Search Documents

By L. E. Collins

"In western Canada, many new wells contain a significant fraction of H2S. As well, many older wells become increasingly sour over their operating lifetime. For these reasons, there has been increased demand for linepipe and casing for sour service applications in recent years. This paper will review the metallurgical factors which must be considered in designing steels for such applications. IPSCO’s development of linepipe and casing, and experience in fabricating products to meet test standards specified for sour service applications will be summarized. IntroductionWestern Canada produces the majority of Canada’s domestic crude oil and natural gas. A complex system of pipelines has been built to gather the oil and gas from the fields for transport to refining and/or cleaning operations. The gas carried in these pipelines can be either sweet or sour (i.e. containing no H2S or containing H2S) depending on the nature of the field from which it came. Many new fields contain a significant fraction of H2S and many older fields become more sour as their time in production increases. This uncertainty regarding product condition influences the user’s choice of materials for both casing and pipeline applications.It is well known (Merrick, 1989) that hydrogen induced cracking (HIC) will occur in steel when three conditions exist simultaneously: (1) the presence of H2S gas, (2) moisture, and (3) a susceptible material. Steelmakers can only address the latter of these factors. Development of steels to meet test requirements of sour service has been a major focus of IPSCO’s development work for several years."

Jan 1, 1998

By L. Yuan, J. H. Rowland, R. A. Thomas, D. Bahrami, G. P. Cole

"The past several decades have seen a steady increase in the use of atmospheric monitoring systems (AMS) in underground mines as sensor technology has advanced and costs for this technology have decreased. The AMS is a reliable tool for early mine fire warning by detecting gaseous products of combustion in underground mines. During a mine fire emergency, mine decision makers rely heavily on the prompt and accurate knowledge of the ventilation and fire situation in the mine, such as fire location, fire size, and the spread of smoke to make effective and efficient decisions on firefighting strategies and miner evacuation. Meanwhile, a prediction of the potential for fire development at a later time, such as whether the currently designated mine escapeways will be contaminated by smoke and toxic gases with the progress of the fire, is critical for effective decision-making to save lives that are in danger. The AMS monitoring data, including carbon monoxide (CO) concentration, airflow rate, smoke, etc., can provide information as to whether the smoke has reached the locations where AMS sensors are installed and if a mine-wide smoke spread has occurred. The National Institute for Occupational Safety and Health (NIOSH) has undertaken a task to integrate real-time AMS monitoring data with the mine fire simulation program, MFIRE, to simulate and predict the spread of smoke and toxic gas in a ventilation network based on the real-time AMS data. This paper reports the developed real-time method for characterizing the size and location of an underground mine fire and for predicting the spread of contaminants throughout the mine ventilation network using sensor data from the AMS.INTRODUCTIONNIOSH conducts research to develop workplace solutions to improve detection of and reduce the risk of hazardous conditions in underground mines. The advancement of senor technology and the increasing demand for real-time mine parameters monitoring have led to extended applications of atmospheric monitoring systems (AMS) in underground mines worldwide. In the United States, AMS is primarily used for early mine fire warning by detecting carbon monoxide (CO) in fire hazard areas, such as belt entries. Mine fires can grow rapidly, and time is the critical element. Prompt detection, timely and accurate warnings to those miners potentially affected, and a proficient response by underground miners can have a tremendous impact on the social and economic consequence of a small underground mine fire (Conti et al., 2005). The early detection of a mine fire could gain time for the first responders to put out the fire before it develops into a disaster. An AMS system with CO sensors has especially played an important role in the early detection of mine fires. The continuous monitoring of an underground mine atmosphere with an AMS could generate a large amount of data in a mine fire event. However, the current application of AMS is mainly limited to sending out an alarm when monitored CO concentration exceeds a certain level. An opportunity arises as to whether these data can be further used in fire emergency response. In order to make effective decisions on firefighting strategies, mine workers’ seeking refuges, evacuation and escape, and the timing on when to send rescuers, decision makers need accurate and timely knowledge of the ventilation and fire situation in the mine. Information about the fire intensity, where in the mine the smoke and toxic gases have spread, and whether designated mine escapeways have been compromised by smoke and toxic gases from the fire would greatly increase the effectiveness of these decisions. However, the monitored AMS data only provides atmospheric conditions in the vicinity of sensor locations. What is concluded from the monitored AMS data highly depends on the decision makers’ capability and experience. Predictive insight into fire growth and smoke transport would greatly help decision makers during a fire emergency."

Jan 1, 2019

By P. Fleming, W. Pascheto

"Rod mills processing nickel and copper ore experienced recurring failures of liner bolts. In some cases failures became very frequent, requiring constant mill intervention and consequently impacting process stability and operating costs. Investigation related to the causes of bolt failures involved a multidisciplinary approach with the participation of engineering, maintenance and operation. It included the determination of bolt failure mechanisms as well as the assessment of mechanical properties, fabrication quality and handling and installation procedures. In addition, other parameters affecting bolt performance such as mill and liner design, operating parameters and maintenance practices were studied. This paper reports the failure investigation results and proposed solutions for failure prevention. INTRODUCTIONOccasional liner bolt failures are common in rod mills. However, chronic bolt failures developed in rod mills processing nickel and copper ore caused frequent shutdowns for bolt replacement to an extent that affected process stability. At first, it was thought that the cause of recurring failures was related to bolt quality. The operation then submitted several failed bolts to failure analysis. However, it became apparent that bolt quality was unlikely to be the main cause of failures. The determination of root cause (s) then became more complex, requiring a multi-disciplinary approach to failure investigation, requiring the assessment of bolt installation methods, mill design, operating conditions and maintenance practices. The results of the metallurgical failure analysis and investigation of other possible causes of failures are reported here."

Jan 1, 2016

By T. Macpherson

ABSTRACT: Drawing on past research experience with sprayable polymer mine support agents (TSLs), Spray On Plastics Ltd. has developed a TSL ground support system called RockWeb. Using a relatively new polyurea polymer technology, RockWeb has been engineered to solve problems encountered underground with polyurethane liners by incorporating rapid curing, moisture insensitivity and superior physical performance. RockWeb possesses a unique, patented ability to be sprayed in a ?cobweb? like consistency allowing the applicator to span fissures in the rock, ensuring no initial defects in the liner, and maintaining design thickness over highly irregular surfaces. This ability, coupled with the high strength and elasticity of polyurea, allows RockWeb to mitigate rock movement through yielding, while maintaining intimate surface confinement. RockWeb provides reduction in logistics through the transport of 1/25 of the material quantities required for shotcrete, rapid deployment rates of as little as 30 minutes per round, and immediate return to the work area. This paper will discuss the technology and advantages of RockWeb as well as opportunities for overall mining cycle cost reduction. The safety benefits, as well as health and environmental considerations regarding application of isocyanate-based liners will also be discussed.

May 1, 2009

By R. K. Jonas

Many leading copper and other mineral processors have rapidly adopted advanced controls in last 5-10 years. Almost 600 multivariable predictive controls have been installed in mineral processing, and almost 50% of those are in copper concentrator plants. In most cases, mineral processors rely on 3rd party support to implement these advanced technologies. One challenge facing advanced control user is the selection providers and services for these technologies. The trend has been towards the use of multivariable predictive control and use of technology provider’s services. This paper will discuss status of advanced control, and the merging trends in the mining industry. A review will be presented of how advanced control is being applied in the mining industry over the last decade, and how user challenges are being overcome. Next the emerging uses of multivariable predictive control (such as multi/inter-unit optimization), focusing on the latest trends in concentrator plants. Finally, a review will be made of emerging technology advances in the that can be advantageous to mineral processors. INTRODUCTION Review of advanced control in mineral processing Advanced controls are serving an increasing role to improve processing plant operations and profitability. As advanced control is being installed into more mining processing plants such as copper concentrators, many of these plants are concerned about the selection technologies and vendors to support the installation and maintenance of these controls. In a study by Jonas and Craw (2011), they found that most new users have not had prior experience with advanced controls. It is the author’s experience of almost 30 years in advanced controls that most mineral processers considering advanced controls can benefit from better understanding of the technologies and their support requirements.

Jan 1, 2019

By Ian S. Thompson

"Exploration properties form a continuum from grass roots to those with favourable geology, geochemical and/or geophysical anomalies, mineralization, showings (prospects), and finally to those with defined mineral deposits. Often properties exhibit a composite of these categories.The most problematic to value are properties or deposits that are not economically exploitable at the time of the valuation, due to a lack of exploration, insufficient grade or tonnage, poor mining conditions, or the imposition of socioeconomic, environmental, or legal constraints.Various acceptable methods of valuing the range of all such mineral properties or deposits are reviewed. Some inappropriate methods are also discussed.BIOGRAPHYIan S. Thompson is President and Principal of Derry, Michener, Booth & Wahl Consultants Ltd. (DMBW), an independent consulting practice, specializing in exploration, ore reserve estimations, engineering and valuations of mineral properties.Mr. Thompson is a graduate in Honours Geological Sciences from the University of Toronto with over 35 years Canadian and International experience in mineral exploration and development, including the discovery of base metal. gold and uranium deposits.DMBW is affiliated with DMBW, Inc. in Colorado, and works with independent engineering and financial groups in North America, Europe, Australia and Africa.Mr. Thompson is a national member of CIM; the Associations of Professional Engineers of Ontario and British Columbia; The Geological Association of Canada; The Society of Economic Geologists; The Prospectors and Developers Association of Canada and the BC and Yukon Chamber of Mines.INTRODUCTIONThis paper is presented in response to the request of the Mineral Economics Society of the Canadian Institute of Mining and Metallurgy for a Review of Approaches to Valuation of Mineral Properties, as recommended by the TSE/OSC Mining Standards Task Force.Exploration properties with undeveloped mineral resources range from grassroots acreage without exploration history, to those containing mineralization (or a mineral resource) that is insufficiently explored, to well explored deposits which lack either continuity, or sufficient grade/tonnage, or have poor mineability or metallurgy, such that they are not currently exploitable at the time of the valuation. This does not imply that they do not have value."

Jan 1, 2003

By D. Seke, E. Katsande, R. Khumalo, K. Seerane

Palabora Mining Company (PMC) processes a multi-component ore body using a circuit consisting of two AG mills in parallel, closed with vibrating double deck screens and hydrocyclones. The bottom screen undersize feeds the hydrocyclones, but the screen oversize products can be treated in a variety of ways. The top deck screen pebbles can be crushed and then combined with the bottom deck oversize and recycled to the AG mill. Alternatively both the top and bottom deck screen oversize can by-pass the recycle crusher and be recycled directly to the mill. A full tap-off is a configuration when both the top and bottom deck screen oversize streams are stockpiled. The other configuration is when the bottom deck screen oversize is recycled to the mill while the top deck screen oversize is stockpiled - termed partial tap-off. This article reports the findings from the surveys performed to evaluate the performance of the PMC auto mill circuit when operated under the four different configurations discussed. Ore characterisation tests were performed to assess the deportment of the key ore components for the different configuration.

Jan 1, 2012

By Karl Houseley, Dr. Robert J. Chapman

"A gravity concentration process has been applied to ores from the Clogau Mine, north Wales, the Tyndrum deposit, central Scotland and an alluvial ore from Leadhills area of Scotland. In the case of the Welsh ore and the alluvial deposit the gold grains in the concentrate and tailings streams have been characterised in terms of their three dimensions.In the case of Welsh ore, the thickness of a gold grain has been shown to be the single most important factor in determining behaviour in a gravity concentration operation. Six indices were used to quantify the overall geometry of the gold grains and those which incorporate a thickness term have proven to be effective in predicting the destination of gold particles within the concentration circuit. It is proposed that the most simple of these, the Heywoods flakiness ratio, has potential for the control of milling operations as an alternative to the established practice of characterising the size of the mill discharge.The effect of grain geometry on the recovery of fine gold has been studied using Tyndrum ore. The recovery of gold by gravity concentration increased from 20% to 70% when the criteria used to design the milling operation was the prevention of over grinding of gold grains.The destination of alluvial grains in the concentration circuit did not show such dependence on shape, and this has been attributed to the effective classification of all the gold grains in the sample by fluvial action producing a population of similar geometric characteristics."

Jan 1, 1996

By E. Johansson, T. Siren, K. Kemppainen

"As part of the preparations for the design of an underground repository for radioactive waste at Posiva’s Olkiluoto site on the west coast of Finland, there has been considerable site investigation work. Except the extensive surface based investigations, Posiva started in 2004 the construction of an underground characterisation facility termed the ‘ONKALO’. The ONKALO has now been completely excavated to the anticipated repository depth i.e. -430–450 m. The research conducted in the ONKALO gives further information on the bedrock and groundwater conditions of the final disposal site, as well as on the impact of the construction. The ONKALO provides an excellent opportunity to investigate the rock at tunnel scale, to conduct in-situ testing in rock, to develop excavation and final disposal techniques in realistic conditions. The ONKALO has aided in collecting the data needed, supported by a Preliminary Safety Assessment, for the application of the construction license that was submitted in the end of 2012. The target is to begin disposal operations in 2022. According to current plans, the final disposal would end in 2112 and the repository would be sealed up by 2120. The testing in the ONKALO still continues several years. This paper presents the current characterisation and research activities in the ONKALO. INTRODUCTIONAfter the Finnish Government's favourable policy decision in 2001, Posiva Oy, which is an expert organisation responsible for the final disposal of spent nuclear fuel of the owners in Finland, has focused further investigations at the Olkiluoto site, western Finland (Figure 1) and has started in 2004 the construction of an underground facility termed the ‘ONKALO’. The ONKALO is not a nuclear waste repository, but more than just an underground research laboratory URL – it is an underground rock characterisation facility. The ONKALO has now been completely excavated to the anticipated repository depth i.e. -430–450 m. In addition to facilitating bedrock research, the ONKALO also provides an opportunity to develop excavation techniques and final disposal techniques in realistic conditions. Later, the ONKALO facilities can be put into use when building and using the repository. The construction methods and materials have been selected in order not to jeopardise the long-term safety of the repository site. The findings of the ONKALO and other investigations will provide the knowledge needed for an application, supported by a Preliminary Safety Assessment, to construct a final repository for spent nuclear fuel at the site. Posiva has submitted an application for the construction licence for a disposal facility in the end of 2012. The target is to begin disposal operations in 2022 and the repository would be sealed up by 2120."

Jan 1, 2015

By Robert D. Irvine

"Enhanced concern for protection of the environment and attendant actions by environ-mental regulatory authorities in support of this concern are influencing, to varying degrees, the demand and supply of a range of industrial minerals in a number of jurisdictions. These influences take a variety of forms.In this paper, the author seeks to delineate certain broad trends which are occurring relative to industrial minerals and the environment and then, through a series of examples, to outline opportunities, developments, and impacts respecting a number of industrial minerals produced and consumed in Canada and the United States."

Jan 1, 1996

By L. Torres, C. S. R. Rondestvedt, M. Bustos

In February 2010, Teck’s newest Concentrator at Mina Carmen de Andacollo (CDA), Andacollo, Chile was commissioned. The Concentrator is a single line configuration, comprising of one 36 ft diameter x 20 ft long SAG mill driven by an 18,000 hp gearless drive. The SAG mill feeds two ball mills each 25 ft in diameter x 40.5 ft long, each driven by a total of 19,000 hp through dual pinion drives. A series of four phases will be reviewed from operational readiness, mechanical completion, commissioning, and ramp-up. Also, now after 6 months of operation, this paper will review the significant steps taken during ramp-up enabling the announcement of commercial production, in October 2010.

Jan 1, 2012

By Y. Zedan

Cutting fluids play important roles during machining, including the reduction of friction and temperature. Using a cutting fluid, however, degrades the quality of the environment and increases machining costs. The aim of the present research work is to study the effect of cutting fluids and their interactions with cutting parameters on the quality of holes during the drilling of 6061-T6 aluminum alloys. The lubrication types and modes investigated are dry machining, flood lubricant machining and minimum quantity lubrication machining (MQL), while the part quality criteria include the surface finish, the dimensional accuracy, and burr forms and sizes. A scanning electron microscope (SEM) was used to investigate the formation of built-up edges (BUE) in the drill flutes as well as the surface texture of drilled holes. It was found that dry machining and MQL machining can produce parts having quality levels comparable to those obtained in wet machining, when using the optimal cutting conditions.

Jan 1, 2011

By D. G. Cerigo, D. M. Bryce, P. H. Jennings

This paper summarizes the results of an experimental and economic study undertaken to evaluate the feasibility of treating an oxidized orebody of about 10 million tons, grading about 0.75 per cent copper, by agitation leaching and by percolation leaching.

Jan 1, 1968

By S. M. Bulatovic, D. M. Wyslouzil

"This paper presents the results of a study of the effect of flowsheet configurations on metallurgical results and describes a general method for developing and optimizing flowsheets used in the treatment of massive sulphide ores. The flowsheet configuration can have a significant effect on recovery and selectivity between valuable minerals and gangue minerals. Placing of intermediate products within the flowsheet, positioning of various pretreatment units, such as conditioners or regrinding mills, and the ability of the flowsheet to cope with wide swings in the feed grade and composition are the major parameters that determine the optimum flowsheet configuration. The complexity of the flowsheet is largely a function of the ore itself and of the number of final, marketable products that have to be recovered from the ore. INTRODUCTIONTechnological ExpansionThe trend of past decades has been towards larger equipment and a better understanding of the chemistry of the flotation process. Despite appreciable progress in these areas little attention was given to the study of the actual configuration of the flowsheet, although the arrangement of the flotation equipment significantly affects the overall performance of the circuit."

Jan 1, 1989

By M. Sokoto, H. Hata, K. Nishina, K. Haiki

Fluoride ions in zinc electrolyte cause corrosion to aluminum cathode plates at zinc electrowinning process, so we have developed an iron compound as a fluoride ion adsorbent used in zinc sulfate solution. The iron compound is synthesized from FeC13 solution with a small amount of sulfate ion by neutralizing reaction with Na2CO3 solution. The fluoride ions adsorbed on the surface of the iron compound are desorbed in alkaline solution and the iron compound can be reuse as a fluoride ion adsorbent. Moreover, if adsorption capacity of the iron compound decreases, it can be dissolved in HCl solution and re-synthesized.

Jan 1, 2008

By J. B. Rubenstein

This work demonstrates the feasibility of using confocal surface profilometry to measure and characterize wear of graphite anode surfaces. This method was tested using anode samples that were electrolyzed for 24 hours in a laboratory-scale magnesium cell with a high oxide molten salt electrolyte. The oxide produced accelerated wear on anodes designed for low oxide electrolytes. Contour maps, which are effective at displaying non-uniform wear, and total graphite consumption values were generated from the collected surface coordinates. Along with both qualitative and quantitative analysis capabilities, this measurement system was shown to have a fine resolution and a low detection limit.

Jan 1, 2004

By Christopher R. Davis

Resource modelling is the basis for any economic appraisal of a mining project and includes a number of steps from data acquisition and validation to resource reporting and classification. At each step in the modelling process it is necessary to define the specific objectives, the methodology proposed to achieve those objectives and to establish a set of checks and validation tools to assess the effectiveness of the proposed methodology. The data used has to be both reliable and relevant for the purpose of the modelling. QA/QC for database validation requires verification of sample location; including correct collar location, topographic modelling and down-hole surveying. Validation is also performed on assaying information such as checks for sampling bias and accuracy of core splits, proper use of pulp duplicates and standards, handling of calculated values, explicit/implicit absent data and data entry errors. The second step involves identifying the mineralized domains resulting from the mineralization process. This step requires a geometric interpretation of all relevant geological features that have influenced the spatial distribution of the mineralization including dykes, faults and alteration. In addition, a geologic reference system rather than a standard Cartesian system is established to measure distances between samples. Once the mineralized domains are established and the database has been validated, statistical and spatial description of the mineralized samples are examined in order to establish the histogram and the variogram of all variables of interest and their correlation. Results are also used to calibrate the global resource estimate within the mineralized domain and to establish the search strategy for grade interpolation. The mineral envelope is filled with polyhedral cells representing mining blocks. The average grade of these blocks is estimated using kriging techniques in order to eliminate global bias and to minimize the local error in the block grade estimate. Visual checks are made to validate the spatial trends in grade distribution while global bias and smoothing effect are assessed from the declustered sample statistics. When required, smoothing correction may be applied using ?change of support? techniques. Simulations are used to perform sensitivity analysis and the simulation models are used if severe smoothing of spatial variability makes the interpolated model inappropriate for mine planning. The keys to successful resource estimation are an integrated team of geologists, geophysicists, geostatisticians and mine engineers using the best available technology and reviews by independent auditors. The resource team is also responsible for performing a QA/QC program in order to measure the effectiveness of the methods in meeting the specific objectives at each step of the modelling process.

May 1, 2001

By W. J. Adams

It is recognized that within life cycle assessment that the eco-toxicity potentials (TPs) derived for metals require additional research to improve their reliability. Current models used to develop TPs do not include important fate process for metals such as speciation and bioavailability. Toxicity potentials are standard values used in LCA to enable a comparison of potential toxic impacts between substances. Huijbrechts (2001) calculated toxicity potentials for 181 substances utilizing the USES model for six impact categories, i.e. freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, freshwater sediment ecotoxicity, marine sediment ecotoxicity, terrestrial ecotoxicity and human toxicity (not considered here). Marine ecotox potential for metals is typically high using this approach, whereas most open ocean metal concentrations are very low. A sensitivity analysis of the USES-LCA model was undertaken using copper as an example. Results indicate: fate processes on the global scale are driving the marine water and sediment TPs for copper most; the second most important fate parameter is sedimentation from the water and burial in deep sediment layers; inclusion of speciation and bio-availability processes would be very beneficial; more accurate estimates of input parameters should be used, and the PNECwater and PNECsediment and all partition coefficients for metals should be updated in the model.

Jan 1, 2007

By W. J. Kuit

"Complex facilities which provide for the collection, management and treatment of effluents emanating from the Sullivan mine and concentrator tailings were made operational in October, 1979. Key features of the system are the use of upgraded tailings ponds for the storage of up to 800 million litres of metals-contaminated effluents, a treatment plant employing lime in a high density sludge process and a sludge-impoundment facility designed for maximum long-term environmental safety. The completed works are cap1ble of satisfying a difficult range of operating requirements imposed by highly variable weather conditions, drainage flows and soluble metals loadi11gs. Final capital expenditures for the project will approach $10 million and annual operating costs are estimated at $0.8 million.This paper discusses the Kimberley effluents treatment project and the major considerations in its development. The treatment process, major plant equipment and initial operating experience are also described."

Jan 1, 1980

By D. Sbarbaro

In many modem concentrators the use of supervisory systems in their grinding circuits has meant more consistent operations and increases in capacity. These systems rely on a series of specific algorithms that uses different pieces of information and drives actions over the process. One of these algorithms is the ball mill overload detection, which plays an important role in any supervisory strategy designed to maximize ore feed rate in wet grinding circuits. This paper introduces different overload detection algorithms, and compares them in terms of the time taken to detect the overload condition. This comparative analysis is based on highly noisy power draw measurements obtained in an industrial plant.

Jan 1, 2007