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By J. Pascoe, J. H. van Laar, J. H. Marais, F. J. L. Matthee

Advanced measurement and verification (M&V) is a process where the impact of an energy initiative is determined in real time. Data prediction models can be used to predict and compare energy consumption with a predetermined baseline. Deeplevel mines can benefit from advanced M&V as the impact of operational changes can be identified in real time. Ultimately, this can ensure that informed decisions are made regarding energy management based on the impact and severity of the occurrence. Previous studies on advanced M&V do not account for operational changes to the model’s baseline. These changes can significantly impact the performance of both the mine and related activities. The aim of this study is to propose a method that can accurately predict the energy consumption of a deep-level mine regardless of operational changes. To achieve this objective, nine different data predictive modelling techniques were considered. The proposed method is based on the Moving Average (MA) modelling technique due to its simplicity, flexibility, and rapid development time. The coefficient of variation for the root mean square error (CV(RMSE)) was used to statistically analyse the modelling error. If the predictions exhibit an unsatisfactory CV(RMSE), the model dynamically adjusts to reduce the prediction error. The model was developed to adapt to operational changes in scenarios where the standard model becomes irrelevant. The method developed in this study was able to predict the future energy consumption of deep-level mines with an accuracy of 99%, improving the mine’s energy and finance management.

Dec 13, 2023

By J. Mácsik, J. Lindblom, C. Maurice, Susanne Nigéus

Using non-hazardous industrial residues in mine waste remediation is beneficial not only for the mining industry where substantial amounts of the waste generated have potential to produce acid rock drainage and pollute the environment, but also the providing industry, minimizing the waste landfilled. In this study green liquor dregs (GLD), residue from 15 different paper mills were characterized to valorize it as a potential product as a cover material. In another part of the study, one of the GLDs and a local till were characterized to determine the optimal mixture of GLD amended till to be used in a field application at the closed Näsliden Mine in northern Sweden. The study concluded 10% GLD-amended till to be the optimal recipe and was successfully applied at the Näsliden mine waste dump. However, the great variability in the characteristics of GLD creates challenges if it is to be valorized as a product.

Dec 7, 2023

By NA UMC

Abstract Booklet

Dec 2, 2023

By IPMI Educational and Scientific Foundation

It is with great pleasure that we announce the availability of this fourth issue of the IPMI Journal, a publication of the International Precious Metals Educational and Scientific Foundation. This digital peer reviewed publication has been created as a vehicle for the sharing of technical information related to the science and technology of precious metals. Since 1976, the International Precious Metals Institute has championed the exchange of information of critical importance to the precious metals scientific and commercial communities through its various communications vehicles. This has included instructional videos, annual conference symposia, special topic committee meetings, regional seminars, and professional and student achievement awards. Due to the breadth of important topics related to all aspects of precious metals, it has been the vision of the IPMI to provide a publication available to the general public that would become a key source of pertinent topics containing high quality publications by experts in their fields of study. Historically, the IPMI has attracted world renowned experts in many fields (including Nobel Laureates Henry Taube, Ei-ishi Negishi, Robert Grubs, Professor Ben Feringa, and David MacMillan) in the dissemination of discoveries, inventions, and industry proven practices. Such information has a total value greater than the sum of its parts as seemingly unrelated innovations from distinct focus areas can be adapted to solve problems. Because of this important characteristic of information exchange, we have decided to create a digital journal, available to the general public, that will not only communicate state of the art discoveries and sound practices, but will also review historical communications from the IPMI’s archives that have value and use even in today’s environment. On behalf of the members and leaders of the IPMI, we hope you will find value in this new publication.

Dec 1, 2023

By Frank Pepe, Nestor Garavelli

The 2023 Rapid Excavation and Tunneling Conference (RETC) will be held in Boston, MA and will include the presentation of 133 papers divided into 20 technical sessions during the 3 day conference that were selected from over 200+ papers that were submitted to the committee. The selected papers are included within this book to provide a comprehensive recap of the conference while also providing a source of reference for contractors and engineers in the future. The selected papers will include contributions from all divisions of the tunneling industry plus risk management and best contract practices. Boston is known to the tunneling industry for its complex and difficult tunneling history, specifically of recent memory the Central Artery/Tunnel Project also know as the “Big Dig” of the 1980s and early 1990s. The selection of Boston as a host city was fitting from a historical perspective and as avenue for the city to present its upcoming tunnel projects. RETC began in 1972 with the idea of sharing ideas, design and project construction experience, and new technology, between contractors, designers, owners and suppliers. The ability to provide a single location every other year for all facets of the tunneling industry to gather and discuss the aforementioned was and still is viewed as a way to help the tunnel industry grow. The lessons learned from completed projects, the advancement of technology which could be implemented into design and the presentation of new projects by owners/designers and contractors allows for the limits and complexity of upcoming projects to be expanded beyond our current capabilities. Our industry has never been as busy as it currently is, and we are seeing more future projects coming out for solicitation across all business sectors. With the good fortune that all of us have been blessed with one of the biggest challenges that we have been faced with is the shortage of future management on all levels for our projects including the labor force. We all want our industry to continue to grow and succeed, our most important assets are the people that we employ. Investing in the education and continued training of our work forces to be up to date with the latest technology and methods is the key to our success. This also includes develop, recruiting and mentoring of young students graduating college to join our industry so that we can all continue to grow. We hope that all those attending the conference will have the ability to attend as many sessions as possible and to expand their network within our industry. As in past years, scholarship students will be in attendance and we encourage all to offer these students an opportunity to visit jobs, attend learning sessions or future internships to expand their interest in our industry that needs an injection of young engineers to contribute and lead our future Rapid Excavation and Tunneling Conferences. The program chairs wish to thank the session chairs, co-chairs, authors, and other members of the RETC Executive Committee for their dedication to this conference. Last but certainly not least, we give special thanks to the SME staff for their hard work and enthusiastic support in making this conference possible.

Dec 1, 2023

By Robert McIvor, Sami Makni, Andreia Rosa, Claude Gagnon

In response to the Natural Resources Canada “Crush It Challenge,” Corem partnered with the University of British Columbia and led a project to develop and demonstrate the use of high-pressure grinding to replace the workhorse of the industry, wet ball milling. Two plant case studies, a small tonnage gold recovery operation and a large tonnage copper recovery operation, were carried out. Plant circuit performances were compared to pilot plants operated on the same circuit feed setup to represent the novel equipment and flowsheet that was developed to produce separation circuit feed. Numerous obstacles to industrial implementation of high-pressure grinding in this role which were recognized at the outset of the work were successfully addressed. In both cases, comminution equipment energy savings alone and final stage total circuit energy savings exceeded 60% and 50%, respectively. Downstream mineral separation performance was the same or better.

Nov 28, 2023

By Ankit Jha, Javad Sattarvand, Aaron Young

Blockchains are one of the prominent disruptive technologies that are being implemented in several disciplines. The application of blockchains in the mining and mineral industry can provide utility for several processes especially when the industry is undertaking digital transformation. The governing principles of blockchain technology are applicable in undertaking transformation in several processes within the mining industry. This study investigates the applications of blockchain technology within the realms of the mining industry and identifies key areas of implementation. A systematic review of publications on academic platforms relating to blockchain technology in the mining industry did not retrieve a considerable number of articles. Consequently, a thorough review of white papers and articles authored by individuals on use cases within the mining industry is compiled and presented in this manuscript. This paper identifies all the potential areas within the mining industry where blockchains could provide value and improve processes through their implementation. The broad area of implementation of blockchains includes supply chain, traceability in spare parts, contract management, regulatory compliance, and cyber security.

Nov 23, 2023

By Sufi Md Gulzar, L B. Roy

Rock engineering tasks like tunnelling, dam and building construction, and rock slope stability rely heavily on properly estimating the rock’s uniaxial compressive strength (UCS), a crucial rock geomechanical characteristic. As high-quality specimen are not always possible, scientists often estimate UCS indirectly. The primary objective of this paper is to assess the efficacy of long short-term memory (LSTM), K-nearest neighbour (KNN), a combination of particle swarm optimisation (PSO) with an artificial neural network (ANN), and adaptive neuro-fuzzy inference system (ANFIS) to estimate the UCS of sandstones from Jharia, Dhanbad, India. Point load index (PLI), porosity (n), P-wave velocity (Vp), density (ρ), and moisture content (%) are the parameters used for the present study. Finally, a comparison was made between the various prediction algorithms outputs. The findings of the study validated the effectiveness of computational intelligence methods in forecasting UCS compared to other models used in this paper. The KNN achieves overall the best results, with an R2 of 0.95 for training, 0.94 for testing, and an RMSE of 0.03 for training and 0.05 for testing.

Nov 23, 2023

By Sheshang Singh Chandel, Prvan Kumar Katiyar, Navneet Singh Randhawa, Prince Kumar Singh

Mineral process wastes, such as metallurgical slags nowadays, are of significant metals and materials resources in the circular economy. The usability of iron-making slag is well established; however, steel slag still needs to be utilized due to various physicochemical constraints. In this context, we have reviewed the global steel slag generation, processing, characteristics, and potential application with suggestions for futuristic possibilities to address the technical, economic, and environmental aspects of steel slag recycling. The steel slags inherit characteristics from ore chemistry and their processing routes, which may be Blast Furnace-Basic Oxygen Furnace (BF-BOF) or Direct Reduced Iron-Electric Arc Furnace (DRI-EAF) steel-making routes with/without treatment in a Ladle Furnace (LF). The average generation of slags in BOF, EAF, and LF processes accounts for 110 kg, 70 kg, and 40 kg per tonne of steel, respectively. Considering global steel production of 1878 million tonnes in 2020, the associated slag by-products possess a significant resource of major components like FeO, CaO, SiO2, Al2O3, etc. Selecting a recycling technique depends on the slag's end use, logistics, and physicochemical characteristics. BOF and EAF slag are used ~ 48% in road construction applications and ~ 10% for industrial specific metallurgical use. EAF slag is preferred as cementitious material as compared to BOF. Hot-stage modification of BOF slag has emerged as a preferred method to achieve desired chemical and subsequent mechanical properties for end use. BOF slag has high carbon dioxide sequestration potential for in-plant remediation among steel slags.

Nov 20, 2023

By CIM Mineral Resource, Mineral Reserve Committee

Industrial minerals are generally considered to include non-metallic minerals, mineral products, or materials that provide raw material inputs for the construction, chemical, and manufacturing industries. They are often relatively low-value and bulky materials that are generally used close to where they are produced; however, some raw materials may be transported hundreds of kilometres to manufacturers and customers (ENDM, 2021). They do not include the metallic minerals, mineral fuels, or gemstones, and are used in industries based on their physical and/or chemical properties (Wikipedia, 2021). In contrast to most metallic minerals, a general distinguishing characteristic of the industrial minerals sector is their general low degree of market elasticity in relation to the market prices and product specifications. The estimation of either a Mineral Resource or a Mineral Reserve (MRMR) for an industrial minerals deposit can be affected to a significant degree by a number of factors that are not typically applicable to metallic mineral deposits. These factors can include such considerations as the particular physical and chemical characteristics of the final product, product quality issues, market size and market access. In some cases, such information may be confidential and proprietary. One of the key challenges of the industrial minerals sector is to define a commonly accepted listing of which types of minerals, materials, or mineral deposits can be considered as industrial minerals (Mining Standards Task Force, 1999). Although definitions for what constitutes an industrial mineral can vary in detail, general descriptions can be found in American Geosciences Institute (2021), Fastmarkets IM (2021), Snowden (2019), SME (2021) and Wikipedia (2021). A brief listing of some of the materials and minerals that are generally considered to be industrial minerals is provided in Table 1. For the purposes of this document, all references to industrial minerals include not only the minerals, materials, and mineral deposits themselves, but also the various commercial products that are derived from these sources.

Nov 19, 2023

By Shenghua Yin, Xun Chen, Rongfu Yan, Zepeng Yan, Wei Chen

The application of cemented paste backfill (CPB) with alkali-activated slag and phosphogypsum (ASP) can contribute to the sustainable development of the mining industry. The effects of PG content, NaOH content, solid content, and waste rock-rod milling sand (W/R) ratio on workability, unconfined compressive strength (UCS), and setting time of ASP-CPB were investigated in this paper. The results showed that the workability of ASP-CPB decreased with PG content and NaOH content. Compared to OPC-CPB, ASP-CPB exhibited better workability and higher long-term (7 days and 28 days) strength at predetermined backfill formulations and curing times. The mid-term strength of ASP-CPB first increased and then decreased with PG content, while the short-term strength (3 days) decreased gradually due to the influence of soluble acidic impurities. Excessive NaOH will harm the strength of ASP-CPB, possibly due to the swelling effect of the reaction products (ettringite and sulfate). Strength and setting time increased and decreased with solid contents, respectively. Moreover, the compactness of the mixture has an important effect on strength and workability. The workability and strength of ASP-CPB reached the minimum and maximum values at a W/R ratio of 5:5, respectively. Pollutant index detection indicated that most of the pollutants in ASP-CPB leachate met the discharge standard, which proved that ASP-CPB is an effective method to recover PG. The results of the research will provide theoretical guidance for the efficient recovery of PG resources and support the achievement of safe, clean, and efficient mining.

Nov 17, 2023

By Micah Nehring, MEHMET KIZIL, Farzad Sotoudeh, Amin Mousavi, PETER KNIGHTS

Production scheduling in underground mines is one of the most important and complex processes in maximising the economic value of an operation over the life of the mine. Due to increasing energy, transportation, processing and smelting costs and reducing water availability, the extraction of ore deposits through underground operations has become more expensive and challenging. A potential productive and efficient solution to mitigate these issues is to integrate pre-concentration systems into the existing mining system to increase ore grades through a preliminary process of rejecting some waste before sending the ore to the energy intensive mineral processing plant. Further benefit of such systems includes the utilisation of the waste and low-grade material in backfilling of open stopes to reduce the transportation costs and surface environmental impact such as reduction of CO2 emissions and waste transportation. The objective of this paper is to present a new mathematical model to optimise the production schedule of underground metalliferous mining operations in the presence of a pre-concentration system. The proposed model optimises the production schedule and sequencing of stopes within a sublevel stoping operation. The results of this study illustrate the potential economic benefits of using a pre-concentration system prior to a mineral processing operation as a result of increased net present value.

Nov 16, 2023

By Nilufer Kursunoglu

Despite being crucial for meeting the world’s energy demands, coal mining operations present considerable health risks, especially when it comes to exposure to coal dust. Longwall coal mining, an advanced technique, has considerably enhanced production but made dust control more difficult. Due to its explosive nature, coal dust continues to be a serious and dangerous concern in the industry despite developments in safety technology. This study aims to comprehensively assess the risk of coal dust explosions by integrating fuzzy risk matrix and Pareto analysis methodologies, offering precise risk ratings for various root causes. A fuzzy risk matrix was developed to assign exact risk ratings to identified root causes. Additionally, a Pareto chart was used to identify the main reasons and suggest particular preventive measures. 17 significant causes were determined for underground coal mines based on the study’s methodology, and some preventive measures were suggested. In accordance with fuzzy risk rating values, root causes were divided into six categories. The root hazard with the highest risk rating was identified as ‘accumulation of inflammable gas/gases’. The proposed approach was used to examine incidents caused by coal dust explosions in Turkish coal mines in order to demonstrate the effectiveness of combining the fuzzy risk matrix and Pareto analysis for assessing coal dust explosions. This study gives not only a solid framework for risk assessment but also critical information for classifying the risks associated with coal mine dust explosions. The results highlight the critical necessity for proactive and preventive actions to reduce the hazards of coal dust explosions and protect the safety of mining workers.

Nov 16, 2023

By K. Witt, S. Steinlechner

In different nonferrous metal-producing industry sectors, the impurity element iron has to be removed from the process solution. Examples for the arising residues are jarosite or goethite precipitates from nickel or zinc production but also red mud from aluminum production. Regardless of environmental concerns, the material is landfilled in almost any case, although valuables such as indium, silver, nickel, or zinc are present in considerable amounts. Within the presented research, a low carbon dioxide emitting multi-metal recovery from such iron-containing residues by means of a selective chlorination extraction has been fundamentally evaluated by experiments but also by comprehensive thermodynamic calculations. The paper summarizes the thermodynamic fundamental concept exploited to separate the dominating iron matrix from the valuable elements and shows verification experiments in a lab size of several grams. Through thermodynamic calculations and smallscale experiments with pure metal oxides and sulfates, it has been proven that the metal chlorides AlCl3∙ 6H2O, FeCl3∙ 6H2O, and MgCl2∙ 6H2O are viable and effective reactants for chlorination. In trials with actual industrial iron precipitation residues from the zinc industry, especially, the use of MgCl2∙ 6H2O and FeCl3∙ 6H2O leads to high extraction rates for the investigated valuable metals Ag, Au, Bi, Cu, In, Pb, Sn, and Zn.

Nov 14, 2023

By Turker Hudaverdi, Yasar Agan

This study tries to predict blast-induced flyrock using intelligent modelling techniques. Flyrock is a site-specific phenomenon. Design variables and rock properties highly influence flyrock throw distance. Site investigations were conducted in a sandstone quarry. Fundamental operational parameters, blast dimensions, bench face condition, and rock mass structure were monitored. Stepwise regression technique was applied for variable selection. Burden–hole diameter ratio, in situ block size, and powder factor were determined as the most significant parameters. Considering output of stepwise regression, artificial neural network, ANFIS, and Gaussian process regression techniques were applied to predict flyrock throw. A comprehensive validation was performed using twelve different performance indices. Pre-determination of input parameters supported development of successful soft computing applications. Rock block size was found to be an appropriate input variable for flyrock modelling. In addition to classical performance indices, standardized and symmetric accuracy metrics were quite useful in model validation process. The intelligent models predict flyrock range with an error less than 6 m. The mean percentage errors are lower than 10%. ANFIS seems to be the best model for flyrock prediction. The calculated mean absolute error is 5.36 for ANFIS model.

Nov 12, 2023

By Arman Hazrathosseini, Ali Moradi Afrapoli

Fleet management systems (FMSs) as the pivotal part of any surface mining operation find it essential to evolve from conventional into intelligent systems because of both Mining 4.0 requirements and some shortcomings inherent in conventional methods. However, this novel transformation needs to be investigated technically and strategically. To this end, the previously published research works on intelligent FMSs are explored to track the latest status of these third generation frameworks within the surface mining context. Following that, their underlying models are compared in terms of five categories of allocation and dispatching features to pinpoint the technical gaps ignored. Having drawn the future lines of research, the present article then leverages the popular SWOT analysis method to outline the strengths, weaknesses, opportunities, and threats associated with the advent of these intelligent FMSs in mines of future. By and large, the analysis indicates that advantages outweigh disadvantages. Solutions are offered to address the existing weaknesses and threats.

Nov 10, 2023

By Jodie Robertson, Isabel Barton, Cristian Caro

Prior to mining, all rocks contained in a mineral deposit must be placed in one of several categories known as ore types. Each ore type describes a different way that the rock will behave in processing. The ore type determines which process stream a particular mined unit will be sent to, sets expectations for process engineers and metallurgists, and forms the basis for recovery predictions and production estimates. At first, ore types are assigned mainly by geologists based on visible geological criteria (dominant ore mineralogy, estimated grade, rock type, alteration type). As metallurgical tests are carried out and process data accumulate, the resulting criteria may be factored into the ore typing process, typically as assays and recoverable metal using the relevant process(es). Other variables may also be incorporated into ore typing at operations if they are particularly important, such as grindability, preg-robbing, gangue reagent consumption, and the presence of especially deleterious minerals such as talc or smectite. The mine operation department may also redefine ore types and/or process destinations based on economic criteria. A “best” ore type is designated that (in theory) best describes how the rock will behave in processing. Codes representing this ore type are entered into the drill hole database, then interpreted on cross sections and level plans, and finally added to the block model. Ore types are iteratively reexamined and adjusted over the life of a project. Major difficulties in effective ore typing are (1) lack of communication between geologists and metallurgists, (2) the imprecision inherent in imposing clean categories on messy natural systems without discrete divisions, (3) the need for ore types to provide useful information for a wide range of processes, (4) difficulties in scaling up laboratory test results to mine production, and (5) conflict among geological, metallurgical, and economic criteria for ore typing.

Nov 8, 2023

By Dairo E. Chaverra, Carlos Argumedo‑Jimenez, Oscar J. Restrepo‑Baena

This paper presents the results obtained by processing a gold and silver telluride mineral concentrate from a mine in Colombia. An acid wash, also known as acidification, was carried out, followed by oxidation with nitric acid as a pretreatment. Cyanidations of the pretreatment residues were carried out and the results were compared with results from cyanidations of base materials. The removal of carbonates in the acidification, a tellurium extraction close to 90% during the pretreatment, and a 30% improvement in the gold recovery compared to the conventional process were achieved.

Nov 8, 2023

By V. A. Leão, V. S. Coimbra, V. A. A. Oliveira, R. F. M. de Souza, G. M. de Lima

A willemite concentrate consisting mainly of willemite (55.3%) and dolomite (15.6%) was reduced in a tube furnace with charcoal as reductant. The effects of temperature and varying reductant additions on zinc extraction were studied. A zinc recovery of 86% was achieved with 20% reductant in the charge at 1100°C. During reduction, the calcium oxide generated through calcination of the dolomite promoted decomposition of the willemite, thus lowering the temperature at which reduction took place. The presence of CaO improved the zinc recovery at all temperatures studied. The best zinc recovery (93%) was obtained in the presence of 5% CaO, 20% charcoal reductant, and at a temperature of 1100°C. The results show that the willemite concentrate studied has great potential to be used as a raw material for the Waelz process.

Nov 6, 2023

By N. Mashaba, D. Botha

The aims of this study were to investigate the factors that influence women’s engagement in technical positions in the South African mining sector and to determine what could be done to promote their successful participation. A convergent parallel mixed-methods research design was used to ascertain the factors that facilitate, inhibit, and influence engagement. In the quantitative phase of the study, questionnaires were circulated to women employeees; and in the qualitative phase, semistructured interviews were conducted with employer representatives, most of whom were human resource personnel. Confirmatory factor analysis showed that the three-factor structure (vigour, dedication, and absorption) of the Utrecht Work Engagement Scale fit the sample data reasonably well. Although there is room for improvement, respondents demonstrated acceptable levels of engagement in their work. On the other hand, the qualitative findings showed that employee engagement is impacted by unfavourable working conditions, work–life balance, and the mining industry’s male-dominated work culture. The findings showed that employee engagement should be elevated to a core human resource function. To increase the participation of women in mining, human resource professionals are encouraged to collaborate with mine supervisors, managers, and employees to develop programmes that promote employees’ absorption in and dedication to their work.

Nov 6, 2023