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By R-H Yoon

The MicrocelTM column flotation technology has been developed based on the fundamental understanding that the first-order flotation rate constant increases approximately as the inverse cube of bubble size. In this technology, bubbles in the range of 100-400 pm are generated by pumping aerated slurry through an in-line static mixer. The high-shear agitation provided by the in-line mixer produces small air bubbles without requiring large frother additions. This column has been tested successfully for processing a variety of non-metallic minerals including kaolin clay, graphite, phosphate, and feldspar.

Jan 1, 1993

By Yakup Cebeci, Leyla Kalender, Ceylan Yarluğkal Altınışık, Hikmet Sis

The abstract highlights the challenges in concentrating complex and non-sulfide lead-zinc ores and emphasizes the importance of froth flotation for their beneficiation. The study focuses on using process mineralogy to understand the flotation behavior of these ores from the Görgü region. The ore samples were characterized using various techniques, revealing oxidation and carbonation of primary minerals. The flotation results were interpreted in light of the mineralogical data, explaining the poor outcomes due to the complex nature of the ore, poor liberation, and lack of hydrophobicity.

Mar 22, 2022

By Dru Brown

More than 150 Mt (165 million st) of material crashed down at the Bingham Canyon Mine (Rio Tinto/Kennecott Utah Copper) near Salt Lake City, UT on April 10, 2013. The mine, one of the largest openpit mines in the world, ceased operations and evacuated personnel prior to the slide when it was discovered that material was moving at a rate of 5 cm/d (2 in./day). The slide destroyed the mine?s visitor?s center, buried several pieces of large mining equipment and severely hampered production. The Kennecott Utah Copper Corp. immediately began to assess the damage and look for options to reestablish operations. The highly unstable ground ? emphasized by another minor slide in September 2013 ? makes any cleanup efforts extremely dangerous. With terrain too dangerous for human operators, Kennecott was forced to look for alternatives that would help the company work on the treacherous slopes of the landslide while also keeping personnel safe.

Jan 1, 2014

By João F. C. L. Costa, Vanessa C. Koppe, Clayton V. Deutsch, Marcel A. A. Bassani, Pedro H. A. Campos

Blending inevitably occurs to some degree during mining and mineral processing operations. Traditional mine scheduling assumes that all variables average linearly, which allows the calculation of the blended material properties as a linear weighted average. However, metallurgical properties such as metal recovery and Bond Work Index (BWI) are known to average nonlinearly. The nonlinear properties of the blended material can be calculated using nonlinear blending models. A simulated annealing algorithm is developed and applied to a short‐term mining face optimization problem to maximize the total metal recovered considering nonlinear blending. Compared to a standard schedule plan, the optimized one shows relevant improvements in synergistic and antagonistic blending behaviors.

Jun 25, 2023

By C. Roos

"Nearly every input to a mine plan is based on an estimate. The estimates may be from sample data, historical information, models, or personal opinion, but in all cases, these values are simply expected values (means). In real life, we do not get to iterate the exact conditions at our mining operation many times to ensure that that average value is attained. The expected value also tells us nothing about the spread of values that that input might take on. The result is a significant amount of unquantified uncertainty in our mine plans. Unfortunately, it is often too expensive or time consuming to update planning processes and software. This paper presents a proof of concept spreadsheet scheduling tool that can be utilized to incorporate many geologic realizations (simulated models) into the mine scheduling process. While this POC is not intended to be a detailed model of uncertainty, it is to show that there are stepping stones available for mine planners to begin to embrace uncertainty and produce more achievable plans without requiring a significant change in their planning process. INTRODUCTION Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years, however many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize and even embrace the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process. Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple ore body realizations to provide a thorough unbiased “picture” of the geologic uncertainty but most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter. Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this paper presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid to long-term mine plans while continuously monitoring the uncertainty in the results. The author hopes that by demonstrating the usefulness of such a system that mining companies will encourage engineers, geologists, and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 1, 2017

By R. E. Mclvor

This is an update of an original dissertation on this topic by Lavallee, McIvor and Stolovitch (1992). A step-by-step, technical procedure used to measure and improve the performance of plant grinding circuits was adapted into a training program. ?Systematic Design of Instruction? was applied to: ? Determine if training was a suitable way to deliver this new technology; ? Define the technical content of the program; ? Select program specifications based on learner and context characteristics; ? Design, create and test prototypes of the training modules; and, ? Establish a process for plant implementation. The training program covers numerous skills that are extremely valuable for plant personnel, not only in the grinding area, but also for many other parts of the plant. This paper describes how new skills are brought into the workplace through designed instruction can be an effective alternative to hiring during severe skilled labor shortages.

Jan 1, 2008

By L. A. Garfield

Since the start of mining operations at White Pine in 1953, over 22 miles of drifts have been driven for the purpose of developing the ore body. The drifts, normally driven in multiples of three or five headings, serve as conveyor belt routes, ventilation ducts, equipment and haulage roads, and initial access to mining blocks. Development openings in the flat-lying, bedded ore body are driven in rectangular section from 16 to 32 feet wide and from 8. 5 to 16 feet high. The floor level normally coincides with the bottom limit of the chalcocite values and the roof or back is carried at the most competent stratum adjacent to the top of the ore. A development front consisting of five headings and associated crosscuts is advanced at an average rate of about 100 feet per month using conventional drill and blast techniques and equipment. The cyclic nature of the functions involved in driving the openings and the need to include them in production schedules preclude significant improvements in advance rates using current drill, blast, muck, and haul sequencing.

Jan 1, 1969

By Alvaro Veizaga, Samuel Cuellar

In recent years, Industry 4.0 has generated a change in the way companies in various industrial sectors design, produce and deliver products and services, and is focused on the interconnection of systems, the advanced access and management of large amounts of data in real time, and the implementation of emerging technologies such as the Internet of Things (IoT). Artificial intelligence (AI), machine learning (ML), digital twins (DT), robotics, virtual and augmented reality (VR/AR), among others [1]. DTs are accurate and dynamic virtual models that replicate physical systems, where it is possible to simulate and optimize operations before implementing real-world changes [3]. These features make it possible to reduce investment costs, minimize risks and improve strategic decision-making. These benefits are of utmost importance for tailings storage facilities (TSF), since they are facilities aimed at the safe storage of tailings and with the constant need for growth [4]. This paper evaluates the applicability of a DT in a TSF from a conceptual perspective, providing the advantages of its implementation, but also the barriers identified in the industry based on the authors’ experience.

Feb 1, 2025

By R. A. Lowe

Smectite is a common impurity in the kaolins of Georgia. This impurity is harmful to the low-shear rheology of kaolin slurries in concentrations as low as a few weight percent. The deleterious effect of smectite on the low-shear rheology is due to the swelling of the mineral. Montmorillonite containing clays were treated to precipitate a compact brucite layer {Mg(OH)2} in the interlayer region of the expandable layer silicate mineral. This treatment forms a hydroxy-Mg-montmorillonite with characteristics similar to chlorite. This treatment effectively reduces the swelling capacity of the mineral and improves the rheological properties of kaolin slurries contaminated with smectite impurities.

Jan 1, 1999

By Claude Froger

The compared advantages of digital and analogue computers for solving ventilation problems have for many years been a matter of discussion among the specialists whose respective arguments have prevailed in turn depending on the progress of technology. In the French coal mines however none of these two techniques has superseded the other so far. In France, between 1956 and 1962 only the digital computer and from 1962 to 1967 only the analogue computer was used. Since then they are both used concurrently and complementarily. Depending on the problems dealt with, the most advantageous method is chosen in each case. In the case of ventilation planning for projected workings, it is possible to test variant forms of the development plans and many parameters can be varied. In such a case the flexibility of the analogue computer is a great help. Wrong lines taken will be rapidly abandoned and little by little solutions will be found. By examining the results of a test, new ideas will generally come into the mind and they can be tested right away. Such an investigation is always-carried out in conjunction with the engineers of the mine concerned. In complex networks it often leads to solu¬tions which could not have been devised from the start. The same work could be done by using a numerical method and the digital computers operating in the different coal mine districts, but for the same tests, the time required would be much longer and the participants would not be encouraged to use their imagination so intensively. Or the other hand for calculations of ventilation networks in ventilation surveying, use is made of the digital computer which gives the possibility of storing the data corresponding to the different mines concerned. The questions to be solved concern problems for which the ventilation network is essentially known, and in which only a small number of parameters can be varied. The few possible alternatives to be calculated can therefore be handled by the digital computer in spite of the relative lack of flexibility of the method. To sum up our ventilation studies are conducted in France as follows: - For ventilation studies and modifications due to projected workings use is made of the ana¬logue computer. For a given mine the updating of such ventilation studies is carried out every 3 or 5 years according to the progression of the workings. - For ventilation surveying while normal working operations are in progress, use is made of the digital computer.

Jan 1, 1980

By Karoly (Charles) Kocsis, Kyle A. Scalise

Understanding the climatic conditions in underground mines is necessary for efficient ventilation design, cost savings, and to ensure the health and safety of mine workers. Large volumes of ventilation and climatic data including air volume, barometric pressure, dry bulb temperature, and relative humidity were collected at active underground precious metal mines in Nevada, which allows for the determination of wet bulb temperature and other key parameters. Through the utilization of neural networks, the wet bulb temperature at the bottom of the intake shafts is predicted, while taking into account the “thermal flywheel effect” (TFE). Wet bulb temperature is one of the most important climatic parameters to model and understand because it significantly affects the work conditions and the cooling capacity of the ventilating air. The accurate prediction of the dry bulb and the wet bulb temperatures at the bottom of intake shafts is critical when assessing the climatic conditions in future underground mines and deciding onwhether a cooling system is needed to assure adequate working conditions throughout themine. By utilizing accurate predictions of wet bulb temperatures and other climatic parameters, mine personnel will be safer as reported by Bluhm et al. (2003), and a more accurate ventilation design can be achieved resulting in major cost savings for underground mines.

Mar 3, 2021

By D. S. Bird

The Kennecott Utah Copper Modernization Project, initiated in 1986, was directed to provide an expansion and modernization of mining and process facilities at the property's Bingham Canyon Mine and ore concentrators. Major components in the project included installation of an in-pit ore crusher, transfer conveying system, and construction of a new copper ore concentrator with a design capacity basis of 70,000 tonnes/day. The Copperton Concentrator was commissioned in February 1988. A principal feature of the plant is the grinding circuit, comprised of three identical lines, each consisting of a 10.37 m (diameter) by 4.57 m (length) Semi-Autogenous Grinding (SAG) mill and two 5.54 m (diameter) by 8.62 m (length) ball mills. The SAG mills are driven by two variable-speed 9,000 kW DC motors coupled through a clutch-pinion gear-ring gear assembly. The ball mills are driven by 4,125 kW synchronous motors coupled through a typical clutch-pinion gear-ring gear system. The expansion and particularly the Copperton Concentrator performance was so successful that by early 1989, management began examining options to further expand production capacity. With regards to the concentrator, numerous alternatives were considered, ranging from installation of a grinding line similar to one of the existing lines, to a "super" line consisting of a 12.8 meter (diameter) SAG mill and a 20,000 kW motor with a capacity of 50,000 tonnes per day. The technical and economic analysis of the various scenarios indicated that one "large" 11.0 meter (diameter) by 4.88 meter (length) SAG mill with a production capacity of 32,000 tonnes per day and a 12,000 kW drive would be optimum. The key question to be answered in the project was whether to continue with the pinion-ring gear combination, or install a gearless drive. The following paper outlines many of the items that were evaluated in the mill selection process followed by actual plant performance, and a discussion of ongoing plant continuous improvement projects.

Jan 1, 1995

By Carl G. Bock

INTRODUCTION The Washington Metropolitan Area Transit Authority (WMATA) has let a contract for the excavation of three rock stations, spaced about 3550' (1082m) apart, beneath Connecticut Avenue in Washington, D.C. Two previous rock stations have been completed, one of which had a crown pilot tunnel excavated to explore geologic conditions that would be encountered during the station excavation. This pilot tunnel was primarily for inspection by bidders and design was based on core hole information. The other rock station had no pilot tunnel and was also designed on the basis of core hole information. The three rock station areas, which are the subject of this paper, have been explored by crown pilot tunnels and an as-built report, with geologic maps and sections, has been prepared, for use by the design engineer as the basis of design for support of the structures. The geotechnical report describes the geologic structure in detail and relates it to excavation and support of the three crown pilot tunnels and the running tunnels which will be enlarged to create the 58'W x 44'H x 700'(+)L (17.6m x 13.3m x 212m +) stations. The information was complete enough to permit the design engineer to visualize the geologic structure and compute loads for the various types of rock conditions. It was therefore possible to determine the size and spacing of the steel sets for the several different conditions of rock structure encountered in the pilot tunnels.

Jan 1, 1976

By ERIK CHARRIER, ADITYA JUGANDA, Jürgen Brune, Patrick Maier, Gregory E. Bogin Jr

Confined explosions are a major risk in underground coal mine operations. Depending on confinement, ignition location and obstacles in the flame path, methane explosions can transition to detonations. As a result, the severity of mine explosions ranges from minor damage to loss of lives and permanent mine closure. Experimental results have shown that the inclusion of obstacles can significantly increase the flame propagation velocity by inducing turbulence. This research focuses on explosion experiments in a 71 cm diameter, 30.5 m long reactor that includes rock piles as obstacles along with developing the corresponding CFD model that captures the observed flame behavior and interaction with the obstacles. The rock rubble increases the flame front propagation velocity by 500% compared to the maximum velocity observed in the empty reactor experiments. The 2D and 3D CFD models predict the experimental flame front propagation velocity, whereas the 3D model shows a more explicit conformity than the 2D model. Although the computational time to complete the simulation is much less for the 2D model than for the 3D model, the 2D model is not sufficient to simulate cases with rock rubble since it cannot capture the propagation of the flame through the small voids between the rocks with the same effective blockage ratio as the 3D model. The validated CFD model can be scaled up to simulate methane explosions in full scale mine and industrial settings.

Nov 20, 2023

By F. Díaz-Fierros, D. Rubinos, M. T. Barral

The present work explores the reutilization of red mud, an industrial waste arising from the production of alumina, as a component of isolation technologies for hazardous substances. The work involved the study and optimisation of the geotechnical properties of red mud in conjunction with adsorption experiments of As(V) and Hg(II). The results from both types of experiments were integrated in a dispersion-diffusion model to calculate migration curves and minimum thickness of the red mud compacted layer. The geotechnical studies showed that compaction increased the stability and decreased the hydraulic conductivity of red mud barrier. Red mud sorbed high amounts of As (up to 44 mmmol kg-1) and Hg (up to 9.2 mmmol kg-1). The calculated minimum thickness of the red mud barrier was 1-10 cm for As and 2-19 cm for Hg, for an operation period of 35 years. The results obtained let to conclude that the reuse of red mud as a component of isolation systems of hazardous substances represents a viable alternative use of this residue.

Jan 1, 2011

By Lukas Walder, Roland Arnold, Raphael Zuber, Richard Gradnik

This paper presents the construction of the ventilation shaft for the single-tube, doublelane Kramer tunnel. The project is located in the Federal State of Bavaria, Germany. This road tunnel, which has been under construction since December 2019, is the key component of the western bypass of the town of Garmisch-Partenkirchen. Once completed, it will relieve the town’s central district from enormous volumes of traffic. The contractor is the joint venture named ARGE Kramertunnel consisting of BeMo Tunnelling and Subterra. The whole project will be completed and handed over to the project owner, Staatliches Bauamt Weilheim, in 2023. The opening of the entire bypass section including the tunnel to traffic is planned for 2024. The tunnel, with a total length of 3,609 m (2.24 miles) and an estimated cost of EUR 178 million incl. VAT (US-Dollar 201 million), is designed as a single-tube, double-lane structure with one traffic lane for each direction of travel. The safety issue that exists for singletube tunnels is solved by a parallel escape tunnel passable for vehicles. For tunnel ventilation, an intermediate shaft has been designed with a depth of approximately 90 m (295 feet) and an inner diameter of 4.5 m (14.8 feet). All tunnels and ducts are excavated according to the principles of the New Austrian Tunnelling Method (NATM). The geological and hydrogeological conditions, the change in the profile (from round to square geometry), and also the shaft being located at a high elevation presented a demanding technical and logistical challenge. The site arrangement with the pit bank was located in a cut, the slopes of which had to be stabilized with shotcrete and soil nails. This excavation was carried out from the fall of 2020 to the beginning of 2021 because construction operations had to be completed outside the nesting period of protected birds.

Jun 13, 2023

By P. Lan

Gold is often associated with arsenopyrite in many refractory gold ores. The selective recovery of arsenopyrite by flotation is therefore necessary in order to maximize the recovery of gold. However, the complexity of arsenopyrite flotation often makes it difficult to obtain a high recovery from real lean gold ore. This paper presents the results of arsenopyrite flotation by ultrasonic pretreatment in micro flotation experiments and bench scale flotation tests. The tests showed that pure arsenopyrite exhibited low natural floatability due to the oxidation on the mineral surface under ambient conditions. Using ultrasonic pretreatment, the oxidation film was ruptured and the floatability was enhanced greatly. The presence of Fe (III) was found to inhibit the flotation of arsenopyrite and this depression was also removed by the ultrasonic pretreatment. This result explained why the arsenopyrite in real ore is often difficult to float and how ultrasonic pretreatment can effectively improve the arsenopyrite flotation in real gold ores. Guanidine (GMM) was found to be a superior collector for arsenopyrite in acidic medium and xanthate in alkaline medium.

Jan 1, 1998

Selective Flocculation process development generally involves single mineral flocculation tests to identify the appropriate polymer and experimental conditions for achieving the desired selectivity. Invariably the selectivity predicted on the basis of such tests is not realized when mixed mineral tests are conducted. A systematic experimental investigation revealed that adsorption of the polymer on various substrates is critical to selecting the suitable flocculent. Simultaneously, a mathematical model was developed to predict the overall process efficiency with a given polymer. In this paper, results of these efforts to scientifically design a suitable selective flocculation process are presented.

Jan 1, 1991

By R. Snoby

Since its introduction in 2002, the modern air jig has processed a wide array of coals throughout the world. This paper explores the reasons and justifications for the installations and provides case history performance data. Specifically highlighted are air jig plants processing metallurgical coal in Colombia, bituminous coal in the United States and India and lignite in the United States and Spain. Each installation has unique reasons to justify an air jig facility. It is important to note that not all of the justifications were based on the ?most cost effective yield?, normally a mantra for coal preparation plant designers and owners. Dry jigging of coal has long been a proven technique for upgrading coal, the modern air jig, with its improved efficiency and operating systems simply extended the range of applications. In some cases, it even allows market quality coal to be produced when no other option is possible.

Jan 1, 2009

By J. Kenneth Wittle

The DC Graphite Melter has been shown to be capable of processing radioactive waste materials. The process is characterized by its high temperature capability and operation in a closed system. From an environmental perspective, the control of emissions coupled with destruction for hazardous organic materials is mandatory. These same characteristics may be applicable to the minerals processing industry. Under normal operation, the system reaches temperatures for nominal operation of 1600°C, with an arc temperature in the order of 5000°C. The system temperature is determined by the melt temperature of the material being processed. In testing of a 750 lb/hour unit, temperatures of 2200°C were reached. Current focus is on finding waste treatment and metals recovery opportunities in the metals processing industry for his innovative technology.

Jan 1, 1999