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Water contact angles in the air/water/francolite, fuel oil/water/francolite and fuel oil/water/quartz systems were measured to describe the wetting characteristics of these minerals. It was found that white francolite is more hydrophilic than black and tan francolite both in the absence and presence of fatty acid addition. The contact angle measurement results do not correlate very well with the flotation response and it appears that kinetic aspects of the bubble attachment process play an important role in the francolite-fatty acid flotation system.

Jan 1, 1997

By Kenneth A. Pietila

The thickening and dewatering characteristics of refuse slurries are as variable as the coal mining operations and preparation plants that create them. This paper discusses these characteristics based on field studies at a number of mine sites. The connection between bench and full scale performance is confirmed with the design, construction and operation of an integrated 18m (60 ft) diameter thickener and 2.5 meter belt filter press system in Western Kentucky. The data from this system are presented.

Jan 1, 1984

By PAITIP THIRAVETYAN, KANJANA KUDPENG

The aim of this study was to investigate the influence of amino acids (glycine, aspartic acid, glutamic acid, lysine and tryptophan) and organic acids (citric, malic, tartaric, fumaric, oxalic, succinic and ascorbic acid) on gold extraction from silicate ore. Use of amino acids to extract gold was preferred compared with organic acids due to the presence of carboxylic group and amine groups in amino acids. Among the assessed amino acids, aspartic acid and glutamic acid had higher capacities to extract gold due to their structures, which lacked aromatic rings and long side chains. Organic acids could also extract gold. In particular, oxalic and succinic acids had the greatest capacity to extract gold versus the other tested organic acids. Moreover, aspartic acid had a greater capacity to extract gold from ores than the same concentration of succinic acid. We confirmed the aspartic acid and succinic acid functional groups by Fourier transform infrared spectroscopy. The findings revealed that aspartic acid had a greater capacity to extract gold than succinic acid due to the presence of both amine and carboxylic groups (succinic acid contained only a carboxylic group). The optimal gold:aspartic acid molar ratio was 1:6 and low concentrations of aspartic acid extracted 35–42%of gold from silicate ore within 15 days. This can be used as an alternative to traditional methods for extracting gold from ore; it is non-toxic to human health and environmentally friendly.

Aug 10, 2021

By S. Frimpong, E. Siami-Irdemoosa, S. R. Dindarloo

"Electric and hydraulic shovels are the dominant loading machinery in surface mining operations. Despite their critical role in production and their high capital and operating costs, no reliable and comprehensive quantitative performance metric is available. In this paper, a stochastic shovel effectiveness (SSE) measure is proposed for the purpose of quantifying the performance effectiveness of these shovels. The SSE is based on the widely used method of overall equipment effectiveness (OEE) in the manufacturing industry. The OEE measures the performance effectiveness of equipment by multiplying its mechanical availability, utilization and production quality. In manufacturing processes, quality rate is the ratio of the total number of products minus the number of defective products – equivalent to the number of acceptable products – to the total number of products. The SSE similarly uses the mechanical-availability and utilization terms, but instead of quality rate it uses a new parameter named bucket rate.The variability or randomness of the input data, that is, availability, utilization and bucket rate, are further incorporated into the SSE, and a final stochastic SSE distribution is derived in the form of a probability density function. One hydraulic and one electric shovel in a surface mining operation were selected to test the validity of the proposed method. The SSE scores for the two shovels, operating continuously for one year, were derived and compared. As with the OEE, the three-parameter SSE method yielded more representative results for overall performance measurement than a single-parameter approach. Using Monte Carlo simulation, a three-parameter Weibull and a normal distribution were derived for quantifying the overall effectiveness of hydraulic and electric shovels, respectively. As a decision aid, the proposed methodology promises to render a more informative tool than traditional metrics for mine equipment maintenance and management."

Jan 1, 2015

By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By Boyd Eisenbraun, Dennis Murr, Milton Rojas

Approximately since 1925, the phenomena of grinding and classification of minerals with screens have been studied. In the U.S. iron ore mining operations located in the so-called “Mesabi Iron range,” magnetite processing plants have made progress in the application of high-frequency screens that have allowed them to process low-grade Taconite ores and successfully achieve the economic benefit of these minerals. In the particular case of magnetite minerals disseminated in the siliceous matrix, the main objective is to reduce the generation of particles called “middlings” with high silica contents. Commonly the primary challenge of the metallurgical task is to achieve high recoveries and iron concentrates with low impurities. To achieve this, several studies and industrial applications have shown success in this regard and not only in iron ores, but also in other minerals around the world. The study described in this paper attempts to describe some key aspects that helped develop an effective solution and list the benefits associated with this modern process design by using industry-proven technologies for minerals in Chile that have similar characteristics to the minerals of the iron belt in the United States.

Feb 1, 2025

By P. T. Bissert, T. J. Lutz, J. A. Yonkey, G. T. Homce

"The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. BackgroundThe Mine Improvement and New Emergency Response Act of 2006, known as the Miner Act (U.S. Department of Labor, 2006), was enacted in the wake of three mine accidents involving explosions or fire that claimed 19 lives that year. Intended to help improve underground coal mine accident preparedness, the Miner Act includes provisions that target mine safety issues in areas such as emergency response planning; adoption of new technology; training and education; and mine safety standards enforcement. Section 13 of the Miner Act specifically directed the U.S. National Institute for Occupational Safety and Health (NIOSH) to provide for research into the effectiveness and viability of refuge alternatives (RAs) for underground coal mines, and the U.S. Department of Labor to act on the results of such research, as appropriate. These mandates culminated in the 2009 adoption of changes to the Title 30 Code of Federal Regulations, or 30 CFR, mining health and safety regulations (U.S. Department of Labor, 2008), requiring underground coal mines to supply mine emergency RAs and associated components so as to provide a life-sustaining environment for persons trapped underground. Such RAs can be either selfcontained mobile units or built-in-place facilities. The regulatory changes also include provisions establishing requirements for the approval of RAs and their components by the U.S. Mine Safety and Health Administration (MSHA), among which are numerous criteria for providing a safe breathable atmosphere under positive pressure within the RAs. One criterion for maintaining a safe RA atmosphere is the inclusion of an air pressure relief valve that will activate at a maximum of 1.25 kPa (specified as 0.18 psi, or approximately 5.0 in. H2O), or as specified by the RA manufacturer, above mine atmospheric pressure in the RA (U.S. Department of Labor, 2008)."

Oct 1, 2016

By Norman E. Lehman

INTRODUCTION The Washington Camp - Duquesne mining district is located on the east flank of the Patagonia Mountains, 98 kilometers south of Tucson and within 5 kilometers of the International border (Figure 1). Since the development of high-grade silver and copper ores by settlers in 1862, the Washington Camp - Duquesne district has yielded an estimated 450,000 metric tons of ore. The mined ores averaged 8% zinc, 2% copper, 3% lead and 124 grams of silver. REGIONAL GEOLOGY The Patagonia batholith, of Laramide age, crops out in the core of the Patagonia Mountains intruding Precambrian granite, Paleozoic sediments and Mesozoic igneous, volcanic and clastic rocks. This granodioritic batholith lies in a northwest-trending zone of Laramide plutonic rocks, which can be traced for a distance of 320 kilometers from the Nacozari district in Sonora, Mexico to the Silver Bell Mountains west of Tucson, Arizona. Several major porphyry copper systems occur within this plutonic belt including the Red Mountain deposit found at the northern end of the Patagonia Mountains. Data from more than 80 mineral deposits within the Patagonia Mountains show metal zoning symmetrical to the Patagonia granodiorite (Graybeal, 1975). Disseminated copper-molybdenum deposits occur within the batholith. Pyrometa-somatic, limestone replacement and vein deposits of copper, lead, zinc and silver occur in the wallrocks adjacent to the. granodiorite and epithermal manganese-silver deposits occur at the outer periphery of economic mineralization. GEOLOGY OF THE WASHINGTON CAMP - DUQUESNE DISTRICT Stratigraphy Nearly 900 meters of miogeosynclinal Permian and Pennsylvanian sediments are exposed in the district (Figure 2). In addition, 700 meters of older Paleozoic rocks crop out 6 kilometers north of the district. The Paleozoic rocks occur in fault contact with a sequence of Triassic-Jurassic pyroclastic and flow rocks, ranging in composition from latite to rhyolite.

Jan 1, 1977

In this paper, the logic and the capabilities of a long term production planning method for open pit mining are presented. The method is the first attempt in obtaining simultaneous solutions to the four interrelated parameters of open pit mining; 1) the mine life, 2) the specific blocks to be mined each year, 3) the amount of ore and waste to be mined each year, and 4) the ultimate pit limits. An efficient cutoff grade can also be obtained through a sensitivity analysis. None of the existing methods can bring such a comprehensive solution to the problem. A production plan for a real life gold deposit is given to illustrate the logic and the capabilities of the method.

Jan 1, 1993

By Patrick McElhinney, Jacob Carr, Bruce Whisner, Cory DeGennaro, Jingcheng Li

Since 2016, electromagnetic interference (EMI) of personal dust monitors (PDMs) with magnetic proximity detection systems (PDSs) has been observed in underground coal mines. The EMI causes the magnetic field measurements of a PDS to change, which, in turn, alters the calculated location of the miner relative to the machine. Any altered location calculation can potentially cause the PDS to fail to warn a worker who is at an unsafe distance from the machine, arousing a serious concern on safety hazard caused by EMI in underground mines. The search for EMI mitigation strategies led to the development and use of large shielding pouches and boxes to hold the entire PDM to reduce its magnetic emission. Research on these pouches and boxes found that although they were able to reduce the emitted radiation from the PDM, they also disturbed the magnetic field of the PDS, affecting its performance. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have focused on shielding internal PDM components rather than shielding the entire PDM. The PDM air pump motor is one of the PDM components that has been identified as a major source of electromagnetic radiation and has been selected for further study and tests. The measurements show that a small copper or aluminum foil enclosure can effectively reduce the magnetic emission of the motor by between 50 and 85% at 73 kHz. This study compares the test results of the air pump motor with various cost-effective shielding materials. The data provided in this paper can serve as a reference for shielding enclosure design of the PDM air pump motor to reduce its electromagnetic emission as one form of EMI mitigation strategy.

By Fumio Wada

Kuroko deposit is a stratabound massive sulphide and sulphate deposit associated with Miocene submarine volcanics and has been considered to be a prototype of meta- morphosed Palaeozoic and Precambrian equivalents. Since the discovery of Uchinotai deposit of the Kosaka mine in 1959, Dowa and other mining companies have conducted intensive exploration work in the Hokuroku district of northeastern Japan. Dowa has been placing its first priority on the exploration of Kuroko deposits and made a series of remarkable successes in finding the Kuroko deposits, i.e. Uchinotai, 1959; Matsumine, 1963; Uwamiki, 1966; Fukazawa, 1969 and Ezuri, 1975. It is emphasized that our successes have resulted from the proper application of exploration technologies accumulated through our experiences. Firstly we defined the Kuroko horizon and favourable felsic volcanism based on the detailed structural and volczno-stratigraphic study of the Hokuroku district, and then delineated the promising areas by means of the quantitative evaluation of geophysical, geochemical and mineralogical parameters such as the magnetic susceptibility and contents of alkaline and alkaline earth metals in the foot wall dacites and clay mineral assemblages of both hanging and foot wall pyroclastics and dacites. Practical application of these techniques is essential to our routine Kuroko exploration.

Jan 1, 1982

By J. A. Organiscak

This paper describes the research con-ducted on bit wear and respirable dust generation conducted by the US Bureau of Mines (USBM) and West Virginia University (WVU), a member of the Generic Technology Center on Respirable Dust. The USBM investigated wear, energy and dust characteristics of various conical bit designs when cutting rock. WVU studied the functional relationships between wear, cutting force, energy, and dust of one conical bit type when cutting coal. The objective of the USBM study was to identify qualitative bit selection guidelines for cut-ting rock; WVU's research objective was to determine optimum bit replacement guidelines. These research studies both found that bit geometry (a function of bit design and wear) influences energy consumption and dust generation. Bit selection and replacement recommendations are given.

Jan 1, 1995

By Ava Segal, Doga Cagdas Demirkan, Abhidipta Mallik, Sebnem Duzgun, Andrew J. Petruska

Search and rescue operations in mining heavily rely on humans. In the context of emergency situations within underground tunnels, the potential to utilize sensory technology for navigation assistance holds the promise of saving human lives. Our research introduces a device configuration designed to enhance the performance of search and rescue teams. This setup integrates LIDAR and thermal cameras with the Microsoft Hololens, facilitated by the NUC computer and ROS Bridge. Performance assessment involves quantifying the extent to which a user is willing to venture into a light-deprived section of the mine prior to necessitating supplementary illumination. The preliminary outcomes highlight the significant potential of augmented reality assistance in offering indispensable aid to first responders, thereby greatly augmenting the efficiency of search and rescue missions conducted during critical circumstances.

Feb 1, 2024

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. DPM exposure is therefore regulated by the U.S. Mine Safety and Health Administration (MSHA). The current monitoring process takes days or weeks for exposure levels to be known, and a real-time monitoring device is needed. It is believed that infrared spectroscopy has potential for use in a real-time, field-portable device. This paper presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. 

By Steven P. Oman

Large room and pillar mines are characterized by numerous and widespread working places. Ventilation requirements are high since each panel employs men and equipment that work simultaneously in multiple headings. Also, it usually is not feasible to redirect airflow from idle to active panels as the demands of each shift vary so every panel in the mine is fully ventilated at all times. Ventilation requirements will be even higher for mines that are classified as gassy. As a result of these considerations, ventilation systems for room and pillar mines are generally designed to handle large quantities of air. But as mining progresses and the mine be- comes larger, greater demands will be placed on the ventilation system. To insure that adequate ventilation is maintained at these times, ventilation engineers must anticipate problems and plan how best to deal with them.

Jan 1, 1983

By R. G. Benson

The San Luis deposit of Costilla county, Colorado contained 11,021,000 tonnes (12,149,000 tons) of ore at 1.4 g/t (0.040 oz/st) gold in two minable zones. Gold mineralization is associated with silicification and quartz-sericite-pyrite alteration localized in breccias along a low-angle detachment fault zone in Precambrian gneiss. Gangue minerals include chlorite, specular hematite, chalcopyrite, chalcocite, and fluorite. Mineralization is mid-Tertiary in age and has a direct genetic relation to the emplacement of felsic intrusions. Portions of the ore body are unconformably overlain by sedimentary rocks of the Tertiary Santa Fe Formation. The deposit formed during the early stages of extensional tectonism along the eastern edge of the present day Rio Grande rift.

Jan 1, 1994

By Paul F. Ph. D. Ziemkiewicz, Courtney D. Black

According to the American Coal Ash Association, 105 million tons of coal combustion products (CCP) were produced by the power generating utilities in 1997. Of that total, 1.68 million tons were used in mining applications (ACAA, 1997). Results have ranged from the environmentally beneficial to neutral and, in some cases, detrimental. Twenty years ago coal ashes: bottom and fly ashes constituted nearly all CCPs. With the shift to new emission control technologies at power plants, however, large volumes of new products are being generated. Many do not lend themselves to traditional ash applications such as cement formulation. Many CCP disposal sites are not documented with reliable pre and post application monitoring. In this report we discuss types of CCP, their relevant characteristics and the mining environment. We have attempted to identify a range of documented applications and to draw conclusions about their environmental effects including benefits and adverse impacts.

Jan 1, 2000

By Brendan Demich, MAHIYAR F. NASARWANJI, Alan G. Mayton

During dusk, nighttime and dawn operations, effective illumination is a crucial component of safety for getting on/off mobile surface mining equipment and for preshift inspections. U.S. National Institute for Occupational Safety and Health (NIOSH) researchers examined whether illuminance levels could be improved for ingress/egress systems and preshift walkaround inspections of equipment using light-emitting diode (LED) area luminaires. Illumination and glare were key metrics evaluated. Although headlamps provided adequate illumination, LED area luminaires illuminated a much broader area compared to the narrow spot lighting of the headlamp. Hence, the use of additional area luminaires can increase slip-trip-fall (STF) hazard awareness and detection. Furthermore, a commercially available luminaire demonstrated better results than a custom LED luminaire relative to discomfort and disability glare.

By Peter G. Chamberlain

Domestic mining will not produce a significant portion of the manganese consumed in the United States unless new mining and processing techniques are implemented that will enable domestic lean ores to economically compete with rich foreign ores. One mining-processing technique that appears promising for certain deposits is in situ and/or heap leaching with aqueous SO2. Since leaching offers economic advantages of low capital costs, low operating costs, and short start-up times as well as environmental and safety improvements over conventional mining-processing, the Bureau of Mines studied the leachability of manganese deposits from several districts. Manganese oxides, hydroxides, and carbonates were leached to 80 to 90 pct recovery in 7 to 40 days of leaching with a solution containing 5 pct SO2 in column leaching tests. Preliminary cost analyses of surface mining-heap leaching, block caving-in situ leaching, and shrinkage stoping-in situ leaching indicate that the products of manganese leaching may be economically produced for the chemical and electrolytic manganese industries. The easiest marketable product to obtain would be a manganese sulfate commonly used as a fertilizer amendment. Manganese carbonates and hydroxides could also be precipitated from the pregnant leach solutions.

Jan 1, 1983

By Paul A. Rittenhouse

First of all, I want to thank John Dunlap for asking me to this AIME meeting in Denver. I was first introduced to Denver and The Rocky Mountains more than ten years ago and immediately decided it was one of the most attractive spots in the world. I've come back many times since and still welcome any opportunity to return, even if it means I have to prepare and give a paper on potash. When John Dunlap gave me this assignment, he told me that the program would include papers on the geology of potash, papers on new discovered potash deposits and new mines and asked me to discuss potash from the commercial point of view. He also asked me to include a supply/demand outlook for potash. However, one thing he did not mention was "how far into the future he wanted me to look" and it seems to me the time element is a crucial factor to you who are both geologists and miners as well as to me. In your case, you have to look far enough into the future to give you time to explore, find, evaluate, develop, and bring into production a commercial deposit. My mining associates and friends don't agree on how long that takes but it's probably somewhere in the range of eight to fifteen years. But, they all agree on one thing and that is that the time required is continually getting longer. Now my time problem is just the opposite. It is "relatively" easy, and I stress relatively, to identify and evaluate the importance of the various factors that impact on both the supply of and demand for a commodity such as potash if the time period is today. It gets a little tough if one has to project into tomorrow or next week or next month. And when we start talking in terms of a year, five years or ten or fifteen years, things really get sticky and the old crystal ball becomes mighty cloudy. But we economists and forecasters are not known for our temerity so let me get on with the job at hand and take a look at the world potash supply/demand outlook.

Jan 1, 1978