Search Documents

By Washington Luiz Mafra

Every year the conventional direct reduction processes ? Midrex and HYL III ? increased their market share in the world steel production, even though they are only economically feasible in countries where natural gas is available at competitive prices. In this context, the new Midrex projects are based on large reactors (Megamod - 1.5 to 1.8 Mt/y of DRI), reduction temperatures of the metallic burden up to 850oC, with bustle gas temperatures between 960oC e 1050oC. Thus, the requirements of metallic burden performance, as well as the evaluating methods, usually based on ISO standards, need to be reviewed. It is well known that the standards usually applied to quality evaluation do not reflect the performance of metallic burden inside the reactors. This paper describes the different methods of evaluating the disintegration under reduction of DR pellets based on ISO 11257 standard. This is the most important method used by pellet producers and customers for evaluating DR feedstocks. The different methodologies tested to evaluate the disintegration under reduction had varying results, evidencing the relevance of the method and the quality of the pellet. Nevertheless, validating the method in an industrial reactor is still fundamental.

May 1, 2007

By J. Baz-Dresch

"The most cost-effective method of placement of the high strength fill used in the Cannon Mine' s overhand cut-and-f ill bench stopes was determined to be truck haulage. Constraint s imposed by the mine layout dictated the use of a truck which could dump its load in a fifteen-foot high drift. The Dux Teledumper truck was selected as the most suitable unit for this application based upon operational and maintenance parameters which included a telescoping, tilting dump box; large load capacity; and robust construction. Development of the truck continues through the cooperation between the manufacturer and user. INTRODUCTIONThe Cannon Mine is situated in the centre of Washington state, approximately midway between the cities of Spokane on the east and Seattle on the west. The mine complex is located three block s south of the Wenatchee city limits at the eastern base of the Cascade Mountain range.Asam era Minerals (U.S.) Inc., with 5I% ownership, operates the Cannon Mine. Breakwater Resources, Ltd. holds the remaining 49%.Annual paroduction is 520 000 tons per year, presently on a 21-shift per week operating schedule for both the mine and the mill.All production is presently won by overhand bench stoping with backfill. Stoping starts with 15-ft high by 24- or 30-ft wide sill cuts driven above and below a stope block . A drop rai se and slot are used to open a bench which is then slabbed toward the open slot. Truck-placed backfill is dumped into the mined - out stope from the upper sill cut. This stoping sequence is repeated until the top of the ore block is reached . The top sill cut is then tightly filled with backfill to minimize subsidence and to provide adequate roof support during extraction of the pillars.Mining equipment consists of hydraulic drills and rubber-tired, diesel scoops and trucks."

Jan 1, 1989

By C. Mills, A. O. Burt

"The paper examines the role of gravity concentration in both an historical context and within the modern mineral processing industry. It discusses the principles of the process on both a theoretical and practical level. The importance of more mineralogy and its effect on the choice of the wide range of equipment available is discussed. The paper concludes with a discussion on the relative merits of gravity concentration with other forms of processing.IntroductionIt is an unfortunate, albeit popular, misconception among otherwise enlightened engineers in the mineral processing industry that gravity concentration was a process developed in the dark ages, perfected in the middle ages, and abandoned in the modern ages.Gravity concentration was developed in the dark ages - long indeed before that. Agricolau: cited examples of gravity concentration, crude examples admittedly, being practiced over 3000 years ago. However, gravity concentration is not dead. Far from it. As recently as 1978 it was reported that the total mineral tonnage treated by this process in the United States was greater than that processed by flotation. Coal represents the bulk of the or e treated by gravity separation in the U.S.A., with iron ore representing a major portion of the balance."

Jan 1, 1985

By Michel Ruel

Most plants do not track how their systems perform. Optimization is the easiest way to benefit from your control systems. We suggest an approach in four phases. The first phase is to assess all equipment to determine the performances for instruments, valves, variable speed drives, and other equipment. The second phase is to remediate instrumentation problems, including the ones pertaining to valves, variable speed drives, analyzers, transmitters. When equipment is in order, loops are put back in automatic mode. If a loop oscillates, use standard default values for this type of loop. The third phase consists in validating the control strategies, properly configuring the systems (control system, programs and parameters, HMI, alarms), and then tuning the loops and control strategies. The fourth phase consists in analyzing the process and expected performances in order to optimize the control loops and control strategies. If performance is not sufficient, a decision tree will be presented to determine the right approach: advanced regulatory control, model predictive control, or fuzzy logic control. Once all steps have been completed, control performance monitoring software is used to sustain the results and pinpoint equipment or loops not performing as stated. Alarm management and rationalization could also be performed after auditing the alarm system, if needed. Examples from plants will be used to demonstrate how this step-by-step method is applied and produces results. INTRODUCTION Maximizing what you already have is the best investment to remain competitive. This article aims to show the benefits of a systematic approach using modern tools to improve plant performance. We at BBA suggest dividing the work in four phases, and a subsequent phase can begin when the previous one has progressed: Assess, Remediate, Stabilize, Optimize, or add advanced control. This approach has been successfully applied to several sites. Examples and illustrations from these plants demonstrate how this step-by-step method is applied and produces results. Under the BBA method, there are four questions to answer before proceeding to the next step. For each control strategy, you should ask the following questions: Assessment: Does it work? Remediation: Do you use it? Stabilization: Is it stable? Optimization: Does it perform? Do you need advanced control?

Jan 1, 2019

An Attractive Investment ?Near term low cost and secure PGM producer ?restricted supply legislated demand ?strong pipeline of resource development ?Building Canada?s largest undeveloped PGM-Cu resource ?All work (resource, reserves, DFS, EA) is NI43-101 compliant ?Strong balance sheet: over $8 m in cash with no debt

May 1, 2010

By G. Graves, J. A. Walker

"Abstract - The Mount Fronsac North volcanogenic massive sulfide deposit is the most recently discovered massive sulfide body in the Bathurst Mining Camp. The deposit occurs within a sequence of intercalated fine-grained felsic tuff and sedimentary rocks (Little Falls member), at the top of the Nepisiguit Falls Formation. Aphyric to sparsely feldspar-phyric rhyolite and related volcanic rocks of the Flat Landing Brook Formation overlie the host sequence. The massive and semimassive parts of the deposit have a north-south strike length of 525 m and a dip of ~45°E; the deposit is continuous downdip for 600 m, and thickness varies from 2 to 20 m. The deposit contains an estimated geologic resource of 14 Mt of low-grade, semimassive (>60%) to locally massive sulfides, and includes a high-grade zone of 1.26 Mt grading 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, and 0.40 g/t Au. The semimassive to massive sulfide intersections occur in an envelope of quartz-sericite±chlorite schist, which is interpreted to be intensely deformed felsic tuff. This sequence has a maximum thickness of 140 m and contains significant (up to 50%) fine- to coarse-grained disseminated pyrite. The pyritic envelope has a strike length of 900 m and extends over 1000 m downdip. Massive sulfides are found throughout this alteration envelope, but more commonly occur at or near the upper contact. The significance of the discovery of this deposit is that it represents a near surface discovery of a large tonnage sulfide body in a mature mining camp, one in which the possibility of discovery of a new shallow deposit had been all but discounted. This opens the possibility for future discoveries in this part of the Bathurst Mining Camp. Sommaire - Le gîte de sulfures massifs volcanogènes du Mont Fronsac Nord est la découverte de sulfures massifs la plus récente dans le Camp Minier de Bathurst. Le gisement est situé dans une séquence de tufs felsiques à grains fins interlités de roches sédimentaires (membre de Little Falls, au sommet de la Formation de Nepisiguit Falls. La partie massive et la semimassive s’étendent du nord au sud sur 525 m et ont un pendage de ~45°E; le gisement est continu sur 600 m en angle de chute et son épaisseur varie de 2 à 20 m. Le gisement contient une ressource géologique évaluée à 14 Mt de sulfures semimassifs (>60%) localement massifs à basse teneur, incluant une zone à haute teneur de 1.26 Mt titrant 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, et 0.40 g/t Au. Les intersections de sulfures semimassifs à massifs se situent dans une enveloppe de schiste à quartz-sericite ± chlorite interprétée comme un tuf felsique intensément déformé. Cette séquence contient une quantité importante (jusqu’à 50%) de pyrite disséminée dont le grain varie de fin à grossier et son épaisseur maximale est de 140 m. L’enveloppe pyriteuse s’étend latéralement sur 900 m et a été tracée jusqu’à 1000 m en angle de chute. Des sulfures massifs sont trouvés partout à l’intérieur de cette enveloppe d’altération, mais ils sont plus fréquents près du contact supérieur. L’importance de cette découverte tient à ce qu’elle est un exemple d’un gisement à fort tonnage nouvellement découvert à une faible profondeur dans un camp minier mature, i.e., un camp ou l’on ne croyait plus qu’il était possible de trouver un gisement près de la surface. Ceci ouvre la porte à la possibilité d’autres découvertes dans cette partie du Camp Minier de Bathurst."

Jan 1, 2006

By Dale Scott

"The Aggregate Resources Inventory Program was initiated 10 produce reports which assess the aggregate resources of municipalities designated under the Pits and Quarries Control ACI, 1971.Each report consists of three copies accompanied by a text. The text describes the local mineral aggregate resources, extractive activity and characteristics of the ""Selected Deposits"". The first map shows the known sand and gravel resources and their quality. The second map indicates selected sand and gravel resources of primary, secondary and tertiary significance. The third map indicates both bedrock resources and bedrock areas suitable f or extraction. These maps and the text are prepared in a formal suited for use by planning personnel.Recently, the Aggregate Resources Inventory Program has undergone evolutionary changes. New sources of data are being utilized in the inventory reports; in particular, detailed field assessment by inspecting, sampling, drilling and backhoe pitting. Liaison and joint assessment with district and regional Mineral Resources staff of the Ministry of Natural Resources, and personnel of the Ministry of Transportation and Communications, are key components of the Program.Twenty-two reports were available to the public as of December 1980, with a further thirty-six awaiting publication. Our present production rate is 3.5 reports per month. The reports appear to be well accepted by the municipalities and have proven effective in conserving prime aggregate resource areas.IntroductionThe urbanization of Southern Ontario has resulted in a major increase in the production of industrial minerals, such as sand, gravel, clay, shale, gypsum and stone, for use as cru shed aggregate, building stone, lime and cement.Although mineral aggregate deposits are plentiful in Southern Ontario, they are fixed-location, non-renewable resources. The potential for extractive development is usually greatest in urban fringe areas where land-use competition is extreme. Comprehensive planning and resource management strategies are required to make the best use of available resources, especially in those areas experiencing rapid development. Such strategies must be based on a sound knowledge of the total mineral aggregate resource base at both local and regional levels."

Jan 1, 1982

By Dale Scott

"The Aggregate Resources Inventory Program was initiated 10 produce reports which assess the aggregate resources of municipalities designated under the Pits and Quarries Control ACI, 1971.Each report consists of three copies accompanied by a text. The text describes the local mineral aggregate resources, extractive activity and characteristics of the ""Selected Deposits"". The first map shows the known sand and gravel resources and their quality. The second map indicates selected sand and gravel resources of primary, secondary and tertiary significance. The third map indicates both bedrock resources and bedrock areas suitable f or extraction. These maps and the text are prepared in a formal suited for use by planning personnel.Recently, the Aggregate Resources Inventory Program has undergone evolutionary changes. New sources of data are being utilized in the inventory reports; in particular, detailed field assessment by inspecting, sampling, drilling and backhoe pitting. Liaison and joint assessment with district and regional Mineral Resources staff of the Ministry of Natural Resources, and personnel of the Ministry of Transportation and Communications, are key components of the Program.Twenty-two reports were available to the public as of December 1980, with a further thirty-six awaiting publication. Our present production rate is 3.5 reports per month. The reports appear to be well accepted by the municipalities and have proven effective in conserving prime aggregate resource areas.IntroductionThe urbanization of Southern Ontario has resulted in a major increase in the production of industrial minerals, such as sand, gravel, clay, shale, gypsum and stone, for use as cru shed aggregate, building stone, lime and cement.Although mineral aggregate deposits are plentiful in Southern Ontario, they are fixed-location, non-renewable resources. The potential for extractive development is usually greatest in urban fringe areas where land-use competition is extreme. Comprehensive planning and resource management strategies are required to make the best use of available resources, especially in those areas experiencing rapid development. Such strategies must be based on a sound knowledge of the total mineral aggregate resource base at both local and regional levels."

Jan 1, 1982

By Scott Hean

"Environment and the economy are interwoven irrevocably. They need to be publicly discussed, and discussed often so that new approaches can be understood and developed - approaches which are complimentary, not confrontational.Discussion on the environment is timely, from the perspective of mining engineers and developers, from that of bankers and from their shared perspective as people concerned with enhancing the quality of life, the environment and the economy.This paper will touch on how what is called the ""environmental economy "" that has evolved has become entangled with regulatory and financial issues in a way that is dangerous for all of us. It will also look at some of the promising possibilities that a world-wide and continuing concern for the environment holds out for us.For many decades, British Columbia has provided some of the key examples of the intertwining of environmental and economic issues, and, very importantly, providing the people prepared to do something about them.Canada's first environment minister, the late Jack Davis, came from British Columbia. He led this country's delegation to the Stockholm Environment Conference in 1972, a conference that laid the groundwork of principles necessary to establish some international certainty as to the legal liability for causing trans-national environmental damage.Another British Columbian who was also a national environment minister, John Fraser - now the Speaker of the House of Commons - was one of the first to dramatize the importance of acid rain and force it into the international public arena.Some 20 years ago, British Columbians made Vancouver and their province one of the major centres of opposition to the Alaska Pipeline and Tanker System - with some justification, it now seems.That a British Columbian , then MP David Anderson, was given legal recognition to sue in a United States' court against a system that was either in U.S. territory or international waters was an important precedent in, and of, itself in terms of environmental law. That old controversy is now a very current case study - in terms of dealing with the question of liability.-"

Jan 1, 1991

By Sylvie Poirier

This paper focuses on new developments regarding thermal rock fragmentation applications. The technology consists in a strong burner powered by diesel fuel and air. The thermal reaction, which is created, allows for the enlargement of 125-mm to 450-mm holes by breaking the rock in a spalling effect. It has been used for over 30 years in Russian open pit mining. Following an agreement between Dynamitage T.C.G. Inc. and the owner of the technology, major improvements have been brought to this technology, allowing for the fabrication of a prototype suitable for the Canadian industry. In Russia and Ukraine, thermal rock fragmentation is actually used to drill large diameter holes in surface mining. Upon having acquired a better knowledge of this technology, it seems that it presents a great potential for selective mining in narrow-vein operations, for either surface or underground mining. Rocmec International Inc., a subsidiary of Dynamitage T.C.G. Inc., and Natural Resources Canada are technical partners in the evaluation of the operational parameters and environmental aspects, such as gas, heat, dust and fog emissions. Furthermore, Canada Economic Development is a financial partner in this project. This paper presents the technology and its history. It also reports on the changes brought to the equipment to adapt it to North American environments. A summary of the tests realized since 1995 is provided, along with the main conclusions obtained. The anticipated applications for the use of this technology in both surface and underground environments are described, such as open pit mining, bulk sampling and narrow-vein ore extraction. An estimate showing a comparison between the thermal fragmentation mining concept and the long-hole mining method is presented and, finally, the future developments planned are listed.

May 1, 2002

"The content of production reports has its origins in raw measurements taken in harsh production environments. The ensuing measurement/estimation errors always affect reproducibility such that, regardless of the fact that they are balanced through statistical data reconciliation, reported numbers are simply the most probable values of inferred probability distributions. This has important implications for how metal recoveries should be monitored and reported. Indeed, in a context where many process optimisation activities are based on small improvements in recovery, there should be no doubt that inadequate handling of measurement/estimation errors can easily exaggerate or mask actual changes in process performance. However, estimates of the reproducibility of reported metal recoveries are rarely reported to plant management. This situation persists despite the fact that a code compliant metal accounting system must inform management about business risks related to metal accounting. To this extent, this paper focuses on the continuous management of reproducibility level of metal recoveries in compliance with the best practices. Sensitivity analysis of primary and secondary metal accounting models is performed to show the resulting probability distributions for metal recoveries. Some guidelines are given for designing and managing metal accounting systems capable of achieving and sustaining predefined levels for the reproducibility of metal recoveries.INTRODUCTIONEach and every mineral processing plant produces daily, weekly and monthly production reports in which metal balances for payable and penalty elements are presented. While such production reports are usually consulted in offices, underlying raw measurements are taken in harsh production environments where mechanical vibrations, humidity, corrosion and dust, to name a few, disturb measurement procedures. It is thus no surprise that several authors (Francois-Bongarcon & Gy, 2002; Gaylard, Randolph, & Wortley, 2014; Holmes, 2010; Spangenberg & Minnitt, 2014) have reported pervasive issues related to mass/sampling measurements in the context of mineral processing."

Jan 1, 2016

By Douglas Brand

"The data that many mineral processing plants make use of, is provided by samples taken from sampling systems which are inadequately designed or improperly maintained, and therefore cause detrimental effects to plant operations, production planning and metallurgical accounting! Poorly designed or maintained sampling systems will likely produce low probability samples which give the operator a false sense of security of the product and the process. If data is the basis for action (Flintoff, 1992, p.2), then using the resulting suspect or bad assays by operators, control systems, or metallurgist and administration personnel will act and make decisions which may adversely affect the profitability of a processing plant. Here we will discuss some of the fundamental sampling problems, propagation of errors and a method to estimate what impact this has on an operations Net Smelter Return.INTRODUCTIONIn order to control a mineral processing plant at its best potential, it is necessary to obtain the best possible measurement results of the metal or mineral in question. The sample which is delivered to a measuring instrument, or lab, needs to be of the highest probability to be able to achieve this. This paper will discuss the effects of sampling errors on grade / recovery and grade / Net Smelter Return (NSR) and provide a method to estimate the monetary advantages of using probabilistic sampling in a processing plant.REVIEW OF SAMPLINGSampling, by definition, is the removal of a small representative portion from a total consignment, or flow, for the purpose of accounting or process control.• A sample can only be considered representative, if each and every increment collected, in each of the sampling stages, is representative.• Each particle of the sampling lot must have the same probability of being included in the final sample.• If both of the above conditions are met, then the final sample will be representative of the complete sampling lot.It is commonly known that in order to take truly representative and probabilistic sample, best practices indicate that:• The total stream should be sampled.• The sample cutter should intersect the sample at right angles to the flow.• The sample cutter should travel through the stream at a linear and constant speed and the speed deviations should be less than 5%."

Jan 1, 2016

By M. Phylli Bray

"Concurrent with the continuing demise of many Canadian mining towns is the rise of a new method of providing remote mine sites with a workforce. This is the Long Distance Commute (LDC) which uses commuter labour and requires no permanent settlements to support the mine operation. It provides a flexible and cost effective method of operation to the industry and relieves both governments and industry of the expense of building and maintaining mining towns. However, little attention has been paid to the effect on workers or their families of the LDC work schedule whereby workers spend a fixed number of days at the site followed by a fixed number of days at home. Off-shore oil rig experience would indicate that negative social impacts may be expected. Research leading to an understanding of the problems involved seems to be indicated. One innovative suggestion has been to use already established but dying mining towns as workforce pick-up points for new LDC operations further north.BackgroundUntil recently, mine towns were considered as a necessary component of mine development. This was a natural symbiosis resulting from the need to provide workforce accommodation close to isolated mine sites. The early mine communities in Canada were often just a huddle of shacks around a head frame. Gradually mining companies began to provide housing which varied from basic duplexes and quads in grid pattern layout to professionally planned and designed towns, either model company towns or the more recent suburbs-in-the-bush, the so-called ""instant towns"" of the postWorld War II era of resource development. The improvement in accommodation reflected the need to attract a stable workforce as mine operations became more sophisticated. City amenities were expected and offered in these mine towns as a way of encouraging a permanent community of mining families. Indeed in towns like Manitouwdage, Schefferville, and others, it was not unusual to find a significant percentage of two- and three-generation families apparently providing the permanent mining communities so desired by mine operators."

Jan 1, 1991

By S-E. Vandat

The goal of this work was to select an appropriate electrode for dummy load of diesel engine in fully salt-water in the DESA factory. The electrochemical corrosion rate of general structural steel, commercial pure aluminum and cathode copper calculated as weighting, volumetric and commercial in fully salt-water by city power. After several tests and then applying the fuzzy logic method, it was determined that general structural steel is the best selection for this purpose.

Jan 1, 2005

By L. Paulino, C. E. Zangiacomi, J. Yamamoto

"This paper presents the learning from Alcoa Po9os de Caldas Smelter in Brazil, after several energy restrictions resulting from the failures of three rectifier units at its power switchyard. Starting on December 27th, fuses and diodes failed in three rectifier units of Potline #1, causing a long and dangerous power interruption. Even after current was reestablished, amperage was only 70% of the line target leading to a bath freezing process that lasted for around 48 hours. The process engineering team played with several potroom parameters as pot resistance, bath and metal levels, alumina feeding and bath chemistry in an attempt to minimize impact on the potline metal output and energy consumption. As it will be illustrated, the first battle was to keep the pots running on a ""survival"" approach. After that, several changes took place on the procedures used to run at reduced current which were considered rather successful. Finally, some recommendations will be given to foresee and prevent transformers and rectifiers from undesirable failures."

Jan 1, 2006

By Paul M. Clifford, David M. Baird

The Great Northern Peninsula of Newfoundland consists of a Precambrian core of gneisses and granitic rocks, cut by numerous diabase dykes. This complex is surrounded by an envelope of sedimentary rocks of Cambrian to Carboniferous age. Radiometric dates from two granite masses in the core give a mini-mum age of -945 m.y. (Grenville) for the last major tectonic activity. This Grenville deformation conferred upon the core substantially its present structure which has controlled later events to a marked degree. Block movements of the core, dominantly in a vertical sense, have ex-posed it to erosion at intervals. The nature and distribution of the flanking sedimentary rocks and the present relief of the peninsula suggest four such movements. THE Great Northern Peninsula extends some 150 miles north-northeast from the northwest corner of the main body of the island of Newfoundland. It separates the Gulf of St. Lawrence from the Atlantic Ocean, except for the 12 mile wide

Jan 1, 1962

By M. Board, R. Pakalnis, S. Seldon, R. Brummer

The Kidd operation mines roughly 10 000 tpd of copper and zinc ore from underground and employs about 700 personnel. In the late summer and fall of 1997, major movements in the proximity of the east wall of the Kidd open pit had been observed. The Kidd pit had been mined from 1965 to 1977 to depths of 260 m (850 ft), followed by subsequent mining by underground methods to current depths in excess of 1830 m (6800 ft). The No. 1 Mine (2600 Level to pit bottom) is approximately 90% extracted, with most of the remaining reserve between 2000 and 2500 levels. Although initial concerns centred on the stability of the pit walls, the potential ramifications of the movements to the underground were recognized and measures were implemented to ensure the safety of personnel as well as to minimize the potential damage to existing operations. In late October, damage to underground operations was observed as deep as the 2000 Level. In the final assessment, the global mobilized mass was a “wedge”-shaped hangingwall block extending from surface to about 610 m (2000 ft) below surface. The “wedge” boundaries are defined by a fault and shear zone which have continuous lengths in excess of 1070 m (3500 ft); its base by shearing through the host rock mass; and its eastern face by deep tension cracks (Fig. 1). Mined and filled excavations at the western face of the “wedge” allowed mobilization of a mass in excess of 30 M tonnes. Movements in excess of 75 cm (30 in.) per day were recorded on the surface stations that preceded the complete shutdown of operations on October 29, 1997. The evaluations in the days following the shut-down were centred on mitigation of immediate and future possible negative impacts on infrastructure and mining of the remaining No. 1 Mine reserves while ensuring the safety of the operators. This effort required the rapid assessment of the potential damage of the block movement on underground infrastructure, stope access, drainage and ventilation, as well as airblast potential due to the falling of a large block into the pit near the ventilation intake at the base of the pit. These assessments were presented in a previous paper (Seldon et al., 1999). In total, the lateral movement of the block on the ground surface was over 4.3 m (14 ft). This paper describes the detailed studies performed to understand the failure mechanism and to assess the impacts on future mining in No. 1 Mine.

Jan 1, 2000

By S. Manning, W. Morris

Mineral exploration assessment file information has long been considered a useful resource for developing mineral exploration strategies, and one of the most common data sets fled in assessment reports is ground magnetic surveys. The new Earth Resources and Land Information System database (ERLIS) now provides a method for rapidly accessing all references to a specific area through a series of raster images. The ERLIS provides access to the Assessment File Research Imaging (AFRI) database which comprises geo-science mineral exploration assessment file data, Mineral Deposits Inventory (MDI), together with provincial aeromagnetic data from the Ontario Ministry of Northern Development and Mines(MNDM). Conversion of the raster images of ground geophysical data to vector data files together with the concatenation of grids from adjacent claims provides a method for constructing high resolution magnetic regional images. The value of this resource is demonstrated through the construction of a single composite magnetic image derived from eight assessment file grids for an area south of Kirkland Lake, Ontario, within Pacaud and Catharine Townships. The composite grid of magnetic data provides a map with resolution that is not achieved by currently available Ontario Geological Survey airborne data sets. Details contained within the new high resolution image, permit the differentiation of lithologies and their boundaries, fault orientations and the location of alteration zones with magnetic response.

Jan 1, 1997

By R. E. Hamilton

"The requirements for effective optimization of a mineral dressing operation are discussed, with specific reference to a flotation system . Also considered are the relation-ships between automatic control and optimization pro-grams. Variables are classified into the following groups, and the significance of the classification is discussed: (a) Directly measurable (b) Directly manipulable (c) Uncontrollable (d) Calculable from measurable variables (e) Affected by changes in manipulable or uncontrol-lable variables. New sensors for measuring variables not normally measured are described."

Jan 1, 1967

By J. B. Mawdsley

"AbstractThe uraninite-bearing deposits in the Charlebois Lake area of northeastern Saskatchewan are unusual and important concentrations of uranium. They were first discovered in 1949 and preliminary development work to the end of the 1951 field season indicates the probability that this will become •another uranium producing district. The deposits are in zones bordering granite masses. These zones are of migmatite (mixed rocks) composed of calcium-rich meta-sediments intruded and replaced by a fine-grained white pegmatite. Locally this pegmatite is replaced by an end fraction which is relatively rich in fine-grained disseminated uraninite; it is these occurrences that constitute the bodies of economic interest.The fine-grained white pegmatite contains plagioclase feldspar more lime-rich than that in the granites of which it is an end differentiate. This extra lime, evidently derived from the intruded sediments, would result in the raising of the temperature of crystallization of the pegmatite-forming magma, thus consolidating it rapidly near the granite contacts as a fine-grained pegmatite. The end liquor containing uranium was evidently locally concentrated in minor fracture zones in these pegmatites. Where no lime sediments were present. the coarse-grained alkaline pegmatites were formed. Their crystallization would not be accelerated and the uranium would tend not to be localized in the pegmatite but to migrate and consolidate at lower temperatures with the end products, possibly in some instances as pitchblende veins."

Jan 1, 1952