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By N. Vayenas, G. Yuriy

"The combination of a predictive reliability assessment model and discrete-event simulation can be an effective methodology to study the impact of equipment failures on the capacity of production systems in mines. In our case, a predictive reliability assessment model using genetic algorithms is combined with a discrete-event simulation model to analyze mine equipment systems.Discrete-event simulation involves modelling of real-life systems based on variables and events that occur or change at distinct points in time. The Simul8 simulation software, by Visual Thinking, is used in this research. It is a two-dimensional (2D), discrete-event simulation/ animation software tool for creating realistic depictions of manufacturing and materials handling systems.The simulation model developed for the purpose of this research represents a typical two-level, sub-level stoping section of an underground mine in the Sudbury region in Ontario, Canada. This 2D model was created to assess the impact of equipment failures to a mine’s production throughput. In more detail, using mean time between failures (MTBF) data of scooptrams derived from a reliability assessment model based on genetic algorithms, LHD failures are incorporated into the simulation model. These failures cause production interruptions to the development cycle and consequently loss of hauling capacity.Another purpose of this research work is to demonstrate how low-cost simulation tools such as Simul8 can be successfully applied to model underground hard rock mining operations. The research discussed in this paper is carried out by the Laurentian University Mining Automation Laboratory (LUMAL)."

Jan 1, 2005

By J. E. De Waele, J. J. Lee, M. J. Mulheron, Luke R. Deamer

There is increasing demand for geotechnical contractors to commit to carbon reduction, net zero or science based targets. A lot of focus has therefore been placed on using low carbon materials and low emission rigs. However, whilst these are ways to help reduce carbon, there is a need to look beyond just substituting materials and fuels to meet net zero. Using the IEMA carbon hierarchy, there is a need to first look at eliminating and reducing emissions, before considering substitute materials. For example, in geotechnical designs, this may mean considering using ground improvement or reducing the number of piles, before considering using low carbon cements. Equally, for remaining emissions, this hierarchy means considering carbon negative products to offset emissions, such as ground source heat pumps. This hierarchy can also be applied throughout geotechnical contractor organisations. For example, considering video conferencing for meetings, before considering public transport or using an electric vehicle. This article explores the carbon hierarchy and how it can be applied to all areas of a geotechnical contractor’s business. Only through embedding this hierarchy across the business can geotechnical contractors achieve the step change required to meet net zero.

May 1, 2022

By Zoë Dugdale, Gerald Poplin, Tim Bauerle

"Fatigue presents several challenges for the mining industry. Depending on the specific occupation, daily work or operational setup on any given mine site, mining jobs can have a fair amount of labor-intensive tasks mixed with monotonous and repetitive duties. Combined with the long working hours and shift-work schedules of mining work, the prevalence of fatigue in mine workers may seem rather unsurprising.Mining is certainly not alone in facing the challenge of addressing worker fatigue. Indeed, many of the characteristics above mirror the similarities of fatigue in other industries, such as health care, aviation and security. To the extent that fatigue in mining acts like fatigue in any other industry, then any fatigue management applications, trainings, or interventions in existence can be borrowed from other industries and applied to mining in a cookie-cutter approach. However, some have argued that mining in particular is especially susceptible to increases in the prevalence of fatigue beyond the characteristics listed above due to the multifaceted combination of factors in mining environments associated with fatigue: dim lighting; limited visual acuity; hot temperatures; loud noise; highly repetitive, sustained, and monotonous tasks; shiftwork; long work hours; long commute times due to mine site remoteness; early morning awakenings; and generally poor sleep habits (Canadian Centre for Occupational Health and Safety, 2012; Legault, 2011). Legault (2011) in particular argues that it is the combination of these factors simultaneously that can make mineworkers particularly susceptible to sleep deprivation and fatigue in comparison to other industries where these factors are often not present all together. If fatigue looks and acts different in mining, as others have argued, more research is needed to determine if, how, and why worker fatigue might need to be managed differently in mining.While the burden of fatigue on the mining population has not yet been evaluated thoroughly, methods and measures of fatigue management remain a popular point of discussion. Many commercial suppliers and consultancy groups have begun to develop technologically based fatigue monitoring systems (McMillian, 2013). Some technologies can monitor vehicle operators for indicators of wakefulness, such as percent eyelid"

Jan 3, 2018

By Aldin Ardian, Mustafa Kumral, Jagjit Singh

Risk assessment of mining projects is a requirement in the mineral industries. In this process, many risk variables are timedependent, and the only available data are historical time series. Moreover, in the case of a multivariate scenario, conventional forecasting methods fail to capture conditional dependency across the variables, which is important when there is an underlying causal relationship that needs to be modeled for accurate project evaluation. Thus, we investigated the use of copulas to capture the conditional distribution of the factors involved in a mine risk assessment study. We employed a multivariate copula-based time-series approach to model several uncertain variables. The Autoregressive Fractionally Integrated Moving Average - Generalized Autoregressive Conditional Heteroscedasticity (ARFIMA-GARCH) model was used for the conditional mean and copulas were used to model the error distribution, thus capturing the collective variation and dependence pattern across the variables. The method was implemented to model gold prices, copper prices, and the 10-year US Treasury bond yields and to determine the project’s net present value and probability of being economically feasible. The proposed approach can be used for cases where simulation of multivariate time-series is conducted.

Apr 13, 2021

By J. C. Mullen

Today, the coal mining industry is more knowledgeable on the potential negative economic consequences associated with improper management of hazardous substances and various types of solid waste. The practices evaluated during environ-mental audits are discussed and example situations are shared from previous audits of coal mines and analogous situations. The importance of assessing and understanding purchasing, warehousing, safety, maintenance, electrical, operations, and environmental management practices and procedures is highlighted as a key to a successful and practical program. A waste minimization approach is presented including strategies for screening product purchases, product substitutions, and testing and record keeping.

Jan 1, 1992

By M Thompson

"The Jaguar concentrator, 60 km north of Leonora, Western Australia (WA), consists of a standard closed circuit semi-autogenous grinding (SAG) and ball mill producing a float feed of approximately 60 micron at 70 t/h. Following comminution, separate copper and zinc concentrates are produced by differential flotation. These concentrates are subsequently dewatered by thickening and then filtration.Separate audits of the Jaguar Operation’s copper and zinc concentrate thickeners were conducted to evaluate their performance, following occasions where site personnel had identified unnecessary loss of copper and zinc concentrate to the thickener overflow. The feedwells were identified as the source of the observed problems due to the following issues with their design/duty:lack of retention time in the feedwell as current design is completely opennot conducive to effective mixing required for efficient flocculationdiameter of the zinc concentrate thickener feedwell was undersize for its duty.To improve the performance of the thickeners, it is planned to replace both concentrate thickener feedwells with a high rate design for their respective duties in February 2016. The audits also identified that the feed system requires modifications with particular importance placed on minimising air entrainment of slurry into the thickener feedwell. Minimisation of air entrainment is hoped to be achieved by providing constant head pressure through installation of weir arrangements in the feedboxes and redirecting each feed pipe so that it feeds tangentially into the feedwell. In addition, improvements to the control philosophy of both thickeners will be made with the installation of an ultrasonic bed level probe and bed mass sensor, in order to make real-time adjustments to the underflow pump speed to maintain steady state operation.Following the feedwell replacement and modifications to both thickeners it is expected that losses of recovered copper and zinc will decrease to undetectable levels. Subsequently it is anticipated that a more consistent, homogenous underflow can be produced for downstream filtration.Citation:Thompson, M, 2016. Concentrate Thickeners Feedwell Replacement, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 273–278 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Emanuelle Garcia Reis, Gustavo de Sousa, Rodney Pardo Alves

Gerdau Ouro Branco´s plate mill started the operation in 2016 with high level technology. In general, national and international plate markets are every day more rigorous about final product quality. Suppliers must be aware about dimensional accuracy, surface quality and flatness of the plates, independent of the quality standards. To guarantee the best service to this increasingly demanding and competitive market, it is extremely important to guarantee the original project conditions executing the right maintenance of the rolling mill main components. In order to maintain the product quality and avoid the production and maintenance cost increase, it is important to find ways to control the mill and the main process variables, through daily measurements of the equipment performance. This paper aims to present the influence of the main equipment variables that affect the mill operational stability and how to control and evaluate the mill performance.

Oct 1, 2019

By P D. Munro

On the occasion of the 14th Mill Operators’ Conference and marking 40 years since the first one was held in Mount Isa in 1978, it is fitting to review the history of the Conference and its development over that time.The first 10 Conferences were irregularly held at three to four year intervals, with 9 of these in regional centres of Australasia. It is only since 2012 that the Mill Operators’ Conference has become a regular biennial event, alternating with the MetPlant Conference.The number of people attending the Conference has more than doubled to 470 delegates at the 13th one in 2016. It has outgrown its regional beginnings.Papers presented to the previous Conferences have been analysed according to commodity, country of origin, technology and theme plus the affiliation of the authors to discern any trends that may assist in planning the future events.Suggestions are made as to how the AusIMM might wish to arrange its mineral processing/metallurgical conferences.Recent changes to the structure of the Conference providing a more meaningful experience for the delegates and increasing their interaction and involvement should be vigorously pursued.CITATION:Munro, P D, 2018. Mill Operators’ conferences – a 40-year retrospective and a vision for the future, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 5–14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By B. Genc, V. J. Mahadeo, S. Ramparsad4, U. Govender

The study was intent on assessing the socio-economic impact of a zinc mine in South Africa through the application of people-centric digital tools using a case study research methodology. The global mining industry is undergoing significant technological shifts to modernize, improve operational sustainability, and align with the environmental, social, and governance (ESG) agenda. While the case study mine is a more modernized mine, continuous improvement around the ‘social’ pillar becomes critical, and to this end application of people-centered digital tools presented as the vehicle to understand community needs and impacts. Despite considerable annual corporate social investment by mines annually, the overall impact or social return on investment is marginally understood. Towards contributing to addressing this gap, digital ESG ‘social-related’ data gathering tools for mines decision-making were developed, including the training-needs assessment tool, community-social needs assessment, small, micro, and medium enterprise (SMME) communications and engagement tool, digital leadership competencies gap assessment tool, and change management blueprint, which further allowed for customization to the mining context. Hence, the novelty of this paper relates to applying digital tools to provide real-time information of the needs of a community, both socially and economically. The findings suggested that these digital tools enabled gathering of information for the establishment of regional and operational baselines towards enabling of social investment returns in relation to socio-economic transformation development interventions. These tools have been applied to a zinc mine context, with lessons and experiences obtained through this study, invaluable to the application of these digital tool in other mines in South Africa. The study was conducted in September 2023 across five host communities, surrounding the zinc mine, in the Northern Cape region, with 120 participants involved in the application of three relevant community-related digital tools, which included the training needs, community-social needs, and SMME communications and engagement tools. It was evident that the digital ESG tools could be used for data gathering for the mine’s informed decision-making and allowed for securing of insights on community needs in near real-time, and further proved practical for community use.

Dec 11, 2024

By Gerald T. Homce

A system capable of monitoring a mine electrical power system to detect incipient electrical component failure could significantly improve power system safety and availability. The U.S. Bureau of Mines funded a contract with The Pennsylvania State University (Penn State) to establish the theoretical and technical framework for such a system. This report briefly outlines the contract, reviewing related Bureau and Penn State work prior to its award, and describes support work carried out by the Bureau. The main focus of the report is on research efforts by Penn State and subsequent results. An existing algorithm for incipient-failure detection and classification was studied, and recommendations are made to improve its performance. In addition, mathematical models of cable-connected motor systems and deteriorating motors were developed and implemented on computers. These models and laboratory tests were used to study and document relationships between component deterioration and electrical terminal effects. The project was supported by the U.S. Navy and the nature of its interest in the application of failure prediction techniques is also included.

Jan 1, 1989

"Mining used to be a business primarily focused on the technical aspects of getting valuable ore out of the ground and extracting the minerals efficiently. Without denying the importance of these skills, a narrow focus on technical issues is no longer enough to guarantee success when it comes to exploiting rare earth element (REE) deposits. Molycorp failed to enter the global REE market in a successful manner, while none of the many REE exploration projects has turned into an active mine so far and none is expected to commence operations in the near future. Accordingly, the world of REE is far more complex compared to other commodities. This paper looks into the REE industry to identify the factors that can connect potential U.S. REE mines to the market. The ability to break free from past thinking and become future-focused is a key driver. Mining of REE is pointless without a corresponding value-adding chain, while developing a value chain without first establishing an uninterruptible source of REE is also senseless. The mining sector must be based on the REE value chain and vice versa, along with the establishment of a market channel for the REE products that come out of the mine. INTRODUCTION It has been seven years since rare earth elements became the subjects of front-page headlines. It was when the controversial Chinese export policy for these critical commodities was epitomised in a maritime border dispute with Japan in September 2010 that resulted in the big REE crisis and price spike of 2011 (Barakos et al, 2016c; Mancheri, 2015). The world was dismayed, especially in REE-importing countries, such as the United States that was and is still totally dependent on Chinese production and exports (Barakos et al, 2016c; Kennedy, 2015). The short-lived alarm initiated a treasure hunt by way of exploration for REE deposits all over the world. The continuously growing demand on the one hand and the Chinese sovereignty of the REE-market on the other, led the rest of the world to explore their own REE resources. In just a few years, more than 400 projects were initiated to explore REE deposits outside of China (ERECON, 2015; Goodenough, 2016). The prices of REE, however, dropped rapidly and at the moment of writing this paper are in 6-year lows, at the level of the price average before the 2011 crisis (Barakos, 2017). The viability of even major established producers is being challenged, not to mention the development prospects of potential REE-market entrants (Barakos et al, 2016b; Rollat et al, 2016). Production cutbacks and industry consolidation in China impel REE market experts to forecast that prices have already reached their lowest point and have nowhere to go but up (Adamas, 2015; Roskill 2015). Yet, expectations for increased REE prices are limited and drastic changes are unlikely to happen in the near future, as there is still excess supply in the overall REE market (Barakos, 2017). Nevertheless, the low prices of rare earths are not the only reason that potential producers are struggling to enter the global REE market. Among other parameters, the separation of the individual elements seems to be the most important factor, as it is technically challenging and expensive to build and to operate."

Jan 1, 2018

By Victor G. Hills

CONTRARY to what seems to be the general impression, the island of Cyprus was not named for the metal copper, but the reverse was the case. The origin of the name is entirely lost. The ancient city Kition, the birthplace of Zeno, is supposed to be the same as Kittim mentioned in Gen. x, 4; Jeremiah ii, 10 and Ezekiel xxvii, 6, and Josephus states that this name seems to have been applied to the city and also to the island itself. Cyprus is 50 miles off the coast of Asia Minor. The mountains on the mainland are plainly visible across the sea from where I write six miles from the shore of Morphou bay. It is 200 miles from Joppa the port of Jerusalem, and 250 from Port Said. The shape of the island is like a lizard, the tail pointing directly toward the old city of Antioch near the northeastern corner of the Mediterranean. The island was once heavily timbered. Among the great trees the cedars were said to even excel the famous cedars of Lebanon. The Odyssey refers to it as the "sweet smelling island" and makes other references. But the continual wars of every race and age completely stripped it of its timber, and for centuries it has been woefully barren. There are two ranges of mountains. One borders the north coast and runs out in a slim rocky ridge forming the "tail." The other occupies the southwestern part of the island, the highest point being Mt. Troodes 6600 ft. high, sometimes called Mt. Olympus. Whether or not it be the Mt. Olympus, anyway right around there the ancient gods and godesses frequently "started things." These peaks are in plain sight 10 miles south from where I live.

Jan 1, 1926

By Alfonso Núñez

There are many assets on a typical industrial site that are not monitored continuously by a SCADA system or the DCS. Many of these assets are critical and must be running correctly for production to meet its targets. Most companies schedule inspections of these assets regularly by sending skilled operators to the field who take notes using paper and a clipboard. There are many advantages related to the digital transformation of operator rounds. In particular, the collection process is supported by digital prompts and the data — once it is collected — is automatically routed to a database and made readily available to all the software applications and stakeholders that need it.

Sep 29, 2023

By D. Emadi

The ASTM B108 Mould and a Modified Mould were used to cast test bars under a variety of conditions: mould and pouring temperatures, mould coating and tilt. Mechanical properties were determined in the as-cast and heat-treated conditions. The ASTM Mould is less sensitive to casting variables. Enlarging the gating system and adding additional gates to the ASTM mould can improve properties in the tilt position. The reproducibility of properties in as-cast and T6 heat treated bars was investigated.

Jan 1, 2004

By J. P. Harrison, N. Bozorgzadeh, M. Dolowy-Busch

"It is common in rock engineering practice to characterize the triaxial strength of intact rock by using only data samples of small size. Practical guidelines such as ASTM support such sample sizes. In this paper, we investigate the reliability of the Hoek-Brown strength criterion estimated from such samples. For this purpose, we use an unusually large published set of triaxial strength data to randomly select a large number of data samples of small size to simulate the situation that frequently encounters in practice. The samples are generated with different arrangements with regards to the confining pressure. We fit the Hoek-Brown criterion to each of these samples, obtain estimates of strength parameters and compare them to those obtained from the complete data set. Our analysis suggests that estimates based on small samples are not reliable and can lead to both over- and under-estimation of strength.Additionally, we use these small samples to investigate the statistical methods for obtaining design values of strength as suggested by limit state design standards such as Eurocode 7. We show that, if used in conjunction with small samples, these methods do not guarantee a safe estimate of strength and in many cases lead to highly over-conservative estimates.We present a potential solution to this problem by augmenting the small data sets with Bayesian informative priors to give much more reliable estimates of strength. We conclude with suggestions for the development of informative prior distributions."

Jan 1, 2015

By G. E. S. Lima, I. K. R. Andrade, N. G. Viana, R. O. G. Martins, L. M. Sathler, L. G. Pedroti, C. M. M. E. Torres, W. E. H. Fernandes, C. M. Silva, M. A. Caetano

In Brazil, kraft pulp mills are rapidly expanding and industrial waste generation is increasing. Technical feasibility of using solid wastes from kraft pulp mills as raw material in other industries may be an interesting approach to manage environmental and economic aspects of the industry. This paper proposes the incorporation, in different proportions (0, 2.5, 5 and 7.5%), of alkaline solid wastes from pulp mills, namely dregs and grits, to clinker in the Portland cement industry. The research was carried out in two steps: (i) characterization of dregs, grits and clinker; (ii) laboratory testing (determination of soundness by the Le Chatelier method, determination of setting times, determination of water content of the paste with normal consistency, determination of compressive strength and static modulus of elasticity). The results showed that the addition of dregs and grits to the clinker up to 2.5% were feasible according to the Portland cement Brazilian standards.

Mar 1, 2017

By John F. Papp

International and U.S. chromium material flow, losses, and environmental releases and transfers from mining through industrial processing, end use, and recycling are identified and quantified. Average (1983-92) U.S. consumption has been: metallurgical industry, 87 pct; chemical industry, 10 pet; and refractory industry, 3 pct. Average chromium content of aluminum, cobalt, copper, nickel, and titanium alloys and alloy, carbon, and stainless steel alloys was estimated. Anthropogenic chromium consumption was estimated for the cement and copper industries. N on-commodity cycle anthropogenic chromium mobilization resulting from U.S. fuel and fertilizer use was estimated. Commodity cycle anthropogenic world chromium loss from mining and primary consumer industry was estimated to be equivalent to about 56 pct of chromium contained in chromite ore production and represented a loss rate of 181 kt-Cr/Mt-CrOre. Chromium released to the atmosphere from natural and from anthropogenic sources were comparable in magnitude. Chromium released to soil was mostly from anthropogenic sources, and aquatic releases were all anthropogenic. Domestic product chromium losses exceed process losses by more than a factor of 10 showing the importance and potential environmental impact of post-consumer recycling. The location of historical and current domestic chromium industry processing sites in 23 States were reported. Chromium releases and transfers to the environment were estimated from 1973 through 2002 by primary consumer industry. A decrease in chromium releases and transfers to the environment was anticipated.

Jan 1, 1995

By M Wortley, J McKay, D La Rosa, O Guyo

It has been a generally held concept that crushing operations were, by their nature, too simple to benefit from the implementation of advanced process control. The commissioning of an OCS¬ expert control system and image-based oversize detection system, VisioRock, at the Pilbara Iron Tom Price facility are dispelling these notions. A constraint-based OCS¬ expert control system has been designed and commissioned on the high-grade crushing and screening plant along with a vision-based oversize detection system functioning on six product conveyor belts. To date, the expert control has demonstrated the ability to increase production by maximising dynamic constraint utilisation. Dynamic constraint utilisation is a concept developed by Rio Tinto Technical Services for effectively evaluating constraint-based control logic performance. The VisioRock system has been installed and configured and has been operating for a period of several months. Currently, Tom Price and Metso personnel are working to define correct oversize detection thresholds. Details of the plant implementation are discussed.

Jan 1, 2006

By Peter L. Swanson

This investigation, which began 90 minutes after the February 3, 1995, seismic event, has benefitted from the assistance of a large number of individuals. These individuals provided information, data, analysis, brainstorming opportunities, field equipment, assistance with communication, conducted rock mechanics tests, and provided insight into mining in the southwestern Wyoming trona district. They include Rich Hodgson, Ron Hughes, Larry Refsdal. Mike Weller, John Kolesar, Joe Vendetti, and Rick Casey (Solvay Minerals), Dave Delling (Solvay consultant - former Solvay President), Karl Zipf (formerly with USBM, now with MSHA), Bob Friend, Bob Ferriter, Dave Ropchan, Jerry Davidson (MSHA Tech Support), Don Stauffenberg, Ben Hohler (Wyoming State Mine Inspector's office), Bruce Presgrave (USGS/NEIC), Chris Wood, Dan O'Connell (Bureau of Reclamation), Sue Nava, Jim Pechmann (University of Utah), John Norgord and members of FMC's mine rescue team (FMC Corp.), Bill Walter (Lawrence Livermore National Laboratory), Ron Gerlick, Kevin Wood, and Mike Harmel (USBM rock mechanics lab), Jim Case (Wyoming State Geological Survey), and Solvay consultants. In addition, many individuals helped us gather information on other recent large mining-related seismic events in Germany, Russia, and Australia. and other parts of the United States. These individuals include Wolfgang Minkley (IfG Institut fur Gebirgsmechanik, Leipzig), Arnfinn Prugger (Potash Corp. of Saskatchewan), Hartmut Spetzler (University of Colorado/ University of Bayreuth), Sergei Stanchits (Ioffe Poly-technical Institute, St. Petersburg), Rocky Thompson (Cyprus-Amax) and numerous seismologists throughout the Internet.

Jan 1, 2011

By A. Saki, P. Gebski, W. Ying

Industrial smelting furnaces are subjected to significant structural changes and deterioration caused by the conditions under which they operate. The current methods for the structural assessment of furnaces include visual inspections, analysis of thermal data, acousto ultrasonic-echo (AU-E) of the refractory lining and surveying of the key structural elements. Acoustic Emission (AE) non-destructive testing (NDT) technique has proven its capabilities for continuous monitoring of industrial installations and structures. Recently, Hatch Ltd. has been successful in applying acoustic emission for monitoring furnace tapblocks, and expanding the scope of the acoustic emission monitoring to the structural integrity of the entire furnace. The capability of detecting emissions related to the fracture development in the furnace shell, movement of the refractory, electrode arcing, combined with efficient source location algorithms makes an acoustic emission system a comprehensive tool for the real-time furnace integrity monitoring. In this paper the concept of such state of the art system for structural integrity assessment is presented. The initial results of the acoustic emission monitoring together with data analysis techniques are discussed.

Jan 1, 2011