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By X. K. Jiang

Pneumatic, triboelectrostatic processing of physical mixtures containing fine (-200 mesh) particulate may have significant application potential in the mining and energy industries. Such dry processing methods, especially for finely comminuted materials, have not been examined in as much detail as wet processing methods nor have been part of the training or education of mining and process engineers. We have examined fundamental and applied physical and engineering factors controlling triboelectrostatic beneficiation of fine-sized physical mixtures, one of which -combustion fly ash -has size, heterogeneity and mineral concentrations typical of those expected in mined minerals. The applicability of dry processing, however, cannot be readily evaluated because of the unavailability of standard procedures for process assessment.

Jan 1, 1999

By Paul C. Miclea, Robert E. Murphy

The behavior of fire and airflows in a confined tunnel differ significantly from more familiar fire situations outside, due to the buoyant effect which tends to create a layer of hot smoke and gases flowing away from the fire near the crown of the tunnel, while air supporting combustion moves toward the fire beneath the smoke layer. A subway emergency ventilation system is designed to force air to flow through the tunnel, shifting the balance of heated air in the direction of the forced flow and avoiding the "back-layering" of hot gases and fumes. This paper presents a computer program, called the "Subway Environment Simulation" (SES), which can be used to predict airflows created by the emergency ventilation system. It utilizes the latest state-of-the-art analytical treatment of fires in enclosed spaces, including observations from mine fires and gas explosions. The program allows designers to reduce construction cost by identifying unnecessary ventilation shafts and by verifying fan capacities. In addition, the program allows the designers and operators to determine safe evacuation routes, in case of a train fire, by predicting the occurrence of back-layering. It can be used to determine when the ventilation system can control the direction of smoke movement to provide a clear and safe path for evacuating people and facilitate fire fighting operations.

Jan 1, 1989

By A. Janwong

Ion exchange technology is becoming more prevalent for metal recovery from low concentration solutions. The products of ion exchange are typically a metal free stream (product stream) and a concentrated metal stream (byproduct). The metals in the concentrate stream are usually precipitated and returned to the process or discarded. The unique features of emew® technology enable metals to be recovered directly from the concentrated stream. The advantage of the IX-emew® combination is the ability to have two product streams: 1) clean metal free solution and 2) metal product for sale. In addition to recovering metals from solution, it is also possible to separate metals from each other and recover more than one metal product. In this paper, examples of IX-emew® combinations are detailed including the recovery of copper, nickel and cobalt from an industrial waste stream, recovery of nickel from a spent electroless nickel plating solution and recovery of cobalt from an hydroxide cake.

Feb 23, 2014

By A. T. Weber, G. T. Adel

Earlier studies on the hydrodynamic interactions between fine particles and air bubbles have shown that fine particle flotation can be improved by using small air bubbles. In the present work, microbubbles ranging in size from 70 to 250 microns have been used in a flotation column for the processing of fine coal. The performance of the microbubble column has been studied as a function of wash water addition rate, aeration rate, feed rate and column length to diameter (L/D) ratio. The information collected from these tests has been used to analyze column behavior and to develop scale-up criteria. The results of this investigation suggest that mixing within the column may not be as significant as bubble size and residence time in determining column performance. Improved recovery can be obtained by decreasing bubble size which increases the flotation rate constant, and also by increasing L/D which increases residence time for a fixed column volume. The increase in residence time with L/D is due to a decrease in the volumetric flow rate of wash water with column diameter.

Jan 1, 1988

By V. O. Tenorio, K. W. B. Requist

As the mining industry begins efforts to examine the feasibility of extraterrestrial resource utilization, the extraction and processing of icy regolith containing water and other volatile materials will be the initial focus for future expansion of capabilities. Pure water is essential for human consumption, and a source of oxygen and hydrogen. The latter, along with the volatile materials, lend themselves to the creation of fuels that may be used for further space exploration at distances not currently feasible. For any extraterrestrial scoping project, the transport of materials to geoscientists remains virtually impossible. Therefore, analysis must be done in-situ, possibly millions of miles away from the nearest human. To address the need for geologic resource estimation in the absence of geoscientists, an infrared framework has been developed for the analysis of water ice content in simulants of permanently shaded lunar regolith. This framework relies on a convolutional neural network model for the rapid analysis of percent water ice content in samples, at which point standard geostatistical methods may be employed.

Feb 1, 2023

By James D. Bennett, David L. Passmore

The Coal Mining Section of the National Safety Council has selected hand and finger injuries of coal miners as a major topic for safety policy analysis [Tinney, 19851. So that facts about hand and finger injuries can be used to guide the Committee's work and the work of policy-makers, we present in this paper detailed analyses of the following factors related to hand and finger injuries received by coal miners between 1975 and 1983: occupations of the injured miners; activities of the miners when injured; machines involved; objects, substances, exposures, or bodily motions that produced or inflicted the injuries; principal physical characteristics of injuries; and events directly resulting in the injuries. We analyze hand injuries for underground and surface mines separately because of the remarkably different production methods and hazards evident in these two operating environments. We do not, however, provide information about hand and finger injuries that occurred in surface operations at underground sites (such as yards, shops, or tipples), auger mining operations, culm banks, dredging operations, mill or preparation plants, offices, or laboratories. The most comprehensive information about the safety of coal mining in the United States is assembled by the Health and Safety Analysis Center (HSAC) of the Mine Safety and Health Administration of the United States Department of Labor. Mine operators in the United States report to HSAC all injuries as required under Part 50, Title 30, of the Code of Federal Regulations (mandated by Section 103 the Federal Mine Safety and Health Amendments Act of 1977, Public Law 95-164). These regulations stipulate that injuries must be reported within ten days of their occurrence on a United States government data collection form, Mine Accident, Illness and Injury Report (MSHA Form 7000-1). HSAC maintains these data primarily to produce federally-mandated reports. HSAC resolves injury reports that are incomplete, checks for errors in data coding and handling, and corrects inconsistencies in data submitted by

Jan 1, 1986

By Alexander N. Winchell

"The deposits of the east end of the Mesabi Range cover very large areas, and consist of the same taconite that produces the hematite of the central and western Mesabi. It is not deeply covered with drift, but outcrops boldly in large masses. It is not concentrated locally into enriched bodies separated by leaner areas, but is all a fairly uniform, hard, banded, unaltered chert, carrying about 25 to 30 per cent iron as magnetite.The Mesabi Iron Company, organized by Hayden, Stone & Co., and under the direction of D. C. Jackling, has taken over these deposits and is building a Concentrating plant at the new town of Babbitt, about fourteen miles east of Mesaba, Minn. This plant is to have a capacity of 2,000 to 3,000 tons per day, and is based on the application to this low grade material of the methods which have made the so-called porphyry copper properties so successful.In 1916, an experimental mill was built in Duluth; containing full sized machinery and capable of handling from 100 to 200 tons daily. A considerable tonnage of material was concentrated here during 1916, 1917 and 1918. The work showed that the resulting product could be varied, almost at will, between 60 per cent and 70 per cent iron and .006 per cent to .030 per' cent phosphorus, and that this could be made on a large scale well within the limits of cost set by iron trade conditions. A small special cargo was sent down the lakes, late in 1918, assaying 63.27 per cent iron (natural and dry) and .008 per cent phosphorus; but it is assumed that large scale shipments will normally be of a Bessemer' grade carrying about 63 per cent iron and .020 per cent to .030 per cent phosphorus. This material is a sinter, carrying only traces of sulphur and titanium, with silica between 6 per cent and 10 , per cent, and alumina, lime, magnesia, and manganese, each below 1 per cent. Some of the iron in this sinter is hematite and some is magnetite, the percentages varying according to the treatment given on the sintering machine. Like the analyses, this hematite percentage is within reasonable control. Sinter made from finely ground magnetite has much the structure of coke, being firm yet porous, and gives good account of itself in the blast furnace."

Jan 1, 1920

By S. Bahrampour

One of the basic requirements for designing an optimized rock support for an underground opening is having reasonably enough geological information. It is often financially impractical to obtain detailed geological information about the rock surrounding the excavations. The geological and geotechnical information which are obtained during the construction phase are also usually inadequate and need periodic operation stoppage. Penn State University- J.H. Fletcher & Co. joint venture is to improve the existing instrumented roofbolter so that the 3D geological and geotechnical map of the rock mass surrounding the underground working can be generated real-time as the data is being collected. This information will also be used to design appropriate support for different sections of mines. In this paper, recent results in improving the performance of the measurement while drilling system will be discussed. Moreover, updates related to borehole probing methods for estimating the properties of the rock masses will be presented.

Feb 23, 2014

By Al. Valero, A. Domínguez

This paper appraises the energy requirements for mineral production through an exergy approach taking into account the long-term decline in ore grades. In this context, the exergy required for restoring resources from the dispersed state of the so called Crepuscular Earth into the physical and chemical conditions in which it was delivered by the ecosystems in light of the available technology, is known as exergy cost. The exergy cost is the point of reference in order to evaluate in a single variable, characteristics such as composition, concentration (ore grade) and the state of technology. The ratio between the exergy cost and the minimum thermodynamic cost required to accomplish the same process is called unit exergy cost and provides a measure of the irreversibility of the analyzed processes. Otherwise, the ore grade is one of the main issues which affects directly the costs associated with mining the ore. Hence, the unit exergy costs to produce minerals from progressively lower ores grades by the current technology is analyzed. The unit exergy cost curves are presented for some important minerals such as aluminium, chromium, cobalt, copper, gold, lead, manganese, nickel and zinc, in order to know the trend when the ore grade decreases.

Jan 1, 2011

By M. L. Matt

The Pittsburgh Safety and Health Technology Center of the Mine Safety and Health Administration has developed the Mine Emergency Responsiveness Development (MERD) program to improve the reaction and response of mine personnel in mine emergency situations. The MERD program simulates problems that may be encountered in underground mine fires, underground mine explosions or surface mine accidents. Since its inception in 1982, the MERD program has been presented to MSHA, Industry, Labor and State Government Personnel. The program is extremely versatile and is easily adapted to suit various training requirements. It gives the participants the opportunity to experience some of the emotions, frustrations and successes of a mine emergency in a controlled environment without having to be involved in one. Past participants have indicated that this training has better prepared them in actual emergency situations through increased awareness and advanced preparation of plans and resources. In 1992, a Mine Simulation Laboratory, which simulates a coal mine and metal/nonmetal mine, was built to improve training for mine emergencies and prevention and fighting of mine fires. This facility has been included in the MERD Program to provide realistic and practical training for mine rescue teams and MERD participants in advanced mine emergency operations. This paper presents an overview of the MERD program.

Jan 1, 1993

By Steven A. Atkin, William D. Schrand

Closure plans for open pit mines require the prediction of final pit lake water chemistry. The geochemical models used for water quality predictions make assumptions about the physical and chemical behavior of the water in the lake; however, few pit lakes have been well documented to provide empirical data for model design. The pit lake at the Sleeper Mine has been characterized with regular water chemical analyses and regular, continuous, multi-parameter profiles through the water column. The lake has undergone repeated periods of chemical and thermal stratification, punctuated by rapid turnover events resulting in vertical homogenization within the water column.

Jan 1, 2000

By Stanley Dempsey

Since its passage, the Mining Law of 1872 has been modified several times to meet the changing needs of America's society and economy. Despite the fact that it continues to provide an effective framework for a robust US exploration and mining industry, the mining law continues to be criticized in some quarters as outdated. Pressure to reform the Mining Law of 1872 has reached new levels in recent years. Many proposals for reform of the law have been introduced during the 1990s. None, though, have been enacted. The issue will not likely disappear and is certain to be raised during the 105th Congress. To provide a better understanding of the status of current congressional reform proposals, this article presents an overview of the major moments in the history of mining laws in the western United States - from the days before the 1872 mining law and the days following its promulgation, to the current dilemma over mining law reform. The future of the mining law is assessed as are the interests at stake for the modern mining industry. Mining before 1872 No discussion of the Mining Law of 1872 is complete without some historical background to provide an understanding of the origins of this unique law. There was plenty of mining activity on the public lands before the mining law was enacted. At first, the federal government's policy was to allow all miners to work freely on the public lands and to resolve disputes among themselves. In this "hands off" environment, miners operated according to laws they promulgated. These were based on previous experiences in Europe and Mexico. These "frontier codes" of groups of individual miners took the form

Jan 1, 1997

By Michael G. Nelson, Hanguang Wu, V. Izaxon, Sukumar Bandopadhyay

The method of mine ventilation involving heated air, which is frequently used in mines in cold regions, does not correspond to the natural conditions prevailing in permafrost regions; it is not economical and leads to a series of complications which can be prevented or greatly reduced by lowering the temperature of the air stream entering the mine until it is equal to or very close to the temperature of the frozen ground This paper presents ventilation design approaches which can be engineered to provide the required micro-climate and thus en- sure the stability bf the ground for placer mines in permafrost. Specifically three ventilation design approaches are presented: 1) design based on minimum thermal impact; 2) design based on positive/negative heat accumulation in the existing mine airways; and 3) design based on heat exchanging devices such as thermosyphons placed above ground.

Jan 1, 1997

By H. G. Linge

The Australian gold industry currently contributes some $4bpa to the national economy [l]. Some 40% of the total gold is produced in the region centred on Kalgoorlie known as the Eastern Goldfields of Western Australia. This region is the largest single centre of production with an output of some 100 tpa of gold [2]. In the Eastern Goldfields, refractory arseno­pyritic gold ore is an increasingly significant source of gold, feeding several operations utilizing bio-oxidation as the pre­carbon in pulp/leach (CIP/L) treatment process [1]. This paper desribes an alternative pre-CIP/L treatment option for use in the Eastern Goldfields based on the chlorination of arsenopyrite by chlor-alkali technology [3] using the salt resources available from saline water present in abundance in the region.

Jan 1, 1995

By Kotaro Ohga, Gota DEGUCHI, Kiyoshi HGUCHI

The situation of Japanes coal mine is in the severe enviroment, because the policy on coal mining has changed. Every year one or two coal mines will be foced to close. To continue the production of coal, we have to reduce the cost of production. Therefore, the mining by longwall method which is more than 250m was attempted at Taiheiyou Coal Mine to reduce the cost and this mining method have had successful results. To get successful results by this mining method, the controlling and prediction of gas emission from the longwall panel will be most important things. In this paper, the comparison of the predicted gas emission from the mining panel based on the measured gas content by using new device with the observed results is described.

Jan 1, 1993

By Stanisław Lasocki

We present an algorithm to integrate the uncertainties of mean activity rate and magnitude cumulative distribution function in the interval estimation of the primary seismic hazard parameters: the exceedance probability and the mean return period. The algorithm is applicable for both the parametric and nonparametric modeling of magnitude distribution. When the Gutenberg-Richter relation-based parametric model of magnitude distribution is used, the interval estimation of its parameters is based on the asymptotic normality of the maximum likelihood estimators. When the nonparametric kernel estimation of magnitude distribution is used, we apply the iterated bias-corrected and accelerated method for the interval estimation, based on the smoothed bootstrap and second-order bootstrap samples. Previous studies indicated that the uncertainty of mean activity rate significantly affects the interval estimates of hazard functions only when the activity rate is low and the inference period is not long (Orlecka-Sikora & Lasocki 2017). With increasing mean activity rate, the uncertainty of magnitude distribution dominates over the uncertainty of mean activity rate in the aggregated uncertainty of the hazard functions. The provided algorithm is generic and can be applied to capture the uncertainty of any multiparameter function from the uncertainties of its parameters. Here we present a further development of the algorithm developed by Orlecka-Sikora & Lasocki (2017) by presenting its implementation in the Traffic Light System approach. As an example of use, we present the confidence intervals estimation of hazard parameters for the datasets related to induced seismicity accompanying underground exploitation of copper ore in the Legnica-Głogów Copper District (LGCD) in Poland. The algorithm is under implementation to the EPISODES platform (https://tcs.ah-epos.eu/) - an IT platform that provides access to integrated research infrastructures of the Thematic Core Service of Anthropogenic Hazards (TCS AH) of EPOS (European Plate Observing System). The algorithm is also a component of the pilot developed within the EPOS SP project (No 871121), which aims to strengthen the interaction with the private sector and the added value for society. The pilot demonstrates the potential of the IS-EPOS platform software applications for the technology-related probabilistic assessment of time-dependent seismic hazard. The pilot supports a Traffic Light System approach. The current seismic hazard is compared to threshold values based on the exceedance probability for a given magnitude.

Apr 26, 2022

By JA Vallejos

High stress underground mining poses a significant challenge to rock mechanics and rock engineering. To overcome theses challenges significative improvements in solutions and best practices of the design and operation of mines under high stress have been developed and implemented. This paper presents certain topics related to the management of high stress for sustainable underground mining. The topics include; the effect of preconditioning techniques (destress blasting and hydraulic fracturing) in the seismic rock mass response to underground mining and the dynamic behaviour of rock support systems. The opportunities associated with research in rock mechanics and practical rock engineering are discussed.

Apr 26, 2022

By Nancy C. Shaver, Alan Tapp

Leach pads of 272,000 tonnes (300,000 st) and 910,000 tonnes (1,000,000 st) with associated operating ponds have recently been constructed on sidehill locations with up to 20 percent slopes. The larger pad was designed in anticipation of ore heights up to 30 meters (100 feet). This paper describes site investigations and civil engineering design as well as construction experience associated with development of these pads. The leach pads were underlain by a double liner system consisting of 2 mm (80- mil) HDPE over compacted fine-grained tailings, with an intermediate leak detection layer. Both sand and geotextile drainage layers were used. Pad slopes were limited by the factor of safety against sliding on the HDPE liner. The sites for the facilities had been substantially disturbed by prior mining and construction activities. Natural conditions included peat layers and locally swampy ground. Site preparation included french drains to lower the water table and stripping of unsuitable subgrade materials.

Jan 1, 1987

By T. Resende, J. Sismour

"Signs in underground mines are subject to variable airflow, which carries dust and moisture. Dust buildup reduces their visibility, hampering production efficiency and safety. Underground workers commonly must stop to clean signs in order to gauge their location, or find critical supplies or services. There are currently a variety of coating products, including dust and water repellants, available on the market that have the potential to reduce dust accumulation on sign surfaces. This paper describes a preliminary study to determine their effectiveness. The study involved a practical testing protocol using a trickle rock duster and samples cut from a clean, used road sign. Product effectiveness, under both dry and wet conditions, was evaluated based on photographic evidence by comparing changes in sign luminosity after a period of rock dust application. By analyzing the frequency of different pixel luminosities on the dust-covered samples, both uniformity of dust coverage and the total amount of accumulation was assessed. Results indicate that at least one product may reduce the amount of dust buildup on sign surfaces and increase visibility. INTRODUCTION In all underground mines, visibility of signage is critical. Signs inform miners of their location, direction toward escape routes, and location of supplies. Over time, sign surfaces can collect dust and can eventually become unreadable. The rate of dust accumulation on surfaces is often particularly high in coal mines, where both mining (e.g., cutting and drilling) and rock dusting activities can contribute significant amounts of dust to the airways. Several factors may contribute to dust buildup on sign surfaces. First, basic principles of fluid and particle flow are at play. When a fluid travels past a stationary surface, the velocity of the fluid at the surface boundary is zero. If a very small dust particle moving with air collides with a surface, it does not immediately fall off since the air velocity is zero at the sign surface. (This is the same reason that dust can collect on a rotating ceiling fan.) Further, once the collision occurs, other mechanisms may help keep the particle there – including friction that resists particle falling due to gravity, and adhesive forces due to humidity and/or static charges the particle and others already on the surface. Currently, the most common way to deal with reduced sign visibility due to dust buildup is for mine personnel (e.g., a compliance foreman, supply worker) to periodically clean sign surfaces – usually just by wiping them with a cloth. As a regular activity, this solution is inefficient; in cases of emergencies, it can also pose unnecessary risks. Application of an off-the-shelf coating to sign surfaces may represent a simple yet effective way to reduce the rate of dust accumulation. There are currently a variety of products on the market that may be suitable for this purpose, including dust and water repellants."

Jan 1, 2017

By Abdullah Arik

In deposits with highly skewed grade distributions, such as precious metals deposits, proper handling of the outlier high grade data is very crucial to the ore reserve estimation. Although some recent geostatistical techniques are available to handle the estimation problems with these outlier data, ordinary kriging or conventional methods are still widely used to estimate the ore reserves for such deposits. One reason for this is the fact that the alternative methods offered are either too complex or too exhaustive for the mine engineers and geologist who often do not have the expertise or the time to apply these methods. This paper presents a new 2-step kriging algorithm "Outlier Restricted Kriging" (ORK) which can be a simple and a practical tool to use where the ordinary kriging will fail to handle the outlier high grade data properly in block grade estimation. The paper details the methodology and discusses the results of its application to a gold deposit.

Jan 1, 1992