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By Tom Shumka

All mineral processing facilities that use girth gear driven mills need to inspect the gear teeth on a routine basis, whether it is every six months or every three years. The inspection frequency depends upon gear tooth condition, and the objective is to ensure operational integrity of the gear teeth. Conventional methods such as magnetic particle testing, visual inspection, or dye penetrant examinations rely heavily on interpretation. At best, these techniques can determine whether a defect exists, but are unable to provide information on defect severity. This paper describes the use of combined Eddy Current Array (ECA) and Alternating Current Field Measurement (ACFM) to provide a complete survey of all surface breaking indications on the whole gear tooth depth. This method accurately determines the size, length and depth of any cracks found on the surface.

Jan 1, 2012

By G. Gauvin

Life span of aluminum smelting electrolysis cells can reach up to 3000 days. During this period, cathode blocks go under various physical and chemical changes that could result in an increase of electrical resistivity. The increase may be due to carbon migration from the cast iron to the steel bars, gap evolution between the cathode block and the cast iron, cathode cracking, etc. This paper focuses however only on the collector steel bar electrical resistivity evolution. To reveal the main phenomena responsible for the electrical resistivity increase, chemical analysis, metallographic and electrical resistivity tests were conducted on two steels bars picked from two Hall-Héroult cells after autopsies. Cathode voltage drop and temperature were measured using electrically insulated internal probes and thermocouples on 16 samples from each steel bar. Electrical resistivity can reach up to 1.21µO-m for a steel bar aged 2505 days compare to 0.142µO-m for steel AISI 1008 at room temperature.

Jan 1, 2011

"THE PACIFIC CONTINENTAL MARGIN OF CANADA is de-fined, for the purposes of this paper, as the area sea-ward from the present mainland coast of British Columbia to the foot of the continental slope. It thus coincides with A. Sutherland Brown's Insular Tectonic Belt. The region is limited to the north and south by the political boundary with the U.S.A., the location of which is still in dispute.The region can be subdivided into: (1) an interior trough comprising the Queen Char-lotte, Comox and Nanaimo basins; (2) a medial uplift comprising Vancouver Island and the Queen Charlotte Islands; and (3) a marginal shelf which is extremely narrow (Jess than 5 km) west of the Queen Charlotte Islands, widens to 160 km in Queen Charlotte Sound and is about 35 km wide west of Vancouver Island, where it is underlain by the Tofino sedimentary basin, with its• extension, the Juan de Fuca Basin, at the southern end.The medial uplift consists of a highly disturbed anticlinorium of mainly Mesozoic rocks, with a core of Palaeozoic. The rocks include thick sequences of eugeosynclinal volcanics and sediments. There is strati-graphical evidence of repeated interruption in sedi-mentation. By late Jurassic, the main eugeosynclinal phase was over and a successor basin was initiated in the interior' trough. This became filled, during Cre-taceous and Tertiary time, with sediments ranging in environment from bathyal turbidites to terrestrial conglomerates and coals. West of the medial uplift, another successor basin developed in early Tertiary times and became filled with mainly deep-water marine sediments. A third effusive sequence marks the base of the Tertiary on Graham Island and over most of the Hecate Strait region and Tofino Basin."

Jan 1, 1970

By C. Liu

Corrosion behavior of the stir zone in a friction stir weld of dissimilar A12024/AZ31 alloys was investigated in the immersion test in distilled water (pH=6) for different times. Microstructures and the distribution of chemical elements were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Due to the difference in the corrosion potentials between A12024 and AZ31, the AZ31 alloy constituent in the stir zone was susceptible to the corrosion attack in the distilled water. The corrosion attack was found to occur in the narrow region of the AZ31 alloy adjoining the A12024 region, where there was a low ratio of anode-to-cathode surface area. The corrosion attack became more severe in the AZ31 alloy regions with increasing immersion time. The A12024 alloy region in the stir zone of the weld was protected by cathodic reactivity due to sacrificial anode AZ31 alloy.

Jan 1, 2007

By S. Makni, G. Gagnon, F. Couët, C. Rochefort

"Comminution represents a significant part of mineral processing plant operating costs. Yet, autogenous (AG) or semi-autogenous grinding mills (SAG) are difficult to control because of disturbances like feed size distribution and rock hardness. AMIRA, within project GeMIII, developed a comminution index from laboratory crusher data. The index correlated with the Bond ball mill work index and with the A×b parameter. The present work extends the use of crusher data as a grindability indicator to real-time industrial applications. The aim is to improve comminution operation using online hardness estimation. Because the operational work index is proportional to the ore work index, rock hardness variations can be estimated from the feed and product size distributions, the throughput, and the power draw of a crusher. Real-time estimation of rock hardness can help understand the dynamic behavior of AG and SAG mills. Multivariate time series were analyzed to understand the impact of hardness on a SAG operation. Results showed that the estimated hardness influences the SAG operation and its throughput. Moreover, non-linear dimension reduction was used to ease the process visualisation and search for potential control strategies. In the future, online hardness measurements should also impact the understanding of comminution circuits and improve their operation.INTRODUCTIONThe variability in hardness, and the feed size distribution, are two of the main disturbances affecting comminution circuits (Sbarbaro & del Vilar, 2010). Size distribution can be measured by imagebased granulometry systems such as WipFrag (Maerz, Palangio, & Franklin, 1996), or by 3D vision systems when the fines are difficult to discriminate by 2D segmentation (Faucher, Makni, Gagnon, Lavoie, & Roberge, 2015).There are few examples of online hardness measurements. One example was the work of Casali et al. (2001) who developed a hardness indicator. The ore grindability soft sensor used the fraction of each lithological class in the ore, as determined by image analysis, to predict the work index of the material. The model was developed using a moving window with a width of 12 months and trends were shown over many years with one data point per month."

Jan 1, 2016

By John Rowson, Caitlin Brown, Kebbi Hughes, Joseph Esslifie-Dughan

The McClean Lake mill in northern Saskatchewan, Canada, is operated by Orano Canada Inc. and has been in production for the last 20 years. The tailings preparation process at the mill has been designed with decommissioning in mind, to produce tailings that are geochemically stable over the long-term within the site’s tailings management facility. Twenty years of study have contributed to a detailed understanding of geochemical and geotechnical properties of the McClean Lake tailings. Validation of the tailings properties has occurred through in-situ sampling campaigns conducted initially every year, and later every five years. Each sampling campaign has applied the same rigorous sampling procedure to provide data with useful correlations year over year. Each campaign result compares elements such as the inherent variability of the tailings, consolidation of the tailings and variations in the tailings placement methods. We will discuss lessons learned from seven sampling campaigns over 20 years and present data to show the reliable tracking of geochemical evolution of the in-situ tailings over time; providing opportunities for continuous improvements.

Jan 1, 2020

By R. A. Kipp

THE dry concentration of ores and minerals is a subject on which there is very little engineering literature available. With the advent of flotation, practically all milling research was turned to this development as it held the answer to large-scale economic operations. However, there are many concentration problems that can be more adequately and economically handled by the dry methods that have been developed, and, consequently, I believe it is very advisable for mining men to become fully 'conversant with just what can be done in the dry state. Therefore, today, I should like to give a brief summary of the processes that are available and, in a general way, how they can be a p-p lied. I shall confine my remarks mainly to two dry processes: THE Am FLOTA'l'ION TABLE AND THE ELECTROSTATIC SEPARATOR Dry Magnetic Separators should probably also be included, but I am

Jan 1, 1961

By M. H. Kotze, V. Yahorava

A gold-selective ion exchange resin, containing tributylamine groups, was developed by Mintek for the recovery of gold from cyanide leach solutions. The Dow Chemical Company and, more recently, Purolite commercialized the production of this gold selective resin for use in the gold mining industry, and it is marketed as Dow XZ-91419.00 and Purolite A194 respectively. A novel application of this resin is the selective recovery and separation of AuCl4 - f rom p latinum group metals (PGMs) in chloride and nitrate solutions. The current paper describes potential benefits of this type of resin for selective recovery and upgrading of gold from low grade chloride or nitrate waste streams, and the possibility of gold separation from PGMs during their refining in chloride media.

Jan 1, 2014

By W. R. Middagh, R. M. Garvey

"Phosphate rock is shipped by boat from Florida to Vancouver, B.C., where it is unloaded and stored in a 50,000-ton silo. It is shipped from Vancouver in 100-ton hopper cars in 80-car trains to Fort Saskatchewan. Both the ship and the hopper cars are on a back-haul with potash. The rock cars are unloaded at Fort Saskatchewan at a rate of approximately 4 cars per hour. The rock is stored in three concrete silos, 40 ft in diameter by 110 ft high, which hold 18,000 tons of recoverable rock with 2,000 tons dead space. The rock is reclaimed from the silos by gravity and fed to the phosphoric acid plant by remotely operated conveying equipment.Problems encountered in the operation include scheduling the rock shipments, contamination of the rock with potash, and handling the 80-car trains both in Vancouver and Fort Saskatchewan."

Jan 1, 1968

By David Morrison

Our present longwall problems in Cape Breton can be grouped under five main classifications. These are: (1) Roof control on the face and on the main roadways leading thereto. (2) Transportation of coal along face and levels. (3) Mechanical loading at the face. (4) Safe method of conducting and applying power at the working faces. (5) Dust nuisance. The usual layout for longwall operation in Cape Breton is to have three, and sometimes four, faces in line with each other, the length of face being from 400 feet to 500 feet (see Figure 1), and producing between 425 and 500 tons per face. Each wall is serviced by a well constructed roadway for transportation of coal, men, and materials, and is operated as an independent unit. Each wall works under a regular cycle of operations: first, cutting and boring; second, drawing hardwood chocks, building midwalls, and shifting panlines; and third, loading. The present method of roof control and operation of longwall faces has developed through trial and error since the commencement of longwall miring in Cape Breton. The basic method of roof control in all longwalls in Cape Breton is: rigid support of the roof in the immediate vicinity of the working faces by hardwood blocks, as shown in Figure 2, accompanied by a cushion support furnished by continuous midwalls, 12 feet wide, constructed of stone obtained from the waste and spaced at 50-foot centres. These midwalls are kept forward to within 4 feet to 10 feet of the working face and allow a gradual subsidence of overhead strata, thus preventing any sudden break at the working face.

Jan 1, 1947

By B. Hart, D. J. Miller, J. T. Francis, M. C. Biesinger, Smart. R. St. C.

Diagnosis of the surface chemical factors playing a part in flotation separation of a valuable sulfide phase requires measurement of the hydrophobic and hydrophilic species that are statistically different between the concentrate and tail streams. Time of flight secondary ion mass spectrometry (ToF-SIMS) can be used to identify sufficient particles of a specific mineral phase for reliable statistics determining a mean value for each species with 95% confidence intervals (1). Using the region of interest (ROI) facility in the Tof-SIMS software, a mass spectrum from each particle, at 1-2 monolayer sensitivity, is recorded and stored. This analysis is reported for a chalcopyrite / pyrite / sphalerite mineral mixture conditioned at pH 9 for 20 minutes in order to study transfer of copper from chalcopyrite via solution to the other two mineral surfaces since this mechanism can be responsible for their inadvertent flotation in copper recovery. Analysis from mineral selection based on specific ToF-SIMS signals (eg. Pb, Zn, Cu, Fe, Fe/Cu) indicated no statistical difference in the copper intensities on pyrite and sphalerite after this conditioning. Principal component analysis (PCA) of the ToF-SIMS imaging data identifies combinations of factors strongly correlated (positively or negatively) in images or spectra from mass spectra recorded at each of 256x256 pixels in a selected area of particles. PCA is a better method of selecting minerals due to multi-variable recognition. It has clearly separated a statistical difference in copper intensities between the sphalerite and pyrite phases. The method has been extended to samples from an operating plant again with excellent phase recognition and diagnostic surface chemistry.

Jan 1, 2004

By Zou Lisheng

The culture of safety is very important to coal mining production. About 90% of mine accidents are caused by human error. This paper analyzes the status of China?s coal mining accidents, and accident cause. This paper explains the concept of safety culture, the value of safety culture, as well as the relationships between safety culture and safety behavior, and between safety culture and science and technology. The paper proposes the model of safety culture and the ways to enhance safety culture of coal enterprises. Safety culture and safety production is closely related and are significant to the improvement of mine safety situation in China.

Aug 1, 2013

By T L. Horsley

The change from a seasonal to a continuous mining operation at Cassiar has been accompanied by increased emphasis on the preventive maintenance of mining equipment. This paper describes how equipment maintenance is organized, and details some maintenance practices that have proved advantageous to the Cassier operation. Introduction Cassiar Asbestos Corporation Limited is currenly carrying out an open-pit mining operation at the 6,300-foot elevation on McDame mountain in northern B. C. A 6-mile road connects the mine to the mill and plantsite at the 3,500-foot elevation. Ore concentrate is delivered to the mill via a 3llz-mile tramline. Naturally level ground does not exist in the mine area. The weather is typical of mountainous regions, exhibiting wide and rapid variations in temperature. It is generally wet and windy at the mine elevation, and a heavy snowfall is common. The rock types vary from a soft, sheared serpentine to massive serpentine, to medium-hard, friable sediments to hard, blocky volcanic flows.

Jan 1, 1964

By Harry Piers

A RAPID glance over the history of The Mining Society of Nova Scotia shows that in its fifty years of service, which it is now rounding out, the Society has had an honourable career, rendered signal service to the mining industry of the Province, and helped to shape and improve legislation bearing on our mines and minerals, besicles publishing very many excellent papers and subsequent discussions thereon dealing with all subjects in its field of activity. THE GOLD MINERS? CLUB OF NOVA SCOTIA: The Society has the distinction of being generally regarded as the oldest mining fraternity in Canada ( 1). Iris the direct outgrowth or reorganization of The Gold Miners' Club of Nova Scotia, which was organized in March, 1887, at a period when the gold mining industry was very prominent in the Province. Mr. Geo. W. Stuart, who, in 1934, was the only living member of the parent association, informed me that the seventeen Charter Members of The Gold Miners' Club were John H. Anderson, Charles F. Andrews, A. B. Cox, Clarence H. Dimock, George E. Francklyn, L. W. Getchell, John E. Hardman, Alonzo A. Hayward, Major R. G. Leckie, W. L. Libbey, Edward M. McDonald, G. F. McNaughton, George A. Pyke, H. A. Sanders, C. E. Willis, Benjamin C. Wilson, and George W. Stuart. Others joined later in the same year.

Jan 1, 1937

By Francois Charette

Corrosion is a significant factor affecting the capacity and working life of ground support. The paper explores a relatively simple method to predict the load capacity of a support system using a Monte Carlo stochastic approach. The analysis uses published field data on existing ground support to evaluate the applicability of the method and its predictive performance. Discussion on corrosion rates found in the field and predicted from laboratory measurement is provided.

Jun 1, 2012

By V. S. Papezik

Pyrophyllite, a hydrous aluminium silicate, is used mainly in the ceramic industry and to a lesser extent as a filler in the manufacture of paper, rubber, insecticides and baby powders. Commercial deposits of pyrophyllite in North America are restricted to the "Avalon Zone" , a belt of late Precambrian volcanic and sedimentary rocks that extends along the eastern flank of the Appalachian orogenic belt f rom Georgia to Newfoundland. The only commercial Canadian pyrophyllite deposit lies near Foxtrap on the A valon Peninsula of Newfoundland. Here, steeply dipping lenses of altered pyrophyllite rock occur in a north-trending rhyolite belt near the contact with a granitoid pluton. The altered rock is massive, light greenishyellow and contains varying proportions of pyrophyllite, sericite and quartz with lesser amounts of diaspore and traces of barite and rutile. A lteration was produced by acid solutions, either derived from or activated by the intruding pluton, at temperatures of 250° to 270°C and pressures not exceeding 2 kbr. The largest of the Foxtrap pyrophyllite lenses, discovered in 1897, was mined intermittently f rom 1903 until the early 1950s. The present owner of the mine, Newfoundland Minerals Limited, acquired the property in 1959 and ships between 27, 000 and 36,000 tonnes annually to th e company plant in Lansdale, Pennsylvania, for use in ceramic tile.

Jan 1, 1984

By P. Reyes

The Codelco Chile El Teniente Division Caletones Smelter has an objective to smelt 1,250,000 tonnes per year of copper concentrate. This is a great challenge for the smelter facilities and particularly for the acid plants. The analysis ensuring that there are no obstacles to achieve the production capacity was of great importance. Therefore a series of activities were undertaken as well as studies dedicated to reach the target. This paper presents work focused on a fluid dynamic study, translated in an operation methodology of integrated handling of the smelting and converting gases with the objective to optimize the gas flow and S02 concentration. The optimization should be done employing the current installations, equipment and instrumentation and/or minor modifications. In the first part of the work the condition of the instrumentation involved in the gas handling was checked, improvements determined and the corresponding corrective actions were carried out. The proposed operation method consists of operation of the Cleaning Gas Plant 2 (TC' s gases) and operation of Gas Cleaning Plant 1 (the remaining gas plus the gases from CPS). The implementation of the operation method involves the modification of the valve of the gas into the duct to plant 1 from On to Off to modulate flow. After modification a three days test was carried out. To evaluate the tests, a "Sulphur Capture" indicator was used. During the test the behaviour of the effluent treatment plants was closely examined. No problems or unusual operating conditions were observed. The reduced flow of gas to Gas Cleaning Plant No. 1 permitted the start up of the 2nd test day treating most of the gas received by Gas Cleaning Plant No. 2. The operation was carried out with the limitation not to increase the effluent pond level, which was maintained constant.

Jan 1, 2007

By A. M. Cormie

Introduction The purpose of this paper is to give a brief, general outline of mining practices at Torbrit Silver mine. The geology of the mine is touched on as it is felt that a rough picture of the geology will result in a clearer understanding of the mining methods employed. The main part of the paper deals with mining methods and a section is included on haulage. Development practice is mentioned only briefly. Torbrit Silver Mines, Limited, a subsidiary of Mining Corporation of Canada, is located in the Alice Arm area of northern British Columbia. Access to the mine is by boat to the village of Alice Arm at the head of Alice arm, then truck road, following the course of Kitsault river for 18 miles in a northerly direction to the plant site. The main portal is a further two-thirds of a mile along the course of the river, at approximately the same elevation as the plant, 1,014 feet above sea level. Geology The ore occurs in a massive, irregular-shaped quartz-barite body replacing a folded area in a series of volcanic breccias, tuffs, and flow rocks locally referred to as 'green-stones'. A series of parallel, nearly vertical, fine-grained basic dykes cut across the formation at right angles to the strike of the ore belt over a horizontal distance of 140 feet. The whole of the quartz-barite vein material, which ranges up to several hundred feet wide in places, carries silver values but commercial grade is confined to lenses and shoots where there have been more than usual concentrations of native silver and silver-bearing minerals. The ore-bearing structure plunges at approximately 25 degrees along an axis striking roughly N.65°W.

Jan 1, 1951

By P. L. Wright

"This is a brief history of the development of the mining project, with a description of the proven geology. The paper describes how the experiences gained progressively demanded change in the mine design. The equipment used is described, together with methods of working. Interesting facts have been proved regarding gas emissions and roof. supi;iort. The. working cycles evolved are completely flexible m operation and lend themselves to maximum utilization of the most productive units. The two underground mines are compared, showing the variance in conditions already experienced. Programs currently in operation to improve standards and production are: the training of miners, maintenance men and officials; experiments in floor consolidation and continuing roof support trials; and the effect of comparative stability of working crews on the performance of the operation."

Jan 1, 1973

By J. A. MacLellan

"CONSTRUCI'ION OF SHERRITT'S CONCENTRATORSSherritt Gordon is operating two mills north of the 56th parallel, and is presently engaged in building a third. The author was closely involved in the design and construction of all three of these concentrators.The Lynn mill is the oldest of these three concentrators-it is a 4,000 ton per day nickel-copper plant built in 1953. The Fox mill is a 3,000 ton per day copper-zinc concentrator built in 1970. The Ruttan mill will be a 10,000 ton per day copper-zinc plant scheduled to go on line in July 1973.LYNN MILL The Lynn mill including the crushing, concentrating, drying and load out plant is about 69,700 square feet or 17.4 square feet per ton per day. '!his plant was originally built in 1927 at Sherridon, 150 miles south of Lynn Lake, as a 2,000 ton per day copper-zinc plant. In 1952 the plant was moved by tractor train to Lynn Lake. The whole plant was re-oriented within the original perimeter walls as a 2,000 ton per day nickel-copper plant. This plant was expanded to 4,000 tons per day by the addition of t1-Jo rod mills and a 5-1/2 short head crusher in 1959.The Sherridon mill processed its last ore in Sherridon in September 1951 and the first load of nickel concentrate was loaded at Lynn Lake on November 9, 1953 when the railroad arrived at Lynn Lake.The site for the Lynn Lake mill was cleared of overburden in the summer of 1952 and foundations for structural steel and SO!l8 equipment foundations were poured the late summer and fall of 1952 • Steel was erected from January to June 1953. Most of the equipment came in from January to March of 1953 by tractor sleighs. Sane sleighs upset but no equipment was lest through the ice."

Jan 1, 1972