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By H. Utsunomiya

Most magnesium alloy sheets show low deformability in rolling. Edge cracks and transverse fractures are common difficulties. In addition, rolled sheets show well-developed basal texture <0001>//ND. The texture causes high anisotropy in mechanical properties and low formability in subsequent metal forming. Differential-speed rolling, where the upper and the lower rolls rotate at different speeds, introduces shear deformation through the thickness. Not rolling texture but shear texture evolves in the sheet so that the asymmetric rolling can be a method of texture control. However the primary slip system of the hcp alloy, is basal, the shear texture should be also basal. Differences between the two basal textures, i.e., the rolling texture and the shear texture, have not been understood completely. In this study, conventional (same-speed) rolling and differential-speed rolling have been applied to commercial AZ31B sheets at 623K. Microstructures, textures and mechanical properties of the rolled sheets before/after annealing are compared. It is found that the basal texture is more pronounced by the asymmetric rolling. On the other hand, the asymmetric rolling is effective to decrease the grain size and the planar anisotropy.

Jan 1, 2006

By M. Zavvari

Flotation, as with most engineering disciplines, involves testwork. Commonly this means going from lab scale to pilot scale to industrial scale. It is important to conduct tests to identify key parameters and to optimize even at the lab scale. To reduce the number of tests while maximizing the information, it is necessary to use Design of Experiment and Statistical Analysis. In this communication Fractional Factorial Design was used to identify the effect of 7 main factors on barite flotation recovery from jig gravity tailings at the Dorrin Kashan operation. The factors include: pH, collector and depressant dosage, impeller speed (RPM), pulp dilution, particle size and flotation time. By analysis of the output with Minitab software all factors were shown to have an effect. Among the factors, pH and flotation time have an interaction effect but the others have wise effect as an interaction effect and main effect. Finally, reliability tests at pH= 9, RPM= 1000, collector 1 000g/ton, depressant l 750g/ton, particle size 90 µm, flotation time 90 s, pulp dilution 23 % solids, the optimum level of each factor, were done. At the optimum level a barite concentrate with average specific gravity 4.308 g/cm3, average grade 93.72% and average recovery 90.04% was produced from the jig tail.

Jan 1, 2009

By K. Sasaki

Ventilation measurements were carried out in a shallow underground-quarry space with relatively large internal volume of 14,600 m3 in order to evaluate its effective ventilation characteristics. Based on air velocity measurements with an ultrasonic anemometer in the exhaust airway connected to the space, it was found that the space was ventilated by natural ventilation airflow with intermittent changes in direction. It was difficult to measure the ventilation flow with typical methods of flow measurement provided from the intake portal and throughout the mine, because the cross-sectional area and volume of the openings were too large and the flow was variable. In the present study, a tracer gas method was applied to evaluate the effective ventilation airflow rate in the space. A photo-acoustic infra-red gas monitor, highly sensitive to SF6 gas used as a tracer gas, was set in the space to determine air exchange rates from gas concentration-time decay curves. The seasonal variations of airflow and thermal environment in the space were investigated through 13 sets of measurements taken over 15 months. Airborne rock dust concentrations were also measured at same time in the opening. The correlations between the effective ventilation airflow rate, thermal environment and dust concentrations in the opening space were analyzed and are discussed based on the presented measurements taken during year. It is concluded that seasonal variations in effective ventilation flow and the dust concentration are mainly due to differences in air temperature in the space, as affected by the rock?s surface temperature and atmospheric temperature. In summertime, the air temperature and associated air density difference generated lower natural ventilation flows resulting in higher dust concentrations.

Aug 1, 2013

By Donald P. MacKinnon

"This paper is a commentary on selected trends within the transportation industry.In general, innovations are taking place within all modes of transport (road, rail and water) serving the industrial minerals industry which will affect future distribution patterns, methods and costs. Significant technical innovations in the transportation of solids by• pipeline will also appear, perhaps in the near future, permitting the transport of specific commodities, including some industrial minerals. However, the timing and magnitude of the commercial exploitation of solids pipelines are heavily dictated by marketing factors and distribution system logistics, as well as by the innovations likely to take place within competitive modes of transport. Competitive technological developments will include increased ship capacities, improved bulk-handling facilities, larger and specialized bulk-handling rail equipment, unit trains, containerization, larger ""off-highway"" vehicles and greater inter-modal integration. Equally significant are some ""soft-ware"" techniques such as the growing interest in total distribution cost concepts. However, the impact of the developments will not be spread uniformly over all Canadian industrial minerals."

Jan 1, 1967

By L. L. Sirois

Because segments of the Canadian mineral-based economy are dependent totally or in part on foreign sources of certain minerals, their well-being may well be affected by inability to obtain these minerals. Where such dependency exists, it is therefore important that contingency plans be available to counteract possible price increases or lack of supplies by means of technology, developed well in advance of any pending crisis . Canada is vulnerable to possible future real or artificial shortages of certain foreign-produced mineral commodities, and science and technology can provide information for the development of policies for counteracting efforts by foreign exporters to control prices or limit supplies.

Jan 1, 1977

By M. Ramström

"In 2002, Atlas Copco Rock Drills AB released the new rig control system (RCS) technology for all of its drill rig types. RCS opened the way for a new generation of computerized drill rigs based on modern, standard PC-computer technology. Drilling accuracy, information logging, reduction in manpower in some types, and serviceability have all taken a quantum leap forward when compared with previous generations of drill rigs. RCS is modularized and distributed by means of CAN-bus technology. This technology, which is well proven in automobile applications, forms the communication backbone of the rig. The modularity facilitates almost unlimited possibilities for the expansion and adaptation of drill rig functions."

Jan 1, 2005

By C. A. D' Odorico

The zinc pressure leaching (ZPL) plant at Teck Cominco&apos;s Trail Operations was started up in 1981 and represented the world&apos;s first commercialization of the technology. From the outset, the process was designed to operate using iron-rich Sullivan Mine zinc concentrate. When the Sullivan Mine reached the end of its life in 2002, the ZPL plant underwent a significant process change with the treatment of 100% Red Dog zinc concentrate. Through careful improvements to existing plant processes, controlled changes to plant operating parameters and a rapid adjustment to the modified process by operations personnel, the plant has been successfully converted to processing a feed of 100% Red Dog zinc concentrate. This paper discusses the challenges faced during the conversion and describes the modifications to plant operating procedures, as well as changes to plant processes.

Jan 1, 2004

By E. J. Sun

The ADS system was developed to reduce accidents related to haul trucks operating under low visibility conditions in surface mining and construction sites, which is based on the GPS, mesh-wireless networks, and the Google-Earth 3D graphic engine as the graphic interface and mine-mapping server. This system has the capability to pin-point and track vehicles in real time using a 3D interface, which is based on user-based AutoCAD mine maps using the Google-Earth graphics interface. All equipped vehicles are shown in a 3D mine map stored in a local server through a wireless network. When low visibility conditions are present, the system indicates available exit/escape routes for driver safety. The research results indicate that the ADS system potentially increases reliability and reduces uncertainty in open pit mining operations by customizing the local 3D digital mining map, constructing the truck 3D models, tracking vehicles in real time using a 3D interface and indicating available escape routes for driver safety.

Oct 1, 2009

By Tassos Grammatikopoulos, Vladimiros Papangelakis, Douglass Duffy, Cheryl Washer, Srinath Garg

Flotation operations in Sudbury, Ontario, seeking to separate pentlandite and chalcopyrite from mixed sulphide deposits, produce pyrrhotite tailings that have been disposed of in tailings ponds for over 50 years. These reactive tailings are viewed as waste, despite containing ~0.8 wt% Ni, and represent an environmental liability because of their acid mine drainage (AMD) potential. Given the large quantities of pyrrhotite currently stored in Sudbury, and declining ore grades elsewhere, these tailings have shifted from being viewed as a waste to a potential resource. Recent advances in the bioleaching of low-grade sulphide ores have raised the prospect of bioleaching as a potential low-cost processing option. However optimization of this proposed process requires a thorough understanding of the mineralogy of the pyrrhotite tailings that would be leached. The work presented here addresses the characterization of two distinct Sudbury pyrrhotite tailings, namely from the Vale and Glencore operations, using electron microprobe, XRD and QEMSCAN analysis. Particular focus is given to how the mineralogy may affect bioleaching as a processing option, through the deportment of nickel and the various phases present

Jan 1, 2015

By J. R. Fisher

"Uranium may be leached to some extent in situ from the Blind River conglomerate uranium ores by using the products of bacterial activity from the bacterium Thio-bacillus ferrooxidans his paper describes some of the laboratory techniques used to investigate the characteristics of the bacteria, and to utilize their properties in uranium leaching. The application of some of the laboratory results underground at the Milliken mine of Rio Algom Mines Limited are de-scribed, along with the method of uranium recovery from the mine waters."

Jan 1, 1966

By S. Qian

Galvanic corrosion is a potentially major concern associated with the application of stainless steel reinforcement which is in direct (electrical) contact with carbon steel reinforcement in concrete structures. Judicious use of stainless steel rebar in both new construction and rehabilitation of older structures is a viable, cost-effective option for extending service life and reducing maintenance costs. Questions, however, had arisen about the possibility of increased corrosion due to galvanic effects. This paper investigates the galvanic-coupling behaviours of three different types of stainless steel and carbon steel. Tests were performed both in electrochemical cells and with specimens in concrete inside an environmental chamber. The results show that oxygen reduction on stainless steel is the rate-determining factor for galvanic coupling of these two metals. It is much lower than that of passive carbon steel. As a result, the galvanic coupling of stainless steel with carbon steel will not increase the risk of corrosion of carbon steel reinforcement.

Jan 1, 2005

By Michel Brissette

"To recover more valuable ore and considering the complexity of minerals, the needs to grind finer is increasing. To reach the desired fine grinding targets, using the existing grinding media size, the energy consumption is increasing exponentially. As already proved at this conference, small grinding media represents the best potential to improve grinding efficiency. How do the small grinding media perform in industrial grinding mills?The use of small grinding media in regrind mills proved that finer grinding can be achieved at lower energy consumption. In ball mills, smaller grinding media versus 25 mm media generate a power saving from 10% to 44%. In vertical stirred mills, the power saving increases from 20% to 60%. More potential savings have been identified.For the same operating conditions, how a vertical stirred mill is performing compared to ball milling? In regrind application, a vertical stirred mill with small media (5-12 mm Millpebs) will require at least 62% less energy than a ball mill charged with 25 mm grinding media.INTRODUCTIONIn some mining applications, fine grinding is needed to liberate further the valuable ore. The purpose of regrind mills is to achieve the last stage of grinding before final flotation stage: the cleaners. In part because of high prices of small grinding media as well as availability, the most widely used size of grinding media is 25 mm.When calculating the recommended ball top size from Bond’s formula (Bond, 1961), the size for regrind applications is much lower than 25 mm. Today, the barrier for small grinding media is broken. They are best suited in regrind application. The size of grinding media is one of the most important variables affecting the mill efficiency (McIvor, R., 1997; Nesset, J.E., Radziszewski, P., Hardie, C. & Leroux, D.P., 2006).Conventional ball milling was discarded for fine grinding because of its very poor energy efficiency (Zheng, J., Harris, C.C. & Somasundaran, P., 1994; Yan, D.S., Freeman, M. & Dunne, R., 1995). Therefore, new technologies as stirred mills were developed to grind finer more effectively. Three fundamental questions should be asked. What is the best fine grinding technology? What should be the best media size to use? Is it possible to grind finer by using less energy with the existing regrind equipment?"

Jan 1, 2009

By S. Averill, B. Schreiner, V. Sopuck

The La Ronge. Kisseynew, Glennie Lake and Flin Flon domains. the main focu for gold exploration in the southeast part of the Saskatchewan Shield, were subject to continental glacial ice advances from the northeast during the Quaternary. Based on forty-four auger hole along with surficial mapping, the general Quaternary stratigraphy in this area is observed to be composed of a lower till unit , an overlying stratified unit of glaciofluvial sand and gravel and/or a glaciolacustrine silt-clay unit. an upper till. and an upper tratified unit. The lower till is commonly found throughout the geological domains except where it has been eroded in glaciofluvial or fluvial channels. Glacial Lake Agassiz fo rmerly covered most of these prospective domains. The lacustrine deposits associated with the lake impede surficial geochemical surveys including soil. lake sediment. and biogeochemical surveys. The approximate extent of clay cover can be predicted from beach elevations. For instance. in the Waddy Lake area. clay i not known to occur above about 1,400 feet (425 m) elevation. Exploration techniques are hampered by clay in at least one third of the volcanic belt. Thi s influence is indicated by the fact that nearly all gold prospect found to date are located above 1,400 feet (425 m) while the area of clay cover is vi rtually unexplored. The upper till i related to a minor ice readvance. This till is the medium often sampled during soil surveys in the area . lts value as a geochemical ampling medium is dependent on the extent of erosional contact with bedrock highs on the lower till. Those areas which are relatively free of lacustrine and fluvial deposits are those where surface geochemical methods work best. In the Waddy Lake volcanic belt approximately 25-50% of the area may be suitable for surficial surveys. The area of the Star Lake prospect occurs above the 1,500 foot (460 m) elevation and was not covered by Lake Agas iz. The effectivene of till sampling as a surface sampling medium was tested in those areas above the clay level. Till orientat ion surveys were carried out at the Star Lake property and the Tower Lake prospect (Waddy Lake area) within the La Ronge Domain . Gold grain counts and analy es of heavy mineral concent rate from 7 kg surface ti ll samples were used to delineate dispersion trains down-ice from mineralization. In addition, the clay fraction and a 30 g (-80 mesh) subsample from the same till sample, were analyzed for gold . In the Star Lake area, ice direction is subparallel to the strike of several narrow northeast trending auriferous structures. arrow dispersion trains down-ice from known

Jan 1, 1986

By E. Amini

"While methods exist to allow the simulation and optimization of existing flotation operations, there is a deficit in the ability to predict the performance of a new ore type pre-processing. A laboratory scale batch flotation testing methodology has been developed to assess the flotation potential of ores (known as the JK Floatability Index or JKFI). Previous work conducted by Alexander and Collins (2008) showed that the test could be used to predict full scale results in base metal ores. In this work, JKFI tests were applied to three different types of ore and one blend from a greenfields gold deposit to show the test applicability to flotation of precious metals. The results from the JKFI test on one ore type were then used to predict the response of all ore types (including the blend). To validate the predicted kinetic parameters, a comprehensive survey was performed on a pilot plant where each of ore types was processed in the circuit. An acceptable agreement was found between the experimental recoveries and predicted recoveries which indicate the potential of this method for use in predicting the flotation response of an ore.INTRODUCTIONOver 100 years, flotation has been considered an efficient method to concentrate different types of sulphide and oxide minerals and coal. Thus, numerous research studies have been undertaken to find an appropriate model to predict the behaviour of particles in flotation circuits (Barnwal et. al., 2006; Bascur and Herbst, 1983; Cecile and Villeneuve, 1991; Deng et. al., 1996; Zheng et. al., 2006). Most methods are based on the ore flotation response in an industrial plant which is expensive and time consuming to characterise. It is difficult to reliably predict flotation response for new types of ores in industrial scale plants.The floatability component modelling (FCM) approach, developed within the Australian Minerals Industry Research Association (AMIRA) P9 project, has been used to derive models of operating flotation plants for the purpose of simulation and optimisation (Alexander and Morrison, 1998; Alexander et. al., 2000; Varadi, 2006). This approach has been applied at a large number of operating sites treating a wide variety of ores. The approach requires metallurgical surveys to be undertaken in conjunction with batch flotation tests and cell characterisation. This allows ore and machine parameters to be derived, which are then used in the P9 Flotation Model. The development of a FCM generally requires a large commitment of resources and time. While there has been significant support of this approach in industry, the FCM approach is limited to ores already being processed (Runge, 2004; Wightman, 2006)."

Jan 1, 2009

By J. Cayouette, C. Bolduc, P. Blatter

"The LaRonde mill was commissioned in 1988 and began treating ore from the Penna shaft in 2000. The mill has been expanded to accommodate 7,500 t/day, but ramped down to 6,000 t/day since the deep extension began. The process recovers gold, silver, and base metals. In 2008, the Goldex plant began trucking gold-pyrite concentrate to a treatment plant feeding pulp to the LaRonde mill, increasing gold output by 40,000 oz. In 2009, the high-grade Lapa ore processing facilities were annexed to the LaRonde plant, increasing gold output by 120,000 oz. This paper outlines the metallurgical considerations related to the treatment of different ore types.RÉSUMÉ Le concentrateur de la mine LaRonde a été mis en service en 1988 et a commencé à traiter le minerai du puits Penna en 2000. La capacité du concentrateur a augmenté afin de permettre le traitement de 7 500 tonnes de minerai par jour, capacité qui est retombée à 6 000 tonnes par jour (tpj) depuis le début de l’extension en profondeur de la mine. Ce procédé permet de récupérer de l’or, de l’argent et des métaux communs. En 2008, l’usine de traitement Goldex a commencé à transporter par camion du concentré de pyrite et d’or vers une usine de traitement alimentant en pulpe le concentrateur de LaRonde, augmentant ainsi la production d’or de 40 000 onces. En 2009, les installations de traitement du minerai à haute teneur de Lapa ont été annexées à l’usine de traitement de LaRonde, augmentant la production d’or de 120 000 onces. Cet article passe en revue les considérations métallurgiques liées au traitement de différents types de minerai.INTRODUCTIONThe LaRonde metallurgical plant in the Abitibi region of Quebec, Canada, evolved into a mature milling site following expansions in 2000–2003, thanks to improved processes, manpower, and water treatment capabilities that better accommodate the complex constituents of the LaRonde ore. The ore requires a sequence of grinding, copper- lead and zinc flotation, and precious metals leaching, ending with a carbon-in-pulp (CIP) gold recovery. A portion (35%) of the tailings is sent back underground as paste backfill after being treated with the SO2-air cyanide destruction process. The tailings area has a dedicated cyanide destruction and metal precipitation area through which the used water passes before returning as recycled water. A biological water treatment plant was built in 2004 to address water toxicity in the final effluent. The water toxicity was the result of the high sulfide content of the LaRonde ore (from thiocyanate or stable cyanide species buildup) and the use of 90% recirculated water in the mill. The water treatment plant uses bacteria to transform thiocyanate into nitrates and precipitate phosphorus from the water before it is discharged into the environment."

Jan 1, 2017

By J. R. CAMERON

Gypsum is mined in all Atlantic Provinces except Prince Edward Island. It is generally thought to have been derived from the hydration of anhydrite in areas of minimal drainage. Late Devonian downwarping and crustal oscillation east of the Appalachian fold belt allowed the Windsor Sea to advance and retreat in a depositional trough and deposit about 1,000 m of sediments in Mississippian time, much of which were evaporites. The best areas for further gypsum development are lowland basins such as the Cape Breton Lowlands, the Hillsborough area of New Brunswick and the St. George's Lowlands in Newfoundland, all of which are already sites of gypsum quarries. Nova Scotia's gypsum is mined from the Lower Windsor Group, which is divided into subzones 'A' and 'B'; 'B' provides most of the province's gypsum production. The Atlantic Provinces gypsum industry has markets from the St. Lawrence waterway to the mouth of the Mississippi River.

Jan 1, 1984

By R. Loney, M. Militzer

There is a significant demand for new high strength steels with fine grain sizes for structural applications. One approach in this regard is to develop hot-rolled HSLA steels where refining the microstructure leads to increased strength levels, e.g. 700 MPa yield strength, that can be attained by suitable modifications of chemistry and processing. Here, an HSLA steel is investigated that contains 0.05wt%C-1.65wt%Mn-0.20wt%Mo¬0.07wt%Nb-0.02wt%Ti and approaches the above strength class. The ability to control and predict the mechanical properties of hot rolled steel depends strongly on the thermomechanical processes, which the steel undergoes. The final microstructure and, thus, the properties of the hot-rolled steel are a function of the austenite decomposition obtained during accelerated cooling on the run-out table and precipitation during coiling. The austenite-to-ferrite phase transformation under run-out table conditions has been investigated using a Gleeble 3500 thermomechanical simulator equipped with a dilatometer. The effects of cooling rate and initial austenite microstructure including the degree of work hardening on austenite decomposition kinetics and ferrite grain refinement have been quantified. Results show that grain refinement can be optimized by the presence of work hardened austenite and accelerated cooling. Based on the experimental results, a model is proposed to predict the transformation start temperature and the resulting ferrite grain size for run-out table cooling conditions.

Jan 1, 2004

The writer presents a concise summary of eleven recent discoveries made in the Maritime Appalachian area, with suggestions for fur the research. This information may prove helpful to geologists working in other fields and to students contemplating further avenues of research in mining geology and exploration. INTRODUCTION THIS paper is not intended as a research study on the subject, but i. merely a brief review of eleven discoveries that have been made in the Canadian Appalachian area. Furthermore, this is not a critical analysis of the merits of any one geophysical method, but it is an un-prejudiced observation of how these discoveries were actually made and what techniques were apparently most fruitful. Some generalizations are attempted whicl1 may suggest further avenues of research in the field of mining exploration. The writer wishes to thank his colleagues in the field for their comments, which he was able to in-corporate into this paper. In particular, he is grateful to Dr. Paul Bevan and

Jan 1, 1963

By W. S. Tremaine

When the Hedley Mascot mill was built in 1935, it was designed as a straight flotation plant. The ore to be treated at that time was a gold ore in which the gold was intimately associated with arsenopyrite and pyrrhotite in highly silicified and garnetized limestone gangue. This material was ground to 85 per cent minus 325 mesh in two-stage grinding and floated in standard flotation cells to produce about a 5-ounce concentrate, which was shipped to Tacoma smelter for refining. This arrangement gave us a recovery of about 89 per cent. Test work indicated that the best way to improve this recovery would be to build a cyanide plant to treat our flotation middling. Arrangements for the construction of this plant were finally approved and work on it was started in the spring of 1940. This plant was of the conventional type in which the flotation middlings were thickened, filtered, and then put through the usual cyanide process. Its capacity was 50 tons of middlings per day. This arrangement worked quite satisfactorily and gave us an increase in overall recovery of 4 per cent. Unfortunately, about the time the plant was completed, we developed, and started to ship to the mill, ore that differed entirely from that met with up to that time. Instead of being hard, it was very soft, the orebody from which- it came being much faulted and brecciated. In many sections, the sulphides were oxidized and the breccia was filled in with a very soft, hydrous iron silicate known as chloropal. When this new ore was mixed with the old ore and sent to the mill, the whole operation was disrupted. The chloropal slimed so badly that the classification, flotation circuits, and cyanide plant would not handle it. The difficulty in the cyanide plant was at the head end, where the 10 ft. by 20 ft. thickener and the 8 ft. by 8ft. drum filter would not handle the middlings containing a large percentage of primary slime and chloropal. This material would not thicken to more than 30 per cent solids in the thickener and, when pumped to the filter, would forma very thin, slimy cake. Overall recovery dropped to between 83 and 84 percent and it was quite apparent that some extensive changes would have to be made in our flow-sheet before this ore could be treated successfully.

Jan 1, 1947

By Harold S. King

TWO summers ago I had the privilege of visiting No. 18 colliery at Glace Bay. Underground, we travelled along the haulage-way behind a powerful electric locomotive. The motor in this locomotive began to smoke badly and a carbon tetrachloride type of extinguisher was used several times during the trip. At the time, I noted a strong odour of phosgene. On my return to Sydney, I spoke to Mr. Harold Gordon, Assistant to the General Manager of the Dominion Steel and Coal Corporation, and warned him of the danger of using this type of fire extinguisher in confined spaces, since it is a well known chemical fact that phosgene, a dangerously toxic gas, is formed by the decomposition of carbon tetrachloride. This danger does not seem to be widely recognized, so it seems advisable that a more general warning be published. Attention was first drawn to the danger by the death of two men in the United States Navy Department subsequent to breathing fumes from carbon tetrachloride used in a fire, and when an employee of the Bureau of Mines also was overcome while fighting a fire with carbon tetrachloride liquid. These accidents led to an investigation of the decomposition products of carbon tetrachloride by a group of workers in the Research Laboratory of the Pittsburgh Experimental Station, U.S. Bureau of Mines, the results of which were published in the October, 1920, number of the Journal of the .Franklin Institute (1). Their experiments were conducted by two methods. The first consisted in applying the liquids to actual fires and -to hot metal in a closed room of 1,000 feet capacity, where the gaseous products, mixed with air, could be retained and analyzed. The second method was to pass the vapour:s in air through heated tubes of iron or quartz, where the humidity of the air and the temperature could be controlled.

Jan 1, 1939