Search Documents

By D. A. Stanley

Researchers at BCD Technologies and the University of Alabama have applied three statistical techniques to the information contained in a large database of measurements from a phosphate ore processing plant. The rust, Principal Components Analysis (PCA), replaces many measured variables with a few fundamental and un-correlated variables. The second technique, Projection to Latent Structures (PLS), is an extension of PCA that explores the relation between variables identified as either independent or dependent. The third technique, Cluster Analysis (CA), is applied to the results of the PCA or the PLS calculations, and identifies individual data clusters that represent uniform operating conditions in the plant. All three statistical methods can be seen as geometrical operations on the data viewed as points in space. A Viewer gives a corresponding graphical presentation of the data points. This paper describes the use of the above three techniques and the Viewer to explore part of the phosphate flotation database.

Jan 1, 1998

By Ernest A. Hodgson

A SERIOUS hazard which must be faced in some mines, though quite absent in others, is that of rockbursts. Bursts cannot be wholly avoided in such mines, but the hazard would largely disappear if they could be predicted. The problem of prediction resolves itself into that of measuring pressure in the mine and determining when that pressure nears a critical value. The geophysical approach to the problem lies in discovering some physical property of the rock, which varies with pressure, which can be measured for rock in place, and for which the indication of critical conditions is sufficiently definite and open scale. A physical property, suggested first in connection with earthquake pre-diction, is that of sub-audible snapping. It was argued that, as the pressure grows, the rock probably yields microscopically and that minute snapping occurs which is so faint as to be inaudible to the unaided ear. Experience has proved this to be the case. Following other earlier work begun early in 1939, experiments with this method were initiated at Lake Shore Mines in 1941, and equipment was slowly being developed in practice when, fortunately, it was found possible to by-pass this tedious development programme. Experiments with sub-audible snapping in mine rocks had been carried out by Dr. L. A. Obert of the U.S. Bureau of Mines and his associates over a period of about four years. An amplifier and a recorder were developed, each reasonably satisfactory in practice. Lake Shore Mines offers a tempting field for rockburst research. Dr. Obert was invited to test his equipment in this and other mines in Ontario and did so. As a result, he and the administrative personnel of the Bureau became interested in the Lake Shore experiments co the extent of most generously arranging for the manufacture of sets of their own designed equipment for use in this programme. The first three sets of recorders were ordered at once and were delivered in May, 1942. A second group of three sets, incorporating various improvements indicated by experience both in the United States and in Canada, reached Kirkland Lake in April, 1943. The pick-up devices, known as geophones, were made in the electronics laboratory at Lake Shore by Mr. Zack Gibbs, who has had charge of all the instrument development in this re-search.

Jan 1, 1943

By J. C. White

This paper, after a brief introduction giving the history and geology of the area, deals with mining operations at the Copper Mountain mine of Gaspe Copper Mines, Limited. It discusses development operations, and then goes into the mining methods employed, covering drilling, grade control, blasting practice, loading and hauling, and the road and service machines used.

Jan 1, 1969

By Peter F. Pullen

The need to apply the latest available technology to develop better tools and methods to meet problems in the mining industry was recognized by six of Canada's leading mining companies. As a result, MIROC (Mining Industry Research Organization of Canada) was chartered to identify problem areas in Canadian mining and to have research carried out to develop the tools and equipment to meet these perceived needs. The initial activity of MIROC has been in the environmental field, with improved clothing and protective devices being developed by contractors. Work clothing for miners is now being field tested. Respiratory protection and a new personal light source combined in a new "space-age" helmet are about to be issued for testing. Further developmental work is being carried on to offer these units and probably other personal protective devices on an individual basis as well as in a combined package.

Jan 1, 1979

By I. Govender

Positron-Emission-Particle-Tracking (PEPT) has enabled the non-invasive observation of charge and slurry transport in model mills under operational conditions. We use high quality PEPT data to infer that the charge motion can be effectively described by a non-Newtonian granular fluid. An improved theory for slurry transport, including inertial effects, is presented.

Jan 1, 2012

By A. H. C. A. Zimmerman

WE have just heard what must be regarded as a thoughtful, constructive and somewhat painful analysis of the financial function of our industry. While thinking about this, it is interesting to reflect on the conditions which have stunted the growth of the financial side of our affairs. Mining must be regarded as a wealthy business. •while immeasurable grub takes and development budgets have been lost, there can be little argument that a productive ore-body nearly always produces the type of wealth that breeds some extravagance. I recognize that this statement can be attacked from many sides, but an historical comparison with a commercial enterprise involving similar investment will demonstrate what I mean. However, these old times are be-ginning to disappear for a variety of reasons. High amongst these are: ( l) Increased costs of exploration. (2) Remoteness of many new finds. (3) Fixed or declining metal prices (particularly when expressed in constant dollars). ( 4) Constant demands for higher wages.

Jan 1, 1962

By W. W. Adams

"Accidents at coal mines in the United States in September 1926 resulted in the loss of 170 lives, according to information furnished to the Bureau of Mines, Department of Commerce, by State mine inspectors. Of this number 125 occurred at bituminous mines and 45 in the anthracite field. As the bituminous output of coal for September was 48,976,000 tons, and the production of anthracite was 8,444,000 tons, the fatalities reported represented a death rate of 2.55 per million tons for bituminous mines and 5.33 for anthracite mines. The industry as a whole showed a fatality rate of 2.6 per million tons of coal produced in September 1925 the rate for bituminous coal mines was 3.29; the anthracite mines were idle in September last year due to a strike.During the first nine months of the present year 1,759 men have been killed by accidents at the coal mines throughout the United States, resulting in a death rate, per million tons of coal produced, of 3.76 as compared with 3.95 for the same period in 1925. Reports for bituminous mines alone showed a nine-month fatality rate of 3.53 which was about the same as the corresponding rate from January to September in 1925. The anthracite rate for the present year, however, shows a decrease of about 17 per cent; that is, the rate has declined from 6.36 to 5.28.Records covering the first nine months of 1926 show that 12 ""major"" disasters, that is, disasters in which five or more men were killed at one time, have resulted in the loss of 271 lives as against 10 disasters and 199 deaths in the corresponding months in 1925. The fatality rates for these disaster: alone were 0.579 and 0.465, respectively. One major explosion occurred at Tahona, Oklahoma, on September 3, 1926, in which 16 men lost their lives.An analysis of the principal causes of the 1,759 fatalities for the first nine months of the present year shows a reduction in the death rate as a whole and for falls of roof and coal and for explosives, but an increase in haulage, gas and dust explosions, and electricity. The comparative rates for these accidents were:"

Oct 1, 1926

By D. P. Cook, Jr. Jones, J. W. Evans

"It is well understood that the flow of liquid metal in the mold region of the caster can have a notable effect on the overall solidification behavior in aluminum casting. Previously our group has characterized the flow in this region in a water model, using particle imaging velocimetry. The flow is significantly effected by the specifics of the metal delivery system, i.e. size, geometry, used during the cast. Recently, a time-averaged 3D numerical model of the nozzle, combo bag and sump region has been developed and its validity has been tested against experimental data. Cases were run for different sized combo bags as well as bags that have been blocked. The results show satisfactory agreement between the physical and mathematical models.IntroductionFluid flow in the head of an electromagnetic (EM) and direct chill (DC) ingots has been shown to effect many important operational parameters in casting such as superheat removal, macrosegregation, and hot cracking. In most cases, the momentum from the nozzle is diverted through a delivery system, termed a bag, before entering the mold region. The specific geometries of the bags vary widely from operator to operator suggesting that there is still some question as to the optimum design. Several studies [1-4] have been carried out to understand the influence of the bag design on the solidification behavior in aluminum casters. However, few studies have included numerical prediction with experimental verification. Unfortunately, many simulations performed today still do not accurately account for flow in such devices.Recently, a significant amount of research into the flow resulting from the metal delivery systems has been performed [5-8]. The thrust of this research has been characterizing the flow patterns by a measurement technique called particle imaging velocimetry. The data suggest that the method of delivering the liquid metal into the mold region has a significant effect on the nature of the flow. With a detailed set of quantitative data from a water model, a numerical model can be built and tested to ensure a proper description of the flow field. The computational model used in these simulations is designed to represent a laboratory scale model of a caster in which ""combo"" bags were simulated. Such bags are mostly of a densely woven glass fiber material with low permeability to aluminum. ""Windows"", of a more open weave, permit aluminum to flow from the bag, see Fig. I. Two different sized combo bags were modeled, each subject to two different outflow window configurations. Furthermore, experimental measurements [9] were used to validate the model results."

Jan 1, 1999

By P. F. Stratton, M Huggahalli, N Saxena

"Several studies have been carried out to determine how the optimum atmosphere conditions in the heat treatment of metals can be established for a given product by using different gas injectors and varying atmosphere flow rate and composition. The most common approach taken to gain insight into furnace atmospheres has been to use commercial computational fluid dynamics codes and examples of their use are shown. However, the complexity of these codes, the difficulty in establishing boundary conditions, their cost and computational demands limit their usability in solving day-to-day production problems.A simplified, web-based model of a furnace atmosphere is described where the conservation equations are solved to determine the composition profiles of the atmosphere in the furnace. Although the model is restricted in scope to certain types of furnace, it is shown to give better results than CFD when boundary conditions are uncertain. The application of the model to the understanding of existing furnace conditions and to determining ways of optimising the use of gases are discussed. IntroductionThe important role of protective atmospheres during heat treatment of metals, furnace brazing of assemblies and soldering of printed circuit boards is well established. The atmosphere in the furnace prevents air ingress and oxidation of the parts, helps flush away any flux or binder from braze and solder pastes and provides an important mode of heat transfer [1]. In a batch furnace having typically one or two gas injectors, the gas utilisation and process can be optimised by minimising air leaks and mantaining atmosphere homogeneity with fans or other atmosphere circulation techniques. In a continuous furnace, however, atmosphere optimisation is more difficult as furnace inlets and exits can also let in air. The atmosphere requirements of different stages of heat treatment, brazing or soldering vary [2]. Achieving these atmospheres in different sections of the open-ended furnace is a relatively complex task. Methods such as atmosphere zoning and the use of physical curtains and gas injectors have evolved with time, though it is hard to predict how effective these techniques will be for a given furnace and process. Experts in the field tend to rely on experience and rules-of-thumb rather than scientific method to achieve the required results."

Jan 1, 2001

By C. O. Campbell

THE recognition by C. W. McKee, field engineer for Springer Sturgeon Gold Mines, Limited, in the fall of 1940, of the economic possibilities of a small outcrop of baryres near Pembroke, in Hants county, Nova Scotia, followed by aggressive exploration and development by the Company, has placed Canada for the first time in its history in the position of becoming a major producer of barytes and its products. In past years, production of this mineral in Canada has been unimportant. Thus the coral output from 1885 ro 1933, inclusive, amounted to only 41,027 short tons, following which there was no production until 1939. Deposits in Nova Scotia, and particularly in the Lake Ainslie district, Cape Breton, have been the main source of supply, with a production between 1866 and 1925 of 31,689 tons. Following the examination of the outcrop of baryres near Pembroke by Mr. C. W. McKee in October, 1940, the area surrounding it was trenched, and, as this work gave encouraging results, a diamond drilling programme was commenced. A grid system was laid our and sixteen holes aggregating 2809.3 feet were put down, spaced at 100-foot intervals, the deepest hole being 300 feet. This drilling outlined a body of high-grade baryres over 600 feet long and 200 to 250 feet wide, with an average depth of 120 feet and estimated to contain well over one million tons of ore. The limits of the body were reached on the west, north, and southwest, but the drilling was suspended before the eastern limit was determined. Quarrying operations, and construction of a 100-ton mill, were commenced in February, 1941. The mill was placed in operation on May 29th, and on June 15th, eight months after the initial discovery, the first shipment of 2,500 long rons of milled baryres was made to Trinidad, British West Indies.

Jan 1, 1942

By Z. Scopa, E. Tarshizi, R. Setterlind, L. Frost, R. Livernois

"THE MINES OF THE FUTURE The mines of the future present a host of challenges, which may appear exciting or daunting depending on one’s perspective. Whether some sectors of the public recognize it or not, the demand for raw resources is not going away any time soon. In fact, it is rising as global population grows, urbanizes and attempts to steadily increase quality of life. Yes, at the same time that much of the highly developed world is calling for greener goods, reduced consumption, and cleaner production, in other areas there are cries for clean water and sanitation, consistent energy supply, access to health care and education, personal security, and support for basic human rights. The balancing act for sustainable development of our global society is indeed precarious, and the mining community is necessarily a key player. Fortunately, many industry members have accepted this role and the responsibility to provide leadership and a solid foundation for progress. Looking ahead, we need new generations of leaders, many of whom will be mine engineers, which are ready to tackle all sorts of complex problems. There are tremendous needs just for technological innovations. Increasingly tough deposits will require that we continue to expand scale toward “super” pits and “deep” underground mining fully develop unconventional recovery techniques like in-situ leaching and gasification or deep-sea extraction, and seriously consider off-earth endeavors. Such work will take entirely autonomous equipment; novel separations, processing and recycling methods; and systems that can withstand extreme physical conditions – just to name a few. It will also take a level of systems integration never-before seen in our field, complete with big data issues, sophisticated analytics and modeling efforts, and cyber-security challenges. Moreover, increasingly complex environmental problems will require creative solutions. Addressing issues like pollution control across multiple media, emerging contaminants, optimal management of wastes, selective mining, and shared use of resources between mine operations and surrounding communities and ecosystems are among top priorities. Really, a complete paradigm shift must occur, such that our focus is on overall improvement of environmental conditions, rather than minimization of impacts. A similar shift will be required in the social realm. How can we make miners safer and healthier on-site and off? How can we contribute to communities such that they are better off, now and long-term, for having a mine next door? How can we help transform artisanal mining practices to also contribute to sustainable development? How can our work be a factor in increasing economic and political stability? How can we improve the public understanding of raw resources and the need for mining enterprises?"

Jan 1, 2017

Cannington Mine is an underground, hard rock, metalliferous mine located in North-Western Queensland, Australia. Weld mesh is installed to prevent the failure of rock from between the installed reinforcement elements. Corrosion reduces the capacity and life expectancy of mesh and presents a real hazard to underground personnel and equipment as it reduces the effectiveness of the support system. Corrosion influences the economics of the mining operation through the need to conduct rehabilitation of the ground support which involves re-installing new mesh or shotcreting over the affected mesh to protect it from further corrosion. The requirement for rehabilitation is determined by the geotechnical engineer based on an individual visual assessment with little or no engineering input. It was identified that a more quantitative method was required that considered the safety and economic risks involved. A project was undertaken to develop a simple method to evaluate corroded mesh and to provide selection criteria for rehabilitation. A weld mesh corrosion classification has been developed that relates the average wire diameter of corroded mesh to the remaining capacity of the mesh. Accompanying selection criteria provides recommendations as to when rehabilitation may be required based on the estimated residual mesh capacity, the remaining development life, and the level of personnel exposure.

Nov 25, 2010

By J Rayo

Andean countries (Chile, Peru, Bolivia and Argentina) have 42 semi-autogenous mills (SAG) in operation and there are more than 30 projects in the pipeline that consider SAG mills. At the end of the next decade, the total amount of SAG mills in this area will likely be close to 100.There is a lot of reliable operational information collected by JRI Ingenieria Sociedad Anonima, the author’s engineering company, for more than 20 years and processed by statistical software, to be used as a reference for design basis of future projects or to improve operations by comparison. JRI Ingenieria Sociedad Anonima has reliable information related to the performance of more than 50 per cent of the Andean SAG plants.The paper presented considers a set of graphs that summarise the collected and verified SAG plants technical data. The figures will show key parameters as circuits and equipment data, energy consumption, technical availability, utilisation rates, throughput variability, pebble productions, steel consumption and others.The data is compared with typical design basis of several engineering companies and the main differences are analysed and/or commented on.CITATION:Rayo, J, 2014. Comparison of semi-autogenous mills operations in Andean countries, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 283–296 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Susanne Pignolet-Brandom

Reflected light microscopy, and scanning electron microscope energy dispersive spectroscopic analysis and backscatter electron images were used to determine if a "slick dross" with undesirable handling properties has an assemblage of phases distinct from normal dross. This study has found that in the normal dross the most abundant lead phases are lead sulfide and lead metal and the most common copper phases are copper-iron sulfide and copper sulfide. In the slick dross, the most abundant copper phase is copper-lead sulfide and the most common lead phases are copper-lead sulfide and lead sulfide. The resulting mineralogical information has provided additional insight into the causes of the handling problem and the reaction mechanism for the formation of normal and slick dross

Jan 1, 1988

By Alex Heath, Andrew Barycki, Baladron. Javier

"Efficient flocculation is important to thickener performance, affecting the overflow clarity, solids settling flux, underflow density and operability. Many factors affect flocculation; from the material/flocculant type, dilution of the feed and flocculant solution, mixing, to the shear rate and shear history. The flocculant addition point (or points) can be used as a tuning method to alter the effective flocculation time in a feedwell, with addition further up the feed pipe increasing the residence time but making the aggregates more prone to breakup if they experience high shear later in the process. Conversely, adding the flocculant later, eg under the feedwell shelf decreases the mixing time but allows some free (unadsorbed) flocculant to be available at the feedwell exit. An extensive trial has been performed on an operating thickener comparing seven individual different flocculant dosing positions through a Vane feedwell, and some combinations of two dosing points simultaneously. Measurements of the velocity, solids concentration and aggregate size were made throughout the feedwell at the different positions, with the dosing points significantly changing the aggregate size and clarity, and also affecting the solids concentration at some positions. The results are accessed in terms of flocculation kinetics and used as CFD validation data."

Jan 1, 2014

By Basar Arioglu, Jaeung Kim, Mehmet Öztürk, Jinmoo Lee, Dongho Lee, Taek-Kon Kim

"Istanbul Strait Road Tube Crossing Project (Eurasia Tunnel) includes 3.34 km of a bored double-deck tunnel under the Bosphorus Strait, at a maximum depth of 106 m from the sea level, and 1 km of twin NATM tunnels on the Asian side. The region’s variable geology, hydrology and propensity for seismic activity, combined with high water pressure and large-diameter/double-deck tunnel configuration, make the Eurasia Tunnel one of today’s most challenging and complex projects under construction. Due to the site’s proximity to the active North Anatolian Fault, the tunnel is designed to withstand a 7.5 magnitude earthquake. The tunnel penetrates through both the Trakya bedrock (on both European and Asian sides) and the alluvial sediments at the bottom of the channel. The tunnel is designed to accommodate differential displacements by introducing seismic/flexible joints at proper locations at the transition zones between rock and soft soils. Tunnel fire is also a significant design consideration for undersea tunnel due to that the rubber protecting it in close proximity of the seismic joint should resist a fire for long term safety and durability. This paper mainly focuses on the design for method of tunnel response analysis in transverse and longitudinal direction against seismic demands relating with the seismic joints. INTRODUCTION Istanbul Strait Road Tube Crossing Project (Eurasia Tunnel) will build and operate a roadway tunnel under the Borphorus connecting Kazlicesme on the European side and Goztepe on the Asian side, to provide additional road-access across the Strait and consist of three main parts as shown in Figure 1."

Jan 1, 2016

By Adrian Dance

Newmont Ghana Gold Limited?s Ahafo operation have been working with Metso Process Technology & Innovation (PTI) since early 2009 to increase mill throughput from a combination of controlled blasting practices and optimised primary crusher and grinding circuit conditions. For such Mineto- Mill projects, PTI?s methodology is termed Process Integration & Optimisation (PIO). Ahafo operate a SAG mill, ball mill and pebble crusher (SABC) circuit that processes a range of primary ore of varying hardness from different pits which is blended with soft oxide material. The PTI study focussed on ball mill limited material from the Apensu open pit. Following a benchmarking study of all blasting, crushing and grinding practices in January 2009, PTI recommended changes in both blasting and crushing conditions in order to generate a finer feed size to the SAG mill. Additional operating changes in the grinding circuit were recommended. A series of trials were conducted in November 2009 where three blasts were fired using a different blast design (hole diameter and explosive type) in the same area of the Apensu pit as the benchmarked material in January 2009. Top and bottom benches (or flitches) from each blast were sent exclusively to the grinding circuit and the material was tracked using PTI?s SmartTag? system. The results from the six trials showed a significant increase in primary ore throughput at a reduced blend of oxide material. Ahafo have since standardised on these modified blasting conditions for all Apensu ore zones and have been able to sustain higher throughput compared to historical performance on similar material. This paper summarises the phases of the PIO project, the changes made in operating practices and the outcomes of the blasting trials that validated the predicted increase in mill throughput.

Jan 1, 2012

By R Cox, S Pandey

The coal seam gas (CSG) industry is expanding rapidly in the Surat and Bowen basins. CSG production involves pumping water from the coal seams to release the gas adsorbed to coal particles. The reduction in water pressure in the coal seams will cause some reductions in water pressure in overlying and underlying aquifers because there will always be some interconnectivity between the formations. The Surat Basin is a sub-basin of the Great Artesian Basin, which contains aquifers of high economic, environmental and cultural value. The Condamine Alluvium is also an important water resource, which overlies parts of the eastern margin of the Surat Basin.Under the Queensland (Qld) regulatory framework, an area of intensive CSG development involving multiple CSG operators can be declared to be a cumulative management area. For such areas the Office of Groundwater Impact Assessment develops assessments of future impacts on aquifer water pressures and develops and manages arrangements. The results are published in underground water impact reports.The Surat underground water impact report (QWC, 2012) was approved in December 2012. This paper summarises the place of the report in the Queensland regulatory framework, the content of the report and progress in its implementation.CITATION:Cox, R and Pandey, S, 2013. Managing groundwater impacts in the Surat Basin, in Proceedings Water in Mining 2013 , pp 169-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By J. McCreedy

This paper reviews new methods of exploration for metals and new techniques of mining the deposits and extracting the metals from their ores. Examples of mining innovations are taken from Inco's Thompson Operation. The importance of presenting a favorable image of the industry to college students and young people deciding on a career is stressed.

Jan 1, 1971

By Jason Mewis

Jason Mewis is the founder and president of ENGCOMP, a consulting engineering firm in Saskatoon Saskatchewan focusing on the mining sector. He has over 17 years of experience working on projects for the heavy industrial market in Saskatchewan, as both a Senior Structural Engineer and Project Manager. Jason is an entrepreneur with experience in many areas including estimating, planning, facilitation, and Risk Analysis. He has presented at many seminars and conferences across North America on the subject of Project Risk and and has become recognized for his expertise in this area of project management.

May 1, 2013