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By G M. Young

IT IS most appropriate that this first Memorial Lecture should be given in the Province of Quebec, near the site of the first metallurgical industry in Canada. At La Forge, about seven miles north of Three Rivers, iron was produced in 1783. We are told that the early settlers obtained most of their iron-ware -stoves, kettles, axes and ploughshares -from this smelter, with its foundry and forge. The Canadian copper industry also had its beginnings in Quebec when, nearly 100 years later, in the 1880's, several small copper smelters were erected in the Eastern Townships. Later, in 1899, Canada's first aluminum smelter was built at Shawinigan. From these small beginnings has grown a vast metals industry, the export value of its products being only exceeded by that of our forest products -newsprint, pulp-wood and lumber. As we are not a large country in terms of population, our domestic capacity to consume is often small in relation to our developed capacity to produce.

Jan 1, 1963

By Daniel Connor, O&apos

The Cal-Sag Relief Sewer is a 2.6 m (8 ft 6 in.) diameter 9.1 km (5.7 mile) rock tunnel bored in dolomite for the Metropolitan Sanitary District of Greater Chicago. Included in the project are 18 shafts varying in depth free 70 m (230 ft) to 41 m (135 ft). This paper discusses how Healy/Vanessa reduced costs by eliminating conventional hand excavation by hoisting muck from a high production Robbins TBM (Tunnel Boring Machine) through small diameter drilled shafts and using a trailing rail-utility backup system.

Jan 1, 1985

By Henry Branes

Para maximizar el retorno de la inversión se aplica la economía de escala pero no se consideran el riesgo financiero al aumentar la escala del proyecto. Las curvas de recuperación metalúrgica vs ley de minera no son lineales. Esto implica elegir un punto óptimo, donde los rendimientos decrecientes de la minería selectiva no justifican el aumento del costo de minado y la reducción de la tasa de alimentación a planta. El artículo analiza las variables más significativas y propone una metodología para definir la capacidad de planta óptima para obtener el máximo rendimiento de la inversión basado en la sensibilidad de una serie de escenarios de planes de minado.

Sep 1, 2017

By W. H. Miller

Introduction In this paper we have endeavoured to present a general description of the electrical applications underground at Copper Mountain, including types of equipment used, problems encountered, and methods by which they were overcome. No attempt has been made to outline in detail the wiring of various circuits. Until recent years, the main use of electrical energy underground at Copper Mountain consisted of direct current for locomotives, trolley systems, .and signal and communication circuits. The prohibitive cost of equipment and distribution systems prevented any extensive use of a.c. beyond that commonly used for essential lighting purposes. However, in 1943 the shortage of manpower and the increased cost of labour and supplies necessitated a general mechanization programme.

Jan 1, 1951

By G. S. Derrickson, R. A. Golobic

Any type of agitation within a confined vessel is primarily concerned with two parameters: a level of agitation describing the homogeneity of the constituents (whether it be suspension or mixing), and the energy efficiency with which this level of agitation is accomplished. The following is an attempt to present a solution to the problem of adequately defining and optimizing these properties. A discussion is included of the application of good design practices to the determination of a mechanically efficient shape to the blade elements of the propeller. These practices, excluding several appropriate modifications, have been known, but not well understood, in aircraft fluid mechanics for a number of years. Having optimized the direct impartation of energy to the medium being agitated, attention is turned to one of the more perplexing phenomena of multi-phase systems - definition and prediction of agitation levels. The result of recent study and testing is a method of scaling that the authors believe provides a lucid understanding of governing physical parameters within the agitator itself, allowing one to scale up and down with confidence.

Jan 1, 1985

LAWFORD H. FRY, Burnham, Pa. (written discussion*).-As a sup-plement to the information given by Mr. Bash, a diagram is submitted showing the results of a somewhat similar experiment carried out at the ordnance plant of the Standard Steel Works Co. In this case the ingot to be heated was a nickel-steel octagon ingot, weighing 14,700 lb. (6667 kg.). This ingot was to be forged into two 255-mm. howitzer jackets. A hole was bored half way of the length of the ingot, extending into the longitudinal axis, and a base-metal thermocouple inserted in this hole.

Jan 11, 1919

By Yuji: Wada Ogata, Kunihisa Katsuyama

It is well known that a compressed stress wave reflects at the free face, it propagates to the backward as a tensile stress wave, and cracks grow when the tensile stress becomes the dynamic tensile strength. The behavior of these cracks has been discussed through the observation of the dynamic photoelastic high speed photography.

Jan 1, 1993

By J. T. Popp

This Bureau of Mines study reviews the geological factors that affect methane in the Beckley coalbed in southern West Virginia, including overburden, coalbed structure, type of and changes in lithology above and below the Beckley coalbed, and presence of fractures in the coal and rock adjacent to the Beckley. Depending on the depth, the Beckley coalbed emits from 216 to 520 ft3 of methane per ton of coal mined, and the Bureau estimates that methane emission in a deep, extensively developed mine in this area may exceed 3,000 ft3 per day per ton of coal mined. Average face cleat and butt cleat trends in the Beckley coalbed measured underground are N 33° W and N 53° E, respectively. Close cleat spacing con¬tributes to the friable nature of the Beckley and provides easy movement for methane and water. Because rider coals, splits, and carbonaceous shales may contribute methane to mine emissions, predictions of methane emission based on gas content of the Beckley coalbed alone may be conservative. Beckley coalbed reserves in the study area are 234 million tons. The gas content of the Beckley coalbed averages 407 ft3/ton, and the coalbed gas reserves are 108 billion ft3.

Jan 1, 1976

This paper reviews the history of refractory materials, highlights the development of refractory technology over the years, draws attention to the technology behind these materials, and comments on future developments in this field. By walking the path with refractory materials, from their initial uses in BC times, to the composite materials that are used nowadays, and the nanotechnology developments that are currently taking place in this field, the reader will come to agree that refractory materials are indeed very ?cool?! Keywords: refractory materials; bricks; monolithic materials.

Jan 1, 2008

By T. Ogasawara, J. P. Barbosa, A. J. Monhemius, F. T. Da Silvia

A thermodynamic analysis of the sulphation of rare-earth phosphates and the water-leaching of rare-earth sulphates was used to guide experimental work on the sulphation and leaching of concentrates from Pitinga. It was concluded that the sulphuric acid digestion of xenotime is technically feasible and could be used industrially to produce yttrium and other rare-earth oxides. Yttrium extractions of more than 90% were obtained by digestion at 503 K for 4 h at an acid:concentrate ratio of 2:1 with particle size -0.053 mm. The apparent activation energy at temperatures less than 473 K, as determined from the Arrhenius plot, was 11.0 kJ/mol, indicating that the reaction is controlled by the diffusion of the reactants or products through the sulphate layer

Jun 19, 1905

By Mark Cadzow, Rodney Lamb

CARBAD is a recently developed Australian process for the recovery of gold and platinum group metals (PGM). The process relies on the selective agglomeration phenomena of the gold and PGM to capture the mineral in a carbon-hydrocarbon media. The precious minerals are then extracted from the loaded media by a solvent gold room process producing a relatively pure concentrate. The media is then reformed and recycled. The process development from batch test work to a 5 t/h commercial scale CARBAD plant is discussed. The operation and results of processing a variety of ore types at several alluvial and hardrock gold mines is examined. The operating and capital costs for the CARBAD process shows that it is significantly less than that the conventional CIP/CIL. The environmental safety of the process is a major feature where precious metal deposits are located within urban environments or within wilderness areas.

Jan 1, 1989

By P. Beardmore, B. W. Howlett, B. D. Lichter, M. B. Bever

The heats of formation at 273°K of the compounds Mg2Ge, Mg2sn, and Mg2b, the heats of fusion and melting points of Mg2Sn and Mg2Pb, and the heats of solution of magnesium, germanium, and lead in liquid tin have been measured. The excess free energies of the liquid alloys and the free energies of formation of magnesium-Group IVB compounds at their melting points and their standard free energies of formation at 298°K have been calculated. The stability and bonding of the compounds are discussed with reference to these properties. Some thermodynatnic aspects of the liquid phases in the systems Mg-Sn and Mg-Pb are also considered. THE compounds of magnesium with the Group TVB elements, silicon, germanium, tin, and lead, have often been considered to constitute a nearly ideal homologous series. In particular, their thermodynamic stability has been assumed to decrease with increasing atomic number of the Group IVB element.' The binary-phase diagrams of the magnesium-Group IVB elements given by Hansen and Anderko2 have the same form. Each system has a single con-gruently melting compound of limited homogeneity range. The structures of these compounds, which have the formula Mg2X, are anti-isomorphous with the calcium fluoride structure. A recent investigation has found evidence of a second compound in the system Mg-Pb.3 The solid compounds Mg2Si, Mg2Ge, and Mg,Sn are semiconductors, while the conductivity of Mg2Pb approaches that of a metallic conductor. This difference suggests that other properties may also show a discontinuity. The investigation reported here is concerned with the thermodynamic properties of magnesium-IVB compounds and particularly their variations with the period of the Group IVB element. The heats of formation at 273°K of the compounds MgzGe, Mg2Sn, and Mg2Pb and the heats of fusion and melting points of Mg2Sn and Mg2Pb have been measured. The results, combined with published data, are interpreted in relation to the stability and the bonding characteristics of the compounds. Some thermodynamic aspects of the liquid phases in the systems Mg-Sn and Mg-Pb are also considered. In the course of the investigation the heats of solution of magnesium, germanium, and lead in liquid tin have been determined. 1) EXPERIMENTAL PROCEDURES 1.1) Samples. Samples of the compounds Mg2Ge, Mg2Sn, and Mg2Pb, supplied by Professor P. Aigrain, Compagnie Générale de Télégraphie Sans Fils, were used in measuring heats of formation, heats of fusion, and melting points. Samples of Mg2Sn and Mg2Pb, supplied by Dr. V. B. Kurfman, Dow Metal Products Co., samples of Mg2Sn, prepared at the Air Force Cambridge Research Laboratories, and samples of MgzPb, prepared in this laboratory, were used for additional measurements of the heats of fusion and the melting points. The samples were stored in evacuated Pyrex capsules or under nonreacting liquids. 1.2) Heats of Formation. The heats of formation at 273°Kof the compounds Mg2Ge, Mg2Sn, and Mg,Pb were measured by tin-solution calorimetry. In this method, samples of the compound and of a mixture of the constituent elements are added alternately from 0°C to a tin-rich bath. The difference between the heat effects, corrected for the change in composition of the bath, is the heat of formation of the compound. Details of the method have been given elsewhere. 4 The bath was maintained at 350°C for the dissolution of the compounds MgzSn and Mg2Pb. Since at this temperature the dissolution of Mg2Ge was too slow, a bath temperature of 400" or 450°C was used with this compound. At least three calorimetric runs, each of approximately six additions, were made with each compound. 1.3) Heats of Solution. The determination of the heats of solution of magnesium, germanium, and lead in tin was included in this investigation because they were not well-established at the time this work was started. To obtain the heat of solution, the difference

Jan 1, 1967

By D N. B Skinner

Changes in the configuration of late Cenozoic volcanic arcs related to Pacific-Australian plate convergence in northern New Zealand may have localised large-scale epithermal gold-silver mineralisation to a particular part of the volcanic arc system, the Coromandel Volcanic Zone (CVZ). The history of arc-type volcanism in northern New Zealand began with the development of the continental margin Northland Volcanic Arc from early-mid Miocene (26-15 Ma). From 18-15 Ma the Northland Volcanic Arc extended south into the northern and western part of the CVZ where it is dominantly composed of andesite with lesser dacite and very minor rhyodacite. In the south, centre and east of the CVZ, younger andesite-dacite volcanism overlapped in space and time (14-5 Ma) with voluminous rhyolitic volcanism associated with rift-hosted calderas and minor basaltic eruptions. This change to bimodal rhyolitic-basaltic volcanism and extensional tectonics was a result of southwest (SW)-directed propagation of the Colville-Lau oceanic island+ arc into the north-northwest (NNW) trending Northland Volcanic Arc and its underlying continental crust. The extensional tectonic regime created in the collision zone between the two arcs is also the site of the 14-6 Ma Coromandel epithermal gold-silver province, which contains some 50 separate deposits and has a production (1862-1996) of about 300 t Au and 1150 t Ag. Extensional tectonics facilitated the emplacement of silicic magma at shallow crustal level and led to reactivation of deep basement faults. The resulting enhanced heat flow and fault-focused fluid flow localised large hydrothermal systems and associated extensive low-sulphidation epithermal gold-silver deposits in the southern part of the province, as at Waihi, Golden Cross and Karangahake.

Jan 1, 1997

By R. Pakalnis, D. Tenney, B. Lang

"This paper describes three case histories whereby numerical methods were employed as a tool in the identification of potential instability. Simple two dimensional (PCBEM) and pseudo three-dimensional (BESOL, MINTAB) codes were employed to identify zones of induced stress which were subsequently related to extensometer, stress meter and observational data as the stope was excavated. The following case histories will be discussed. MacLellan Mine - sill pillar stability; Ruttan Mine-Hanging Wall Stability; and Detour Lake Mine-narrow vein mining.The MacLellan case history showed how modelling and instrumentation enabled mining to be conducted safely and under controlled conditions. MINTAB and PCBEM were employed to predict sill pillar failure. The sill pillar failure was associated, with an unloading of stress which was recorded by instrumentation (stress meter) and a decrease in the over-all rock mass strength. The yielded pillar, however, maintained its over-all configuration enabling access through the pillar.The Ruttan case history is an example of hangingwall and footwall design whereby the existence of adverse structure coupled with a zone of relaxation results in dilution. BESOL and PCBEM were employed to model a test stope and to verify the observations and measurements through instrumentation . Empirical methods of dilution estimates are employed to determine the level of walls lough with respect to the rock mass rating, stope dimensions and rate of excavation.The Detour Lake case history in an example of open stoping a narrow steeply dipping deposit. Stope dimensions are 135m in strike length, 47 m in vertical height with an average width (F/W to H/W) of3.6 m. Stress meters coupled with visual observations are related to modelled estimates of stress and dilution."

Jan 1, 1991

By D. E. Kirby

In line with the Bureau of Mines' goal of providing technology to maintain a supply of minerals adequate to meet national economic and strategic needs, a method for recovering chromite from lateritic materials was investigated. Laterites are a large resource of Ni, Co, and Cr, critical metals of which the United States has insufficient domestic sources. A roast-leach method was developed by the Bureau to extract nickel and cobalt from domestic laterites. A concurrent effort was made to recover chromium from either unprocessed laterites or the leach residues. This report characterizes laterites and laterite leach residues. It describes a chromite recovery procedure using conventional industrial beneficiation equipment for sizing, low-intensity magnetic separation, and gravity concentration. Concentrates containing 20.0 to 22.4 pct Cr (29.0 to 32.7 pct Cr203) and with a 1.6:1 to 1.9:1 Cr-Fe ratio were recovered from laterites and residues containing 1.3 to 2.5 pct Cr with recoveries exceeding 50 pct. Because of their low grade and fine size, these concentrates would be suitable for preparing chromium chemicals. The direct beneficiation of laterites for chromite recovery resulted in the minerals containing nickel and cobalt concentrating in slime products. No iron oxide coproducts of acceptable grade were recovered from either laterites or residues.

Jan 1, 1982

By Y. Tao

The professional status and characteristics of mineral processing were discussed along with the importance of innovative personnel training for mineral processing engineering. Reform ideas and models for the mineral processing engineering education system were suggested to formulate and implement new training program for the mineral processing specialty. It is suggested to strengthen engineering training practices, cultivate the culture of innovation, improve innovative education system and insisting on the combination of teaching with production and scientific research as the important means of training innovative talents for mineral processing engineering.

Jan 1, 2010

By D. S. Burgess

A commercially available Halon 1301 extinguisher has been evaluated as part of an explosion-suppression system for use in coal mines. Studies were made both of the dispersion pattern of the Halon 1301 at an initial pressure of 280 psig, and of the efficacy of this suppressant against 9.5 percent methane-air flames. These flames were quenched successfully only when the suppressant was applied before the fireball diameter exceeded 18 inches.

Jan 1, 1971

By S. D. Graham

"The extractive metallurgy of gold is largely controlled by mineralogical factors such as the presence of refractory gold, particle size, gangue mineral associations, presence of preg-robbers, oxygen and cyanide consumers, and locking characteristics in base metal sulphides. Light microscopy and automated mineralogy techniques are regularly used to characterise the effect of these variables on gold recovery. However, despite their widespread application there are a range of limitations when grades are low. Typically, the analysis of low-grade samples requires the preparation and analysis of numerous polished blocks. This is often costly and time consuming, with complexities regarding analysing statistically representative particle quantities and problems overcoming stereological bias. This is compounded by the “nugget” effect and high tenor nature of gold mineralisation. X-ray Microscopy techniques have the potential to overcome many of these problems, in particular the statistical representivity of analysis, removing stereological bias and effectively locating phases that are present in ultra-trace proportions. In this paper we outline the potential benefits of employing X-ray Microscopy (XRM) in characterising gold losses from a typical Cu-Au porphyry project, which were illusive in 2D based analysis. The talk will also outline additional application areas of XRM within the extractive value chain."

Jan 1, 2017

By Adshead ND, Blake KL, Rotherham JF, Rotherham M, De Jong G

Magnetite deposits with distinctive ¦ actinolite ¦ apatite -bearing gangue and spatially-extensive sodic-calcic wall rock alteration occur in both Proterozoic metamorphic terrains and Mesozoic-Tertiary magmatic arcs. Examples from both settings constitute significant sources of iron ore (e.g. Kiruna, Sweden; El Romeral, Chile) and some host major Cu-Au deposits that have a local association with K-silicate alteration (e.g. Cloncurry district, NW Queensland; Copiapo district, Chile). A growing body of evidence points to a hydrothermal origin for these systems involving high temperature, low S oxidized fluids. The Cloncurry magnetite-Cu-Au deposits are products of the local structurally channelized influx of a specialized high salinity ore fluid into larger-scale alteration systems developed during pluton emplacement at greater depths than those associated with subvolcanic (porphyry) Cu-Au deposits. The geological characteristics of deposits in magmatic arcs are consistent with a similar mode of origin albeit in rather different tectonic settings.

Jan 1, 1995

By Bruno Bussière, Michel Aubertin, Anne-Marie Dagenais, Johanne Cyr

A five steps remediation program was commissioned in 1998 for the acid generating Lorraine mine site, located in the Témiscamingue region, Quebec, Canada. It included, as the main expenditure, a cover with capillary barrier effects (CCBE) used to limit oxygen migration. After construction of the cover, instruments were installed on site to monitor the CCBE performance. Modified oxygen consumption tests were also done to measure the oxygen flux through the cover. Results from water content and suction data, measured from 1999 to 2003, show that the capillary barriers effects are effective and that the water retention layer stays near saturation throughout the years. Oxygen fluxes estimated from monthly water content measures are generally below 10 g/m2/year. Results from modified oxygen consumption tests made on the site give almost similar oxygen fluxes. A two dimension numerical model of the Lorraine mine site was also constructed to verify that mathematical models could predict realistically the in situ conditions on such a large scale site. Numerical results obtained for three years show a good concordance between measured and calculated values. The results obtained form these different evaluation methods for the performance of a CCBE concur and confirm the efficiency of this cover in limiting acid mine generation.

Jan 1, 2005