the Beaver river, in east-central Alberta, it flows in an easterly direction across Saskatchewan and northeasterly across Manitoba to Hudson bay, through a remarkable basin of some 115,500 square miles, only 6,000 square miles less than the area of the British Isles. A journey down this river leads one through three distinct belts of country, each vastly different from the others geologically and in surface characteristics. For the first five hundred miles the river flows through a basin of 36,000 square miles of the great central-plains country, which is covered with fertile soil and carpeted in its southern part with prairie grass, which gradually gives way to the mixed forests of poplar, spruce, birch, and jackpine in the northern and eastern sections: About midway across Saskatchewan, bald-headed knolls and ridges begin to make their appearance as the river meets the western margin of the Canadian Shield. Then, for some seven hundred miles, it passes through country underlain by the pre-Cambrian rocks of the Shield, which continue to within one hundred miles of Hudson bay. Here the character of the country again changes to a low, clay plain underlain by sandstone, and through this 'clay belt' the river flows between steep clay banks, to empty into Hudson bay.

Jan 1, 1935

By A. Boeing

Rock-breaker automation and remote operation improves the safety and efficiency of mining operations. This article presents an overview of the Rocklogic rock-breaker automation system architecture that provides collision avoidance, automated parking, and remote operation functionality. The system consists of a distributed computer control system that interfaces with sensors attached to the rock-breaker, the rock-breaker hydraulics, and the site infrastructure. We present results of an automated Transmin rockbreaker installed in a production environment at an underground Australian mine site. The system has been in production use for over 900 days during which there have been no reported collisions, and 100% adoption of the remote operation technology. As a result, Rocklogic has significantly improved the safety of rock-breaking operations and reduced the rock-breaking cycle time, thereby improving the sites overall throughput.

Aug 1, 2013

An Atomic Force Microscope (AFM) was used to measure the surface forces between glass sphere and silica plate in CnTAC1 (n=12, 14, 16, 18) solutions. The results showed the presence of long-range attractive forces that can be fitted to single exponential functions. With a given surfactant, the attractive force increased with increasing concentration, and reached a maximum at the point of charge neutralization (p.c.n.). The decrease in the attractive force above the p.c.n. is probably due to the inverse orientation of the surfactant molecules. A plot of the log (p.c.n.) vs. the number of carbons in the hydrocarbon chains of the Cn TACI homologues showed a linear relationship with a slope of -0.37, indicating that the surfactant adsorption entails a decrease in free energy by -0.85 kT per mole of CH2 (or CH3) group. These results suggest that the adsorption of long-chain surfactants is controlled by hydrocarbon chain association during the process of forming surface hemi-micelles (or domains). Possible origins of the long-range attractions are discussed on the basis of the results presented in this communication.

Jan 1, 2006

By R. A. L. Drew, F. Jalilian, M. Jahazi

Joining of superalloy Inconel 61 7 with a foil interlayer using transient liquid phase bonding (TLP) technique was studied. Inconel 617 is a solid solution, Ni - Cr - Co- Mo alloy with an exceptional composition of high temperature strength, oxidation, carburization resistance and thermal stability. In this investigation, two bonding temperatures, 1065°C and 1150°C, and two interlayer thicknesses with joining times varying from 5 minutes to 24 hours were employed. Experiments were carried out using nickel base interlayer (A WS BNi-3) with boron as the melting point depressant (MPD) element. Joints were characterized using optical microscopy, SEM, FEG-SEM, EBSD, XRD and microhardness. The results indicated that the rate of elimination of the liquid phase with increasing the bonding temperature, holding time and decreasing the thickness of the interlayer increased. The main precipitates in the diffusion layer had platelike and blocky morphologies for both bonding temperatures and all holding times.

Jan 1, 2006

By Y. Luo

The rock breakage process in drilling is a main source of noise in roof bolting operations, especially when hard rocks are encountered. Proper control of drilling operation can provide an opportunity to improve energy efficiency of drilling and to reduce noise and heat generated from bit-rock friction. Drilling tests have been conducted in laboratory settings to confirm this noise-reduction strategy. Preliminary results show that the drilling parameters, penetration and rotational rates can be controlled to achieve in a desirable range in drilling medium hard rock. Based on the theoretical and experimental studies, rational drilling control strategy is developed for noise control while maintaining a safe and productive roof bolting operation. Applying this strategy in underground roof bolting operation, the noise exposure of roof bolter operators will be significantly reduced.

Aug 1, 2013

By J. Lu, D. G. Ivey, H. Henein

Microalloyed steels are widely used in the oil and gas industry. They are a class of high strength, low carbon steels containing small additions of niobium (Nb), titanium (Ti), molybdenum (Mo) and/or vanadium (V). These steels have good strength, toughness and excellent weldability, which are attributed in part to the presence of nano-sized carbides, nitrides and carbonitrides. In the pursuit of developing higher strength microalloyed steels, it is of great interest to quantify the size, distribution, volume fraction and chemical speciation of these precipitates. However, characterization techniques suitable for quantifying fine precipitates are limited. Possible characterization techniques include SEM, TEM and matrix dissolution. A comparison is presented of the various techniques.

Jan 1, 2005

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher productivity rates and a resultant reduction in activity costs. Increased advance rates, by examination of the key components (face preparation and drilling, hole loading and blasting, scaling, mucking and support installation) in the development cycle, and optimizing these processes is a high priority for research in the Canadian mining industry. Support installation time alone is typically 36 to 46% of the total development cycle time. A reduction in support installation time or techniques and alternative scaling strategies could result in significant gains in drift development advance rates. Support Staging and hydroscaling within the drift cycle could offer alternative drift development sequences that could reduce the overall cycle time. MIRARCO?s research into the support and hydroscaling processes for rapid drift development also suggests that there are many other factors (e.g. mine ventilation services) that have a significant impact on the rate of advance. These factors should be considered to promote and manage safe and rapid drift development. Constraints to the rapid drift development processes can only be overcome by sound construction management practices. In other words, the goals of rapid drifting can be achieved by the implementation of contractor-type construction management. This paper examines various constraints and processes affecting rapid drift development and draws attention to other factors affecting safe rapid drift development.

Apr 1, 2005

By D. M. Muir

The mineralogy of residues formed during the pressure acid leaching of arid region nickel laterite ore varies according to the salinity of the process water, alkali cation additives and the overall acid loading. In fresh water, hematite is the main iron-bearing leach residue component, together with amorphous silica and hydronium or sodium alunite/jarosite [(H3O,Na)(Fe,Al)3(SO4)2(OH)6]. As the process water salinity increases, or as NH4+ or K salts are added, alunite/jarosite is the kinetically favoured iron-bearing phase accompanied by an increase in acid consumption. The alunite/jarosite appears as two XRD distinct phases with different Fe:Al molar ratios. In weakly saline water, iron-rich alunite/jarosite slowly transforms to hematite and an aluminium-rich alunite/jarosite together with the release of acid. The addition of potassium salts forms a more stable alunite/jarosite whilst the addition of ammonium salts leads to greater transformation of alunite/jarosite at 250°C. Weakly saline process water gives enhanced nickel recoveries, whilst strongly saline process water gives lower nickel recoveries but higher soluble iron because of chloro-complexation. SEM and microprobe analysis shows very little nickel is associated with the alunite/jarosite and hematite phases. Nickel losses to the residues are attributed to adsorption on amorphous silica and to a lesser extent on alunite/jarosite.

Jan 1, 2006

By Raj K. Rajamani, Nikhil Dhawan

"Agglomeration has become common pre-treatment step to improve heap leach percolation thereby recovery, the fundamental understanding of the agglomeration process for crushed ores is still lacking. Agglomeration is required for ores which either contain excessive amounts of clay or an excessive quantity of fines generated during mining and crushing. Numerous experiments have been carried out in laboratory scale batch drums using different ores. It has been found out that experimental agglomerate size distributions exhibit self-preserving spectra. The self-preserving/ similarity distribution of the agglomerates is found to be independent of operating conditions and is uniquely determined by the size enlargement mechanism. An empirical model based on the absolute difference between moisture applied and optimum moisture was developed. This model uses self-preserving spectra in the form of a Rosin-Rammler distribution function to predict size distribution at different operating conditions. The empirical model was considerably easier to work with plant scale agglomeration drums. Also, a test known as dip test is developed which improves fundamental understanding of the agglomerate formation and growth mechanisms. This test also provides the progeny size distribution of each agglomerate size. The progeny size distribution was analyzed with a model that partitions the particles into a host and guest category. The ensuing partition coefficient identifies the behaviour of a particle as a host for other particles or a guest layering on other particles. This concept helps in identifying the type of agglomerate that would result for a specific feed size distribution. INTRODUCTIONHeap leaching is one of the hydrometallurgical processes that have served as a green and economically viable process for the treatment of low grade complex ores of copper, uranium, nickel, silver and gold (Dhawan et al., 2013). Heap leaching appears to be a favorable candidate for the least energy consuming process for low grade ores. In heap leach operations nowadays a pretreatment step known as crushed ore agglomeration has been implemented (Dhawan et al., 2013). A bed of agglomerates improves the uniform percolation of solution through the heaps of ore. Therefore, it was possible to treat wastes and mill tailings via agglomeration and heap leaching. Agglomeration pretreatment is required for ores which either contain excessive amounts of clay or an excessive quantity of fines generated during mining and crushing (Bouffard, 2005; Dhawan et al., 2013).While agglomeration has become common practice pretreatment step in heap leach operations, the fundamental understanding of the crushed ore agglomeration process is still lacking. The author reviewed publications up to 2012 on the crushed ore agglomeration process and did not come up with modeling studies on the topic (Dhawan et al., 2013). Some of the possible reasons can be the stochastic nature of the process, experimental difficulties, and lack of instrumentation for fundamental studies."

Jan 1, 2016