Search Documents

By Steve Kral

Through advanced technology and innovative thinking, the mining industry has become one of the world’s leading industries in environmental protection. But it only takes one Summitville, Omai or, most recently, the Aurul gold tailings retreatment operation in Romania to provide ammunition to the industry’s critics in their attempts to sway public opinion against mining. So for the mining industry to continue operating with the public’s support, it must continue to improve its tailings waste-disposal processes and the dams that hold this waste. In January, about 120 specialists in the mine waste management field gathered together to discuss the available technologies and materials for controlling mine waste and mill tailings disposal. “Tailings and Mine Waste’00” was held at Colorado State University in Fort Collins, CO. This meeting, begun in 1978, is a continuing symposium. It provides a forum for environmental professionals to discuss the state-of-the-art in mill tailings and mine-waste disposal methods.

Jan 1, 2000

By J. L. Furtney, C. Fairhurst

"Although global mineral resources are considered to be adequate to meet the needs of a rapidly growing world population, the United States is becoming increasingly dependent on imports. This could have implications for both the economy and national security. The US is a country with a strong tradition of leadership in science and technology. Impressive advances in autonomous underground mining systems reduce the adverse effects of heat and humidity in deep mines and focus renewed attention on ground control. Developments in computing power open opportunities to develop improved understanding of the important role of discontinuities (faults and fracture systems) and more effective design of deep excavations. Establishment of mining R&D Centers at leading US research universities, jointly funded by industry and US federal agencies is recommended as an effective step for the nation to remain an influential partner in world mining. INTRODUCTION. “None of the arts is older than agriculture, but that of metals is no less ancient.. . for no mortal man ever tilled a field without implements. If we remove metals from the service of man, all methods of protecting and sustaining health and more carefully preserving the course of life are done away with.” Agricola (1558)i Homo sapiens, generally acknowledged as the species from which modern Man has evolved, is considered to have originated in Swaziland some 100,000-200,000 years ago. Evidence of use of minerals in that region has been dated to earlier than 40,000 BC.ii Today, a large fraction of the elements of the Periodic Table are derived from minerals, and finding new applications in development of innovative technologies. Agricola’s comments are as applicable today as ever.iii Metals such as copper, tin, lead, iron and aluminum were mined and smelted several thousands of years BC. It was not until the Industrial Revolution, started in the latter half of the 17th Century in Northern England, where coal was available as an energy source, and iron as the basis for fabricating machinery, that dramatic change to society began to occur. Human toil was replaced by far more powerful machines. Rural communities migrated to work in factories in urban areas. Rapid transportation over long distances became possible, leading eventually to the world of today. The change spread to other parts of the world, bringing wealth and power. Although now well established in some regions, the Revolution has still to arrive in many other parts of the world. This can be seen in Figure 1, which shows the relative wealth, or ‘Standard of Living’ as measured by the GDP/capita, of regions around the world. Regions such as North America, Europe, and Australasia iv are seen to have the highest standard. Thanks to today’s global communications systems, regions with relatively low GDP/capita are well aware of ‘how others live’ – and eager to emulate them."

Jan 1, 2018

By M. J. Virnig, B. D. Boley, G. A. Wolfe, J. M. W. Mackenzie

A flowsheet for the recovery of nickel and cobalt from laterite ores has been developed which involves acid leaching followed by hydroxide precipitation of the metal values and then releaching of the hydroxide cake with ammonia. Investigations of the chemistry of extraction of nickel by LIX® 84-I and a developmental reagent, XI-84-IT, along with the physical properties of the organic phases are described. Based on these investigations, suggestions with regard to design of a solvent extraction plant and operating conditions are made.

Jan 1, 1999

By C. Athanassopoulos

Geomembranes have been used in the mining industry since the early 1970s in solution and evaporation ponds, tailings impoundments, and heap leach pads. Traditionally, heap leach pad lining systems have consisted of a single geomembrane liner placed directly over a prepared subgrade of locally available soil. Heap fills are constructed by placing a layer of highly-permeable drainage stone (overliner) over the geomembrane. Crushed ore is then placed on the leach pad in 3- to 10-m (15- to 30-foot) thick lifts, sometimes reaching final heights of several hundred feet. The crushed ore is irrigated with a chemical solution which dissolves the precious metals from the ore. The nature of the chemical leaching solution depends on the metal being targeted. Low pH sulfuric acid solutions are generally used to leach copper and nickel; high pH cyanide solutions are used to leach gold and silver. The metal-laden pregnant leach solution (PLS) passes down through the ore pile and is captured in a drainage system. Metals are extracted from the leach solution and the solution is then recycled back onto the leach pile. When under load, geomembranes are vulnerable to damage from large stones both in the soil subgrade and in the overlying drainage layer. Although intact geomembranes are virtually impermeable, installed geomembranes will have a small number of holes due to imperfect seams or damage during construction and filling operations. These holes serve as open pathways for leakage into the soil below. Smith and Welkner (1995) estimated liner leakage rates ranging from 5 to 10,000 L/ha/day, depending on the type of heap pad liner and level of construction quality assurance (CQA). Thiel and Smith (2003) reported liner leakage rates up to 2,000 L/ha/day for a valley fill facility with heads ranging from 15 to 35 m.

Jan 1, 2011

By Steve Kral

Americans are taking a more critical view of various environmental laws because the effects of those laws are becoming more pervasive and intrusive, according to William Perry Pendley. And Secretary of the Interior Bruce Babbitt is seemingly so unpopular in the West, he no longer campaigns there for Clinton Administration policies. Pendley is president and chief legal officer of the Mountain States Legal Foundation, a public service, non-profit law association that takes on property rights cases for people who cannot afford representation. He was one of the luncheon speakers at the 101st Northwest Mining Association meeting, held in Spokane, WA in early December.

Jan 1, 1996

By Serhat Özdemir, Derya Öz Aksoy, Pınar Aytar Çelik, Ahmet Çabuk, Sabiha Koca, Hüseyin Koca

In carbonate flotation, oleate has been used for many years as a collector in industrial scale. Compared to sulfide minerals, the flotation of carbonate minerals requires more collector consumption and has lower yield and selectivity. It has been previously shown that surfactin provides higher yields in smaller amounts than oleate in the bioflotation of calcite as one of the carbonate minerals. In this study, the usability of surfactin as a flotation collector for magnesite was investigated. For this purpose, the adsorption of surfactin on the magnesite surface was inspected with analyses such as FTIR, SEM–EDS, contact angle, and zeta potential measurements. In addition, the effect of surfactin on the surface tension of water was also revealed. The same analyses were also performed for oleate as a reference point. All flotation experiments were performed without optimizing with both collectors. FTIR results showed that the surfactin, like oleate, was chemically adsorbed on the magnesite surface. Surface tension analyses showed that the surface tension of water decreased to approximately 32 N m− 1 at 10− 4 M oleate concentration, and this value decreased to below 25 N m− 1 at the same surfactin concentration. According to contact angle measurement results, the contact angle of magnesite was 85° after the surfactin adsorption of 2 × 10− 4 M concentration, while this value remained at 46° for oleate. Finally, according to flotation experiments, high temperatures and high collector dosages are necessary for acceptable flotation recovery with oleate, yet surfactin can produce the desired result at ambient temperatures and lower collector amounts.

Dec 13, 2022

By John T. Bartlett

During the last decade, the increasing price of gold has renewed interest in the various metallurgical techniques for recovering precious metals. Much of the recent technology advance has been aimed at low grade deposits resulting in more complex processes and the necessity of tighter economic control. These factors along with more stringent environmental constraints have made it necessary to optimize each process to minimize energy and raw material consumption and reduce waste discharge. In most cases, detailed process analysis is required to detect inefficiencies and provide alternative solutions for process improvement. Also during this same period, the computer has become widely accepted and computerized mathematical modeling has been applied to an increasingly broader range of problems. Microcomputer based process modeling and simulation systems are routinely used to analyze and improve communition, hydrometallurgical, and pyrometallurgical processes for the recovery of precious metals.

Jan 1, 1987

By Michael N. Maltezos

"There is certainly no argument that LED lighting systems have taken a strong foothold in the lighting marketplace over the last several years. This has even proven true in the world of transportation and transit lighting, for which new LED cobra head style luminaires are replacing traditional HID cobra head luminaires on North America’s roadwaysand linear LED light fixtures are replacing conventional linear fluorescent light fixtures in North American rail transit facilities. However, LED technology has taken a while longer to penetrate the very specific market of vehicular tunnel lighting in this continent. Though both the New York/New Jersey Holland and Lincoln Tunnels have recently been retrofitted with LED lighting, and an LED Lighting RFP is currently out for Boston’s Central Artery Tunnels, very few vehicular tunnels in North America to date have been illuminated with LED light fixtures. This is largely because cost effective LED lighting, that met our typically stringent tunnel lighting standards, was until recently simply unattainable. However, with the rapid advances in LED technology over recent years, owners and specifiers of North American tunnel lighting projects have finally begun to adopt LED lighting systems as the norm. In fact, a recent Lux Fit/Yole Development “LED in Road and Street Lighting Report” stated that “LED luminaire growth will be driven firstly by tunnel lighting, and then relayed into highway, road, residential and amenity lighting applications starting in 2014.” 1 Our highways are continually becoming more congested. As a result, Provincial and State Departments of Transportation (DOTs) are constantly looking for innovative ways to improve traffic flow. One way DOTs are now helping to ease congestion is by expanding the use of tunnels and long underpasses in large interchange reconstruction projects. With less available right-of-way to work with, and the high costs of maintaining elevated bridge structures over the years, it often makes more sense to “go under” (rather than over) the traffic congestion points. With the addition of these new tunnels and long underpasses comes the issue of proper illumination within these structures, for a safe and efficient driving task. DOTs use recommended lighting practices and guidelines for highway lighting, which include specific criteria for tunnels, set by either the Illuminating Engineering Society of North America (IESNA) or the American Association of State Highway and Transportation Officials (AASHTO). However, both IESNA and AASHTO point out that these recommended practices and guidelines are not a mandate, and DOTs are free to make their own decisions about lighting criteria. Accordingly, effectively illuminating tunnels is often times a challenge. This paper will examine the key considerations of the tunnel lighting application in generalas well as what LEDs now bring to the table and how, accordingly, traditional lighting technologies will be phased out in the future illumination of tunnels."

Jan 1, 2016

By M. K. Mohanty

A modified coal flotation characterization procedure, referred to as the Advanced Flotation Washability (AFW) technique, has been developed which, compared to traditional procedures, provides a more accurate prediction of the optimum separation performance achievable by a froth flotation process. The AFW procedure uses a vertically-baffled flotation column which provides enhanced selectivity among particles of varying degrees of hydrophobicity due to a plug-flow environment and an improved carrying-capacity environment. In fact, the separation performance of the traditional procedures was enhanced by increasing the possibility of operating under improved selectivity conditions. The separation performance provided by the AFW procedure was superior to that obtained from multiple cleaning stages using commercially-available flotation columns under both kinetic and carrying-capacity limiting conditions.

Jan 1, 1997

By Alan A. Campoli

The US Bureau of Mines (USBM) conducted research to develop improved guidelines for selecting the type and pattern of roof support in different geologic environments. The goal is to minimize the over and under design of mine roof support, resulting in more productive and safer mines. To obtain the necessary data on roof behavior and support performance, USBM conducted several field studies. Each study covers roof geology, stress regime, ground reaction, support interaction and mining environment. A consistent experimental design is being used. This includes measurements of roof bolt loads and roof movements. So far, 10 studies have been conducted in several geologic settings.

Jan 1, 1996

By L. Yuan, J. Soles, W. Tang, R. Thomas

Lithium-ion battery pack fires pose great hazards to the safety and health of miners. A detailed experimental study has been conducted at the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) to investigate the effectiveness of different fire suppression systems on Li-ion battery pack fire extinguishment. Tests were conducted in a well-ventilated container. Two sizes of battery packs (12V, 24V) were heated by heater strips to trigger thermal runaway and fire. Water mist with different flow rates, ABC powder, type D dry chemical, and water mist with F500 additives were used as the fire suppression agents. Multiple thermocouples were installed on the battery packs to measure the temperature evolution during the tests. The results indicated that the water mist with F500 additives is the most effective suppressant among the agents tested. Dry chemicals, however, do quench the fire for a moment, but cannot prevent re-ignition of the battery since they do not provide enough cooling. The findings of this paper can be used to develop safer battery fire suppression techniques in mining environments.

Feb 1, 2023

By Marko Oosthuizen, Charl P. Botha, Lidia Auret, Annelette Malan, Marthie de Leeuw

Flotation performance is affected by upstream disturbances (e.g., mineralogy, water quality, flow rate) and controlled variables (e.g., pulp level and air addition). Process disruptions can lead to undesired conditions, such as pulp overflowing flotation cells (with insignificant/absent froth, and thus no valuable mineral concentration). Early detection and appropriate intervention of pulping events improves concentrator performance. An approach to real time flotation pulping event detection by means of convolutional neural networks is presented, including a case study of the industrial application of this technology on three flotation banks.

Feb 22, 2026

By William Detty

An architect representing the Atlanta office of the Brick Institute of America periodically presents a slide lecture to interested groups entitled "The First 10,000 Years of Brick". The title signifies the fact that brick, man's oldest manufactured building material, has been around for quite some time and will continue to be utilized by architects and builders in the foreseeable future. This is not to say that the brick industry can rest on its laurels and ignore the competition presented by newer more innovative products. The industry will have to be equally inovative and market oriented in order to maintain its market share of the predicted construction boom between now and the year 2000. The implication is made, however, that brick can be produced under rudimentary conditions and that the desire to use the product has been long standing. In addition, history has sham that there has been plentiful clay available to produce the product. This paper is an attempt to assess the climate in which the brick industry will operate during the next 26 years. An analysis of regulatory conditions affecting the manufacture of the product will be followed by an assessment of the materials environment in which the industry will be operating. These factors are then reconciled with a projected demand for the product to determine the ability of the industry to satisfy future demand for brick. From a mineral point of view this paper will address itself generally to the availability of and demand for clay. However, other than a brief overview of the uses of other specific types of clay, it will concentrate on the clays utilized in the production of structural clay products, specifically brick.

Jan 1, 1974

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

Reducing the contribution of heavy- and light-duty diesel-powered equipment to concentrations of aerosols and gases is essential to industry’s efforts to improve air quality in underground mining operations. The results of this study demonstrated a potential of control strategies based on retrofitting existing power packages with diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) systems and repowering existing systems with advanced power packages to reduce contributions of diesel-powered vehicles to concentrations of diesel aerosols and criteria gases in underground mines. The implementation of viable exhaust aftertreatment systems and advanced diesel power packages could be instrumental in the underground mining industry securing a clean, economical and dependable source of power for mobile equipment.

By James G. McKelvey

Owners have seen several major tunnel projects in recent years fall victim to a general reduction in the number of bidders as well as an erratic range of pricing. It should be noted though that this is not a universal trend and some projects have seen good competitive bids. Contractual terms and conditions are an important factor in attracting good competition. The Front End documents of tunnel projects have come under increasing scrutiny as tunneling contractors in the U.S. industry are looking much more closely at their risk exposure in the contract terms and conditions. Considering the amount of tunnel construction work upcoming in North America, it is important that General and Special Conditions are put together in a way that provides a reasonable basis to execute the Contract and also provide a fair, balanced and swift way to resolve disputes.

Jan 1, 2008

By L. Yuan, D. Bahrami

Underground mine fires remain a concern for mine operators, posing a health and safety risk to mineworkers. In the last decade, the number of mine fires has decreased significantly. However, dealing with an unknown fire in underground mines can be a challenging task, which could lead to a hazardous condition for miners during an evacuation and rescue operation. A timely detection of a mine fire and monitoring its characteristics—namely, size and location—are of great importance in reducing the risk of mine fire injuries. A new, improved fire location algorithm has been developed and integrated into an atmospheric monitoring system (AMS) program by researchers from the U.S. National Institute for Occupational Safety and Health (NIOSH). This paper describes the new fire location model and presents the results of verification fire tests conducted at the Safety Research Coal Mine (SRCM) facility of the Pittsburgh Mining Research Division (PMRD) using the collected AMS data. NIOSH is endeavoring to develop workplace solutions to improve the detection of and reduce the risk of hazardous conditions in mines. The results demonstrate successful application of the improved fire location model and provide a useful tool for solving the problem of unknown fire location and reducing the risk of hazardous conditions.

By Emre Karakaya, Niyazi Bilim

Boreholes are used for many purposes in mining operations, petroleum engineering, and construction works. Numerous factors affect the performance of drilling equipment. Researchers continue to work on the variable drilling parameters that can be adjusted in order to reach more efficient drilling operations. Penetration rate is an essential indicator in drillability analysis and estimating. This parameter is of great importance in mining projects. There are almost no models that can estimate the penetration rate for core drilling operations. Under the abovementioned circumstances, this paper focuses on developing models that allow estimating the penetration rate based on rock material properties. During the conduct of this study, drilling experiments under 11 different pressure forces were performed on 8 different rock units, and the equations which estimated the penetration rate depending on the physico-mechanical properties of the rock samples were derived. Experiments were carried out under different pressure forces to investigate the effect of the pressure force on the derived estimation models. The obtained results allowed deriving equations that ensured estimating the penetration rate based on the physico-mechanical properties of the rocks and the applied pressure force. Using these equations, the penetration rate in core drilling operations can be estimated.

Sep 30, 2020

By Gabriel K. Nzulu, Lars Hultman, Per Eklund, Martin Magnuson, Abu Yaya, Prosper M. Nude, Hans Högberg

Pyrite is the most common among the group of sulfide minerals in the Earth and abundant in most geological settings. This gangue mineral in association with garnet, hematite, magnetite, and other sulfide minerals acts as an indicator mineral in the Kubi concession of the Asante Gold corporation in Ghana. X-ray diffraction (XRD), air annealing in a furnace, energydispersive x-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were applied to investigate the crystal structure, identify individual elements, permanence, transformation, and chemical/electronic properties of such pyrite. The study aims to identify individual elements and to gain an understanding of the surface reaction mechanisms, as well as the properties of precipitated pyrite particles observed during the hydrothermal formation of the ore deposit. XRD shows that pristine and annealed samples contain some hematite and quartz besides pyrite. Results from air annealing indicate that the relationship between pyrite and hematite-magnetite is controlled by temperature. EDX reveals that the sample has O and C as contaminants, while XPS in addition reveals Ba, Au, P, Al, and N. These elements are attributed to pyrite that bonds metallically or covalently to neighboring ligands/impurity minerals such as oxides, chalcogenide sulfides, as well as the gangue alteration minerals of magnetite and hematite in the pyrite sample. These findings suggest that during the hydrothermal flow regime, pyrite, pathfinder elements, and impurity minerals/metals were in contact with quartz minerals before undergoing hematite transformation, which thus becomes an indicator mineral in the Kubi gold concession.

Feb 27, 2024

By Andre Vien, Frank Laroche, David Di Sandro

Back in 1994, Claude Bazin presented a novel method for linking size data from milling models to the feed input of flotation models. It was achieved with the simple addition of a metal/mineral distribution—size distribution relationship. This allows grade and recovery predictions from a varying mine plan via product size distribution predictions. This paper presents a case study where this elegant method has been used to build a very powerful forecaster at a process plant, built from historic operating data. The methodology has been used by this operation to forecast production on a quarterly, annual, and life-of-mine basis since the late 1990s. It has been upgraded several times to incorporate new drivers as the complexity of feedstocks has increased over the years.

By Michael McNinch, LaTasha R. Swanson, Jennica L. Bellanca, Justin Helton

As manufacturers and mine operators develop and implement proximity detection systems (PDSs), they need to be mindful of the systems’ compatibility with mineworkers’ tasks, and possible unintended consequences. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) interviewed mineworkers at mine sites that currently use or previously have used PDSs on mobile equipment, including shuttle cars, battery haulers and scoops. Mineworkers reported that mobile PDSs affect loading, tramming, section setup, maintenance and general work on the section. Mineworkers discussed the operational effects and increased burden, exposure and risk. Mineworkers also suggested that improved system task compatibility, training, logistics and PDS performance might help address these issues. Manufacturers and mine operators implementing this or similar technologies may also consider mitigating task incompatibilities up front, performing additional site-specific usability testing and restricting the use cases of the system to improve performance.