Search Documents

By Don Peel, Jeremy Richards

Abstract - Aggregates (sand, gravel, and crushed stone) are low unit-cost products extracted in very large volumes for the construction of buildings, roads, and other infrastructure essential to modern society. Because of their low unit value, transportation costs are a key factor in resource economics, and deposits are commonly developed close to market (i.e., close to towns and cities, or along low-cost transportation corridors). This proximity results in potential conflict with residents over land use, disturbance, and pollution. Management of aggregate resources in Alberta is examined in the light of resource geology and distribution, and governance. A case history of development of the Calahoo-Villeneuve deposit is described, and the conflicts between residents and developers that led to establishment of an Area Structure Plan (ASP) are explored. The plan sets limits to, but at the same time safeguards, resource extraction, and defines terms for compensation to residents through a voluntary levy on production (Community Enhancement Fund). This fund is used to support community activities and to pay for a groundwater monitoring program. The ASP is examined within the context of the "Seven Questions to Sustainability" as set out by Mining,Minerals and Sustainable Development-North America (2002). It is concluded that the ASP, for the most part, provides a good model for conflict resolution and sustainable resource development, which could usefully be applied in other jurisdictions. The ASP was developed at a municipal level, and adoption at a provincial level would aid sustainable development of aggregate resources across the province.

Jan 1, 2003

By J. A. R. Faucher

"Autogenous grinding may be an efficient and economical solution to your ore comminution problem.An important potential economic advantage of autogenous mills results from the availability of very large capacity units.Autogenous grinding could be more economical in terms of both capital and operating costs.Satisfactory pilot plant testing and thorough economic evaluation are required for a sound decision in comminution plant selection.INTRODUCTIONMankind's first weapon was probably the wooden club, but men soon learned to shape, smooth and polish stone for tools and weapons by pounding and rubbing them with sand and water. It was only about four thousand years ago that rocks were first broken to concentrate, smelt and return the metals they contained. In spite of our recent great technological advances we still break rock in essentially the same manner that was used thousands of years ago - by pounding, rubbing and squeezing - and we still waste much energy and metal in the process"

Jan 1, 1969

By Guy Chevalier

QCM?s pellet plant, located in Port-Cartier, Quebec, produces up to 8.6 million tons of iron ore pellets annually. Four different types are produced: three for blast furnace operations and one for direct reduction furnaces. The paper presents the scientific approach that led to the installation of new process equipment to improve the reducibility of direct reduction pellets (DR pellet). The findings, the equipment selection and some post start-up modifications are presented. This low silica DR pellet is used in Midrex and HyL shaft furnaces. A good DR pellet has to meet strict chemical, physical and metallurgical specifications. An important metallurgical property is its ability to release oxygen when exposed to reducing gases. Considering that the market for DR pellets is expanding and being aware that reducibility is critical for our clients, a program to improve the latter was undertaken. Test work showed that one factor which has a negative effect on reducibility is the proportion of particles larger than 75 microns. Knowing that the best way to reduce the amount of coarse particles was to close our open grinding circuits, we began evaluating the most suitable classification equipment applicable to our process operations. We settled on hydro-classifiers based on their very sharp cut and their low operating costs. In light of the hydro-classifiers performance it was also decided to replace the hydro-cyclones of an already closed circuit.

May 1, 2003

By C. Bazin, D. Hodouin, M. Ounpuu

Sensors are now available in mineral processing circuits to monitor pulp flowrate and density, as well as ore characteristics and other process variables. The amount of information provided by these instruments is considerable but in many cases poorly exploited. This paper gives the results of the application of time series analysis techniques to signals generated by the sensors installed on an industrial Pb dezincing flotation circuit in New-Brunswick. Autocorrelation and cross correlation functions appear to be interesting tools for a preliminary circuit analysis, however the calibration of single input single output discrete transfer functions using collected sensors signals leads to conflicting results. For this reason a phenomenological approach, based on the kinetic and transport properties of the flotation process, is also considered. It has several advantages over the empirical transfer function modelling but also limitations in its applicability to industrial processes. A combination of the transfer function and kinetic modelling approches appears to be a promising avenue for better process modelling and control.

Jan 1, 1985

By D. G. Cerigo

"INTRODUCTIONAn interim report covering an uncompleted project on revenue mill optimization was presented at the invitation of Mr. C.S. Stevens, the Secretary of the Canadian Gold Metallurgists. The work described summarizes the preliminary work carried out at the Noranda Research Centre on computer mill optimization and is an attempt to arrive at a model of a circuit using the ""black box"" approach and hence by using economic factors related to concentrate dollar value to maximize revenue. The help and cooperation of Mr. J.D. Wild, Mr. M.J.S. Bennett of Noranda and Dr. A. Bobkowicz of McGill University is gratefully acknowledged.DERIVATION OF MODELHistorical data from the Normetal mill were used for the study. Normetal ore contains chalcopyrite, sphalerite, gold, silver, pyrite and pyrrhotite. For simplicity, data were chosen for days when only two concentrates had been derived, a copper concentrate which also contains the gold and silver, and a zinc concentrate. In these periods when pyrite concentrate was not produced, its circuit was used as an extra zinc scavenger unit. Figure I is a schematic drawing of the circuit and Table I explains the nomenclature.The mill had been operated to obtain a fixed grade of copper and zinc in the copper and zinc concentrates respectively, at the same time insuring acceptable recovery levels. The target grade for the copper and zinc concentrates had been derived by manual calculations based on past experience. The data used were 170 sets of daily mill reports, a sample of which is shown in Table II. The data consist of daily tonnages of feed, concentrates and tailings and their average compositions obtained by taking samples every twenty minutes from each stream and analyzing the daily composite samples."

Jan 1, 1967

By K. Chotruangprasert

This paper explores Global Reporting Initiative (GRI) reporting practices within the mining industry. Specifically, this paper investigates how and why a mining company makes voluntary reporting decisions to include the GRI indicators that may be considered ?negative? to the company?s reputation. Due to the voluntary nature of the GRI Guidelines, a GRI adopter is not legally obligated to report every GRI indicator. Not surprisingly, empirical studies that evaluated the extent to which companies? sustainability reports meet the GRI requirements (Guenther, Hoppe, & Poser, 2006; Morhardt, Baird, & Freeman, 2002; Samy, Odemilin, & Bampton, 2010; Skouloudis, Evangelinos, & Kourmousis, 2009) have found that reporting practices of the companies under their studies are well below the standards reflected in the GRI Guidelines. An influential study by Clarkson et al (2008) uses economic-based and socio-political theories to explain variation in companies? environmental disclosure. They have found that, as predicted by economic-based theory, superior environmental performers disclosed more ?hard? (i.e. verifiable) environmental information. Inferior environmental performers are found to disclose more ?soft? (i.e., not easily verifiable) claims, which is consistent with socio-political theories (Clarkson, Li, Richardson, & Vasvari, 2008). However, this study and the existing literature do not adequately explain why a company may act in a way that cannot be explained by economic-based and socio-political theories, for example, why it would report some negative soft data that it is not required to report. This paper intends to address this literature gap. GRI reporting by a Canadian mining company, which I would like to call ?Company C?, is used as a case study for this paper. Company C was selected for this research because in addition to ?positive? information, its GRI-based sustainability report also includes both hard and soft ?negative? information such as grievances. Research methods include interviewing Company C?s employees who are involved in preparing GRI reports and reviewing documents prepared both by the company and by external parties. I find that integrative social contracts theory (ISCT) offers a valuable explanation to Company C?s reporting practices. From the ISCT perspective, Company C?s management appears to feel that the company is obligated under social contracts to be transparent. Therefore, Company C disclosed both positive and negative social and environmental information to the public because the management appeared to think that it is the right thing to do. At the same time, being transparent about the bad news gave the company an opportunity to conclude that it had done something to avoid future occurrence of the negative incidents. Therefore, I propose that, in addition to the economic and socio-political theories that are more often used in literature, insights from ISCT are instrumental in improving our understanding of the corporate non-financial reporting practices phenomenon.

Aug 1, 2013

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

By Michael K. Watkeys, Jacobus E. Potgieter, E. Guy Charlesworth, Carl R. Anhaeusser, Roger L. Gibson, Alexander F. M. Kisters

Intrusive features of cupriferous noritoids from the deeply eroded Proterozoic granite-gneiss terrane of the Okiep Copper District in South Africa illustrate the emplacement of basic magmas into a mid- to lower-erustal environment. The small, easterly trending intermediate to basic intrusions of the so-called Koperberg Suite display a wide variety of geometries, occurrence and emplacement modes, including dike-, sill- and plug-like bodies. Coeval granulite-facies metamorphism, partial melting and ductile deformation of country rock gneisses during intrusion of the basic magmas led to emplacement and dilation processes of the intrusions which differ significantly from those described for dikes and sills at shallow crustal levels. Regional tectonic stresses are largely negligible due to very low differential stress [( )] during deformation and intrusion, which permits emplacement at high angles to the principal compressive stress and which follows favorably inclined structural anisotropies. Dilation of the basic intrusions is largely determined by compositional differences of host rocks and occurs by thermal erosion, i.e., assimilation of wall rock gneisses. Low length-to-width ratios of basic to ultrabasic dikes and predominantly diapir-like outlines of mesocratic bodies are indicative of low viscosity contrasts between the mafic magmas and high-grade metamorphic host-rock gneisses. Buoyancy-controlled ascent of the basic to intermediate intrusions is expressed by a broad compositional zoning of basic bodies with respect to the granite-gneiss stratigraphy. Various intrusion modes within the stratigraphic column of the granite-gneiss sequence reflect a lithological and structural stratification of the seemingly homogeneous granite-gneiss terrane.

Jan 1, 1994

By Z. D. Hora

Several deposits of crystalline magnesite are known in southeast British Columbia. Deposits at Cross River and Marysville have been thoroughly explored, but as yet there has been no commercial production.

Jan 1, 1984

By Peter Van-De-Velde

"The results of applying Japanese pumping technology to North American reclamation projects will be discussed.IntroductionEconomic high-density mineral reclamation and subsequent transportation of solids through a pipeline presents many formidable engineering problems.In North America where space has rarely been a facto r, industry has generally relied upon the traditional dumping of material into various waste ponds, etc . In Japan, where confined geographies and stringent environmental regulations are enforced, alternative solutions for disposal or reprocessing of waste material had to be found.High-density mineral reclamation system designed by theoretical formulas is almost impossible because solids composition, i.e. concentration, velocity, moisture content, solid size, etc. can only be controlled within a broad pumping range.Traditionally this has restricted dredging of material to relatively dilute slurries whereas it is usually preferred to reduce water usage with its associated power and reclamation costs to a minimum and reclaim as high a concentration as possible.At Toyo Pumps North America we recognized these pumping limitations and began to develop and manufacture a range of standard and auxiliary equipment that would exceed these technical restrictions."

Jan 1, 1985

By James A. Deeks

"Motor failures and equipment bearing failures are responsible for reduced productivity.With the introduction of computers and data acquisition systems, users are now able to monitor, report and trend deteriorating conditions and take corrective action before a critical shutdown occurs.This paper discusses the monitoring and trend analysis of' motors, and motor and equipment bearings. With today's digital electronics technology users are now able to monitor their equipment, detect deteriorating or abnormal conditions quickly, alarm the condition locally and or remotely, and decide if immediate corrective action is necessary or if it can be delayed until the end of a work Shift. All of this can be done long before any damage is done to the equipment.Monitoring Trend AnalysisIt is no longer necessary to compromise in selecting products, since state-of-the-art designs allow the adjustment in such small increments that the users are able to detect minute changes in a system's performance.Monitoring and trending of motors and equipment bearings is now available in economical packages which can be expanded as a system grows. Simply select the information you need, set the parameters, choose the scan time, and decide on the degree of reporting.Buffer storage of short-term monitoring of a number of analogue channels permit the user to view the recent history of motor data such as: motor average load, unbalance, motor current, ground fault, reserve thermal capacity, plus all of the settings of the protective device.A decision can be made to freeze the stored information after the motor stops or after the motor starts. Then the user is able to recall the conditions and diagnose the performance and the cause of the abnormal condition. Typical scan times range from ¼ second to 5 seconds ."

Jan 1, 1992

By S. Kapusniak

Specialist Machine Developments (SMD) is a design and manufacturing company involved in the design of Remotely Operated Vehicles (ROV?s), ploughs, trenchers and mining machines for use in submerged environments. Established in 1971, the company has made over 500 vehicles for subsea use. These range in size from small remotely operated swimming vehicles with a weight of less than a tonne to heavy duty seabed crawling machines with a weight of up to 310 tonnes (in air). Primarily, these machines have been designed for offshore vessel-based applications, but the machines are equally suited to other submerged mining applications onshore. Many onshore deposits can technically and theoretically be mined using currently available submerged mining ROV technology. Similar equipment to that in use subsea could easily be fast-tracked into use to extend the life of opencast mines facing severe hydrological problems. It could also easily be used to mine vertical ore-bodies where the stripping ratio has become uneconomical due to increasing depth. In some cases mining ROVs could even be suitable for use as the primary extraction method for a new mine. Exploration and extraction techniques used in oil and gas gradually developed and moved from land to offshore in the middle of the last century. Are we about to witness a similar shift with other minerals? This paper describes the design concepts of submerged mining equipment, targetted subsea mineral deposits, the suitability of submerged mining ROVs for onshore deposits, limits to their application and parallel research and development activities which will help to accelerate the use of such equipment in the emerging submerged mining sector.

Aug 1, 2013

By J F. Short

The jet piercing process, developed by Union Carbide Canada Ltd., is well established in blasthole production in open-pit mining. By this process, holes can be drilled, shaped and chambered for blasting. In suitable ore or rock formations, a considerable cost reduction can be achieved. This paper reviews the equipment used, relates how cost savings may be accomplished, and concludes with a mention of the most recent developments in this field. JET piercing and chambering, a process for blasthole production in open-pit mining, leads, in many instances, to improved drilling and blasting techniques and costs. It is a method of working rock with a supersonic flame and, to be most effective, depends upon a characteristic of the rock called spallability. Spalling, in this case, is the breaking away of surface particles from the rock body due to stresses caused by the thermal shock of the jet flame. Various rock properties contribute to this action, but, in general, the harder the rock the greater the spallability and the more effective and economical is the jet process. The jet process has the capability to drill, ream, shape and chamber holes for blasting.

Jan 1, 1965

By Lisa J. Renaud

For generations, the mining industry has been committed to work toward developing new technology that can improve safety and increase production. Now with a more environmentally conscious society and tighter environmental regulations, a natural progression for the industry is to develop and take-on ?green? or environmentally friendly technologies. Not only could this improve the sustainability of operations, but could also reduce the long-term environmental impact footprint that is left behind. Algae represent a new frontier in research and development. As discussed specifically in this paper, algae, specifically microalgae, can be used for the production of biodiesel and other green chemicals by exploiting carbon dioxide and waste heat contained within process off-gasses. The potential positive benefits of this approach in terms of contribution to community and the environment are significant, and the focus of our research and development on microalgae production technology.

Oct 1, 2010

By F. Parada L

Two copper concentrate with medium and high enargite content were leached in a 3 L autoclave reactor under conditions based on the CESL process. Copper, arsenic, sulfur and iron were checked in all the experiments and antimony, zinc and molybdenum were evaluated in selected tests. The 98% of the obtained copper extraction is agree with others authors, but the behavior of arsenic, iron an sulfur have some differences. The solid residue was characterized by chemical analysis, DRX and QEMSCAN®. Finally a comparative analysis with neutral roasting as an option for the treatment of this concentrate is done.

Jan 1, 2014

By A. Ingelson, C. Nwapi

"With growing international interest in mineral resources in Central Africa, the importance of transparency in resource development cannot be overemphasized. Without transparency, the region cannot maximize revenues from resources. Although the importance of transparency is beginning to be recognized, many factors can hold back the gains of transparency from resulting in real economic development for the countries involved. This paper reviews current financial, economic, and development literature for Central African countries, with a focus on identifying underlying conditions and specific transactional conditions impacting the effectiveness of transparency in mining development in the region.RÉSUMÉ En raison de l’intérêt international croissant pour les ressources minérales en Afrique centrale, l’importance de la transparence dans le développement des ressources ne peut pas être surestimée. Sans transparence, la région ne peut pas maximiser les revenus tirés de ses ressources. Bien que l’importance de la transparence commence à être reconnue, plusieurs facteurs peuvent freiner les gains acquis de la transparence à produire un véritable développement économique pour les pays touchés. Le présent article analyse la littérature financière, économique et développementale contemporaine pour les pays de l’Afrique centrale, tout en ciblant l’identification des conditions sous-jacentes et les conditions spécifiques transactionnelles qui ont un impact sur l’efficacité de la transparence dans le développement minier de la région."

Jan 1, 2015

By Xuehui Xia

Abstract -There are a number of sedimentary exhalative massive sulfide (SEDEX) deposits in the Proterozoic Langshan-Zhaertai rift at the western segment of the northern margin of the North China platform in China, including more than ten large, medium and small deposits located in a belt of 300 km EW by 50 km to 100 km NS, with large Cu, Pb, Zn, Ag, and S reserves. In several representative SEDEX deposits in the rift, the mineralizing elements are prominently zoned, horizontally or vertically, with Cu decreasing but Pb increasing from west to east, Cu decreasing but Zn increasing from bottom to top, and Zn restricted to the bottom half. The ore-hosting rocks, characterized by a clear manganese halo, have developed a polymetallic mineralization in positive relation with their carbon contents. Their isotopic aspects are: ?34S has relatively large positive values, fluctuating between +5‰ and +35‰, compared with Pb isotopic compositions which are less variable, with a model age of 1600 Ma to 1800 Ma, showing that they are mantle-derived. The mineralizing materials were associated undoubtedly with the contemporaneously faulting events in the rift. The deposits owe their origin to seafloor exhalation, with sedimentary rocks as their hosts.

Jan 1, 1999

By Deng Yang-wu, Zhang Yan, Chen Chun-fei, Luo Xian-ping, Luo Cai-gui

This paper summarizes the ecological imbalance status of abandoned rare-earth element (REE) mines in southern China. These include large areas of vegetation damage, serious water and soil erosion, landslides, mudslides, heavy metal pollution, water pollution, soil contamination, and fluorine pollution. The causes which lead to the ecological imbalances at abandoned rare-earth mines are analyzed, such as: the inadequacies of using vat leaching, heap leaching, and in-situ leaching processes to extract REE resources; low mineral thickness and low grade of REE ore; and low utilization rates of the resource. Southern ionic REE resources are not fully integrated, with limited access and ineffective supervision of REE mining by relevant departments. The ecological recovery research for ionic-type REE mines is lagging behind, and there is no deployable ecological restoration method for REE wasteland. In the end, the following suggestions are made to improve the ecological imbalance status of rare-earth mine in southern China: develop new rare-earth extraction processes, accelerate the integration pace of REE resources, increase investment in ecological restoration research in rare-earth wasteland, and so on.

Jan 1, 2014

By J. Mosher, G. Banini, J. Hollow, A. Villanueva

Prior to installation of High Pressure Grinding Rolls (HPGR) at PT Freeport Indonesia (PT-FI) a series of laboratory tests were carried out to determine the design parameters and also determine key performance indicators (KPIs) for the industrial unit. The design parameters derived from the lab test work were then scaled up to estimate the industrial capacity of the HPGRs to be installed. These parameters include specific power draw, specific throughput, and specific force, rolls speed, product size distribution and wear rate of the rolls. This paper compares the performance of the scale-up procedure against the installed industrial size HPGR. Overall, the specific throughput of the industrial size HPGR is higher by a minimum of 30% compared to the expected scale-up value. As a result of the high specific throughput, the specific power draw and grind sizes are below the scale-up expectations in the commercial application. The impact of these factors also contribute to a lower than expected wear rate on the industrial rolls. Installed rolls achieved a service life in excess of 18,500 hours relative to the target of 6,850 hours predicted from the laboratory testing.

Jan 1, 2012

By J. C. Ingles

"A survey of possible methods for controlling cyanide concentration indicated that the simplest method would involve the use of a potentiometric technique. Such a method was suggested by a paper from the laboratory of Mines Safety Appliances, which described a method for determining hydrogen cyanide in air. In this application, the cyanide was absorbed in caustic and a silver electrode immersed in the caustic solution provided a measure of the cyanide concentration. However, our attempts to use the silver electrode in this simple manner to measure the cyanide concentration of solutions were not very successful. A study of the mechanism by which a silver electrode responds to cyanide concentration made it evident why this simple procedure is not satisfactory.Basically, the silver electrode provides an indication of the free silver ion concentration of a solution, and generally speaking, ignores the other ions' present. It can be used to measure an anion if this anion complexes silver. This technique has been used in complexing studies to determine the activities of such anions as acetate, citrate, oxalate and chloride. To do this, the electrode has to be placed in a solution which initially contains a known concentration of free silver ions. Addition of the complexing anion causes a drop in the free silver ion concentration and hence a change in the potential of the silver electrode. The change in potential can be expressed in terms of the concentration of the complexing anion, and used to indicate its concentration in the solution being analysed. The determination of chloride-ion by a silver-silver chloride electrode is an example of an application of this technique. The solubility of the silver chloride with which the electrode is coated provides the initial free silver-ion concentration. Depression of this free silver-ion concentration by the presence of the excess chloride ion of the sample solution results in a change in the potential of the electrode which is proportional to the chloride-ion concentration."

Jan 1, 1965