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By Rolland L. Blake

The Bureau of Mines investigated the mineralogy, tonnage, and beneficiating characteristics of oxidized (nonmagnetic) taconite iron resources of the Western Mesabi Range as part of its program to insure adequate future domestic mineral supplies. Magnetic taconite currently provides about 95 pct of Mesabi production, but the large tonnages of oxidized taconite between the magnetic deposits will be needed to help meet future domestic demand for iron ore. Three bulk samples that represent large tonnages from the Western Mesabi Range were selected to determine their mineral composition and liberation by light optical microscopy and to test their beneficiating response. This report describes the mineralogy and liberation characteristics of the three samples of the Biwabik Iron-Formation for 26.5 mi (42.7 kID) from Keewatin to Grand Rapids, MN. (Details of response to beneficia-tion were reported previously.) The samples represent mostly material from the Lower Cherty Member of the Biwabik-Iron Formation, although one sample included some Upper Cherty Member. Minerals of all three samples were quartz (chert), hematite, goethite, and minor to trace amounts of magnetite, iron carbonate, and iron silicates. It was concluded that the oxidized taconites of the Western Mesabi Range represent a subeconomic indicated resource that can be selectively mined and beneficiated as a future large source of iron feed for steelmaking.

Jan 1, 1983

By Kristine L. Pankow, Keith D. Koper, Michael K. McCarter, Jared R. Stein

"The Wasatch Plateau region of central Utah contains a number of active underground coal mines in an area of well-documented natural seismicity. As a result, there are several hundred seismic events recorded in this region every year that may or may not be attributed directly to mining activity. Previous studies have linked the majority of this seismicity to mining activity through various means, but have not attempted to develop a method for categorizing individual events within a seismicity catalog. This study uses both relative relocation and waveform cross-correlation to separate events based on hypocentral depth and waveform similarity, respectively, in the area surrounding a single longwall coal mine within the Wasatch Plateau. We conclude that relative relocation can help with depth discrimination, but there are some unavoidable limitations caused by sparse seismic network coverage. The cross-correlation technique is more promising, with the ability to group events by waveform similarity and track mining progress over both space and time. With cross-correlation based clustering, we confirm that the vast majority (97.6%) of events in the study area are directly related to mining activity, but that a small population of natural seismicity is present as well. Eliminating this natural seismicity from the catalog of seismic events, leaving only those events related to mining, can give operators valuable information about the changing conditions as mining progresses and eliminate concern over events unrelated to mining activity.INTRODUCTIONA number of underground coal mines are located in the Wasatch Plateau region of central Utah, and have been in operation since the late 1800s. This activity has resulted in a well-known history of mining induced seismicity (MIS) (Wong, 1985). Additionally, this area is situated near the border of the Basin and Range and Colorado Plateau physiographic provinces, where naturally occurring tectonic earthquakes also occur (Arabasz et al, 1980). Seismicity separating these physiographic provinces is part of a larger band of seismic activity known as the Intermountain Seismic Belt (ISB) that runs from Montana to Arizona and cuts through the western boundary of the central Utah coalfields (Smith and Arabasz, 1991) (Figure 1)."

Jan 1, 2015

By G. Scamans, J. Lazaro-Nebreda, Z. Fan, J. B. Patel

"Melt quality is crucial for both continuous and shape casting of light alloys and in order to improve it, removal of excessive inclusions, accumulated impurities and unwanted gases becomes necessary. To address this problem, a new multi-purpose high shear liquid metal treatment technology, based on intensive melt shearing by a rotor/stator unit, has been developed. The device ensures achieving uniform temperature and chemical composition and an efficient dispersion of gas and solid phases in the melt with minimal disturbance of melt surface, and can be used, among other things, for de-gassing and de-ironing of Al-alloy melts. Efficient degassing is achieved by dispersing each argon bubble into many small ones, which significantly increases the overall surface area of the bubbles and the time they remain in the melt capturing hydrogen before reaching the surface. This allows using much lower inert gas flow and mixing times than conventional rotary degassing. When applied to Al-alloy scrap, with accumulated iron, the high shear melt treatment speeds up the nucleation and growth of primary Fe-rich intermetallic particles, allowing a faster removal rate. Therefore it reduces processing times, increasing recycling productivity, and facilitates full metal circulation of secondary Al-alloys.INTRODUCTION Aluminium and magnesium alloys are widely considered in various industrial sectors for the purpose of weight saving (Polmear, 1995). In particular, they are used in the automotive sector, where components are mostly manufactured by high pressure die casting (HPDC) because of its simplicity and relatively low cost, but efficiency and mechanical properties are quite low compared with other processes. To date, the main focus to overcome this problem has been for improving the HPDC machinery (Dahle, 2001) but little attention has been paid to the opportunities of controlling the nature and quality of the molten metal supplied to the die. In this way, liquid metal treatment, which involves a variety of physical and/or chemical processing methods to improve melt quality prior casting, is crucial for both continuous and shape casting products."

Jan 1, 2018

By K. S. Gritton

The U.S. Bureau of Mines has investigated methods for extracting metals from a variety of arsenic-containing smelter flue dusts. One proposed flowsheet includes a sulfuric acid leach, a cooling step to precipitate hydrated copper sulfate, and a reduction-precipitation of As2O3. Arsenic extractions greater than 90 pct were achieved, while copper extraction ranged from 50 to 85 pct under the conditions examined. Copper was removed from the leach solutions by crystallization followed by SO2 precipitation of arsenic which resulted in a 98 to 99.9 pct As2O3 product. Other metals, such as lead and zinc, were concentrated in the leach residue or in other byproduct streams for recovery of their valuable metal contents.

Jan 1, 1990

By Brian Hart, Liuyin Xia, Staman Dimov

The recovery of rare earth elements (REE) is fast becoming of significant interest globally. Modern research and development programs (outside China) towards the optimization of REE mineral recovery by flotation have been lacking. Due to the mineralogical nature of many hosting deposits, the separation and recovery flotation flowsheets can be very complex. As part of a research project, a selected suite of hydroxamic acid collectors (Naphthoyl, Cyclohexyl, Benzoyl, Octyl, Terta-butyl benzoyl, Salicylic) were tested in order to examine their potential for recovery and selectivity. Micro flotation tests were conducted on a feed sample, recovery and grade of the products were used to evaluate their relative flotation efficiency and selectivity and these results (flotation with the hydroxamate collectors) were compared to a phosphoric acid/sulphonate collector mix(shorten as "mixed"). In the testing, the flotation response with the hydroxamate collectors was significantly better than the "mixed" collectors on freshly ground (no slimes removed) samples. Furthermore the tests revealed that for most of the hydroxamate reagents tested, their dosage requirements to achieve recoveries at the same levels was less than that for the "mixed" reagents. Product assays show that recovery of both La and Ce is significantly better for using the salicylic hydroxamate and that Nb, Y and Zr recovery are favored by using octyl hydroxamate. These results indicate mineral flotation selectivity could be achieved by using selective hydroxamtes. Spectral fingerprinting by TOF-SIMS surface analysis has allowed for the identification of reagent species. TOF-SIMS surface analyses of grains analysis confirmed that REE bearing grains reporting to the concentrates are doing so in response to collector attachment whereas grains reporting to the tails are doing so in response to a lack of collector. The TOF-SIMS surface data bas been used to examine the factors promoting flotation stream partitioning.

Jan 1, 2014

By K. R. Griffin

New and developing communication systems enable underground miners to not only connect to the surface from an increased communication coverage area but also to be discovered in the event of an emergency. Communication and tracking systems are required by MSHA regulations, aiming to enhance health and safety and routine production in underground operations. Modeling a mine?s potential communication coverage area will increase overall coverage and efficiency of the communication network itself. Modeling the propagation of wireless communications enables ideal broadcast locations to be found when designing a communications network. Strategic placement of broadcast devices results in a reliable communication network that can better withstand disruption in both daily operation and emergencies. This paper will discuss recent regulatory developments in underground coal communication systems, the implementation of these new technologies, and how communication system?s networks can be modeled and analyzed using computer simulations.

Jan 1, 2010

By George J. Tamara

The urban environment presents special challenges for the design and construction of earth retention systems. Complications arising from difficult subsurface conditions are compounded by the presence of urban infrastructure and existing and prior construction. The proximity of adjacent structures as well as intense prior use can cause special concerns including the potential for archeological artifacts or contaminated ground or ground water. Utilities and structures may be particularly vulnerable to the effects of ground movement, dewatering and vibrations. Difficulty of access, congestion and limited work areas may severely restrict means and methods of construction. Dewatering may be limited or prohibited because of concerns for disposal of clean or contaminated water, depletion of aquifers, drawing of contaminants to the site or dewatering induced settlements.

Jan 1, 2003

By Jordi Vives-Costa, J. J. de Felipe, Lluís Sanmiquel, Maria Niubó

The article evaluates the convective heat transfer coefficient of ventilation air in a potash mine. The energy balance is obtained through thermal characterization of the ventilation air and rock, allowing for the calculation of heat transfer parameters. Different models for calculating the convective heat transfer coefficient are analyzed. The results indicate that the Pethukov–Kirilov, Gnielinski, and modified Dittus–Boelter models are optimal for this mine. The study also indirectly examines the conductivity of the adjacent rock, suggesting saturation throughout the studied section and the presence of liquid water upwelling in a specific section.

Apr 7, 2022

By Osvaldo A. Bascur, J. Pat Kennedy

"The profitability of mining and metallurgical operations continues to lag behind that of other industries despite the technical advances that have occurred in recent years. A primary reason for poor performing in this economic sector is the lack of integration of mining and metallurgical information. The mine cut-off grade can be optimized if mining and metallurgical engineers have the data to optimize milling for the type of ore in hand.Integration of mine transactions, stockpile inventories, process flows and assays is the key to determining the economics for each blast strategy in a mining site. Real-time information from manufacturing assets greatly affects the profitability and flexibility of a company, but gross errors from faulty sensors, inaccurate instrument calibration, or incorrect process models may corrupt actionable information. New software tools can model the process, sift through available data to identify and eliminate gross errors, and use statistical data reconciliation to create materially balanced and consistent readings. The reconciled data is unified for use by both monitoring and decision making processes.Creating a real-time information environment where upgrade and change are allowed is becoming an accepted methodology to accelerate and simplify the integration of applications such as production monitoring, equipment performance management and yield and inventory management.This paper describes the data integration requirements in a mine, concentrator and port for unification of the redundant data. The capture of the mining events, stock pile management and the metallurgical information is the base requirements for a dynamic environment to reduce the overwhelming amount of information to unified set of information. Part of any decision support program should entail these results to continuously improve the measurement system to address the costs in mine and milling the ore."

Jan 1, 2003

By W. J. Wiehagen

The Work Crew Performance Model (WCPM) seeks to define performance variability within similar tasks of an underground work crew and relate observed variability to a cost consequence. Performance variability is described using work site observations to determine the adherence to job elements con¬tained within a standard operating procedure. Key components of the WCPM include (1) job definition through task analyses and the ranking of job elements by perceived cost consequence, (2) observational techniques for establishing performance baselines by measuring adherence to safe and proficient job procedures, and (3) cost linkages between adherence to task procedures and measures of consequence for noncompliance. Data presented within this report were obtained through the study of shuttle car operation in an underground mine in Appalachia. Observed adherence to safe and proficient job procedures by opera¬tors matched well with the consensus profiles (measured through a nominal group technique) with min¬ing personnel. It was also found that experienced operators consistently outperformed less experienced, incidental operators. These findings imply potential use of the WCPM as a practical procedure for thinking systematically about the choices available to reduce performance variability. Field application of the model can offer useful data to evaluate training and financially support performance improvement strategies that can be tested for their ability to reduce human error.

Jan 1, 1994

By Jim A. King

The total pressure oxidation of copper concentrates is a potentially viable option for treating copper concentrates that are either low grade or contain significant impurities. Both concentrate types are heavily penalized in smelter contracts. The total pressure oxidation process involves autoclaving the copper concentrate at temperatures of 200-220 C under oxygen pressure. The autoclave discharge can be separated into a solid (oxidation residue) and a liquid (oxidation solution) product. The oxidation solution can be treated for copper recovery by solvent extraction - electrowinning or by direct electrowinning. The direct electrowinning recovery of copper requires prior removal of selenium and tellurium by cementation on finely divided scrap copper. The oxidation residue is washed thoroughly to remove acid and dissolved copper prior to precious metals recovery by conventional cyanidation in the presence of lime. The results of a benchscale investigation involving a number of copper concentrates are reported. Copper recoveries in autoclave oxidation and gold recoveries by cyanidation of the oxidation residue exceeded 99%. The results of benchscale experiments to demonstrate copper recovery are described. Various flowsheet options are presented.

Jan 1, 1993

By Charles E. Michener

This paper deals with the occurrence of basic and ultrabasic rocks and their relationship in space and time to major structures of the earth. In order to introduce the paper properly, I must go back a little and try to put the subject in perspective. In the brief time that geology has been a scientific occupation, ore deposits have been grouped and classified in various ways depending on the theories that happened to be popular at the time. Some of the early scientists said that ore came from fire, other schools argued that ore originated from water. Then came the lateral secretionists and in later years the hydrothermalists led by the Lindgren school and the latter has largely been accepted as the modern concept of ore deposits. It now seems apparent that the hydrothermal school is being seriously challenged by other schools of thought. It also seems that we have reached the point where we should be willing to admit that we do not really know in most cases how the ore got to its present position. However, for practical purposes, we can classify ore deposits as to the environment in which they do occur. This is not difficult and gives the field geologist and the mining engineer something to work with and to believe in, and it gives them a basis for carrying out their field work. On the screen, Figure 1, there is a classification of ore deposits based on the environment. Under each classification is listed the more prominent metals which are characteristic of that

Jan 1, 1971

By J R. Barber, B. E. Rogers, R. Fukuzawa

Mercury is sometimes present in non-ferrous ores including gold, zinc, copper and lead. The selection and use of appropriate mercury abatement technology is critical for preventing its release to the environment during ore processing and to protect workers from mercury exposure. This paper presents a general decision-making process for mercury abatement technology selection for major emission sources in the gold industry. Mercury abatement can be accomplished through making process changes and/or by adding a process step to an existing system (i.e. "end-of-pipe control"). Advantages and limitations of the technologies along with waste / by-product management options are discussed through case studies of current operating mercury abatement systems.

Jan 1, 2015

Avoca Resources LimitedÆs Higginsville Gold Project has a resource base of over 1 300 000 oz of gold. The Trident underground mine, which forms the basis of the project development, has a resource base of 927 000 oz of gold. Avoca is building the Higginsville Gold Project based on a minimum ten year vision, producing over 150 000 oz per annum. The project development has taken less than three years from the Trident discovery hole in October 2004 to the first ore production in June 2007. This paper discusses the background work associated with the development of the Trident underground mine in a difficult period for new project development in Western Australia. The resources boom, led by the iron ore industry in the Western Australian Pilbara region, is creating cost pressures and, combined with a lack of people and equipment, is placing cost and timing stress on a small developing project. Avoca Resources has developed a project execution management strategy aimed at mitigating cost blow outs and schedule delays.

Jan 1, 2008

By I Canbulat, J Oh, A Mcquillan, D Payne

This paper presents a new risk assessment tool for coal mine excavated slopes. This new empirical-statistical Slope Stability Assessment Methodology (SSAM) is intended for use by geotechnical engineers at both the design review and operational stages of a mine’s life to categorise the risk of an excavated coal mine slope. A likelihood of failure is determined using a new slope stability classification system for excavated coal mine slopes developed using a database of 119 intact and failed case studies sourced from open cut coal mines in Australia. Consequence of failure is based on slope height and stand-off distance at the toe of the excavated slope. Results are presented in a new risk matrix, with slope risk being divided into low, medium and high categories. The SSAM is put forward as a new risk assessment tool to assess the potential for, and consequence of, excavated coal mine slope failure. Unlike existing classification systems, assumptions about the likely failure mode or mechanism are not required. Instead, the SSAM applies an approach which compares the conditions present within the excavated slope face, with the known past performance of slopes with similar geotechnical and geometrical conditions, to estimate the slope’s propensity for failure. The SSAM is novel in that it considers the depositional history of strata in an excavated slope and how this sequence affects slope stability. It is further novel in that it does not require explicit measurements of intact rock, rock mass and/or defect strength to rapidly calculate a slope’s likelihood of failure and overall risk. Ratings can be determined entirely from visual observations of the excavated slope face. The new SSAM is designed to be used in conjunction with existing slope stability assessment tools. CITATION:Mcquillan, A, Canbulat, I, Payne, D and Oh, J, 2018. New risk assessment method for coal mine excavated slopes, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 473–495 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By J. A. Sweet

The issues facing graduate training in the mineral processing industry are not too different today from those that prompted the initiation of the Anglo American Platinum Graduate Development Programme (AGDP) in 2002. Graduate metallurgists in South Africa enter the industry from different undergraduate programmes at various tertiary institutions, and so the knowledge and skills of the young graduates varies. Further, the geographical expansion of the industry combined with the downsizing of business units means that there are fewer opportunities for young graduates to be mentored through their first few years on site. Anglo American Platinum chose to address these issues by implementing an intensive, structured graduate training programme for all their new metallurgical graduates, known as the AGDP. The first two years of experience of the AGDP, from the viewpoints of both graduates and lecturers, were presented to the mineral processing community at the IMPC in Turkey in 2006 (Sweet et al, 2006). From the beginning, the programme was structured in a modular fashion to include a basic technical ?toolbox? including statistics, the scientific method and sampling protocols, while the mineral processing content comprised advanced learning in comminution, classification and flotation (later extended to include hydrometallurgy). Technical communication ? both written and verbal ? was included from the start. The programme was focussed very strongly on site work (?learning by doing?), with a major integrated site campaign conducted and analysed by each cohort. In 2012 the AGDP will accept its ninth cohort into the programme. This paper describes how Anglo American Platinum and the University of Cape Town have developed and adapted the programme over the last few years, in response to the challenges of the global recession, skills retention, and the changing operational needs of the company. The programme, which was drawn up to accommodate around 15 concentrator-only graduates, now accommodates 35-40 concentrator, smelter and refinery graduates annually. The programme has also been modified to facilitate new graduates spending most of their first year on the operations. The benefits of the programme for Anglo American Platinum have been tangible, and will be discussed in the paper. Keywords: graduate training, technology transfer

Sep 1, 2012

By J Harris, P Kirsch, R LaBouchardiere

æMining + Health in DevelopmentÆ is a project funded by the International Mining for Development Centre (IM4DC, 2012) to develop a centralised database of corporate sustainability initiatives for managing and improving occupational and public health, based on information extracted from social and environmental reports of major mining, oil and gas (MOG) companies. This register of materials has the potential to increase stakeholder awareness of the unique health risks impacting the minerals industry, employees, their families and surrounding communities, as well as to inform stakeholders on global industry approaches to health management.Data and preliminary outcomes from analysis of different MOG corporate sustainability reports on public health and disease management are presented for six African countries (Democratic Republic of Congo, Ghana, Mozambique, Sudan, Tanzania and Zimbabwe) and six Asia-Pacific countries (Indonesia, Mongolia, Pakistan, Papua New Guinea, Philippines and Vietnam).With the minerals industry facing ongoing rapid growth worldwide, including continuous expansion into developing regions, the æMining+Health in DevelopmentÆ project will inform industry, civil society and regulators of current health management practices and programming among the different sectors of the minerals, oil and gas industries and across various regional operations. This baseline information will serve as a resource for minerals industry managers, providing a forum for sharing best practice health management approaches amongst MOG companies.CITATION:LaBouchardiere, R, Harris, J and Kirsch, P, 2012. Mining and health in development - An inventory of global resource industry health initiatives in developing countries, in Proceedings International Mine Management 2012, pp 75-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Francis Martino

Just as coal producing mines are faced with various handicaps which control the quantity of coal produced and sold, the subsequent user of that product is faced with parameters that impact the optimum utilization of coal. Traditionally, the industry focused on the quantity of mineable coal in a reserve. The mine planning development was primarily concerned with two important criteria: (1) safety and (2) the productive efficiency in a quest to produce the lowest cost coal.

Jan 1, 1982

By V. A. Chanturiya

There is an obvious disproportion in Russia gold-mining industry between the structure of gold reserves and the gold-mining techniques. The bulk of gold (over 70%) is extracted from alluvial deposit, 20%~25% from bedrock occurrences and 5%~7% from complex copper-zinc and polymetallic ores. The proved gold-bearing reserves are distributed as follows: alluvial ?19%, bedrock ?80%, the latter being sufficient to supply gold at the current production level for 100 years to come. In Russia, like elsewhere in the world, development of primary gold deposits is considered a first-priority line of development for gold-mining industry. Most of the gold-containing ores characteristic of Russian gold deposits are resistant ores with gold content varying between 3 ppm and 5 ppm usually showing quite low gold and silver recovery by cyanidation. Processing resistance of gold-containing mineral complexes is related to the presence of gold particles of submicrometric (<1.0 µm) and nanometric (10~100 nm) size, mostly asso-ciated with pyrite and arsenopyrite. Therefore switching over to processing bedrock entails a num-ber of technological problems that stem from chemical and physical resistivity of ores. The chemical resistivity can be overcome through flotation, oxidation roasting, autoclave leaching (biohydro-metallurgical oxidation), etc. The physical resistivity can be dealt with by resorting to traditional power-intensive methods,e.g. grinding to a ?40µm size, thermal treatments of sulphide concentrates and non-traditional high-energy methods of liberating the sulphides by means of power attack, e.g. electro-chemical oxidation, exposure to electron beam radiation and other methods. The modern non-traditional processes for treatment of rebellious noble metal-bearing ore, aimed at improving disintegration efficiency for finely dispersed mineral complexes are analysed. Advantages and perspectives of a new high-efficient, energy-saving and ecologically safe process of the nanosecond high-power electromagnetic pulses (HPEMP) effect are proved. The said process provides a stable increase in the valuable component recovery at lower energy consumption and production costs of the finite product at the stage of dressing rebellious gold-bearing ores and concentrated products. The experimental data prove high efficiency of the preliminary impulse treatment, thus, the increase in the gold recovery at the cyanidation stage amounted to 4%~12% from rebel-lious ores, 10%~30% from gravity concentrates, 5%~45% from flotation concentrates, 30%~80% from oil flotation tailings.

Jan 1, 2014

By J. Castaneda, J. Schmidt

"INTRODUCTION Chino is an open-pit copper mining complex faced with intricate material routing requirements. Historically, this was challenging at the mine, in part because the shovel dig plan, haul plan, and dump plan were prepared completely separately. The mine now uses an integrated workflow for faster evaluation of schedules, which facilitates preparing balanced cutoff grade-to-equipment requirements, supports better mineral production, and improves schedule viability, while considering operational implications. Located in the state of New Mexico, Chino is one of nine Freeport-McMoRan mining operations in North America. This presentation discusses the benefits of implementing an integrated approach to tactical mine planning, and shares practical examples that were learned as Chino implemented an integrated tactical planning method. This includes improvements in completion time for preparing a schedule, minimal risk from manipulating Excel macros, data integration required to make short-term planning decisions, and better understanding of the mine plan’s effect in relation to the business’s key performance indicators. Ultimately, the integrated approach to tactical mine planning at Chino has led to production forecasts which are more achievable and reduced planning and execution variance. PROJECT OVERVIEW Chino mine is a porphyry copper deposit wholly owned by Freeport-McMoRan, the largest publicly traded copper producer in the world. Chino mine is located in Grant County, New Mexico, a short distance east of Silver City. Ore material mined from the pit today includes oxides, primary sulfides, and secondary sulfides. The mineralized material is sent to a mill, with a rated throughput of 42,000 tons per day, or to ROM leach pads with variable dumping capacities. At Chino, the short-range objective is to maximize total copper pounds sent to the mill, but no fixed cutoff grade accomplishes this for all periods. Instead, 12 different material classifications, including four sulfide classes that can feed either the mill or other destinations, and 38 cutoff bins, are aligned with the needs from operations, leaching, and the concentrator to create a schedule. Cutoffs vary from one week to another to cope with a highly intermittent ore body."

Jan 1, 2018