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By Alexander Smith

"The three principal known mineral deposits of the Taku River area lie in the Tulsequah synclinorium. The axis of this north-south trending structure is along Tulsequah River valley; about 6 miles east of the eastern contact of the Coast Range batholith.The one proven mine of the area, the Polaris-Taku, is on the west side of the valley. It is a gold property, the gold occurring in fine needles of arsenopyrite disseminated in carbonatized volcanics. The mine was originally called the Whitewater, and the adjacent area the Whitewater gold belt. During the years 1937 to 1942 gold having a value of $3,284,000 was produced from 313,500 tons of ore milled."

Jan 1, 1954

By M. Nakai, G. Itoh, R. Yamada, A. Kurumada

In order elucidate the mechanism for poorer fatigue properties of 7000 series aluminum alloys than those of 2000 series alloys, the effect of the test environment on the fatigue crack growth of the two series alloys was investigated, considering the relationship to hydrogen embrittlement. Two 7075-type and four 2024-type alloys were T6-tempered and T4-tempered respectively, and subjected to fatigue crack growth tests in moist and dry environments. When tested in moist air, fraction of intergranular crack path was higher in the 7075-type alloy with coarse equi-axed grains than in the 2024-type alloy with similar microstructure. This was in accord with the larger crack growth rate in the 7075-type alloy. Both the intergranular crack path fraction and the crack growth rate were decreased by changing the environment to the flow of nitrogen gas. Thus, the large fatigue crack growth rate of the 7075-type alloy is attributable to hydrogen embrittlement.

Jan 1, 2015

By M. Kosugi, Y. Kon, M. Kawata, J. V. Satur, K. Mitsuhashi, C. Tokoro, K. Horiuchi, R. Kawarabuki, B. Calabia

"Liberation of copper minerals is important in ensuring high flotation efficiency in copper sulfide flotation. The high pressure grinding roll (HPGR), microwave (MW), and electric disintegration (ED) are known to feature enhanced liberation over conventional comminution machines such as jaw crushers and ball mills by producing internal stresses on minerals or mineral grain boundaries through high compressive forces, thermal expansion of minerals, and pulsed high voltage discharges, respectively. In this study, each of these methods was applied before ball mill grinding to investigate its effect on enhancing the liberation of copper minerals in a low grade and fine-grained copper ore. The copper minerals observed in the tested ore sample are bornite, chalcocite, and chalcopyrite, and their grain sizes range from 10 to over 100 µm. Calcite, quartz, and feldsparare confirmed as gangue minerals. The liberation of the copper minerals by the different methods was analyzed using the mineral liberation analyzer (MLA) and compared. The result showed that the HPGR crushing was the most effective for enhancing copper mineral liberation. HPGR bench-scale test was then conducted on the copper ore and flotation was applied on a HPGR-treated sample to confirm the improvement in the flotation performance by applying HPGR.INTRODUCTIONIn order to recover copper minerals by flotation, copper ore is usually ground by ball milling to liberate the copper minerals from gangue minerals. In the case that the fine size copper minerals are targeted, grinding of the copper ore to a finer size is necessary to increase the copper recovery. However, finer size grinding by ball mill increases energy consumption significantly, which might deteriorate the economies of the mineral processing operation. HPGR, MW, and ED have been recently the focus of researchers as new techniques for enhancing the mineral liberation in mineral processing (Tavares, 2004; Kingman, 1998; Wang, 2010).HPGR crushing is considered to generate micro cracks along mineral boundary when rocks pass between two rolls by applying high compressive force. In the MW treatment, micro cracks are reported to be generated at crystal boundaries by differential thermal expansion of crystals attached to each other. In the ED treatment, micro cracks are known to be produced by plasma current flowing along mineral grain boundaries. These treatments are expected to increase mineral liberation (Fujita, 2001),improve flotation performance(Michaelis, 2005), and reduce ball mill work index(Kaya, 2010)."

Jan 1, 2017

By D. M. Baird

"THE Island of Newfoundland lies on the extreme eastern edge of the continent of North America and at the extreme northeastern end of the Appalachian geological province. Its belonging to the Appalachian province is shown in the geological history of the region and in the rock types and structures.Geosynclinal sedimentation in early and middle Palaeozoic times was interrupted by Taconic and, more profoundly, by Acadian, mountain building activity. Mid-Palaeo-zoic intrusions range from masses of serpentinized ultrabasic rocks to granite batholiths. A Carboniferous overlay of continental and shallow, drying sea types covers the earlier developed complex. Local basins in these times were filled with products of the erosion of tl1e earlier rocks, and, locally, grew the right kind of vegetation to make thin, discontinuons seams and pockets of coal. Post-early Pennsylvanian history is one of erosion and pene-planation with renewal of movement along many of the older fault systems."

Jan 1, 1960

By F. M. Doyle, G. Sidhu, A. J. Dussault, A. Raygani

There is a growing demand for rare earth metals for use in high strength permanent magnets, most notably Nd2Fe14B. Rare earth metals are extremely reactive, with reduction potentials around -2.5V SHE, and are conventionally produced by molten salt electrolysis. The current work was done to investigate an earlier report of electrodeposition of a neodymium ferroalloy from aqueous solution, to determine whether this approach could be an environmentally and economically competitive commercial approach for producing feedstock for permanent magnets. Such a process would be analogous thermodynamically to the Castner- Kellner process, in which aqueous sodium chloride brine is electrolyzed in cells with mercury cathodes. Metallic sodium forms an alloy (amalgam) at the cathode, thereby lowering the activity of the metallic sodium significantly below unity and making the reduction potential of sodium significantly less negative than the standard reduction potential. Here we report the effects of Nd/Fe ratio in the electrolyte, current density, temperature and two different complexing agents, glycine and cysteine, on the composition and morphology of the electrodeposits, along with current efficiency. The energy needed to produce neodymium as Nd:Fe alloys by aqueous electrodeposition was compared with values estimated for production by molten salt electrolysis and the thermodynamic energy requirement.

Jan 1, 2014

By A. Fahr, T. Byczkowski, M. Genest, C. Mandache

"Layered aluminum structures assembled with rivets are often found in aircraft fuselage. These structures are exposed to various mechanical loads and a range of environmental conditions that contribute to their ""aging"". The rivet holes are the source of stress concentrations and the location of crack nucleation and growth. Detection and sizing of second and third layer cracks under fasteners represent a major challenge for non-destructive evaluation (NDE) technicians. Electromagnetic methods are currently the most feasible NDE techniques that are capable of successfully inspecting such structures. However, different probe lift-offs, due to protruding rivets and paint coatings, or interlayer separations, due to sealant or air gaps, pose difficulties in detecting and sizing cracks. In addition, the use of conventional eddy current technique is limited due to the inverse relationship between the probe spatial resolution and its field penetrability. In this paper, we present an alternative approach that overcomes the previously mentioned shortcomings by using pulsed eddy current excitation and magnetoresistive sensor pick-up. Various signal manipulations are employed for defect detection and quantification."

Jan 1, 2006

By R. Roufail

"Energy consumption in stirred mills has been studied, in the last couple of decades, on a macro scale. Effective operation and meeting particle size required for downstream operations used to be the main objectives behind energy utilization of stirred mills. In this paper, three energy terms are defined to assist in understanding the breakage mechanism for various types of minerals versus mill operation. The types of minerals studied had diverse physical and mechanical properties that are summarized as specific gravity, hardness and crystal structure. The minerals utilized in this study were quartz and galena. The effect of quartz and galena mix has been addressed as well as Lead-Zinc ore sample from SAG mill discharge. The energy input to the mill is function of the agitator speed, therefore three agitator speeds were evaluated, 1000, 1500 and 2000 RPM, respectively. The energy terms studied are specific energy (kWhr/ton). Effective energy is the ratio between net energy and total energy consumed by the mill. Last type of energy is the specific breakage energy, which is the net energy consumed by the mill per one-micron breakage. Results showed that specific energy and specific breakage rate are functions of mineral type, while effective energy is only function of mill input power (agitator speed).INTRODUCTIONGrinding is the largest energy consuming component of a mineral processing operation and typically consumes about 50% of the total energy used at a mining operation (Botin, 2009). Over the last two decades, stirred mills have been extensively utilized in mineral processing operations due to increased mineralogical complexity of ore bodies. Stirred mills grind particles to less than 10 µm by applying a high power intensity. The technology has been the focus of several research studies to investigate mill energy and grinding mechanisms. Becker, et. al. (2001) studied the relationship between different types of energy including input energy, specific energy, volume/mass specific energies, to stress intensity and final product particle size. Other studies such as by Kwade (1999), Kwade and Schwedes (2002), Blecher et al (1996), Partyka and Yan (2007), Stender et al (2004), focused on mill design and/or stress intensity distribution. Peukert (2004) studied the effect of mechanical properties of the grinding media and ground material on the comminution process."

Jan 1, 2016

The dynamic breakage process of rocks by the impact of a hydraulic hammer is more complex than one normally assumes. It is even more difficult when one has to conduct the breakage under water. In such cases one does not know exactly what the surface topography and composition are at the bottom of the sea or river and, hence, it is more difficult to select the best position of the hammer before starting the hammering. Typically, an industrial hammer has a diameter of about 250 mm, a length of about 1.25 to 1.75 m and a mass of several tons. The hammer frequency can be up to 50 impacts per minute. The general principles of rock hammering can be easily summarized, but this knowledge is not sufficient to adapt adequately the method for less common rock conditions (e.g. less brittle rock, presence of vertical and subvertical fractures, etc.). That is the reason why we initiated a research project, whereby a scale model has been developed to conduct experiments in the laboratory and whereby discrete element simulations are being conducted. Both aim at a better understanding of the basic mechanisms of rock hammering. The scaled experimental model allows varying the impact energy and the static weight independently. Within the experiment, the hammer is in contact with the rock specimen under a certain confining pressure and with a certain contact pressure due to the static weight. A weight falls on the hammer, creating the dynamic action or impact; the height over which the weight falls can be varied. The penetration is recorded after each impact. After a certain penetration the test is stopped and the internal crack patterns are described. Some simulations have been conducted, allowing the modeling of individual fracture initiation and growth during the penetration of the hammer by either a constant displacement rate (using the UDEC-code) or by introducing the dynamic process (using the PFC-code). Some of the observed features in the laboratory experiments can be visualized in the simulations. However, further research is needed to allow the simulations being an adequate tool to well understand the dynamic process in laboratory experiments, as well as the in-situ behavior.

Aug 1, 2013

By D. W. Heard

Electrospark Deposition (ESD) is a low heat-input, high energy density, micro-welding process. The short pulse duration and high-pulse frequency, in combination with the small amount of material transferred during each pulse, results in the evolution of extremely rapid cooling rates, believed to approach 105-106 °C/s [1]. This rapid solidification event results in the refinement of the microstructure to the nanostructured or amorphous level [2, 3]. Figure 1 displays the resultant microstructure of an Al-17%Si alloy deposited by the ESD process. Furthermore, it was determined that the microstructure of the deposit remained unchanged after subsequent layers were welded onto the presented layer. Freeforming of materials is a rapid prototyping process in which the deposited feedstock is built-up to the desired geometry in a near-net shape manner. Figure 2 displays the automated set-up employed produce three dimensional freeformed objects via multiple deposition trials of the ESD process. The automated XYZ table is equipped with CNC software to transform CAD renderings into three dimensional tool paths. Figure 3 displays an Al-12Si freeformed gear (2" diameter, 12 teeth) produced by the ESD process, prior to removal from the substrate. An SEM analysis of the freeformed component showed that the microstructure did not coarsen during the deposition of subsequent layers during the freeforming process, as depicted in Figure 4, resulting in the production of a bulk nanostructured component. This paper represents a summary of the capabilities of ESD to fabricate advanced materials possessing refined microstructure. In particular, results on the microstructural evolution obtainable for various wear-related systems will be presented. In addition, the feasibility of using the ESD process to freeform three-dimensional objects via multiple deposition passes will be presented and accompanied by a characterization of the properties of the freeformed component. [1] R. N. Johnson, "ElectroSpark Deposition: Principles and Applications," in Society of Vacuum Coaters, 2002, pp. 87-92. [2] J. Milligan, D. W. Heard, and M. Brochu, "Formation of nanostructured weldments in the Al-Si system using electrospark welding," Applied Surface Science, vol. 256, pp. 4009-4016. [3] S. Cadney and M. Brochu, "Formation of amorphous Zr41.2Ti13.8NilOCul2.5Be22.5 coatings via the ElectroSpark Deposition process," Intermetallics, vol. 16, pp. 518-523, 2008.

Jan 1, 2010

By James Ransford Dankwah

High sulphur carbonaceous materials like petroleum coke and rubber tyre are unsuitable as reductants in ironmaking because part of the sulphur is transferred to the reduced metal. Globally, while large amounts of petroleum coke are produced annually from the industrial processing of crude oil, billions of end-of-life rubber tyres are held in landfills and stockpiles. This work therefore investigates the potential feasibility of utilising these high sulphur carbonaceous materials as reductants in ironmaking without transferring the sulphur into the reduced metal. Composite pellets of iron oxide containing end-of-life rubber tyre (RT), petroleum coke and blends of RT/petroleum coke and petroleum coke/high density polyethylene (HDPE) were heated under argon atmosphere in a horizontal tube furnace. Reduced pellets were analysed after 10 minutes of reduction for their sulphur content. The results showed that sulphur-free metallic iron can be successfully synthesized using RT and petroleum coke as reductants. The level of desulphurisation depends on the nature of blending of the carbonaceous materials.

Jan 1, 2014

By A. Dunnett, N. J. Turner, J. Koyanagi, M. Ji

The analysis of rare earth element (REE) samples is a necessary part of the metallurgical process for rare-earth bearing ores, providing invaluable information during testing procedures. This requires a fast, multi-element technique, capable of analyzing a variety of matrices for all rare earth elements. X-ray Fluorescence spectrometry and Instrumental Neutron Activation Analysis are typically used for high concentrations of REE, but they have limitations for some process work applications due to an inability to measure all elements, longer analysis times, significant interferences and elevated detection levels. The work reported here uses new approaches with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in order to achieve high precision and accuracy within acceptable timeframes. A combination of aerosol dilution and Kinetic Energy Discrimination (KED) produce a process solution assay method that is robust enough to deal with changing sample matrices and concentrations, whilst maintaining low reporting limits and precisions of less than 5% Relative Standard Deviation (RSD). For high concentration metallurgical and geological samples, a sodium peroxide fusion digestion procedure was used, followed by ICP-MS analysis using extended dynamic range (EDR) and KED. Using these technologies, it has been demonstrated that the necessary support can be given to metallurgical process work for REE extraction.

Jan 1, 2014

By M. P. Hay

"For a model to be successful it must address the concerns and needs of a target audience. Further, the model must demonstrate the same patterns of behaviour as the real system, and need only be complex enough to meet this objective. If the model is too complex it can become unusable to those who need it most.With this in mind, SUPASIM has been developed for the practical metallurgist requiring only laboratory flotation rate data as input. Some 35+ successful plant simulations have been completed since 1985. The approach of SUPASIM is to characterise an ore, organise information in an understandable way and add structure to the complex flotation situation and hence support the metallurgist to interpret the relationship between variables and optimise the flotation process.The paper describes the basis on which the model was developed and sets out to provide an insight into interpreting laboratory flotation kinetics and their physical meaning in a production plant and the influence floatable gangue has on float performance and plant design. A case study illustrates how the ratio of slow floating mineral to gangue can influence circuit design and improve recovery on a plant scale.INTRODUCTIONThere is an enormous amount of useful data in the results of a laboratory scale rate test. Each variable of fraction and rate, for mineral, metal and gangue has a physical meaning in the plant. The link between float kinetics and the plant in respect of recovery, grade, pulp density, pulp flowrate, residence time, number of stages of cleaning and circuit configuration has been established by the author in the process of developing SUPASIM."

Jan 1, 2005

By D. C. Fraser, W. J. Scott

"Airborne electromagnetic surveys were flown during 1965 in the Moose River area of Ontario. The systems used were INPUT Mark II and the Canadian Aero Otter. Anomalies indicated by both systems were located on the ground with vertical-loop EM. Two such anomalies were drilled, with no explanation being found in the bedrock geology. Subsequent seismic, resistivity and gravity surveys indicated that the sources of these anomalies lay in the overburden. Current work in the similar geological environment of the Winisk River area has shown that comparable AEM anomalies can still be misleading. The lesson to be, learned from these experiences is that additional geophysical work can help to resolve doubtful cases before drilling decisions are made."

Jan 1, 1973

By R. C. E. Bray, Peter Price

"The property of Pamour Porcupine Mines, Limited, is in the eastern Porcupine area, about 12 miles northeast of Timmins. It covers parts of lots 3-6 (inclusive), cons. 5 and 6, Whitney tp., Cochrane district, Ontario. It is an amalgamation of the old La Palme, Three Nations, and Porcupine Grande properties.The first discovery on the Pamour was made in 1911. During 1911 to 1914 a small shaft was sunk on the Three Nations vein to the 200-foot level and a 100-ton stamp mill was put in operation, but only a small production was achieved. The property remained idle from 1914 to 1923. In 1924 some diamond drilling was done along the Keewatin-Timiskaming contact with some encouraging results, but the gold mineralization encountered was too low in general at the price of gold then prevailing to warrant further · work. The increase in the price of gold revived interest in the area, and the above noted amalgamation was effected in 1934. Options were taken and successively dropped by two large mining companies. Following this, exploration both on the surface and underground was started by Quebec Gold Mining Corporation, Limited. Diamond drilling in the early part of 1933 showed considerable ore in conglomerate and greywacke to the east. In the middle of 1935 Noranda Mines, Limited, assumed control and management. A new shaft was sunk and the property was ·equipped with a mill having an initial capacity of750 tons a day. This was subsequently enlarged to 1,500 tons a day.From the commencement of milling (May 16, 1936) to the end of 1946, 5,025,545 tons of ore having an average grade of 0.1327 oz. a ton ($4.64 at $35 an oz.) have been mined and milled."

Jan 1, 1954

By Niklas Willemsen

Introduction to SVCs ? SVC = Static var Compensator ? Dynamic step-less control of reactive power without switching of passive components: ? Voltage control/stabilization ? Harmonics- and flicker mitigation ? Dip mitigation ? Main components: ? TCR (Thyristor Controlled Reactor) ? Tuned harmonic filters ? Control- and cooling systems ? Typical applications: ? Mine hoists ? Large mining complexes ? EAF, SAF, rolling mills, wind/solar farms etc..

Aug 1, 2013

By G. B. Hobbs, S. Saimoto, L. Collins

"Plastic yielding and flow in metals is dependent on the microscopic process of simple shear along crystallographic planes and directions known as slip. Thus, by altering the crystallographic direction of the stress axis or placing constraints in the direction of plastic flow, anisotropy of yield strength for the same material is observed. This phenomenon is called texture strengthening. The application of this concept to highly anisotropic crystal structures such as the hexagonal group of titanium and zirconium alloys, the former in missile casing and the latter in nuclear reactor fuel tubing, seems obvious. The outstanding example in cubic structures is the case of deep-drawing steel. The R value, the width strain over the thickness strain during a tensile test, is taken as a measure of texture strengthening. In face-centred cubic structures, texture strengthening has been completely ignored on the basis that materials with R less than one are not amenable to this beneficiation. This study will review two aspects of texture which will lead to strengthening, first the thermal stability of the deformed microstructure, which is dependent on the stress axis, and second, the texture strengthening aspect of fcc metals.A review of recovery and recrystallization in textured aluminum wires, copper and cupro-nickel sheet will be presented with the view of extending these concepts to the manufacture of heat-exchanger tubing. The superior creep properties of specially processed commercial products such as TD-Ni, TD-NiCr and MAR-M200 will be shown to be a manifestation of the same physical phenomena."

Jan 1, 1981

By E. A. Hart, J. E. Gill

"The property of Arntfield Mining Corporation, formerly Arntfield Gold Mines, Limited, covers an area of 2,110 acres and lies in Beauchastel township, western Quebec. The Francoeur mine lies to the west, and to the east are the West Wasa and Wasa Lake properties.The property was staked in September, 1923, by the late F. S. Arntfield. The early surface work was concentrated in the west part of the property along the Francoeur-Arntfield shear zone. The zone was opened by No. 1 shaft, which was sunk for an inclined depth of 250 feet. A series of silicified lenses were discovered farther east, where No. 2 shaft was later raised to the surface. A third shaft explored a shear zone about 1,900 feet to the east, where No. 3 shaft orebodies were developed.The mill was built at No. 3 shaft and production commenced in July, 1935, at 125 tons a day. This was increased to 280 tons by 1938, and later to 350 tons. The mine continued operations on this scale until April, 1942, when the exigencies of war necessitated closing. The Company was reorganized in 1944 and underground development was resumed in June, 1945. The total value of gold and silver produced to April, 1942, was $2,011, 755 from 529,987 tons of ore.ROCK TYPESThe area is underlain by highly deformed and altered Keewatin volcanics overlain by little deformed Cobalt sediments along the south boundary. The lavas in the vicinity of the mine workings are rhyolite, trachyte, andesite, and a flow breccia of intermediate composition. The fragmentals range from fine, well-bedded tuffs to coarse agglomerate in which acidic and basic horizons can be distinguished.The intrusive rocks are diorite and quartz-feldspar porphyry in the form of stock and sills, and narrow dykes of mica lamprophyre and syenite porphyry."

Jan 1, 1954

By Barrie Robb

Outline 1. Mackenzie Aboriginal Corporation (MAC) 2. ACR background 3. ?Learning from Experience? project - What - Why - lessons 3. How Industry could contribute to sustainable Aboriginal communities 4. Concluding words What is the Mackenzie Aboriginal Corporation (MAC)? ? Aboriginal owned ? Established construction capabilities ? Commitment to development of northern resources ? Partners have extensive experience

May 1, 2008

By G. Zeng

Although the solubility of oxygen in zinc electrolyte is less than 9 mg/L, the effect on deposit stability and zinc-dust consumption can be significant. Sodium sulfite is used to deoxygenate the electrolyte. The effect of the sodium-sulfite concentration on cobalt removal is investigated. The results show the reduction of sulfite to elemental sulfur that adhered to the zinc dust surface forming a passivating layer, and small amounts of sodium sulfite have no effect on cobalt removal. The optimum amount of sodium sulfite is 100 mg/L. It is an important consideration in purification circuits to use sodium sulfite as an additive to cobalt cementation.

Jan 1, 2005

By C. Larsen, I. Orford, L. Strah, M. Renaud, P. Radziszewski

"An AG/SAG mill was commissioned at the Brunswick mine concentrator in October 1998. This paper discusses the original shell top hat liner design for the bi-directional AG/SAG mill, observed liner wear, subsequent liner design modifications, and benefits.The original liners were chrome-moly steel Norsteel with rubber grates and rubber-lined pulp lifters. The design was based on experiences of other AG/SAG mills and recommendations by the liner supplier, Norcast. Liner design modifications were made in an iterative fashion after observing the wear rate profile of the liners; over ten liner sets were implemented. Shell liner design improvements were supported by a design of experiments approach in conjunction with discrete element method (DEM) charge motion simulations. Design optimization took into account lining costs and impacts on operating performance. The team approach to the liner design improvements process is described with emphasis on the application of the design of experiments. The liner wear history and mill operating performance are presented."

Jan 1, 2005