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By M. H. Moys, J. A. Engelbrecht

"Large-diameter flotation columns are subject to severe axial mixing which has reduced column recovery and has generally limited it to cleaner applications. It has been assumed that columns with diameter greater than 1 m should be baffled to reduce axial mixing, but little work has been reported quantifying the effectiveness of baffling. Tests were done on a 0.2 m by 2 m column fitted with baffles of different geometry. It was generally found that the inclusion of baffles in the column worsened rather than improved mixing conditions in the column. This is explained in terms of a model for the effect of poor gas distribution on the behaviour of the column; this showed that under typical conditions a 16% excess of gas flux in the one compartment of a two-compartment column could result in one of the compartments being ""dead"" (i.e. with no net flow of slurry through it), resulting in a substantial loss of performance. The quality of mixing in the laboratory column was only reliably improved when the baffle was raised so that its top was positioned above the froth-slurry interface level. It should be possible to increase column recovery substantially with this configuration. The improved residence time distribution also means that columns can be used more effectively in roughing and scavenging applications. IntroductionFlotation columns have generally been used in cleaner applications, starting with their dramatic success at Mines Gaspe(1). Their lack of applications as roughers and scavengers is probably due to their poor residence time distribution (RID) when compared to the conventional cells they would replace. Espinosa-Gomez et al,(2) recently used them in rougher applications but installed three columns in series, presumably to cope with this disadvantage.Dobby and Finch in their seminal papersl(3,4) on the scale-up of flotation columns were the first to quantify the impact of axial mixing on the performance of industrial flotation columns. Laplante et al.(5) collected further data from the literature for column diameter D, ranging between 5 cm and 183 cm, gas superficial velocity Jg ranging between 0.7 cm/s and 2.8 cm/s and per cent solids in the feed S ranging between 3% and 52%. These data were analyzed with reference to the axial mixing model using the boundary conditions for closed vessels (the latter are more appropriate for flotation columns but the model is more difficult to use because analytical solutions for the RID are not available). The data were correlated by:"

Jan 1, 1993

By Tom Brady

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate weak rock masses (such as are associated with operations in the Carlin Trend in Nevada) into existing design relationships. The original database that led to most of the empirical design relationships presently employed in hard-rock mining was derived from fair-to-good-quality rock. In this study, the relationship between weak rock quality and opening design (nonentry/entry methods) is being investigated. The common factor in all mines is a weak back or wall. This work attempts to provide tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2003

By R. A. S Villegas

The Brazilian government announced in 2007 its plans to reactivate the nuclear program. As a result of this decision, a new nuclear power plant is already being built and there are studies dealing with, among other activities, the building of 4 to 8 new ones until the end of 2030. Such increase on the country?s uranium demand affects INB, the Brazilian state company that?s in charge of uranium supply. This paper describes scenarios predicted to the Brazilian nuclear industry for the next years and the INB plans to meet the country?s needs in terms of uranium exploration and production.

Aug 1, 2010

"Since all gold mills must sooner or later be cleaned up for permanent shutdown it was felt that a record of what was done at one mill might be of some help to those who will have to do the same job in the future,In cleaning up the mill of Delnite Mines Limited, I had an advantage that most mill superintendents will not have in that I started up the mill and was there until it was shut down, It was also known for two years approximately when the shutdown would be and for a year almost the exact time. This, of course, made careful planning possible and enabled me to get advance information that wouldn't have been available had the shutdown come unexpectedly,Early in 1964 calculation of ore reserves and the known number of working places available indicated that the mine would run out of ore sometime in August or September but not later than October, The time of course would vary with the number of competent miners that could be retained until the shutdown. Since the mining method used exclusively on the ore then remaining was cut and fill, it was known that once mining operations ceased it would require at most two days to crush and grind the last of the ore.In March 1 964 I took samples of the concrete floor under the precipitation presses, in the flux room and furnace room of the refinery and from the assays obtained proved that there would be no profit in breaking up the concrete to recover the gold from it, Samples taken from the top half inch of the concrete floors assayed less than 0, 10 oz per ton,"

Jan 1, 1966

By Zygmunt Wegrzyk

Poland is rich in hard and brown coal reserves, which have become the most important, and steadily developing, primary source of energy. With 192.6 mill. t of hard coal production and 40 mill. t of exports in 1978, Poland is fourth and second in the world respectively. The paper discusses the various mining methods adopted in the country's history of mining. Particular emphasis is placed on longwails, their mechanization and equipment assembled in the form of fully mechanized face complexes suited for varied geological conditions. Measures to improve the recovery ratio of coal resources are dealt with. investment efforts undertaken in the coal industry are outlined. An account is given of the ever improving techno-economic results of coal mining. The country also exports a wide range of mining equipment and transfers its well-founded technical know-how to others. There are strong cooperative links with many foreign partners.

Jan 1, 1979

By Terry J. Briggs, Ian J. Kelso

"Abstract- The Century mine in northwest Queensland,Australia, is a major sediment-hosted zinclead- silver orebody, located within the western Mount Isa Basin. Stratiform, carbonaceous shalehosted mineralization is developed within Proterozoic shale and siltstone sequences of the Lawn Hill Formation. CRA Exploration Pty Ltd (CRAE) discovered the Century deposit in 1990 and open pit mine development commenced in 1998 under the ownership of Pasminco Century Mine Limited (PCML). The deposit contains an identified mineral resource of 105 Mt @ 12.1% Zn + 1.7% Pb + 46 g/t Ag (Broadbent and Waltho, 1998) which is currently being mined at a rate of 5 Mt/y.In December 1998, an exothermic reaction was observed between explosives spilt onto shale drill cuttings from a blasthole. This reaction is referred to as ‘reactive ground’ and has the potential to cause premature detonation of explosives in a charged blasthole with catastrophic consequences. The incident led to a subsequent geological and geochemical assessment of the different rock types at the Century deposit and their potential reactivity with ammonium nitrate-based (AN) explosive products. This assessment was conducted in an attempt to characterize zones safe for blasting with uninhibited AN-based explosive products. A direct result of this study is a set of procedures outlining the use of different AN-based explosives in areas defined as potentially reactive or non-reactive for the different lithologies present. Black shales contained in both the waste and mineralized sequences contain the sulfide mineral pyrite (FeS2), which is thermodynamically unstable with AN contained in commonly used explosives. The potential reactivity of partially weathered pyrite can ultimately result in the decomposition of an AN-based explosive. It was determined that only pyritic black shales showed any potential to react with AN, irrespective of their position in the stratigraphic sequence. Other lithologies present at Century, including Proterozoic sandstone and Cambrian limestone, are classified as non-reactive with AN. This is a geological risk management situation present at the Century mine."

Jan 1, 2001

By Dave N. K., T. P. Lim

"A fast, reliable and accurate method for radium-226 determination in environmental water samples has been devised, using an alpha spectroscopic technique. The correlation between barium-133 and radium-226 in the barium-radium sulphate precipitation mechanism was studied and in the limited experimental recovery range, the coefficient of correlation was r = 0.986. A self-absorption study for various barium carrier concentrations was also undertaken to obtain the least broadening of alpha energy line widths. An optimum value of 0.3 mg barium carrier was obtained for chemical recovery in the range of 85%.IntroductionWith the increase in uranium mining activities, the migration and spread of radioactivity via various environmental pathways is of great concern. Because of its inherent biological hazard and relatively long half-life, (approximately 1620 years), raidum-226 is frequently monitored as a measure of radioactive contamination of the environment. It is, therefore, necessary to modify existing methods for rapid determination of radium-226 in environmental samples for quick corrective measures in the event of seepage, dam leakage or discharge violations."

Jan 1, 1981

By J. Smit, F. Parada, R. Parra, E. Balladares, M. P. Merino

"In this study, a two-step process was developed for recovering copper, molybdenum, zinc and iron (hematite). In the first step, grinded slags (-65 mesh) were sulphated with SO3 at 350-500ºC to form iron, copper and zinc sulphates. In the next step, the formed sulphates were decomposed to hematite, copper and zinc sulphates and oxysulphates at 700-750ºC. The generated SO3 was recirculated back to the sulphation step. The generated calcine in the decomposition step is leached with 25 gpl acid at 50ºC to dissolve the copper, zinc and molybdenum for further conventional separation and recovery. The hematite residue, of intense red color, can be used as pigment, in the ceramic industry or as pellet feed. The fine crystalline silica remains in the hematite residue."

Jan 1, 2014

By Robert K. Jonas

Mining companies can improve production and reduce costs by using the best available technology to control their operations. Many mines are challenged to use multivariable predictive control due to limited experience or staffing, as well as being concerned over the robustness and sustainability of predictive controls. As a result many mines are not realizing optimal performance from their assets, and thusly are not realizing the production increases or cost reductions that this technology can deliver. Over the past few years, the application of multivariable model-based predictive control has gained acceptance in many mining processes and has proven to be robust and sustainable for some of the most challenging mining processes. New automated modeling and performance monitoring software have greatly simplified the effort to implement and maintain these solutions. In addition, many progressive companies have chosen to co-source the implementation and service of these solutions to assure project success and continued benefits stream. This technology has been successfully applied to a wide variety of processes; grinding mills, alumina digestion, CCD washer and thickeners, kilns, calciners, roasters, flash smelters, heat exchangers, evaporators, and most recently in the demanding process of flotation. This paper discusses the state-of-the art in advance control technologies in the mining industry, including the impact of these technologies on maximizing benefits, and implementing best practices for long term sustainability. Benefits from recent multivariable predictive control applications in copper mining will be reviewed, and the use of the latest predictive control technologies and practices in mining will be discussed.

Oct 1, 2009

"High Pressure Grinding Roll (“HPGR”) technology is applied in a broadening range of minerals processing applications for relatively wet or moist materials. HPGR grinding of dry material or involving drying and air classification is more common, for example in cement manufacturing. A number of minerals processing plants are also operating with dry material, either due to process reasons, such as considerations of preceding or subsequent process stages, or as dictated by local conditions of arid areas and scarcity of water. The present world-wide expectation of decreasing availability of water supply urges us to look for alternatives that minimize water consumption.Recently established and envisaged future HPGR applications with dry ores have indicated that the technology of dry crushing and classification as practiced in cement and limestone grinding can be applied in minerals processing. Moreover, dry technology could very well be applied for generating a final fine product at sizes near or below 100 microns, as may be required for beneficiation by, for instance, flotation, magnetic separation or tank leaching.Dry HPGR grinding requires special attention in maintaining suitable process economics, when considering power input in grinding, drying and classification. In some cases, HPGR capacity and roll surface wear life may be negatively affected by a lack of moisture in the feed.This publication summarizes some of the features of, and experiences in dry HPGR applications. This includes design aspects of the classification system and discussion of the wear protection of the roll surfaces. The paper also includes examples of operational experiences of dry practices in minerals processing and cement plants."

Jan 1, 2012

By S. F. Dudka, T. Dang, M. L. Wong

Abstract - The Nui Phao W-F-Cu-Au-Bi deposit is located in one of the poorest regions of northern Vietnam. The deposit is currently undergoing a pre-feasibility study by Tiberon Minerals Ltd., with a view to developing what would be the largest WO3 mine and one of the five largest fluorite mines in the world. The project is being planned in close compliance with World Bank and national guidelines for environmental and social protection. Development of the mine is anticipated to bring the following benefits: remediation of serious pre-existing environmental conditions (natural and anthropogenic heavy metal contamination and acid rock drainage); provision of employment and training, and thereby wealth, to local communities; significant tax and royalty payments to government, which will be reinvested as social spending; and development of municipal and industrial infrastructure to build sustainable post-mining communities. The role of governments at all levels is critical in guiding and facilitating this process. This paper was written prior to development of the mine, and relays the intentions of the developers. Future studies will be needed to evaluate the degree of attainment of sustainable development objectives, both during mine operation and after closure.

Jan 1, 2003

By P .. D. Vaillancourt, D. F. Sangster

Several occurrences of disseminated galena, including a former producing mine, are found in Pennsylvanian fluviatile sandstone of the Salmon River Basin, Cape Breton Island, Nova Scotia. Detailed study of the distribution of these occurrences has revealed that highest galena concentrations are found in sandstone overlying channel-shaped depressions in felsic basement rocks. These buried depressions, in turn, correlate in position with modern streams in areas of basement exposure. This correspondence suggests that the latter are at least partially controlled by an exhumed Pennsylvanian topography. If this is correct, then several other streams in the area, lying on basement, may be used to locate possible undiscovered lead deposits in sandstones of the Salmon River Basin.

Jan 1, 1990

By Tyson C. Birkett

Initial indicator mineral sampling covering 425,000 square km of northern Quebec and subsequent follow-up of positive results convinced the Ashton ? SOQUEM joint venture to acquire mineral rights to 380,000 hectares prospective for diamond in late summer, 2000. Drilling in 2001 and 2002 identified eight kimberlitic bodies, all significantly diamondiferous. Commercial size stones (retained on a square mesh sieve with openings 0.85 mm) and encouraging grades have been returned by several bodies tested to date: The Renard bodies are formed by steep-sided breccia pipes with kimberlitic matrix surrounded by irregular outboard breccia zones within country rock. These bodies were emplaced in high-grade metamorphic rocks of the Superior Province of Archean age. Orthogneiss with lesser tonalite hosts the breccias, although regionally paragneiss is also present. Diatreme facies portions and nearby country rock are intruded by minor to major (Renard 1) amounts of hypabyssal-facies kimberlitic rock. Renard bodies are macrocrystic, with large olivine crystals set in a groundmass of olivine, phlogopite, monticellite, spinel, carbonate, apatite and serpentine. Proximity of various Renard bodies, with most in a core area of 0.5 square km will allow planning of an efficient mining operation. Geophysics, especially magnetic surveying, has contributed to identifying bodies of kimberlitic rock.

May 1, 2003

By C. F. Hews, P. N. Calder

"MIROC and The Mining Industry The Mining Industry Research Organization of Canada (MIROC), incorporated in 1975, is a non-profit organization sponsored by member companies from within the Canadian mining industry. The Canadian mining industry is a world leader in technological development and in organizational and human resources development. A prime objective within the industry is to retain this leadership and also improve its competitive position worldwide.MIROC is dedicated to support the objectives of its member companies and their common interest, and the objectives of the industry. In this context: MIROC's mission is to encourage the formulation of ideas to improve mining technology and methods by any source, and to foster the development and testing of promising initiatives in progressive steps from the early stages of conceptual and feasibility research through manufacture to delivery of new technology to the mining industry. In so doing MIROC plays an important role in the development of individuals skilled in mining research. Management ApproachMIROC's research program is driven by member companies who have interests throughout Canada. The board of directors approve projects that are acceptable to its members. While MIROC's basic research funding is provided by its member companies, about 30% of its annual research budget is now derived from royalties generated from previous research activities."

Jan 1, 1994

By E. Ozberk, N. Gibson, W. G. Davenport

"In the 1950s, Canada produced more than ninety-five percent of the non-communist world's nickel and achieved dominance in terms of production, technology and pricing policies.Over the past thirty years there have been dramatic changes in the nickel industry to the extent that Canadian production is now less than thirty per cent of the total.In this document we have presented statistics relevant to this transformation and reviewed the technology, particularly with regards to energy and environmental considerations.Under the new market conditions nickel producers are likely to face more difficult competition than they have encountered in the past.The economic scene and measured nickel reserves dictate that for the purpose of increasing production, new nickel smelters will not be built in Canada in the foreseeable future. However, in order to reduce sulphur dioxide emissions, Canadian nickel smelters will possibly go through some modifications or rebuilding.IntroductionThis paper presents a review of the Canadian nickel industry in relation to the world nickel industry. Major changes are described which have occurred in the characteristics of the nickel market over the last thirty years. The pre sent status of the nickel market with respect to Forecasting future trends is reviewed and attempts are made to predict what further changes will take place in the next two decades. Comparisons are made of the economics of producing nickel from sulphide ores and oxide ores and the advantages and disadvantages the Canadian nickel producers face.A brief critique of the existing and emerging nickel production technologies in Canada and the world is carried out and attempts are mad e to predict the changes which may take place in the foreseeable future."

Jan 1, 1983

By L. A. Gomieroa

The Caetité-Brazil uranium facilities produce about 340 t/y of uranium from an ore averaging 0,25 U %. The process steps are ore crushing, heap leaching with sulfuric acid, U separation and purification by solvent extraction with tertiary amine followed by stripping with sodium chloride solution and precipitation as ammonium diuranate that is dryed. A change in the milling process is being evaluated to increase the production and the uranium recovery. Heap leaching will be changed to conventional tank agitated leaching of the ?590 ground ore slurry in sulfuric acid medium. The replacement of the stripping reagent is also being considered.

Aug 1, 2010

By John G. Henning

Low quality rock is encountered in many manifestations in underground hard rock mines, ranging from weak and poorly consolidated rock to highly altered or foliated rock. Lateral mine developments driven in low quality rock pose on-going challenges to a mine operator, as ground stability issues, such as caving of under-supported ground, drift closure due to surface deformation or buckling processes, and degradation of exposed rock surfaces are a persistent concern. For many operators, ground support design is an iterative process, as support practices are refined with time. Using case studies from a variety of underground hard rock mines, this paper reviews techniques for the classification of low range rockmasses and examines the rationale and effectiveness of adopted ground support systems.

Oct 1, 2010

By C. P. Verschuren, P. W. Kingston, W. F. Caley

"In recent years, there has been rapid growth in the use of natural stone building and construct ion products. The largest growing markets are for pre-fabricated natural stone panels for interior and exterior wall facing and flooring. This increased demand is attributed to advanced quarrying and processing technologies, renewed appreciation for the aesthetic appeal of natural stone, and to the superior durability of natural stone when compared to glass, steel, and concrete. Geologically, plutonic rocks, and to a lesser extent marble and limestone/dolostone, are used extensively for these applications. This paper details the economic structure of the dimension stone industry, describes the necessary characteristics of a stone quarry, and outlines the geological criteria which favour an economic quarry.INTRODUCTIONThe world building stone industry has remained relatively stable over the last 5 to 6 years. In contrast, the North American stone industry has experienced substantial growth during that period. The increased use of commercial granite is primarily responsible for this growth, where use as exterior wall veneer for commercial, industrial, and institutional buildings represents the largest and fastest growing market.This increased usage in the construction industry has been sparked by the application of new technologies in quarrying, processing and installation , ma king natural stone more competitive with man-made materials which are energy intensive to produce, and have risen dramatically in price. The development of safer, time-saving stone installation techniques has also appealed to the liability-conscience construction industry. Finally, there is a trend by designers and architects toward utilizing long-la sting weather-resistant building materials, and a renewed appreciation of the aesthetic appeal of natural stone. The other large user of granite is the monument industry of North America which, although it has decreased slightly in recent years, still consumes approximately 40% of all commercial granite produced. The local use of commercial marble has remained relatively stable, and North America still relies heavily on European sources and suppliers. There has been some concern over the use of marble for exterior applications in areas subject to acid rain, and in colder climates where the marble ma y be vulnerable to freeze thaw cycles. Despite these concerns, the greatest problem is not with the structural breakdown of marble but the inability of some marbles to retain their polished finishes in the se environments. As a result, there has been an increase in the use of granite at the expense of marble for exterior applications. Finally, commercial marble is used extensively for interior flooring, wall s, counter tops, furniture, sculptures, and stairway components"

Jan 1, 1989

The PEMAC Commitment to World Class Industry in Canada The Plant Engineering and Maintenance Association of Canada PEMAC is a national, not-for-profit industry and technical association for plant and facility maintenance, engineering and physical asset management practitioners and professionals. Founded mid 80?s in the last century PEMAC is a knowledge based organization that focuses on sharing knowledge with our members and the profession. We provide education and professional development programs and certification for maintenance practitioners and professionals. We develop, produce and participate in conferences, seminars and trade shows.

May 1, 2008

By C. -M. Katsari, G. N. Anastassakis

"Copper is considered one of the most important industrial metals because of its properties (conductivity, malleability) and variety of uses. Approximately 70% of the global copper is used for various electrical applications, with a significant part of copper originating from recycling, since copper can be recycled and re-used countless times, without any loss of performance and difference in the quality of recycled copper in comparison to that from ore. Copper recycling significantly contributes to natural resources conservation, waste minimization, energy saving, and overall cost reduction. Approximately, 35% of the globally produced copper originates from recycled copper.The objective of the current work is to investigate the recovery of copper from electric wire scraps using wet shaking table as an alternative to air separation methods that prevail over the wet ones in recycling processes. The tests were carried out using feed of correspondingly high- and low-grade in copper. In the first case, the wire scraps had been subjected to shredding only, prior to tabling separation; in the later, the low-content tailing of prior air separation was used as feed ?n table separation.In regard to testing, the following factors were examined: table tilt, water flow-rate, and reciprocating speed. The results of the tests clearly denote that copper wire separation from plastic polymer is feasible, as in most cases, table separation resulted in heavy products of high purity in copper and high recovery, and tailings of very low copper grade. The results of the current work clearly denote that wet tabling can be applied efficiently for the separation of recycled copper wire from plastic, as an alternative to air separation methods, as well as for the recovery of copper from the low-grade tailings derived from air separation methods."

Jan 1, 2016