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By P .. H. Grimley, N. Champigny

"Fourteen companies (Appendix) representing senior mining organizations in Canada were canvassed in order to assess: (1) the current usage and trends, and (2) the usefulness of computer applications in ore reserve estimation and grade control. The results of the questionnaire suggest that:• computers are unsurprisingly, predominant in the mining industry for calculating reserves and performing grade control;• time and cost savings are realized;• computer-based approaches are applicable to underground situations;• geological information is incorporated to the computerization process; and• computer usage does not hinder the collaboration of geologist and mining engineer.A clear need is identified for case histories comparing computer-calculated ore reserves and actual production data.IntroductionAmong the management and technical staff of some mining companies there is a perception that the application of computer based technology for the estimation of ore reserves and grade control, has as many drawbacks as benefits. Some of the objections raised against the utilization of computers for ore reserve estimation are that:• computer-based reserve models work for large open pit mines but not for underground situations;• computer-generated reserves ignore the geologist's knowledge base; they are strictly a number crunching exercise; and• the use of computers for ore reserves hinders collaboration between the geologist and mining engineer.In order to determine (I) the extent of current computer usage and future trends and (2) whether the objections noted above are borne out by experience, a number of senior Canadian mining companies were canvassed.The respondents were asked to provide:• an assessment of the importance of the computer in the ore reserve estimation and grade control process;• the level of involvement of individuals and staff groups with computer-based ore reserve estimation;• the advantages perceived and realized from the utilization of computer-based ore reserve approaches;• the current and future human resources requirements for the evaluation, implementation, maintenance and development of computer-based ore reserve systems;• the hardware and software resources presently used and planned; and• the developments needed to increase the use and acceptance of computer-based ore reserves."

Jan 1, 1990

By A. P. E. Dirige

The stability design of cemented backfills is normally conducted using conventional approaches. Analytical or numerical models, backed by trial-and-error methods, are the primary means used to describe or predict the support performance of backfills during mining. The stability of paste backfill free-standing faces is a major concern due to potential consequences to production, ore dilution and safety. Available analytical or mathematical models are developed based on assumptions of the failure modes that may occur when vertical fill faces are exposed during adjacent mining. Numerical modeling serves to provide an understanding of backfill strength and deformation behaviour. Such approaches offer inherent limitations and generally result in conservative designs. In this paper, centrifuge physical modeling was conducted not only for performance evaluation studies, including stability analysis, but to develop an understanding of the strength and deformation behaviour of paste backfill exposed faces when the adjacent ore zone is removed. The failure mode and mechanics of failure observed in the centrifuge model of a given prototype situation are discussed in detail. Centrifuge model results were compared to numerical modeling and it was concluded that a sliding block failure mechanism that resembles a circular slip appears to be the predominant failure mode.

Aug 1, 2013

By Evelynn Stirling

"The paper/presentation will review the evolution of diesel technology from older diesel engines (1990 vintage) through to the latest technology as a result of the ever changing emissions regulations. It will encompass the EPA Tier levels as well as the latest Euro Stage V emissions. The next step with technology will be to address the CO2 emissions, which translates to improving fuel efficiencies of the product as well as other technologies like battery electric, hybrid and fuel cells. As technology progresses it also becomes important to improve connective diagnostic systems to support maintenance practices and improve efficiencies. What will also be presented will be the key emissions changes to the different gaseous and particle mass elements as the products have transitioned from the EPA Tier 3 through to Tier 4 Final regulations. Offering a range of different technologies to the underground mining market matters as not all pieces of equipment will perform optimally due to its duty cycle and application. INTRODUCTION Rudolf Diesel built his first well-known prototype of the high-compression engine in 1897. Since that time, the diesel engine has evolved into one of the world’s most capable and reliable forms of power generation. Diesel engines can be found in a wide variety of vehicles and equipment, powering everything from agriculture and construction equipment to power generators and marine vessels. In the early days the emissions from diesels was very poor and extensive work has been accomplished over the decades to make the product more environmentally friendly. This is more important in underground mining where the space is limited and ventilation is expensive and challenging. DISCUSSION The key driver of the development of diesel technology is the legislation globally around engine emissions. The emission level requirements over the years has forced diesel engine manufacturers to build a deep technical understanding of the system and how to innovate and optimize key elements of the engine. Cummins expertise has been built over the years as the diesel engine has evolved from a relatively simple mechanical engine to an electronic system with advanced air handling, fuel system, after treatment, and controls. Cummins has also continued to expand into systems beyond diesel, including natural gas. Many new components have been added to diesel engines to reduce emissions while improving fuel efficiency and reliability and, at the same time, reduce the total cost of ownership to the customer."

Jan 1, 2019

By H. M. Lizama, R. L. Stephens

Secondary leaching of previously leached supergene copper ore has been developed and implemented at Teck’s Quebrada Blanca operations. This consists of using in-situ leaching techniques aided by geophysics to recover the residual metal value from dormant copper leaching heaps. These heaps of crushed and agglomerated ore had been leached 20 years previously but still contained significant copper values. The concept was first tested on a 3,200 m² sector, where injection wells introduced leaching solution into a production zone and electro-resistivity tomography was used to track solution movement within. Operating parameters such as well spacing and injection flow rates were determined. Copper recovery and leaching performance were evaluated based on solution and metallurgical balances. Both ferric leaching and bacterial leaching were enhanced through strategies to pull air into the heap. Positive results from the initial test prompted a larger, industrial pilot test on a 60,000 m² area and 97 injection wells. This larger test obtained a copper recovery of 30% in 457 days. Secondary recovery is now being implemented to all of the abandoned heaps at Quebrada Blanca and has become a production stream. This technology has the potential of wide application to mature copper heap leach operations, and Teck has patented the process and associated methodologies. INTRODUCTION Heap leaching of copper secondary sulphides has been carried out at Quebrada Blanca (QB) since 1994. Ore from the supergene deposit was crushed and agglomerated prior to leaching. Originally, the ore was leached in 6 m lifts stacked one on top of another, known as a static pad configuration. However, in 1998, after the second lift, the operation changed to a dynamic pad configuration; the ore was leached in a single lift and the resulting residues were removed to make way for fresh ore (Yáñez, Ahlborn, & Ramos, 2007). The first two static lifts were left in place and served as a foundation for the dynamic lifts above. Those two buried lifts of leached residues, some 16.8 million tonnes and covering an area of approximately 0.71 million m², remained buried under the dynamic pad.

Jan 1, 2019

By Peter Radziszewski

"Typical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5% to 20% ). Cornminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and linerkharge wear (50 %). Developing the ability of predicting mill wear will allow a more accurate estimation of wear costs. However, total media wear in a given ball mill grinding process is a product of three recognized wear mechanisms those being abrasion, corrosion and impact. Further, the contribution to total media wear of each of these wear mechanisms has not been well established. In this paper, a overview of abrasive, corrosive and impact wear mechanisms is made from which an empirical wear prediction procedure is proposed. Further, future directions in wear prediction research is outlined. INTRODUCTIONTypical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5 % to 20 %). Comminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and lined-charge wear (50 %). With respect to wear, world wide steel consumption as grinding media is estimated at over 600 000 tomes per annum (Malghan, 1982). As such, developing the ability of predicting mill wear will allow a more accurate estimation of wear costs.Charge media wear prediction is actually estimated using the Bond abrasion test. From Bond abrasion index tests, it is possible to determine a wear rate using the following function:"

Jan 1, 2000

By Louise H. Michaud

Albian Sands Energy is scheduled to begin production at its oilsands operations in the fall of 2002. Start-up includes the selection and implementation of over 75 IT systems or computer applications. These include engineering applications, systems required to control mining activities, maintenance, the processing plant and utilities, and also systems required to run the company, such as human resources, finances and inventory/warehousing. This paper outlines the processes used for the selection, implementation and integration of these systems in order to optimize the use of information and to meet the technical, business and IT requirements of the company. The first step in Albian?s approach to identifying system requirements is the development of a Business Activity Model, outlining all tasks involved in running the operations. The computer applications required to accomplish each task are then identified by having the IT team work closely with each technical and business unit. Historically, at some companies, the selection of systems has been lead by the IT team or by consultants, with little input from the technical or business units. Typically, this results in products that don?t meet the company?s expectations. To ensure a more positive outcome, Albian believes that it is imperative that the company?s technical and business people are closely involved in the selection process. Integration of the IT systems is also key, including linking all applications through a Data Warehouse and EDMS. Over 120 required integrations have been identified. This ensures the storage of all data in only one location, data security, and easy data and document retrieval for all requirements throughout the company.

May 1, 2002

By P. A. Peach, W. H. Gross

The modern economic geologist in Canada is well equipped to apply geological, geochemical or geophysical techniques in the exploration for ore. Recently, great advances have been made in geophysics and geochemistry, and a large number of new orebodies have been discovered by these methods. An attempt is made in this paper to show that there has also been a considerable advancement in geological knowledge and that the most effective application of geophysics and geochemistry often occurs in areas already considered geologically favourable for the occurrence of ore. Ali exploration methods sooner or later suffer from diminishing returns. Therefore, as time goes on, one can expect to see the application of some of the more subtle or refined geological techniques that are presently being developed.

Jan 1, 1967

By N. Katsikaros, N. S. ‘ Yap, B. Adaszynski

"Cyanide is a well proven, effective lixiviant that has been utilised for centuries in gold extraction processes. Despite being used in close to 90% of gold processing plants, cyanide leaching is still being scrutinised due to its toxic nature. With governments tightening the regulations on cyanide management, and recently erected sites situated closer to community and environment, leach waste and tailings treatment has become increasingly important. Gekko Systems has worked with engineering companies and directly with gold producers to provide technical services and supply complete modular cyanide destruction (detox) systems for plants leaching both run-of-mine ore and high sulphide gravity and flotation concentrates. Although similar in principle, the different materials presented unique challenges in design and implementation. Similar to designing any section of a processing plant, the development of the cyanide destruction plant design began with laboratory test work to simulate the full scale operation. This paper focusses on the laboratory test work and how other critical factors such as geographical location, logistics, and local community play a role in the process design and construction. Two design and supply cases are discussed in this paper; one treating intensive cyanidation concentrate leach tails and one treating whole ore CIL tails. Although these plants both use the SO2/O2 process, each presented different challenges in laboratory testing and plant design, resulting in variations in final implementation including reagent choice, oxygen supply, and process control.INTRODUCTIONSince 1887, cyanide has played a large part in the beneficiation of gold from gold bearing ores. Cyanide is used to solubilise gold into solution, and is typically added in excess to maintain the leaching process. Some or all the excess cyanide can often be recovered and reused in the process however chemical destruction of cyanide is often necessary to manage cyanide levels in the tailings storage facility (TSF)."

Jan 1, 2016

By D. J. W. Piper, T. Hundert, G. Pe-Piper

"Abstract - Potentially commercial deposits of kaolin are found in the fluvial Lower Cretaceous Chaswood Formation, the sedimentologically proximal equivalent of deltaic sediments of the offshore Scotian basin. The geological setting of the kaolin deposits has been interpreted from high-resolution seismic-reflection profiles and boreholes, and mineralogical studies on one reference borehole. The kaolin is a product of early diagenesis involving meteoric water below the water table. The distribution of kaolin is controlled by the presence of intraformational unconformities that were sites of ground water recharge, and are marked by the development of oxisols above the water table. Such diagenesis was facilitated by interbedded, loosely consolidated, permeable sandstone. The highest-grade kaolin deposits are found in areas close to river belts, where overbank muds were not sufficiently drained to develop paleosols, but where later uplift created intraformational unconformities. In the sandstone, meteoric water flow altered feldspars to kaolin, thus yielding commercial silica sand deposits. It also altered ilmenite to rutile, which is concentrated as secondary placers in modern rivers that have eroded the Chaswood Formation and tills derived therefrom. Sommaire - Des dépôts de kaolin potentiellement économiques ont été notés dans la Formation de Chaswood d'’âge Crétacé Inférieur, laquelle constitue un équivalent latéral en milieu fluviatile aux sédiments deltaïques du bassin de Scotian. Le contexte géologique de ces dépôts de kaolin a été interprété a partir de profils de seismique-réflection à haute résolution, de sondages, et d’études minéralogiques sur un sondage de référence. Ce kaolin est un produit diagénétique précoce formé par de l’eau météorique sous le niveau de la nappe phréatique. La distribution du kaolin est contrôlée par la présence de zones de recharge associées à des discordances intraformationelles marquées par le développement d’oxisols au-dessus du niveau de la nappe phréatique. La présence d’interlits de grès perméables faiblement consolidés a contribué à l’efficacité de ce processus diagénétique. Les dépôts de kaolin les plus riches se trouvent en périphérie des rivières, là ou les boues de la plaine d’inondation n’étaient pas suffisamment bien drainées pour permettre le développement de paléosols, mais où des mouvements verticaux subséquents ont crée des discordances intraformationelles. La circulation d’eau météorique dans les grès a entraîné l’altération des feldspaths en kaolin, générant ainsi des dépôts économiques de sable de silice. Elle a aussi causé l’altération de l’ilménite en rutile, que l’on trouve dans des placers secondaires situés dans des rivières contemporaines qui ont érodé la Formation de Chaswood et les tills qui en sont dérivés."

Jan 1, 2006

By A. W. Jacob

THE shatter cut, or burn cut as it is often called, is one in which the centre of the round is almost reamed out by drilling holes so close together that the blasting of a few holes shatters the rock embraced by all of them. The idea of shattering the centre of a face by shooting holes drilled parallel to one another is not new. Some miners have used this method for years past, when drilling quartz or a face near timber. But, they followed the age-old practice of first blasting the cut, then the square-up. It was not thought possible to shoot both together. In the case of machine men, the two largest contributors to silicosis are dust from drilling and dust from blasting. It follows, then, that material reduction of exposure to either constitutes an important step in lessening the incidence o silicosis. It was? the hope of being able to do away with the necessity of the men having to return early to a face, through dust concentrations of 60,000 to 80,000 particles per cubic centimeter, that aroused interest "in the shatter cut at McIntyre. Efforts to this end were successful. Now, with this kind of cut, all holes of a round are shot simultaneously.

Jan 1, 1942

By I. Westermann, K. Marthinsen, M. S. Remøe

"Al-Mg-Si alloys often add small additions of e.g. Mn or Cr, to form dispersoids, which may act as nucleation sites for Mg2Si particles after homogenization. The purpose is to ensure a high density of uniformly distributed small ?’-particles, which can be dissolved during further processing prior to the final age hardening step. However, their density and spatial distribution are critically dependent on the homogenization procedure. It is therefore important to have a robust and reliable method for assessing their spatial distribution. In the present work an existing methodology for assessing spatial uniformity, the Global Shannon Entropy (GSE), has been implemented and evaluated for different dispersoid structures characterized by scanning electron microscopy. This metric is highly dependent on the parameters used, but by careful selection of adequate parameters, it can be effective in detecting non-uniformity. An important weakness with the GSE was identified, and a modification to improve on the ability to differentiate degrees of non-uniformity is suggested. To evaluate the proposed methodology, the effect of heating rate on dispersoid precipitation behaviour during homogenisation of four Al-Mg-Si alloys with different Mn/Cr-content has been investigated. The metric with the new term has demonstrated promising results, and improved the ability to differentiate degrees of spatial uniformity.INTRODUCTION Al-Mg-Si series alloys are the most common aluminium extrusion alloys and are attractive for applications in a range of sectors (e.g. construction, automotive and recently also in consumer electronics), due to their generally good combination of strength, ductility and corrosion resistance. However, their extrudability and end properties depend critically on the alloy chemistry as well as prior processing conditions. Coarse ß-AlFeSi or Mg2Si-particles typically have a detrimental effect on extrudability, while small dispersoid particles may affect recrystallization, grain growth and precipitation of Mg and Si. The strengthening potential in the final age hardening step depends strongly on the amount of Mg and Si in solid solution after extrusion. The manner in which these particles are spatially distributed will decide whether the final product will exhibit uniform properties, and the number density and sizes will determine the extent of the effect. As such, these are important characteristics."

Jan 1, 2018

By Markus Timusk

This paper describes a research project that focuses on developing a diagnostic routine to assist in decision support for the condition based maintenance of mobile mining equipment subject to unsteady duty. The objective is to develop a general method for initial identification of mechanical faults in machinery operating under non-steady state conditions. The platform to be used for the experimental development and validation of the system is the swing machinery in an electric mining shovel operating in an open pit mining environment. The strategic approach that is proposed for the diagnostic routine will involve using novelty detection augmented by temporal classification.

May 1, 2004

By Robert Harris, Peter Pheeney

"The Murray Brook gold mine operated from September 1989 to March 1991. Approximately 1.2 million tonnes of gossan were mined from an open pit and treated at a rate of 900 tonnes per day. The facility applied an agglomeration vat-leaching cyanidation plant for gold and silver recovery. The leached ore or tailings were rinsed of residual gold and cyanide and placed on an adjacent clay lined pad for storage and containment. A 50,000 tonne heap-leach demonstration project was constructed at Murray Brook in 1992 to recover copper and zinc from ore located in a sulfide-rich zone occurring beneath the gossan. The operation proved unsuccessful because of poor recoveries and low metal prices. The project terminated in the same year.A corporate decision was made in September 1999 to undertake complete and final reclamation of the Murray Brook site. Jacques Whitford and Associates Limited were contracted to develop the final reclamation plan and to assist the company in presenting the plan to the New Brunswick government for approval. The government approved the plan in January 2000. Two important reclamation issues were the mobility of mercury from the gossan tailings and the potential of acid mine drainage from exposed sulfides. The mine site is situated upstream of a productive river system, and the issue or impact of chemistry changes to the environment over the long term became an overriding factor in the development of the reclamation plan.A resource assessment of the gossan tailings in 1999 indicated an average concentration of mercury of 40 ppm. The mercury occurred naturally as the mineral cinnabar, but the exposure to residual cyanide (less than 10 ppm) over several years in the pile has likely caused much of the cinnabar to decompose into more soluble mercury forms. The reclamation plan specified the replacement of all sulfides to the pit followed by approximately 600,000 tonnes of gossan. To ensure “fixing” of the mercury, the gossan was replaced in compacted lifts and both the remaining pile and that replaced to the pit covered with available till and compacted. The reclamation work was successfully completed in September 2000 and the chemistry of the receiving environment will be monitored over a three-year period, after which the company expects to achieve walk away conditions."

Jan 1, 2001

By R. D. White

"The Cumberland Basin of Nova Scotia has long been considered a structural basin by virtue of the elliptical outcrop and inward dip pattern of the Pennsylvanian outcrops. Recent published and unpublished data indicate that subsidence began in the late Devonian, perhaps resulting from a graben or rift. The Mississippian sediments which filled the growing depression were continental, lacustrine and marine with evaporites. The cessation of the riftforming processes is recorded by the alluvial swamp-type sediments of the Pennsylvanian which filled the depression. In excess of 25,000 feet of Carboniferous rocks are believed to be present in the deepest part of the Basin. Starting with the rift hypothesis, we can speculate on the kinds of sediments, their location and the structural features present beneath the Pennsylvanian surface. Using surface exposures and a limited amount of subsurface data, we theorize that (1) the Mississippian evaporites acted as glide zones which effectively divided the Basin into two horizontal structural layers. The rocks above the evaporites, responding to Appalachian stresses, formed the long diapiric folds with cores of overthickened evaporites. Below the evaporites the structures are related to movements of the rift floor, compaction closures and structures formed by differential horizontal movements of the rift walls. (2) The rift, in its deeper parts, will have more and a greater variety of marine rocks than the outcrops indicate. Should the rift hypothesis be correct, the possibility of finding hydrocarbons is enhanced."

Jan 1, 1972

By M. C. Harris

"Excess Gibbs energy is a thermodynamic parameter which quantifies the difference between the value of the Gibbs energy for a real mixture and that for an ideal mixture. More specifically the partial molar excess Gibbs energy of a species (i) in a mixture is indicated by the change in the overall excess Gibbs energy of the solution as the number of moles of species (i) changes while keeping temperature, pressure and the number of moles of all other species in the solution constant. Generally it is obtained from the activity coefficient which in turn can be obtained for a species in a mixture using a variety of models. The most widely used method is to use UNIFAC. Flotation is probably the most important process in the concentration of minerals and requires the use of reagents such as collectors and frothers. There is abundant experimental data which illustrates that collectors of different alkyl chain lengths will change the contact angle and that frothers of different structures and molecular weights will result in changes in key flotation properties such as froth behavior, surface tension and critical coalescence concentration. In this paper it is shown that there is a strong linear relationship between measured parameters such as froth volume/height, surface tension, critical coalescence concentration and contact angle and the partial molar excess Gibbs energy of the molecules used. Proposals are made to explain these correlations.INTRODUCTIONAs is well known froth flotation is arguably the most widely used process in the separation of minerals. In broad terms the process relies on the use of reagents known as collectors to adsorb onto a mineral surface and thus render the mineral particle hydrophobic. Alkyl thiolates are very commonly used for this purpose. The hydrophobicity is induced as a result of the alkyl group’s molecular structural properties which results in it forming a non-ideal mixture with the process water. Surfactants (or frothers) are typically alcohols and are known to lower the surface tension of the system and also inhibit bubble coalescence and reduce bubble size. Since alcohols are polar they will also form a non-ideal mixture with water. The hydrophobic mineral attaches to the bubble and rises to the froth phase where the valuable mineral is recovered as a concentrate. Frothers have often been characterized using the so-called HLB (hydrophobic-lipophilic balance) number but recently it was shown that the use of activity coefficients (?) or excess Gibbs energy (G ex ), which is calculated using equation (1) is a much more appropriate way to describe the behavior of these reagents in non-ideal mixtures with water (Corin and O’Connor, 2014)."

Jan 1, 2016

Over five decades ago Kitchener et al. in England and La Mer and Healy in the US were advancing our understanding and application of flocculants, primarily related to water treatment and filtration of sludge. This paper identifies the beneficial uses of flocculants in the mining industry and revisits some less common applications. Flocculants are used in unique ways in the mining industry: (a) to increase the effectiveness of sediment ponds to achieve discharge compliance; (b) to eliminate air emissions and costs associated with concentrate drying; (c) to reduce soil loss by applying a flocculant to erodible soils, and reducing wind and water erosion; (d) to remove/thicken metal precipitates in acid rock drainage treatment; and (e) to enhance clarification and thickening in mineral processing. The mechanism of how flocculants, coagulations and potentially-determining ions function is described and how their use can be controlled and optimized. The potential toxic effects of flocculants and coagulants when used to achieve effluent permit discharge compliance for suspended solids is discussed. A review of numerous best management practice (BMP) guidelines for the design and operation of sediment ponds treating mine site runoff to remove total suspended solids (TSS) and turbidity revealed an absence of a predictive methodology to address regulatory discharge compliance for TSS concentration, turbidity and flocculant-induced toxicity. An essential component of pond design is the need to determine whether flocculants and/or other settling aids are required based on the site-specific soil particle size distributions upslope of the pond. Procedures are provided to predict the need for settling aids and estimate pond discharge quality and downstream impact for TSS, turbidity, toxicity and sub-lethal toxicity. The need to develop BMP guidelines are discussed for (a) the application of flocculant to surface soils to reduce erosion, (b) the application of flocblocks to increase the ?sediment control? aspects of erosion and sediment control, as part of the mine site erosion control plan strategy and (c) the application of flocculant to silt socks to treat mine site runoff.

Aug 1, 2013

By Northeastern University, B. Y. Cui, B. Y. Wang, D. Z. Wei, W. G. Liu, Z. C. Guan, S. L. Gao

To recover iron values from low grade ores by reverse froth flotation method, further research on cationic collectors used in reverse flotation of iron ores is launched to promote the utilization efficiency of iron ores. In this paper, one new cationic surfactant, bis(2-hydroxylethyl) dodecylamine (BHD), that could be dissolved in water easily was used as collector for quartz flotation. Flotation results indicated that BHD shows stronger collecting performance on quartz than hematite. The maximum recovery of 96.30% to quartz is obtained at a collector concentration of 20.0 mg/L in the pulp pH range from 5 to 7. This collector can be used to float quartz from hematite. And optimal separation results with 86.59% iron recovery and 66.60% iron grade to synthetic sample were achieved at a collector concentration of 20.0 mg/L and pulp pH of 5.02 when hematite and quartz were mixed at a mass ratio of 3:2. The adsorption mechanism of the collector on quartz surface was investigated by XPS analysis, infrared spectroscopic analysis and zeta-potential measurements, which revealed that electrostatic attraction and hydrogen bonding adsorption occur between collector and quartz surface.

Jan 1, 2016

By C. Pelley, S. Kelebek, G. Kunzel, S. Gregersen, M. Pollanen

A series of small-scale tests was conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the material properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Poisson’s ratio, Pwave, S-wave velocity, point load test index, crushing, and grinding work indices were evaluated for samples without any blasting load and for samples which had received a variety of blast loads ranging from a single impact with a lowstrength detonating cord to a combination of impacts at different times and significant impacts with powder factors close to those used in practical blasts. It was shown that the rock mechanics parameters change even at low impacts, suggesting easier crushing of the rock. Damage values appear to be affected by timing as stress wave superposition affects the damage process. Fragmentation is achieved at higher impact levels while work index modification of the fragments is also observed when high powder factors are used, suggesting improvements in grinding.

Jan 1, 2006

By G. Whittle, R. Peevers, P. Moryoussef

Enterprise optimization is a relatively new optimization approach to mine planning used to jointly consider all aspects of a mining operation affecting the mine planning process and related valuation. In this paper, it is applied at SEMAFO's Mana operations in Burkina Faso, consisting of several open pits and a proposed underground mine. The surface-minable ore is relatively shallow, and the pits are long and linear. The underground operations, as currently envisioned, will consist of a stoping operation accessed by two ramps from the surface. Power is a concern at this property due to local power being produced largely by diesel generators, and it has become one of the key optimization constraints. Other important parameters are the mining and processing rates, underground configuration and cutover elevation. Enterprise optimization was found to improve net present value for the Mana Operations property by simultaneously optimizing multiple parameters and constraints to arrive at an optimal pit and mining phase design, optimal cut-off grades over time, and optimal ore feed based on ore hardness, power constraints, and head wades. Reserves were expanded several times over the course of the study to improve the valuation of the mining operation and put SEMAFO in its present enviable position of ongoing reserve increases.

Jan 1, 2011

By James A. Robertson

"This paper is the result of a continuing investigation begun in 1953 by government geologists and mining companies. Previous work is reviewed and the development of several stratigraphic nomenclatures and correlation schemes is traced, culminating with the interim report of the Federal-Provincial Committee on Huronian Stratigraphy formed in 1966.The stratigraphy, structure and correlation of the Huronian rocks of the Blind River area and the region between Sault Ste. Marie and Sudbury are reviewed. The area is underlain by three Precambrian units: (1) the Archean greenstones and granites, (2) the Huronian sedimentary and volcanic rocks and (3) the post-Huronian intrusive rocks. The Huronian rocks, largely quartzite and conglomerate with greywackes, argillites and carbonates, were laid down in shallow water transgressing over the eroded Archean basement. Thickness and facies changes indicate a northwesterly source, northerly overlap and deposition controlled by basement topography. Polymictic conglomerates, occurring at least at three horizons, represent tillites and are associated with varvites with dropped clasts. These are best developed in the Gowganda formation, which varies from a continental glacial environment in the north to a marine glacial environment in the southeast.There were at least three phases of post-Huronian igneous activity, probably related to several periods or phases of late Precambrian deformation and metamorphism: (1) sills of Nipissing diabase and rather younger diabase dikes; (2) the Cutler Granite and Croker Island Complex; and (3) dikes of Keweenawan olivine diabase.Copper mineralization is associated with the Nipissing diabase. The uranium ores are found in pyritic quartz-pebble conglomerate near the Huronian Archean unconformity, particularly in ancient valleys; they are considered to be placer deposits modified by later events. Uranium production from the Blind River camp to the end of 1966 was 128,160,096 pounds U308 valued at $1,203,840,848 derived from 56,077,179 tons of ore grading 0.11 per cent U308.Within the Blind River and adjacent areas, future discoveries will probably be the result of costly systematic deep-drilling programs accompanied by detailed geologic studies of the type carried out by oil companies and probably computer-oriented."

Jan 1, 1969