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By Shadia J. Ikhmayies

"Nanocrystalline CdS thin films were prepared by vacuum evaporation on glass substrates at ambient temperature. The films were characterized by recording and analyzing their transmittance, X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) images and Energy dispersive X-ray (EDAX) spectra. X-ray diffractograms revealed that the material is nanocrystalline with predominant cubic crystal structure and preferential orientation along (1 1 1) plane. SEM micrographs confirmed the nanostructure of the material and showed uniform and well covered surfaces. EDAX reports revealed that the films are cadmium rich and contain oxygen. The first derivative of the absorbance was used to estimate the effective bandgap energies of the nanocrystallites and the hyperbolic band model was used to estimate their radii. The results were compared with those obtained by XRD and SEM measurements.IntroductionCdS thin films are of considerable interest as they can be used in fabrication of solar cells and other opto-electronic devices. In particular, heterojunction solar cells with a narrow band gap base and wide band gap window have been investigated in an attempt to develop efficient, stable and low-cost solar cells [1]. The CdS quantum dot embedded in a glass matrix is one of the well-known quantum dot systems and its electronic and luminescent properties have been studied extensively [2].Three-dimensional confinement of carriers within the quantum dots leads to the blue shift of the optical band-gap and to modification of many properties of semiconductor material [3]. It has been argued that in these semiconductor nanoparticles the hyperbolic band model gives a better fit to the observed quantum size effect as compared to the effective mass approximation [4]."

Jan 1, 2012

By John A. Herbst

Mineral processors have evolved from "handbook-based" decision makers to "model-based" decision makers. With this evolution have come significant improvements through increasing productivity, decreasing capital and operating costs and increasing product quality. This paper traces the development of model-based decision-making technology over the last 40 years and documents the benefits resulting from systems optimization using these tools. Some speculation is ventured concerning the future of model-based decision-making tools and their use in the field of mineral processing.

Jan 1, 2000

By P. Duran

The metallurgical gas handling system at Chagres Smelter, like that of many smelters, can be the limiting constraint to processing more concentrate through the smelter. Mass and energy balances for the metallurgical gas handling system processing off-gases from the flash furnace and Peirce-Smith converters have been used by both operations and process engineering groups to help evaluate different operational scenarios in which the use of the installed capacity could be maximized and/or an operational strategy can be change with the purpose of removing a bottleneck or justifying an investment to relieve a constraint in the gas handling system. The present work describes the development of these process balances that were carried out in Exce®. The results were validated with operational data and, subsequently, some cases of industrial interest were simulated, detecting some conditions that were limiting the operation due to the present installed capacity in the Chagres Smelter.

Jan 1, 2007

By Emiliano Mauro Giraldo Paredez

El presente estudio señala la capacidad de anclaje de los pernos de roca más utilizados en el Perú y la relación existente con la longitud. Originalmente, las pruebas en bloques de granito se debieron realizar dentro del campus de la UNMSM, pero por no reflejar las condiciones reales, se ejecutó en la mina Reliquias de la Cía. Minera Castrovirreyna (Huancavelica). Los perons estudiados son Splet, Barras Helicoidales, Hydrabolt y Swellex, convenientemente acondicionados para tener anclajes efectivos de 1, 2, 3 y 4 pies, donde los resultados demuestran que la capacidad de anclaje de los pernos no guarda una relación lineal con sus longitudes, es decir, al duplicar la longitud de un perno, su capacidad de anclaje no necesariamente será el doble. Asimismo, La elongación de los pernos, tiende a guardar una relación lineal con la carga aplicada, mientras que el comportamiento de las Barras Helicoidales es irregular, sobre todo cuando se instalan con cemento.

Sep 12, 2011

In dealing with the pulverization and treatment of auriferous ores, it may be stated that there is not one system of treatment applicable to all classes. In the southern portion of New Zealand the ores generally contain free gold, with scarcely any impurity that is, it is found in an almost pure state, without any alloy, and its dissemination amongst the matrix is generally in tolerably coarse particles. The only difficulties the mill man has to contend with, are the economical concentration of pyrites, which in some of the lodes are rich in gold, and the extraction of the gold the pyrites contain. In some of the lodes there is what may be termed float gold, that is, the particles of the precious metal are so finely divided that it passes over the quicksilver tables, and, unless there are other appliances for saving it, this class of gold is entirely lost.Indeed it is only within the last five years that any attention has been given, in the southern portion of the colony, to saving the fine gold that has passed the amalgamating tables. In the North Island the ores are very complex there are scarcely two mines, although they may be adjoining each other, where the bullion is of the same character. On every field the gold is alloyed with silver', and in combination with other metals and mineral substances, such as copper, zinc, antimony, galenfl, iron, sulphur, arsenic, etc., and, in some instaaces, cinnabar, as in the case of the Champion lode at Tui Creek, Te Aroha. Ores of this class are extremly difficult to treat satisfactorily.

Jan 1, 1903

By L. Avramovic, B. Han, R. Jonovic, Z. Stevanovic, K. Haga, S. Dimitrijevic, A. Shibayama, L. Godirilwe, Y. Takasaki

Pyrite (FeS2) and chalcopyrite (CuFeS2) which could not be recovered, are present in mine tailings discharged from Bor copper mine. About 0.3% of copper (Cu) is contained in these tailings, therefore it can be considered as a useful copper resource. At the same time, pyrite is known to promote acid mine drainage, therefore it is necessary to detoxify the tailings. An efficient method has been proposed to recover copper and reduce the environmental impacts of tailings by a combined hydrometallurgical process of high pressure leaching (HPL), solvent extraction (SX) and electrowinning (EW) process. HPL process yielded high copper leaching rate (>95%) when water (H2O) was used as a leaching media. On the other hand, pyrite contained in the tailings was converted to iron oxide by high pressure leaching. Stability evaluation of the residue obtained from high pressure leaching, confirmed almost no elution of metal ions. The percentage of copper extracted and stripped from the Cu-loaded organic phase reached 97.4%. Moreover, it was confirmed that a low iron concentration in the electrolyte of copper electrowinning, resulted in the improvement of current efficiency of copper electrodeposition. INTRODUCTION Mine tailings are a by-product obtained from the flotation process and there are billions of tons of already existing tailings all over the world. Moreover, several billion tons of additional copper tailings will inevitably be produced in the coming years (Onuaguluchi & Eren, 2012). With the declining average copper ore grade, alternative sources of copper are highly sought, mine tailings have a comparable copper grade to that of low-grade ores (0.2–0.3%) therefore, it can be said that copper mine tailings present a very important source of secondary raw material for copper production (Antonijevi´c et. al., 2008). Consequently, it is necessary to confirm the possibility of the valuable metals (such as copper) recovery from mine tailing in which copper content is about 0.2–0.3%. Our group investigates the flotation and high pressure leaching processes for recovering of copper from mine tailings. Previous work on related samples include copper and nickel flotation tailings from Botswana, and a low–grade copper ore sample from Chile. Impurities, which are associated metals in mine tailing such as iron (Fe) and aluminum (Al) co-dissolve into the solution during the HPL treatment process. Therefore, separation of copper from impurities is necessary for selective extraction of copper from mine tailings and upgrading the copper concentration in the leachate to enable further purifying of Cu by electrowinning. Thus, it is important to investigate the possibility of applying solvent extraction for concentration of copper from leachate solutions of mine tailings (Onuaguluchi & Eren, 2012; Antonijevi´c et. al., 2008). In this study, LIX-84I was used as an extractant of copper from the leachate of high pressure leaching of mine tailing. As a fundamental solvent extraction investigation, the extraction behavior of copper was studied using a simulated solution of the leachate from the high-pressure oxidative leaching of mine tailing. The effects of; solution pH, extraction time, extractant concentration and phase ratio on copper extraction and sulfuric acid (H2SO4) concentration on stripping were investigated.

Jan 1, 2019

By Jose A. Caceres

Mine planning and mineral processing optimization are usually treated as two unconnected problems, especially at open pit and panel caving mines where the cut-off grade is practically the only variable optimized and analyzed for in the planning proposes. Using existing planning tool, the output is a reserve consumption strategy privileging higher grades. With the earlier consumption of the highest grades, every year produces revenues which are closer to the cost and potentially even below cost. However, there are other ore characteristics that can also affect the profitability of the operation. A new methodology has been developed, incorporating the grinding and flotation relationship into the mining economic models for the simultaneous analysis and optimization of the throughput-work index-recovery relationship through changes in the mining limits, sequence and redefinition of the reserve consumption strategy. A mine-site that implements this new planning strategy, can expect to increase the NPV from 5 to 15% depending on the actual operational settings. Two case studies have been developed, showing how the inclusion of the work index in the economic model changes the phase and mining sequence in an open pit mine and the caving sequence and the optimum column height in a panel caving mine.

May 1, 2004

By B Roberts

The Department of Industry and Resources (DoIR) is responsible for several sets of legislation, which, among other things, regulate the storage, handling and transport of dangerous goods as well as every aspect of the life cycle of explosives in order to prevent explosions, fires and spillages. The legislation with particular relevance to explosives includes: The Explosives and Dangerous Goods Act 1961; the act deals with the storage, manufacture, sale, import, authorisation and use of explosives. It is primarily framed for use of explosives and fireworks in the general community but also has relevance for storage on mine sites. The Dangerous Goods (Transport) Act 1998; this act regulates the transport of explosives on public roads, but not on mine sites. The Mines Safety and Inspection Act 1994 (MSI Act); this act and supporting regulations deal with the full spectrum of occupational health and safety in the mining industry. There is a substantial section in the regulations dealing with the use of explosives at a mine site.DoIR has identified the need for security upgrades of the Government Explosives Reserves, the need to tighten security measures at mine sites, the need for improved security checking for licensed shotfirers and the need to restrict the availability of explosives to authorised people who have had appropriate security checks. It is also clear that we need restrictions on the sale and use of ammonium nitrate (AN). A number of additional security measures are being proposed and all proposals are being refined by ongoing industry consultations. These will be adopted into new explosives regulations in association with the new Dangerous Goods Safety Act 2002 (DGS Act). Government finalised the act in June 2004. The act remains dormant until new explosives and dangerous goods regulations have been prepared. When the DGS Act and a suite of regulations are proclaimed as a package, sometime between December 2004 and April 2005, the old legislation consisting of the current two acts, will be automatically repealed. It is also proposed that all explosive regulation, including those under the MSI Act will be consolidated in one place under the DGS Act for user friendliness.

Jan 1, 2004

By Sun Jiale

This paper presents a brief description of information construction technology for supported excavation to assure satisfactory performance of engineered system. As a successful example of application of the technique, quite a few troublesome problems, such as high groundwater level in soft ground and crowded buildings around the excavation, were solved satisfactorily in the construction of the new tower of Guangzhou Overseas Chinese Manison.

Jan 1, 1991

By Frank Haehnig

Ground freezing is a technique which is used more and more in tunnelling under complex ground conditions. This paper will present three case studies which highlight different aspects of the ground freezing technique when applied in urban environment. The first project is the City-Tunnel in Leipzig, Germany, which is being built beneath the central station and which is the largest ground freezing project currently under construction in Germany. The second case study is part of the North-South-Line project in Amsterdam, Netherlands where ground freezing will be carried out to al-low the TBM drive through old wooden foundation piles. The freeze tubes for this project will be driven using Horizontal Directional Drilling (HDD). The last project is the Hallandsas Tunnel Sweden where the ground freezing equipment has to be installed against high water pressure. The paper illustrates that ground freezing can be implemented in difficult ground conditions such as soft ground, highly fractured rock and high water pressure. The case studies highlight the importance of good workmanship. With the increasing numbers of large tunnels being constructed in difficult ground conditions the paper concludes that the complex case studies presented will be-come more representative for future tunnel projects in urban environments.

Jan 1, 2008

By Lewis M. Haupt

IT has given me great pleasure to read, in the papers recently published by this Society, the discussions on the subject of Technical Education, which were developed at the joint meeting held at the Franklin Institute in June, 1876; and since it was impossible for me to be present, I desire to improve this my first opportunity of adding the weight of my testimony and experience to what has been so ably presented by others. It is a subject about which the people need to be kept agitated, that their views may expand with the demands made for a higher and more thorough education. It is the public at large, the capitalist, the manufacturer, and the laborer, who are to be benefited more or less by this elevation of the standard of our professional schools, and it is but just, therefore, that the schools should look to them for the means with which to accomplish so desirable an object. It is no doubt to the interest of a metallurgist to employ a skilled laborer who will prevent waste by properly proportioning his materials ; by regulating the supplies of air and fuel ; by arranging his plant in the most economical manner, and by disposing of his products to the greatest advantage. The engineer is benefited by selecting for an assistant a person able to determine the values of his factors of safety for the same materials in different forms and positions, avoiding expensive suits for damages and cost of reconstruction; he should be able to so locate a road as best to fulfil the requirements of a through traffic, and yet develop local industries. But I need not multiply instances to show what all will readily concede, viz.: the advantages of a theoretical education ; that was fully demonstrated at the previous special meeting, but it is still an open question whether the practical instruction should precede, accompany, or follow the theory.

Jan 1, 1877

By Jhon J. Silva Castro

Blast vibration records used in mining contain unwanted information in the form of noise due to long-period drifts, background noise, and noise due to the conversion of the analogue signal to a digital signal. When recorded signals from blasting are used to find other physical variables, such as going from particle velocity to acceleration or displacement, the additional information in the vibration signal can result in inaccuracies in the estimation of the peak values and more dramatically, the results in displacement or acceleration can be nonzero near the end of the record. There are different proposed methods to clean or filter the unwanted information from the signal. All of the methods are based on finding the best fit of the record average value (baseline) and then subtracting from the record under analysis to produce the desirable adjustment. Different criteria and functions are used to define the best fit. The function to use will depend on the shape of the record average values. The main characteristic of the baseline function is that it represents a low frequency wave. Such a low frequency wave can be a periodic function or a polynomial expression of nth order. According to the order of the polynomial expression, the baseline correction can be linear, parabolic or high order. In this document the detailed procedure and the results for the baseline correction of a blast vibration record using a periodic function and a polynomial expression of different order is presented. The results show that the drift problem when displacement is calculate using velocity records increases with the increase of the distance from the blast.

Jan 1, 2015

By Stone AM, Romensky G

The requirement for economic operation of unit trains carrying bulk materials has dictated that rapid and accurate bulk loading methods be provided. The train loading station at Phosphate Hill, built for Queensland Phosphate Ltd. to load rock phosphate, provides this facility and whilst the concept used is not unique, it contains a number of novel features that are considered to advance the "state of the art'' in this field. This paper briefly reviews some alternative concepts evaluated, and describes the design and operation of the scheme ultimately selected as being most appropriate to the project requirements. it is one which utilises a variable speed belt feeder whose speed is controlled in proportion to the weight rate of material moving on the belt as measured against a set point

Jan 1, 1978

Various influences determine how an Environmental Management System (EMS) for a mining or petroleum project is developed and administered. These influences include the environmental and resource legislation applying to the project, the culture of the organisation, the environmental sensitivity of the area, and the administrative policies of the regulatory agencies involved. While financial penalties and even imprisonment may be imposed for non-compliance with environmental legislation, there are other compelling reasons for the establishment of an effective EMS. If a company wishes to be considered by Governments for the grant of exploration or mining rights, it is important that it can demonstrate environmentally responsible operations at existing facilities. The development of an effective EMS requires commitment from the Board of the company and the issue of an Environmental Policy to empower all levels of the staff and workforce to achieve environmentally responsible operations. This must be supported by the provision of appropriate human and financial resources, and environmental training of staff at all levels from the Board to the mine site, workshop and office. A regular environmental auditing programme is essential to ensure that the EMS is in place and is effective in achieving compliance with regulatory requirements, corporate policies and protection of the environment. An EMS can be developed on the basis of existing management systems, quality management systems, existing and emerging environmental management standards (such as BS7750 and ISOI4000), or sophisticated computerised systems which may incorporate international experience, standards, and codes of practice.

Jan 1, 1995

By R. Feenstra

In the course of time, an increasing number of investigations on jet cutting all kinds of material, such as rocks1, 2, 3, metals4, 5, and wood6 have been reported to serve various applications. This paper deals with one particular application of jets, viz deep-well drilling for hydrocarbon exploration and production. A number of papers have been published on this subject 7, 8, 9, some of which refer to jets purposely containing abrasives, termed 'jetted particle drilling'7. Since such abrasives complicate fluid handling considerably and do not appear to be absolutely necessary for making hole we have restricted ourselves to conventional drilling fluids. A large part of our investigation has been performed with the aid of three laboratory-type drilling machines, which permit tests on both micro-bits (12 in) and full-scale bits (62 - 9 5/8 in). In view of the application of jets in deep wells, care has been taken to simulate hydrostatic pressures as they exist in the field on the hole bottom. These have been found to have a major effect on the bit-penetration rate for various drilling fluids. Following experiments with single nozzles, laboratory bits have been designed, improved further and developed for field use. Field runs on 9 5/8 in bits, using conventional equipment and pumps, served to verify the feasibility of the jet drilling concept. Further efforts are evidently needed to evaluate the jet drilling method. It is encouraging that one of these10, a field test programme, is supported by a number of oil companies jointly. Such a combined effort is of paramount importance to evaluate and develop this new method of drilling to its full potential in a reasonable period of time. This paper aims to contribute to that ultimate goal.

Jan 1, 1974

By M. G. Spengler

A new type of pack has been developed primarily for the support of narrow stopes. It was shown in the laboratory that it has characteristics that very closely approximate the optimum required by underground support to achieve hangingwall stability.

Jan 1, 1978

By S A. Johnson, J Cassidy, J L. Mauk

Geophysical anomalies at Puhipuhi reflect both diverse lithologies and different degrees of hydrothermal alteration. Most significant is a strong negative gravity anomaly (up to 50 g.u.), encompassing but extending beyond areas of known alteration, which is modelled as a deep zone (up to 3 km) of reduced density in the host greywacke basement. This zone, interpreted as being due to alteration (at least in part), closely correlates with the extent of overlying basalt flows. The gravity data indicate that the most intense alteration occurs below the basalts and correlates with the location of previously inferred hydrothermal upflow zones. These observations suggest that the basalt may have acted as a cap rock to a mineralising geothermal system. Aeromagnetic data identify highly variable but typically low magnetisations in the basalts which suggests that alteration may have been contemporaneous with volcanism. These geophysical data at Puhipuhi confirm the locations of centres of known alteration and suggest potential exploration targets below the basalt cap where there is no surface manifestation of alteration. Further implications of these results are discussed in Locke et al. (1999).

Jan 1, 1999

By B. Ndlovu

The world mineral industry has over the years experienced growth in the production of nickel (Ni) due to its use not only in the catalytic industry but mainly also to its demand in the stainless steel production industry. Hence there is a need to produce more pure and marketable grades of Ni through the use of efficient purification routes such as solvent extraction. The V10-LIX®84-IC system resulted in nickel (Ni) extraction isotherm shifting to lower pH levels. The pH window of opportunity for the extraction of Ni subsequently increased in solution containing magnesium (Mg) and calcium (Ca) even though the system also resulted in slight shifts to less positive pH values for Mg and Ca curves. Results showed a synergistic effect of LIX®84-IC when added to V10 for all elements, Ni, Mg and Ca. The pH50 values for elements Ni, Mg and Ca in the V10-LIX®84-IC system were 2.95, 8.10 and 7.70 respectively. Comparing results obtained when using V10 alone produced ?pH50 for Ni, Mg and Ca being 3.35, 0.15 and 0.70 respectively, which was a confirmation of the synergistic shifts for all the elements. The ?pH50 (Mg-Ni)value was 1.95 with no synergism and 5.15 with synergism and that for ?pH50 (Ca-Ni)was 2.10 with no synergism and 4.75 with synergism. This showed that the Ni-Mg separation factor was relatively larger than the Ni-Ca. Improved loading and stripping kinetics were also observed. Keywords: Nickel solvent extraction separation, magnesium, calcium, versatic 10 acid and LIX®84-IC.

Jan 1, 2008

By Toru Yamasaki

"Bimodal lithostratigrafic assemblages are of significance in volcanogenic massive sulfide (VMS)-hosted lithology. The largest deposits are either bimodal-siliciclastic or maficsiliciclastic, and the presence of a significant siliciclastic component in the host stratigraphic succession favors large VMS deposits (e.g., Franklin et al., 2005; Barrie and Hannington, 1999). In the case of modern sub-seafloor VMS deposits in arc-related settings, the majority of deposits have been discovered in association with calderas or cauldrons (Halbach et al., 1993; Ishibashi and Urabe, 1995; Iizasa et al., 1999). These features are formed by the explosive eruption of silicic volcanoes, so that silicic host rocks and/or pumiceous volcanic clasts are generally observed around the ore deposits (e.g., Binns and Scott, 1993; Fiske et al., 2001). Caldera-like and graben-like morphological features therefore attract attention in geophysical surveys. However, silicic lithologies (dacite and rhyolite) normally contain only small amount of metallic elements (e.g., a few ppm to a few dozen ppm of Cu), whereas mafic rocks, such as basalts and basaltic andesites, contain significant amounts of metals (e.g., a few hundred ppm of Cu). Thus, the origin of metallic elements in VMS deposits associate with the silicic host rock remains unclear.The Iheya North Knoll is a volcanic complex in the middle of the Okinawa Trough. It is located in a young and actively spreading back-arc basin that extends for 1200 km behind the Ryukyu arc-trench system (Lee et al., 1980; Letouzey and Kimura, 1986). Several active hydrothermal fields have been recognized in the Iheya North Knoll. Mineralization at the Iheya North Knoll is characterized by relatively juvenile features consisting of VMS deposits with associated hydrothermal alterations to various degrees. Massive sphaleriterich sulfides at this site, recovered for the first time from beneath an active seafloor hydrothermal system, strongly resemble the black ore of the Kuroko deposits of the Miocene age in Japan (Takai et al., 2011). From February 11 to March 17, 2016, the SIP CK16-01 (Exp. 908) D/V Chikyu cruise was conducted at Iheya North Knoll and the rifting center of the Iheya Minor Ridge area, middle Okinawa Trough. The Iheya Minor Ridge area is also an active hydrothermal field, located ~30 km southeast of the Iheya North Knoll. In this area, basaltic rocks are widely distributed, and drilling has confirmed that the basaltic materials continue to ~120 m below the seafloor (Kumagai et al., in prep)."

Jan 1, 2017

By M. A. Reyes, J. Bickson, J. R. Srednicki

Federal laws mandate the presence of refuge alternatives (RAs) in underground coal mines and provide guidelines for harmful gas removal. After an explosion, harmful gases can follow survivors into an RA and can reach a deadly concentration. Investigators from the National Institute for Occupational Safety and Health (NIOSH) tested 12 ventilation system configurations (VSCs) to purge sulfur hexafluoride (SF6) tracer gas from a built-in-place (BIP) RA in the Experimental Mine in Bruceton, PA. Using a borehole air supply, tests were conducted with airflows of 750 and 1,000 standard cubic feet per minute (SCFM). Excluding a VSC where the air inlet was 1.98 m (78 in) from the air outlet, the results show that the time to purge the SF6 concentration from 1,000 parts per million (ppm) to 25 ppm ranged from 26 to 29 minutes for an airflow of 750 SCFM and ranged from 18 to 23 minutes for an airflow 1,000 SCFM. Mines can use this information to reduce purge time in case of a mine disaster and determine which VSC to avoid. INTRODUCTION After a fire or an explosion in an underground mine, the concentration of carbon monoxide can reach a fatal level. In a mine disaster, the main goal is to escape. However, if miners cannot escape, they have to migrate to a location to find refuge and, if possible, communication, and a borehole source for a fresh air supply. To ensure survival of the miners, Federal laws mandate the presence of a refuge alternative (RA) within 304.5 m (1,000 ft) of the nearest mining face. In addition, Code of Federal Regulations Title 30 CFR Section 7 sets the guidelines for personnel tracking, RAs, and the removal of noxious gases in underground coal mines (Mineral Resources, 30 CFR, 2014). Federal regulations define an RA as a protected, secure space with an isolated atmosphere and integrated components (Mineral Resources, 30 CFR, 2014). There are three types of RAs: portable metal RAs, portable tent-type RAs, and built-in-place (BIP) RAs. A BIP RA is constructed using masonry or other stoppings to create an isolated space in a mined-out area. Blast doors are installed in one or both of the stoppings for the miners to enter the RA. Furthermore, RAs must provide the following components: breathable air, food, water, air monitoring, and harmful gas removal. Federal regulations have emphasized the mandate for breathable air and harmful gas removal in the following words: “Purging or other effective procedures shall be provided for the airlock to dilute the carbon monoxide concentration to 25 ppm” (Mineral Resources, 30 CFR, 2014). The purpose of the mine ventilation system is to provide a sufficient quantity of air to the underground mine workings, to dilute methane and other contaminants, to maintain a suitable working environment, and to prevent accidents from happening (Cheng and Wei, 2014). In addition, the organic nature of coal amplifies risks from poisonous gases, explosions, and fires (Engström et al., 2018). If an underground coal mine ventilation system fails after an explosion, the concentration of toxic gases, most notably carbon monoxide, will increase. Carbon monoxide is dangerous because it creates tissue hypoxia by binding to hemoglobin (Özmen and Aksoy, 2015).

Jan 1, 2019