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By Chee Theng

"What do you think are the most important topics in mineral processing today? It is a question that begs to be asked when more than 100 of some of the best and brightest in Colorado mineral processing and their invited guests are gathered in one room. They are there for the 66th Annual Colorado MPD Meeting held at The Broadmoor in Colorado Springs: three days of finely curated talks and social events where participation was strong, and information was exchanged and connections forged in a relaxed, informal atmosphere.Water, tailings and social licenseNot surprisingly, water management, with the associated issues of tailings and social license, was high on the minds of those present. The Mount Polley and Samarco tailings dam failures have had repercussions across the industry. “There are big challenges with respect to tailings, and social and environmental pressures to find better ways to treat them,” said Steve Hearn of Huntsman Corp., a view echoed by Bob Kilborn of Kilborn Group LLC. Metso Minerals director Keith Butler said, “Water conservation is a key issue today. Many mining activities are now located in remote areas, so it has social and economic impacts on mining operations.” For Brian Olson of Samuel Engineering, wastewater and reclaimed-water treatment is interesting.Fittingly, the first talk of the meeting was on dry stack tailings by Michael Blois of Takraf USA, who went over both the advantages and disadvantages. “The average now is over one tailings dam failure a year,” Blois said, “and that is one too many.” But the technology may not be the right fit for all projects. In his talk on the KSM project, Jay Layman, president and COO of Seabridge Gold, showed how it isn’t practical for KSM and how Seabridge reached the decision on a cyclone sand tailings managementfacility as the preferred management strategy.The luncheon keynote also dealt with a tailings pond spill, but of a different kind. Bob Schafer, chief executive of Eagle Mines Management, spoke on the federal missteps that led to the spill into the Animas River from the Gold King Mine, a mine that had been a dry mine throughout its life and up to the 1990s."

Jun 1, 2016

By EDER DOMINGOS OLIVEIRA, Leandro Viana Teixeira, Carlos Antonio Morais, Ruberlan Gomes Silva

Special attention must be considered in the production of high-grade rare earth products, such as mixed rare earth oxalates or carbonates. In the main minerals used industrially, the rare earth elements (REEs) are finely associated with impurities like calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), aluminum (Al), thorium (Th), uranium (U) and phosphorus (P). Most of these impurities must be removed to avoid losses of rare earth oxides (REOs) as well as to prevent product quality degradation and low operational performance in the downstream steps of solvent extraction or ion exchange. The present study aims at investigating the conditions required to precipitate REEs, either as rare earth oxalates or carbonates, from purified rare earth sulfuric liquor with low Al3+ and UO22+ concentrations and very high Ca2+, Mg2+, Mn2+, and SO42− impurity contents.

Just 104 km (65 miles) from Phoenix, AZ, Rio Tinto hopes its new Resolution Copper Mine will be a showcase for the Rio Tinto management philosophy. Its goal is to have a net positive impact. In every place that Rio Tinto mines, it wants to be able to have an overall beneficial effect on the local community, environment and economy. ?We?re constantly working to understand our impacts, to understand how to minimize our impacts and understand how to mitigate those impacts,? said Resolution Copper Mining chief executive officer David Salisbury, from the global headquarters of Rio Tinto Minerals in Green-wood Village, CO.

Jan 1, 2010

By Stephen P. Mulqueen

Searles Lake is an evaporite basin located near the community of Trona in northwestern San Bernardino County, CA. Searles Valley Minerals Operations Inc. (SVM), a subsidiary of Nirma Limited, currently manufactures more than 1.58 Mt/a (1.75 million stpy) of industrial minerals from natural brines produced from several lakebeds within the basin. The chemical manufacturing facilities in Searles Valley represent extremely complex operations involving solution mining and mineral extraction processes.

Jan 1, 2012

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

The amount of energy used to break rock is of interest in mine-to-mill operations to minimize energy consumption during blasting at the mine site and comminution at the processing plant. In this research, a direct energy measurement was made using high-velocity impact to cause breakage of long granite cores, and to study the energy dissipation along the entire bar length. The results show the formation of three zones of damage — fragmentation, fracture and elastic — that have been characterized in 3D using X-ray tomography. The fragmentation zone of the granite bars was studied in detail to describe the particle size distribution and the particle shape characteristics. The experimental energy dissipation in the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work index (BWI) equation [1] when the anisotropic granite particles in the fragmentation zone are defined by length rather than by sieve size. The results increase our understanding of rock breakage and energy consumption and may find future applications in mine-to-mill operations.

By Andrea Brickey, RICHARD AMOAKO, Akshay Chowdu

Production forecasts derived from the medium-term schedule represent the best path forward for underground mining operations to achieve corporate and operational goals. Unforeseen circumstances, such as equipment breakdown, can cause significant deviations from established production forecasts in the short term. Such situations require timely mitigation of the effects of the deviations in order to stay as close as possible to the medium-term plan. This paper presents a deterministic mathematical formulation for short-term scheduling that addresses this challenge. The formulation is able to make up for deficits resulting from operational disruptions by minimizing deviations from medium-term production goals and medium-term activity start dates. We demonstrate this in a case study by simulating disruptions involving reduction in ore extraction capacity and development advance rate. Aside from the rescheduling capability, this formulation can help mine planners conduct analysis on the impact of various disruptions on the schedule. The formulation can help identify those conditions or disruptions that are more detrimental to the achievement of forecast targets, or otherwise. The formulation also affords mine planners the flexibility to prioritize one production goal over the other, depending on operational conditions at the mine. In the future, we seek to incorporate in the formulation respirable dust, diesel particulate matter and ventilation constraints in order to create more realistic schedules, and enhance miners’ health and safety.

Jan 1, 2024

By V. O. Tenorio, D. Tolmachoff, K. Willa Brown, K. J. Kingsbury, J. B. Nickels, G. J. Nail

A major design feature to consider from the initial pioneering works until reaching full mine production of icy regolith at the South Pole of Moon will be the ramp. This will allow the access of equipment and personnel in and out of the excavation area. Although most of the requirements considered when designing a ramp on the Earth are similar, the fact of working in low gravity, with zero atmosphere, the potential exposure to high radiation, extreme temperature levels and drastic changes of illumination, from intense light to total darkness, are new factors to be included. Transversal sections are obtained according to the progression sequence of the production levels, with changes in length, gradient, friction factor of the terrain and curvature when required by the location characteristics and the specification of the equipment utilized. A MATLAB script was developed to calculate all the variables, in order to obtain 3D generated surfaces from the range of possible profiles.

Mar 2, 2022

By Thomas Novak, Sampurna Arya

Controlling dust generation and keeping it below permissible limits to meet federal dust standards at the working face of a room-and-pillar coal mine is a challenge for a mine operator. With the recent changes in federal dust regulations requiring lower worker exposure, maintaining compliance has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the U.S National Institute for Occupational Safety and Health (NIOSH) indicated that a flooded-bed scrubber could achieve cleaning efficiencies between 58 and 90 percent. But the operation of such a system is maintenance intensive. The flooded-bed scrubber screen becomes clogged with dust particles and requires frequent cleaning to maintain performance. However, the dust control issue is not solely a mining-industry problem. Other industries face similar issues. The University of Kentucky collaborated with Toyota Motor Manufacturing on the development of a novel wet scrubber, called the vortecone scrubber, for capturing over-sprayed paint particles in automotive paint booths. The vortecone scrubber achieved a cleaning efficiency of 99 percent and required minimal maintenance. This study aims to assess the ability of this vortecone scrubber to capture respirable dust in an underground coal mine. The paper presents the results of computational fluid dynamics (CFD) modeling of this vortecone scrubber. It discusses the effects of air quantity and dust particle size on the performance of the scrubber. 

By Isabel F. Barton, Matthew J. Gabriel, CARSON ROBERTS, JOHN LYONS-BARAL, LEON DUPLESSIS, Mark D. Barton

Geometallurgical characterization is increasingly used in the mining industry to model ore types, predict process performance and identify potential recovery issues ahead of time. However, most geometallurgical assessments are based on bench- or laboratory-scale analyses of relatively sparse samples, leaving most of the orebody characteristics known only by inference until the rocks are actually mined. In this pilot study, we test drone- and tripod-based hyperspectral imaging for mapping mineralogy across mine highwalls, dumps and leach pads. The results show that hyperspectral imaging can successfully map the types and distribution patterns of key minerals (especially carbonates, sulfates, clays, other phyllosilicates) and other important features (such as lixiviant ponding on leach pads), bringing geometallurgy into the field to provide crucial inputs to process decisions.

By VÍCTOR VÁZQUEZ-VÁZQUEZ, GUILLERMO TIBURCIO-MUNIVE, María M. Salazar-Campoy, JESÚS L. VALENZUELA-GARCÍA, OFELIA HERNÁNDEZ-NEGRETE

This study examines a process for the recovery of precious metals from difficult minerals that exhibit refractory characteristics to cyanidation: low extraction of metals and high consumption of leaching reagent. A mineral sample from Monte del Favor Mine, located in Hostotipaquillo, Jalisco, Mexico, was physically and chemically characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), fire assay and atomic absorption spectroscopy (AAS). Two stages of leaching were carried out, first to eliminate manganese from the sample using sodium sulfite (Na2SO3) as a reductive reagent along with sulfuric acid (H2SO4), and second to dissolve gold and silver with hydrochloric acid (HCl) and sodium hypochlorite (NaClO). The results show extractions of around 96 percent for manganese (Mn), 98.73 percent for silver (Ag) and 83 percent for gold (Au). The usefulness of high acidity and Na2SO3 to obtain better results in Mn and Ag leaching are discussed along with the roles that HCl and NaClO play in Ag and Au dissolution values.

By BURCU NILGUN CETINER, Serdar Aktas

Antimony has been used extensively in industry and in everyday life since the 19th century, and antimony sulfides have been known since around 4,000 B.C. Antimony’s most significant applications are as a flame retardant in the manufacture of electronics and textiles, as a catalyst for plastic fabrication, and as paint pigment and fining agent in glassware, opacifier in ceramics and an alloying element in ammunition and battery manufacturing plants. It is also used in vehicle brakes and tires. Brake pads contain stibnite (Sb), the sulfide compound of antimony. In particular, stibnite is used in automobiles as a lubricant, vibration reducer and friction stability improver. Anthropogenic activities are the primary source of antimony in the atmosphere [1,2]. Annual global consumption of antimony has increased to more than 1.4 × 105 t, and China is the most significant producer [2].

By TOMI GIORGIO DE, Ricardo Tichauer

Mineral exploration is a key factor for success in the mining industry. However, exploration best practices are often ignored in small-scale mining. This works presents the Tichauer-DeTomi Matrix, a methodology that measures the level of compliance of exploration programs in small-scale mining with the industry best practices. The matrix has been applied to three projects in Brazil: an artisanal gold mine in the state of Pará, a small-scale manganese project in the state of Bahia, and a small-scale manganese project in the state of São Paulo. The application of the matrix resulted in indexes that represent the level of maturity of the exploration program in each project and indicate priority actions for reduction of the geological uncertainty. Therefore, the Tichauer-DeTomi Matrix has shown potential to be a useful tool for assessment of geological uncertainty in small-scale mining. As a risk indicator, it may contribute to promoting investment in small-scale mining and development for communities that depend on this activity around the world.

By Richard A. Thomas, Liming Yuan, Wei Tang, JOHN SOLES

Lithium-ion (Li-ion) battery applications are increasing for battery-powered vehicles because of their high energy density and expected long cycle life. With the development of battery-powered vehicles, fire and explosion hazards associated with lithium-ion batteries are a safety issue that needs to be addressed. Li-ion batteries can go through a thermal runaway under different abuse conditions, including thermal, mechanical and electrical abuse, leading to a fire or explosion. The National Institute for Occupational Safety and Health (NIOSH) mining program is conducting research to prevent and respond to lithium-ion battery fires in battery-electric vehicles in the mining industry. In this study, experiments were conducted to investigate the effectiveness of different suppression systems including dry chemical, Class D extinguishing powder and water mist for lithium-iron-phosphate (LFP) battery pack fires. The effects of activation time and release time of the water-mist system on the suppression of the LFP battery (a type of Li-ion battery) fires were studied. The results of this study may be helpful for developing strategic firefighting and response plans for battery-powered vehicles used in mining.

Aug 1, 2024

By William C. McBee

A sulfur concrete technology has been developed by the U.S. Department of the Interior, Bureau of Mines, in which chemically modified sulfur is utilized with suitable mineral aggregates to produce construction materials which are resistant to corrosion by acids and salts. This report presents a summary of the basic technology and results of testing the materials under actual operating conditions in 50 corrosive environments in 40 commercial plants. After 4 years of testing, there was essentially no evidence of material degradation or loss of strength. Regular concrete materials were attacked and in some cases completely destroyed under the same conditions. Testing is continuing to establish ultimate longevity and durability of the sulfur concretes. The materials are finding widespread applications in metallurgical, chemical, and fertilizer processing plants.

Jan 1, 1983

By M. A. Trevits, G. Frampton

"Mine safety training materials have long included pictures of mine conditions, equipment, hazards, etc. These images are invaluable to both the trainee and the trainer to convey many important concepts. The human eye takes in a tremendous amount of information, while the field-of-view from a consumer grade camera is, generally, 40 degrees to 90-degrees. This difference in field-of-view is a primary reason that pictures, especially of dark and dusty areas, don’t adequately describe the scene. For conveying information to a trainee, these images lack context. Today, 360-degree cameras are available with consumer-grade cameras costing a few hundred dollars. Also, the display technology is already owned by most trainees and trainers and is widely available. The resulting 360-degree videos and pictures can be readily viewed on smart phones and inserted into Microsoft PowerPoint slideshows. These images and videos can easily be included in existing training modules, disseminated using the internet, and used by trainees easily. We propose a methodology for utilization of 360-degree video and images with simple display technology for miner training. INTRODUCTION AND BACKGROUND In mining, as in other production-related industries, the safety of workers is dependent upon many interrelated factors. One of the more important safety factors is a miner's ability to recognize hazards in their workplace. The ability to perceive and identify hazards is perhaps more difficult to master in underground mining than in general industry because the work environment is confined, noisy, dark, and inherently dangerous because of the hidden unknowns created by the geological setting and the conditions created by the mine opening. Further complicating the situation is a setting that is continuously changing as mining advances (Barrett 1995) [1]. Hours of excellent mine safety training have been developed and utilized over the years. Pictures of mines, activities, hazards, etc., are included in many of these training courses. These photographs, especially those taken underground, often lack context because of the limitations of the cameras and lenses. Notable research by the US Bureau of Mines and then later by NIOSH showed that the use of stereoscopic three-dimensional slides in training exercises was an effective aid for improving the ability of miners to recognize hazardous ground control conditions (Barrett 1988) [2]. An example of type of three-dimensional slides and slide viewer is shown in figure 1."

Jan 1, 2018

By J. Stowe

"While there has been continual improvement in the models for predicting deposition velocity and pipeline friction losses, the fundamental design philosophy for tailings pipelines has remained the same over the previous three or four decades: design the tailings pipeline to operate in turbulent flow without a deposit on the pipe invert for all expected process conditions. Recent improvements in the understanding of slurry pipeline flows allows for the design of pipelines operating with a deposit on the pipe invert, allowing the system to operate at moderate velocities for high flow rates, optimizing system energy requirements and maximizing pipeline wear life.Tailings pipelines are increasingly operated at higher solids concentrations when there is a greater likelihood the pipeline will operate in laminar flow due to the higher tailings slurry rheology. Historically, slurry pipelines have been operated in turbulent flow. We now know that laminar-flow pipeline operation is possible as there are several operational laminar-flow tailings pipelines. While our understanding of laminar-flow slurry pipelines is not complete, recent research provides guidance on how to approach the design of these pipelines.New sensor technology has led to the development of an instrument that provides reliable indication of bed-deposit height within a pipeline. This technology is particularly helpful in operating pipelines with a deposit and has application in better understanding the operation of laminar-flow pipelines. Failure of tailings pipelines can result in consequent damage to surrounding structures and unacceptable spillage into the environment. Modern pipeline leak detection technology allows operators to better manage this risk by ensuring safe and reliable operation of tailings pipelines.This article provides an overview of the each of the above advances in the design and operation of tailings pipelines.Operating tailings pipelines with a depositTailings pipelines, and slurry pipelines in general, are typically designed to operate without a deposit on the pipeline invert. Meaning, the minimum operating velocity exceeds the turbulent deposition velocity. This approach has been adopted due to concerns regarding potential blockage of a pipeline operating with a deposit."

Jun 1, 2019

By Aimee A. Woolsey

Enterprise unmanned traffic management (E-UTM) is a holistic system concept evolving from technological developments in radio frequency (RF), where dynamic tracking can be added into current and emerging platforms. This is done through inexpensive RF sensors capable of real-time and cooperative, non-GPS tracking enabling digital visualization of assets, including unmanned aerial systems (UAS). The RF sensors are low in size, weight and power (SWaP), creating efficiencies in energy and material consumption while transmitting positions in real time and at long ranges. Multiple UAS and other unmanned vehicles can be visualized for risk mitigation in operations, thus enabling mine management to have better decision-making capabilities in the current and future mosaic of mine operations.

May 1, 2023

By ERIK CHARRIER, HUGH MILLER, JOSEF BOURGEOIS

In this study, a unique excavation system was characterized using waterjet technology as the primary tool for material removal during rehabilitation of reinforced concrete and shotcrete structural liners. Through empirical testing, this research seeks to validate the hypothesis that waterjet removal of these support systems will result in less unintended damage than conventional removal methods. The intent is to develop a viable technology that will reduce the collateral damage caused to surrounding liners during excavation, improve the adhesion between shotcrete and the substrate for longer lasting ground support, and improve overall safety for workers in underground environments. An analysis on the fracture mechanisms and operating parameters of each method was completed. Instrumented shotcrete panels were physically tested and examined through visual inspection and ground penetrating radar (GPR) to compare substrate damage according to each testing method. After testing was completed, the data strongly indicate that waterjet cutting causes less collateral damage to the surrounding intact liner and substrate than conventional impact hammers. This research is intended to provide a scientific basis for additional applied research in the rapid excavation and repair of shotcrete support systems.

By KALLAM VK REDDY, VADAPALLI SANJANA, Veerendra Singh, Gajanan Kapure

Mining activity around the world has increased significantly to meet stepped-up demand for various metals [1]. Apart from the target minerals, mining also generates huge amounts of unwanted minerals that exit the mines as overburden. Due to the active mining activity, high-grade mineral resources are being depleted, leaving inferior-quality ores [2]. The mining of low-grade ores further increases the amount of overburden/waste per ton of metal equivalent of ore mined. Currently, overburden and other mine waste is most commonly used in the construction industry and as feedstock for making cement and concrete, but the overburden can also be used as a source of valuable minerals and metals [3]. 

By M. Schreiner, J. Brune, D. Theisen, C. S. -J. Tsai

This study reports that routine mining activities could produce a high number of nanometer sized particles which have not been well characterized and may represent an unacknowledged exposure present in the mining environment. A preliminary survey of the particle emission from the feed-leg drilling activity was conducted in the excavations of an experimental mine. The level of particulate exposure was monitored by real time direct reading instruments include a NanoScan scanning mobility particle sizer (measurement range 10-420 nm) and an optical particle sizer (measurement range 0.3-10 μm). Particulate morphological and structural examination was conducted through transmission and scanning electron microscopy and x-ray dispersive analysis of samples collected by a thermophoretic sampler, and a novel nanoparticle sampler. The real time instrument data revealed high concentrations (> 3.5 x 106 particles/cm3) of ultrafine/nanoparticles generated from the drilling activity. Analysis of particle sampler specimens with energy-dispersive x-ray spectroscopy showed a large amount of submicron silica, spherical primary particles and agglomerated soot particles rich in carbon. Exposure to particles in the nanometer size from various sources within the mining environment may be associated with the poorly understood rise in respiratory and systemic disease among miners. INTRODUCTION Exposures to mine dust have been measured and evaluated for decades. Exposures to aerosolized dust such as coal or silica particles can cause lung and other diseases (1-7). One way that The Mine Safety and Health Administration (MSHA) characterizes inhalation exposures within the mining environment is through measuring the respirable dust mass concentration within the breathing zone of workers (8). Respirable particulate matter (RPM) is of great concern due to its ability to deposit in the alveolar region of the lungs (9-10) where it can affect respiratory function. Interventions championed by MSHA have greatly reduced the prevalence of coal workers pneumoconiosis (CWP) and progressive massive fibrosis (PMF). Although great progress has been made, the prevalence of CWP and PMF appears to be trending upwards and the measured increase in prevalence is not elucidated in RPM measurements (11-12). Though the presence and risk associated with ultrafine particles such as emission from diesel engine within the mining environment has been previously established (13-14). There is suspicion within the mining industry that this resurgence of lung disease may be due to very fine particulate matter from various source that is not properly characterized by current sampling methods. Nanometer sized particles, in the range of ultrafine particles, fall within the RPM size range and have been found to deposit in all regions of the respiratory tract (15). Nanoparticles are commonly accepted as particles that are greater than 1 nm in two or three dimensions but smaller than 100 nm (16). Once in the lungs, nanoparticles can enter the blood stream (17) and selectively affect other target organs such as the heart, liver, bone marrow, lymph nodes, spleen, and brain (15,18-19). The size of nanoparticles has been shown to correlate with their translocation behavior on secondary target organs (20-21). There is strong evidence that the clearance mechanisms used to rid the lungs of particulate matter are not as effective on nanometer sized particles, leading to a greater fraction of never-cleared particles which may enhance disease development (20). Research has demonstrated that nanometer sized particles have unique properties (22) whose adverse health impact is greater than what has been found with micrometer sized particles of the same type (23-26). The large ratio of surface area to mass compared to larger particles is believed to make nanoparticles a greater hazard. Utilizing mass to measure these types of exposure will be very difficult to accurately characterize the quantity of

Jan 1, 2019