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By M. L. Jeremic

The design of the long-hole sublevel mining method was originally based on the traditional assumption that the principal load was due to the weight of the overlying rock, and that the horizontal stresses are equal to one-third of the vertical stress. However, as mining progressed, the virgin lateral stress was found to be equal to or greater than the vertical stress. The virgin stress in the rock mass is not uniform throughout the folded orebody and adjacent strata. From detailed investigations, three basic patterns of virgin stress in ore panels have been inferred: uniform, bent and twisted. Stresses induced by stoping are up to three times greater than original stresses in the rock mass; they cause heavy ground conditions and make extraction of ore difficult. In the last ten years, the original mining system has been modified several times in order to destress the ground and improve the extraction of ore.

Jan 1, 1978

By T. T. Chen

The iron- and elemental sulphur-rich residues generated during batch and continuous pressure oxidative leaching of Inco Limited's Voisey's Bay nickel sulphide concentrate at 150°C in sulphate-chloride media have been characterized by X-ray diffraction analysis and scanning electron microscopy. The residues produced during the continuous leaching of the pentlandite- and pyrrhotite-rich concentrate consisted predominantly of hematite and elemental sulphur, with minor amounts of goethite. Although the iron species generated in the batch leaching tests were similar to those formed during continuous leaching, the morphologies of the hematite and goethite particles were significantly different. In addition to the tiny spheroids and bubble-like particles, the hematite and goethite generated during batch leaching occurred as larger "hollow" shell-like particles that contained residual pentlandite or sulphur cores. Although the leach solution from which the iron oxides had precipitated contained 5-15 g/L sodium, sodium jarosite was detected only in trace amounts in a few of the leach residues.

Jan 1, 2006

By D. E. Deegan, P. M. Keeley, N. A. Rowson, T. Stachowski

An investigation into the use of Tetronics International’s thermal plasma technology based pyrometallurgical smelting process for the recovery of both platinum and rhenium was conducted. 1000 kg of Pt-Re catalysts containing 0.36 wt% Pt and 0.21 wt% Re was blended with fluxing agents, reducing agents and an iron based collector metal precursor and then fed into a plasma furnace over five individual trials at Tetronics International’s facility in Swindon, UK. Both platinum and rhenium partitioned to an iron rich collector metal phase in the furnace, which formed in-situ and accumulated beneath a less dense slag phase, derived from the inorganic substrate of the catalyst, and was easily separable. The levels of Pt and Re concentration achieved in the iron collector made it suitable for subsequent final refining. Technical recovery efficiencies of =98% for both platinum and rhenium were achieved and the concentrations of the metals in the recovered metal bullion were 2.23 wt% Pt and 1.35 wt% Re.

Jan 1, 2015

By R. F. Coulter

THE Flin Flon concentrating and metallurgical plants (Figure 1) of the Hudson Bay Mining and Smelting Co., Limited, lie adjacent to the town of Flin Flon, on the Manitoba-Saskatchewan border, 400 miles northwest of Winnipeg. Since the start of milling operations in 1930, over 50 million tons of ore from the Flin Flon mine have been treated in the concentrator. During the past few years, newly discovered orebodies have been brought into production and their ores processed at the company's main metallurgical plants. All these properties are within a 75-mile radius of Flin Flon and have aided substantially in augmenting plant metal production as well as retarding depletion of ore reserves in the Flin Flon mine. •Current satellite producers are the Schist Lake, Coronation, and Chisel Lake mines. The Schist Lake mine, located 3 ½ miles southeast of the main plant, is a copper-zinc producer. It was brought into production in 1954. The

Jan 1, 1962

By E O. Foster

When roasting started at Giant Yellowknife Mines in 1949, it became apparent that, to prevent air and water pollution in the surrounding district, it would be necessary to collect the arsenic that was contained in the exit gases of the roaster. The arsenic collection problem was finally solved by the installation of both electrostatic and baghouse collectors. It was realized that a considerable quantity of gold-bearing dust was leaving the roaster with the exit gases. When the collection problem was solved, it was possible to measure this loss. The loss proved to be considerable and it became evident that a substantial quantity of gold could be recovered. Research programs on dust treatment began in 1958, and by May, 1960, the treatment process which is currently being followed was started in the plant. At present, the two electrostatic preci11itators, Operated at temperatures above 600°F, collect the gold-bearing dust.

Jan 1, 1963

By S. A. Briggs

Bioremediation has been accepted as a treatment technique for groundwater contamination in subsurface soils and shows promise for contaminated fractured rock environments. Biological growth in fractured rock is expected to occur predominantly as biofilms attach to the fracture surfaces. Biofilms in rock fractures are subject to a complex system of forces and other phenomenon due to the dynamics of the bulk fluid in which they grow. In this paper, through the applications of computational fluid dynamics (CFD) to rock fractures, where the boundaries are rough and the flow is complex, a precise analysis was conducted of the interaction of a fluid flow and the rock fracture. Specifically, hydraulic parameters and velocity profiles of an actual rock fracture were calculated and compared to a fracture of equivalent aperture. From the analysis it is clear that it is important to use more complex models such as the Lattice Boltzmann Method used is this paper to describe fracture flow.

May 1, 2009

By H. J. Chalmers

THE H.B. MINE and concentrator are located in the Nelson Mining Division of British Columbia, on the north side of the Sheep Creek valley about seven miles southeast of the town of Salmo. It is an operation of The Consolidated Mining and Smelting Company of Canada, Limited (Cominco), which has its metallurgical plants at Trail, about 25 miles west. The property was originally staked about 1907 by Horton and Benson, whose names are commemorated in the designation "H. B." Up until 1927, a considerable amount of development work was done in the upper levels by various companies. Cominco purchased the ?property in 1927 and carried out intermittent work until 1946. Following this, an extensive surface diamond drilling programme and a subsequent underground exploration were undertaken. Sufficient ore was outlined 'to warrant the construction of a 1,000: ton concentrator. This was started in April, 1952, and completed by the spring of 1953. However, because of adverse base metal market conditions, operation was deferred until May, 1955.

Jan 1, 1957

By L. Bichler

Lightweight magnesium alloys are gaining in popularity for applications in the automotive and aerospace industries, Their use, however, remains limited due to their relatively low strength and creep properties. Lost Foam Casting (LFC) is a new casting process and the strength of foam cast magnesium alloys has not been investigated in great detail thus far, In this research, magnesium alloy AZ91 E and three new alloys were cast by the LFC process to study the effect of varying aluminum and manganese content on the alloy's tensile properties, The study reveals, that the tensile strength of the magnesium alloy is closely related to the relative amount of aluminum in the system. Formation of ß-Mg17Al12 phase was seen to significantly affect the yield strength and ductility of the alloy, Furthermore, formation of manganese intermetallic compounds was seen to effectively increase yield strength of the base alloy, Individual alloy morphologies were analyzed via optical and SEM techniques.

Jan 1, 2004

By G Anders

Underground tests of slusher cables at first might seem to be quite simple and inexpensive. They do, however, take a long time and give results that may be ambiguous and unreliable. Also, because underground test conditions are not exactly duplicable, tests carried out at different times or in different mines could not be compared. An attempt was made to develop a laboratory test method that would provide for all factors affecting slusher cable performance underground in such a way as to make it possible to achieve comparable results from different series of tests by exactly duplicating test conditions. Such a method should also make it possible to vary individual factors systematically in order to give a proper assessment of the effect of changing conditions on cable performance. A set of tests, comparing the same two types of cable both underground and in the laboratory, is described. AN assignment at the Algom Nordic mine called for the comparison of two types of %-in. slusher

Jan 1, 1964

By N. Valkanov

This paper presents results of an investigation into the connection between minerals liberation management and flotation, responding to lead-zinc concentrator ?Erma reka?, in Bulgaria. Monitoring of a Zn flotation circuit was carried out. The causes for the high silica content in the final Zn concentrate were established. Quartz is present mainly as liberated particles (> 60?80 %) in the fine fractions of the products; therefore the selectivity of the flotation process is not effective. Two approaches were tested to reduce the quartz content of Zn concentrate: froth washing in Zn cleaner flotation and new gangue depressants in the Zn circuit. Experimental results from bench-scale flotation and industrial tests show that it is possibile to reduce the silica content of final Zn concentrate more than 2 times without the need for extensive regrinding. The depression of liberated quartz particles on all operations of Zn circuit using stage depressant addition is the right solution to produce high-grade Zn concentrate that meets the metallurgical requirements.

Aug 1, 2013

By C R. Crook

A brief outline of production methods and processes is given to show how maintenance fits into the picture at this plant. The work force, and the tools needed to carry out this function, are then described. Preventive maintenance practices, scheduled annual shutdowns and routine check-downs are explained, especially as related to planning and to the materials and labour involved for a mini-mum downtime. A brief explanation of the materials, sup-plies and spare parts program, as well as the part played by the Stores Department in conjunction with the Maintenance Department, is given. Cost control and equipment expenditure indicators are explained. Some specific examples of maintenance jobs are described in order to show the flexibility of the program. S HERRITT GORDON Mines Limited has been in continuous production, except for the planned downtimes needed for expansion tie-ins, or the annual shutdown check-over periods, since the first shipment of nickel on a commercial basis in July of 1954.

Jan 1, 1964

By R. D. Brown

"""A matter of serious concern to the mining industry in British Columbia""; this comment reflects the attitude of the Mining Association of British Columbia toward the proposed new B.C. Mineral Royalties Act. The proposed legislation, introduced by the provincial government in February and now being debated by the legislature, combines a basic 5% royalty on the selling price, less approved p1ocessing and transpo1•tation costs, of minerals produced in B.C. with an ""excess"" royalty of 50% of any price increases over a predetetmined base. Government estimates project annual revenues of $20 million from the new royalty structure. The accuracy of these figures has been contested by the mining industry. Based on current world prices for copper the industry estimates that the provincial revenues from this mineral alone may run as high as $140 million in 1974 and $150 million in 1975. The Mining Association has warned that the new royalties “threaten to become confiscatory""."

Jan 1, 1974

By T. Y. Chong, J. A. Folinsbee, M. Fullam

PJV Dome Mine has used some form of gravity concentration since start of milling operation in 1909 to recover free milling gold. Amalgamation and conventional jigs were first used and were replaced with the Knelson Concentrators in 1993. The Knelson concentrates produced were upgraded on a conventional shaking table prior to smelting and refining into gold bullion. In May 2002, a comprehensive review of the latest gravity recovery technology led to a piloting campaign aimed at further improving gravity recovery. The Knelson concentrates, subjected to intensive cyanide leaching in an Acacia pilot plant, were found to be amenable to intensive cyanide leaching with over 98% of the gold being dissolved within 24 hours. An Acacia Intensive Leach Reactor was successfully installed and commissioned in December 2002, to replace the shaking table. his paper describes pilot scale testing, installation, commissioning and optimization of the Acacia Intensive Leach Reactor. Also, the economic impacts on down stream processes are highlighted.

Jan 1, 2005

By George A. Guess

The making of contracts for the purchase of ores is a business which the metallurgist usually understands better than the miner. Companies in the custom ore business often employ an ore buyer who is aware of the class of ore which the smelter needs, and is thoroughly conversant with the business. The miner on the other hand makes ore contracts but seldom, and it is often only after a settlement has been made that he realizes the meaning of the terms of the contract under which he has sold his ores. He has expectations usually greatly in excess of the amount 'net proceeds' shown at the bottom of the settlement sheet. Seldom does the occasional shipper really know his contract. A somewhat similar parallel is to be found in insurance policies. We all have insurance policies; we never know the conditions contained in them until after the fire. The clauses in the policy are for the protection of the Insurance Company. An Insurance Company has no friends.

Jan 1, 1926

By S. Shrestha

Magnesium-based alloys are of growing interest for many industrial applications due to their favourable strength-to-weight ratio and excellent castability. Mass reduction has advantages in many industrial sectors for example, in automotive, a reduction in mass improves fuel economy and can lead to more efficient mechanical systems by reducing the weight of moving parts like wheels, gears, pistons. However, the relatively poor corrosion and wear resistance limits the use of magnesium and its alloys in many potential applications. The patented Keronite® plasma electrolytic oxidation (PEO) process enables manufacturers to overcome such problems and, in its latest generation equipment has been developed to industrial realisation for high volume production. This paper presents microstructural characteristics and corrosion performance of two most widely used high pressure die-cast magnesium alloys AZ91D and AM6OB with a duplex corrosion protection coating system that comprised a thin Keronite pre-treatment followed by a subsequent automotive grade final powder coat.

Jan 1, 2006

By L. St-Georges

In aerospace and transportation industries, severe problems are related to fatigue failure. Aluminium is frequently used in these industries to optimize the solidity and minimise the weight of the structures. Nevertheless, the fatigue life of aluminium alloys is limited and specific efforts have to be made to reduce the vibratory stresses in the mechanical parts. When riveted, the life of the sheet metal structures can be increased compared to welded structures, due to the energy dissipated by the friction between the rivets and the sheet metal and the sheets themselves. In the past decade, a new tool was developed to assemble aluminium structures; the friction stir welding. With this new technique, fatigue life of the aluminium welded joints can be increased by a factor from two to ten. However, less energy can be damped by the friction between the components and increased vibratory stresses may occur. In this investigation, the potential of the friction stir welding to create damped aluminium sheet metal structures is evaluated.

Jan 1, 2006

By G. E. Parsons

"The Bidgood is a small gold mine about 5 miles east of the main Kirkland Lake camp. Since the beginning of production in 1934, gold having a value of $5,000,000 has been produced from the property. Practically all of this production has come from seven veins in a diorite stock that intrudes the Timiskaming sediments and lavas of the area. The veins consist of quartz, pyrite, and molybdenite with minor amounts of chalcopyrite, calcite, and tellurides, and occupy northeast striking and northwest dipping thrust fault fractures. They have no apparent direct structural association with the faults of the main Kirkland Lake camp or the Larder Lake 'break' to the south; however, the veins closely resemble the former in their mineralogical composition and in their close association with syenite intrusives.ROCK TYPES AND THEIR STRUCTURAL CHARACTERISTICSThe dominant and, from an economic standpoint, most important rocks in the ore area consist of two separate families of Algoman intrusivesa diorite and a later syenite group."

Jan 1, 1954

By G E. Craig, W. M. Williams

A simple, easily constructed apparatus suitable for the zone refining of iron and other reactive materials is described. After eight passes at one inch per hour, the iron produced showed a marked drop in hardness to 49 Brinell. In addition, an arbitrarily -defined recrystallization temperature was lowered by about 35°C and the rate of grain growth greatly increased. CERTAIN materials, of which iron is one, are so reactive that they cannot be zone refined in any known container without becoming contaminated. For such substances, the floating zone method ( 1) may be used. In this method, the specimen is supported vertically in an inert atmosphere and the molten zone supports itself by its own sur-face tension. The method was first applied to silicon (2) and has since been used for other reactive metals such as zirconium and titanium. Smith and Rutherford (3) have previously reported on the floating zone refining of iron; the efficiency of the method for reducing the car-bon content was demonstrated on

Jan 1, 1962

By Y. Wang

In this study, homogeneous (unseeded) precipitation of nesquehonite (MgCO3.3H20) by the reaction of MgC12 with (NH4)2CO3 in supersaturated solutions at 30 °C was investigated. Factors which influence the precipitation of MgCO3.3H20, such as initial concentration, temperature, stirring speed, titration speed, equilibration time, have been studied. SEM images show that the initial concentration and titration speed have significant effect on nesquehonite's crystal morphology and particle size. In addition, stirring speed and equilibration time also have some influence on its properties. With the optimization of operating conditions, the crystals can grow up to a length of about 40µm and a width of 5µm, indicating good filtration properties. High purity nesquehonite obtained in this study was calcined to produce highly pure MgO at 800 °C as shown by XRD results. The novel process may be used to separate Mg and Li from high Mg/Li ratio brines in Qinghai, China.

Jan 1, 2007

By Xueyuan Nie, Xuezhi Zhang, Henry Hu, Shen Xinwei, Jimi Tjong, Li Fang

With the demand for weight reduction in vehicles and airplanes, researchers have shown great interested in casting wrought aluminum alloy 7075 because of its potential advantages such as high strength-to-density ratio and stress-reduction capabilities. It is therefore essential to conduct a fundamental investigation on solidification behavior and grain microstructure of alloy 7075. In this study, a commercially-available wrought aluminum alloy 7075 was used to study the solidification behavior of alloy 7075. A thermal analysis was performed based on the cooling curve and its corresponding first and second derivative curves. The nucleation of the primary a-Al phase and eutectic phases were analyzed. The comparison between the microstructures of the wrought and cast 7075 alloys shows that coarse microstructure and porosity are present in the cast alloy. The techniques for grain refinement in casting, such as the addition of the nucleating particles and applied pressure, should be employed to reduce the dendrite arm spacing and the porosity.

Jan 1, 2015