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"Developing markets for western metallurgical coal have continued to stimulate considerable exploration activity in the Rocky Mountain foothills and to influence major segments of a wide-ranging carbonization R&D pro-gram. Adjunct studies have included expanded petrographie investigations.Coal preparation has• been principally directed toward utilization of prepared small coal and was, like much of the year's combustion work, strongly influenced by concern over atmospheric pollution. Particular attention has been given to desulphurization and to the suppression of pollutants in combustion systems.In the area of non-fuel utilization of coal, interest has centered on plant nutrients and on a series of coal-based carbons which, inter alia, possess utility as filtration media.Other projects included the development of improved sampling and analytical methods, investigations into the effect of storage on coal proper-ties and R&D in solids pipelining. In addition, a significant volume of basic 'uncommitted' research has been maintained."

Jan 1, 1968

By N. A. Beier, R. Amos, Smith. L., C. Atherton, D. R. Barsi, D. Blowes, D. C. Sego

"Waste rock is one of the most abundant materials at mine sites and must be properly characterized and managed to limit acid rock drainage and other harmful byproducts. An experimental waste rock pile—part of the test piles research program—located at the Diavik diamond mine (Northwest Territories, Canada) was deconstructed and sampled to study the spatial variability of material properties. Bulk samples were classified based on the amount of material finer than 4.75 mm. Hydraulic properties of each sample were estimated and particle size distribution analysis was completed. These datasets and classification methods might be used to improve the understanding of hydraulic and geochemical behaviour of the material and to study waste rock at other sites. ¦ KEYWORDS Acid rock drainage (ARD), Material classification, Particle size distribution (PSD), Waste rock RÉSUMÉ Les stériles font partie des matériaux les plus abondants sur les sites miniers et, en tant que tels, doivent être correctement caractérisés et gérés afin de limiter le drainage rocheux acide (DRA) et la pré¬sence d’autres sous-produits nocifs. Dans le cadre du programme Test Piles Research Program, un amas de roches stériles expérimental situé à la mine de diamant Diavik (Territoires du Nord-Ouest, Canada) a été décomposé et mis à l’essai afin d’étudier la variabilité spatiale des propriétés des matériaux. Les échan¬tillons en vrac ont été classés en fonction de la quantité de matériaux plus fins que 4,75 mm. Les propriétés hydrauliques de chaque échantillon ont été estimées et l’analyse de la composition granulométrique effectuée. Ces ensembles de données et méthodes de classement serviront à mieux comprendre le com¬portement hydraulique et géochimique du matériau et à étudier les stériles sur d’autres sites. ¦ MOTS CLÉS classement des matériaux, composition granulométrique, drainage rocheux acide (DRA), stérilesINTRODUCTION Statement of problem The characterization of mine waste rock remains a challenge in active mining sites. The large volume of material and the large size of particles make it difficult to collect representative samples. Sampling techniques are often dis-ruptive to mining operations because they alter the structure of the waste rock pile or interfere with mine traffic. The convention at most mine sites to collect little to no information on waste rock material means that models and predictions of how waste material will behave and interact with the surrounding environment are based on general information that might not be site specific. This could lead to environmental damage or higher costs if environmental effects are underestimated during the construction of waste rock structures."

Jan 1, 2019

By Kris Inwood

"In 1879, when the Dominion government initiated its controversial program of industrial promotion, iron smelting in Canada was limited to one company producing coke iron on the mainland of Nova Scotia and three small charcoal blast furnaces in Quebec. There was no steel production. By the eve of the First World War, iron and steel were being produced in very large quantities, the companies active in 1879 had disappeared and new centres of integrated iron and rolled steel production at Hamilton, Sydney and Sault Ste. Marie had come to resemble the industry as we know it today. The most dramatic change was that at Sydney, Nova Scotia, where in the early 1900s, two steelmaking companies established works. The Sydney developments have been explained as the result of resource discovery and technical change. W.J. Donald, in his authoritative account of the Canadian iron and steel industry, observes:(1) ""The most rapid growth of the Canadian iron and steel industry has occurred since 1897 ... The remarkable growth has been caused largely by the new conditions of the industry. The discovery and use of Newfoundland ores, together with the availability of Cape Breton coal, has made the Nova Scotia industry not only possible but profitable .... It is a safe conclusion that the Canadian industry would not have been an important one, had it not been for the discovery of the Michipicoten and especially the Wabana (Newfoundland) ores:' Donald also argues that metallurgical progress had been necessary to render the ores valuable. ""Newfoundland ores ... contain a considerable amount of phosphorus, and were made available for steel-making by recent inventions:' The purpose of this paper is to re-examine Donald's story. It will be argued that the origin of steel-making at Sydney is somewhat more complicated than Donald has indicated. The difficulty with Newfoundland ore extended beyond its phosphorus content and a resolution required more than the basic open hearth furnace identified by Donald. Moreover metallurgical change was only one of several developments necessary to induce industrial investment at Sydney. Surprisingly, however, the discovery of iron ore in the late nineteenth century does not appear to be part of the explanation."

Jan 1, 1999

By K. C. Marsden, B. Pesic

"Interest in the efficient production and recycling of rare earth elements has increased in recent years along with the prices of these elements. The molten LiCl-KCl eutectic is one ionic solvent which can be utilized for these purposes. The LiCl-KCl eutectic has also been selected as the electrolyte for focused research for advanced pyrochemical recycling processes for used nuclear fuel in several nations. Rare earth elements are fission products with notable neutron absorption characteristics, and thorough understanding of the properties and behavior of these elements is critical to their successful partition from the electrochemically-similar actinide elements. The number of research papers investigating individual rare earth elements has greatly expanded in the approximately 35 years since the last review. These research papers are presented in a variety of languages and technical formats, making data difficult to compare, and are sometimes contradictory. A review and summary of diffusion properties of rare earths in LiCl-KCl eutectic was performed, and the data translated to a common format for evaluation. INTRODUCTIONThe rare earth elements have experienced growing importance in recent decades due to their application in high technology, including optical lenses, lasers, high-temperature superconductors, improved alloys, high energy-density batteries, and powerful magnets for compact electronic devices. Their historic production methods and uses are detailed in several texts (Hampel 1971; Bautista &Jackson 1992; Gupta & Krishnamurthy 2005). A s the p rice o f these e lements has r isen in r ecent years, so has interest in their efficient production and possible recycling options. Rare earth oxides are concentrated through hydrometallurgical techniques, but the high thermochemical stability of their oxides precludes production of rare earth metals in aqueous systems. However, the wide electrochemical window and better control of pO2- in fused salt systems allows the production of these reactive metals from their halides or oxides. The high ionic conductivity and diffusivity of the molten ionic electrolyte allow high currents with limited resistive losses (Fray 1980). Electrolytic methods in fused salts are commonly adopted for the production of bulk rare earths in a variety of molten salt systems. Fluorides are sometimes proposed for oxide electrowinning processes due to ability to dissolve the rare earth oxide, reduced hygroscopic behavior, and the wider electrochemical separation between O2 and halide gas evolution (Mohan Das, Damodaran et al. 1988; Gibilaro, Pivato et al. 2011). However, in most electrolytic production processes, such as that for mischmetal, the rare earth oxides are converted to chloride prior to electrolysis in a chloride bath (Gschneidner Jr. & Eyring 1978; Sharma 1987). Of the chlorides, the LiCl-KCl eutectic is one specific medium in which metal production and production-related investigations have been conducted (Gschneidner J r. & Eyring 1978; Driscoll & Fray 1993). L iCl-KCl eutectic has the advantages o f h igh conductivity, but relatively low viscosity and operating temperature. The low operating temperature allows simpler design, with reduced energy consumption, salt volatility and cell corrosion."

Jan 1, 2012

By M. Dupuis

It has been previously demonstrated [1,2] that using selective collector bar rodding has a big impact on the uniformity of the current density at the top surface of the cathode block and hence on the intensity of the horizontal current in the metal pad, The present study investigates the impact of using selective collector bar rodding on the MHD stability of a 500 kA aluminium electrolysis cell, For this purpose the recently developed MHD package for the aluminium reduction cell time dependent behavior is used.

Jan 1, 2005

By L. F. Haven

"The desirable shovel speed-torque curves are described, along with the characteristics of the more important electrical components used to approximate these curves. A particular shovel regulator system combining these components is discussed in detail and some of the advantages and disadvantages of the system are given.INTRODUCTIONIN 1959, STATIC CONTROL was for the first time successfully applied, installed and operated on a mining machine in North America. Since that time, a great deal has been learned about this control by the people maintaining these machines as well as by the de-signers.In 1961, the first SCR (Silicon Controlled Rectifier) or thyristor control system was installed on an excavator. This control differed from the earlier static control in that thyristor excitors supplied the generator fields directly. The development of thyristors of a sufficient rating to supply amounts of phase-controlled power to the generator fields eliminated the bulky Mag. Amp. -Rectifier combination previously used."

Jan 1, 1969

By Primak. George J.

"In the development of a new product as well as during its introduction on the market, it is very important to give due consideration to problems involving patents, licenses and trade marks. At the very beginning of the research and development program, it is obviously essential to ascertain, through a suitable patent search, that the product in question will not infringe any patents which are still in force. Then, a possibility of achieving one's own patent or proprietary position on the product or the process of its manufacture should be carefully explored. Licensing arrangements that one may reach with respect to patents and know-how covering such new product may, in the final analysis, determine its over-all success or failure. If one can count on licensing revenues or some favourable cross-licensing arrangements with respect to a newly developed product, this may go a long way to achieving profitability and success. The selection of a good trade mark is probably one of the most important acts that one has to perform once the product is developed, as customers will identify the new product by such a trade mark. In many instances, successful marketing and widespread acceptance of a product are largely due to its appealing name or trade mark, accompanied by proper promotion and advertising. Once the trade mark has been adopted, it should be registered in the Trade Marks Office to provide the protection afforded by federal statute. If the product is to be manufactured, sold or licensed in some other countries, similar considerations should be made with regard to each such country."

Jan 1, 1973

By Greg Baiden

Telerobotics focused on mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run? A new Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University. This chair will investigate these questions and many more through a series of experiments in a newly established telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian college?s eDome. The laboratory will support many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one/quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments and some preliminary results.

May 1, 2003

By Xiaoguang Zhao

The coal mining area in Northern Shaanxi, China, has been taken as the study area, and the damage mechanism of the ecological environment is discussed on the basis of analyzing the characteristics of natural eco-environment and resource development in this area. Mining subsidence is taken as an example, and by using the Gray Correlation Analysis method, the key impact factors have been selected. An assessment model with fuzzy comprehensive evaluation has been constructed, and 12 coal mines have been quantitatively assessed. This paper also constructs an ecosystem health assessment method and index system in the coal mine area on the basis of ecosystem health theory, and assesses the ecosystem health status in the Shenfu coal mining area from 2000?2006. The research results are expected to help the eco-environment protection process in the designated coal mining area.

Aug 1, 2013

By L. D. Smith

Net Present Value Impact of Discount Rate The Discounted Cash Flow (DCF) method of valuations is universally used and accepted. The main criticism of the method is that it does not recognize the value of projects long life projects. This can be seen in the preceding graph where the present value of cash flows in later years are small for discount rates over about 10%. This graph covers a project that has a 25 year operating life. It is clear from the low height of the NPV bars at 10% and 15% in the last years of the project that an additional 25 years would add almost no value to total project NPV. As an example of this effect, an colleague undertook the evaluation of a pulp and paper project. The plant could be justified, but it was not possible to justify planting the trees as they took too long to grow and so had not appreciable NPV. The plant had to purchase wood to feed the plant.

May 1, 2013

By Vincent Jourdain

Located in the James Bay Territory of Quebec (figure 1), the Clearwater property is jointly owned by SOQUEM Inc. and Eastmain Resources Inc. Exploration on the property since the early 70's has resulted in the discovery of several gold showings. Exploration work by the joint venture since 1995 has led to the definition of the Eau Claire Zone containing an indicated resource of 540 000 tonnes grading 11.1 g/t Au (8.7 g/t Au cut at 34.28 g/t Au). Hosted by the archean Eastmain Greenstone Belt, the property geology is dominated by mafic volcanics containing thin horizons of felsic volcanics and/or sedimentary rocks (figure 2). The sequence is metamorphosed to the amphibolite facies and contains two small toalitic intrusions. Regionally, the structural trend is oriented E-W but in the area of the Eau Claire Zone a second trend oriented NE-SW is also present. The first exploration work on the property was conducted by SEREM and SDBJ from 1973 to 1976. It consisted of an airborne electromagnetic survey and a ground follow-up program on several grids. This program, comprising geological mapping, geophysics and drilling, led to the discovery of the Natel showing where a drill intersection returned 8.89 g/t Au over 2.65 m. From 1978 to 1985 the area was withdrawn from staking because of the hydroelectric projects of the James Bay. In 1985, Westmin Resources Limited and Eastmain Resources began an exploration program based on a helicopterborne electromagnetic survey. Once again, a ground follow-up program was conducted on several grids. This program included a soil geochemical survey that identified a strong (up to 10 g/t) gold anomaly. Drilling of the anomaly led to the discovery of the Eau Claire Zone where resources were estimated at 270 000 tonnes grading 6.1 g/t Au at the end of 1990. In 1995, SOQUEM Inc. took an option to gain a 50% interest on the property and obtained its interest in 1998. Since 1995, two principal mineralization zones were identified on the property. The "Rosemary Zone" consists of veinlets and disseminations of pyrite and chalcopyrite within a magnetite-rich amphibolite. The mineralized zone was identified by stripping within an area of 1000 by 500 metres. Drilling indicates copper grades up to 0.32 % Cu over 49.2 m. with locally grades of 0.75 % Cu over 5.9 m. The mineralised zone is associated with QFP dykes and corresponds to a strong magnetic anomaly and a strong copper and molybdenum soil anomaly. The "Eau Claire Zone" consists principally of a set of gold bearing quartz-tourmaline veins oriented E-W and dipping at 45-50??to the south (figure 3). More than ten different veins are recognised in the zone and up to eight veins were observed in a single trench (figure 4). The host rock between the veins shows a degree of deformation similar to the regional volcanosedimentary rocks. Each vein is hosted by a unit of actinolite-tourmaline-biotite schist up to one meter thick. The veins and their hosting schist clearly cross-cut the schistosity of the hosting lithologies and the contacts between amphibolites and felsic to intermediate rocks. Usually, the veins are less than a meter thick and are composed of quartz, tourmaline and calcite. The proportion of quartz and tourmaline varies from 0 to 80% within a single vein. The veins commonly show massive, banded or brecciated texture. Sulphides, mainly pyrite, pyrrhotite and chalcopyrite, generally form less than 5% of the vein material.

May 1, 2001

By B. Qiu

The large surface ground movements induced by underground mining could threaten the safety of the pipelines laid across the subsidence-prone area. Existing analytical methods for the stress analysis of buried pipeline over mine subsidence area were based on the assumption of ?thin? pipeline, which limited their applicability. This paper presents the improved model with the capability to determine the stress distribution of the ?thick? pipeline. The pipe-soil interaction in this model was also updated to adapt various pipe soil contact conditions. In addition, the time-dependent effects of dynamic subsidence effects were also added to the model. A case of protecting a long section of a buried large-diameter pipeline over two longwall panels in a shallow mine is shown. The stress distribution along the pipeline is determined and the overstressed sections are identified. A partial uncovering plan was developed based on the predicted stress and complicated terrain at the site.

Aug 1, 2013

By I. Yutronic

Compañía Minera Doña Inés de Collahuasi's (CMDIC) Concentrator Plant is located at 4300 meters above sea level, approximately 2000 kms north from Santiago, Chile. The concentrator has three grinding lines. Each one, Lines 1 and 2, have one SAG mill at the primary grinding stage followed by a secondary grinding and classification stage consisting of one ball mill, two hydrocyclone batteries and a sump with two pumps. Line 3 has one SAG mill (Gearless Mill Drive), followed by a secondary grinding and classification consisting two ball mills, four hydrocyclone batteries and a sump with four pumps. Average throughput for these three lines is 150 Ktons per day. Peak values of 180 ktons per day have been achieved. Since late 2008 and throughout 2009 and 2010, Operations and Automation areas developed an optimization program for the grinding process, considering the implementation of Model Predictive Controllers (MPC) for the three SAG mills, and later, extending MPC to the secondary grinding and classification stages. The implementation of a MPC solution was based on stability considerations (high variability of the SAG process, high interaction between sump level control and classification efficiency, etc), requirements for an automated and consistent operation, the need to maximize throughput under timevarying scenarios and, in the long term, optimization of grinding process considering Specific Energy Consumption, among other parameters. MPC solutions had proven control robustness and strong optimizing capabilities in terms of helping in discovering new operational points and so achieving all of the aforementioned goals. On the first stage of the program, MPC implementation considered identification of dynamical process control models based mainly on historical data, in order to know the impact of a group of Manipulated Variables over Controlled Variables. Also, the impact of measured Disturbance Variables was modeled in order to take into account the high impact and interaction of these variables over the processes. At the end of this stage, 4 controllers were successfully operating for the 3 SAG mills and the secondary grinding and classification process. In response to challenges made by the working group, the second stage of the development of control applications in the grinding process required to achieve a design and implementation of a solution capable of governing the milling process, in addition to stabilization and optimization of both processes (SAG milling and secondary grinding), to integrate from a point of view of process control and automation. Therefore, in the second stage, MPC performance was continuously monitored and optimized through advanced tuning, inclusion of more process models (with proper step tests), redefinition of specific optimization criteria and adjustment to new process needs. Finally, successful MPC implementation at Collahuasi has proved that fast development and deployment of process control solutions is possible and allows immediate process stability, higher throughput, specific energy consumption reduction, and successful product size control, among many others.

Jan 1, 2012

By J. A. Haskin

The Engineering Department at Flin Flon has the following responsibilities: 1. Underground Surveying. 2. Open-Pit Surveying and Supervision of Blasting. 3. Mine Geology and Examination of Prospects. 4. Design of Plant Additions and Improvements. 5. Miscellaneous Field W ork, Reports, etc. The entire surface plant, as well as the underground workings, are located by co-ordinates based on a triangulation system covering an area approximately one mile long by one-half mile wide. The origin of this system and one end of the base-line is the southwest corner of Township 67, Range 29, west of the Principal Meridian. The bearing of the base-line was determined from the township boundary, which runs true north, so that all other bearings are almost astronomical. This is a great convenience when our surveys must be tied to mineral claims, rights-of-way, and land subdivisions. As the base-line extends across Flin Flon lake, its measurement across smooth ice was simple and accurate. The length, slightly over 1,600 feet, has been adjusted for the temperature and tension of the standard tapes used and checked sufficiently to ensure a maximum error of 1 : 15,000. Each angle was repeated ten times, but as no special refinements were used, errors of as much as four or five seconds are possible. The elevation of the origin of the triangulation system was approximately 1,050 feet above sea level. The use of this true elevation in our surveys would have resulted in negative elevations underground as soon as the mine reached a depth greater than 1,050 feet. To avoid this complication we therefore added 4,000 feet to this elevation. The collar of the Main shaft, for example, which is actually 1,072 feet above sea level, appears in our records as at elevation 5,072. Underground surveying, which follows standard practice, is done by two mine surveyors who share three helpers. The meridian is taken underground from two wires hung in either of the two vertical shafts.

Jan 1, 1935

By M. Courtin, D. Berthelot, M. Haggis, D. McClarty, R. Payne

Over forty years of uranium mining in the Elliot Lake region of Ontario (1956–1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity, Rio Algom Limited and Denison Mines Limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and, thereby, significantly inhibit acid generation, have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program. All five of Rio Algom Limited’s effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on “Fix Dmacs” technology. Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.

Jan 1, 1999

By D. Janney

Kennecott's Utah Smelter commenced operations in June 1995 utilizing Outokumpu Flash Smelting (FSF) and Kennecott-Outokumpu Flash Converting (FCF) technology. After some initial teething and equipment problems the smelter achieved its design capacity in mid-1997 and now processes over 1.0 million tonnes of copper concentrate per year with exceptional environmental performance. The smelting furnace has operated for 11 years and the converting furnace for 5 years without major shutdowns. The first major smelter shutdown commenced in September 2006 after extensive planning. The FSF was completely re-bricked and the latest above and below bath containment systems installed. The FCF was inspected and re-bricked with some improvements made to the above bath containment system. The FCF life is now anticipated to be the same as the FSF. Numerous improvements and modifications were made to the rest of smelter facility including extensive upgrades to the dry electrostatic precipitators. Production ramp-up was smooth with the smelter now frequently operating at acid plant capacity.

Jan 1, 2007

By Troy Boisjoli, Sean Hillacre, Matt Batty

Discovered in 2014, the Arrow Uranium Deposit has undergone rapid development through successive drilling programs informed by geostatistical drill hole spacing studies. An independent third-party geostatistical drill hole spacing study was completed by Clayton V. Deutsch Consultants Inc. in 2017, evaluating the uncertainty of thickness, grade, density, and areal limit of the Arrow Deposit to determine a drill hole spacing suitable for Indicated Mineral Resources. Indicated spacing was defined to be 24 to 32 metres (“m”) to be within 15% of predicted for a nominal quarterly production volume with a probabilistic tolerance between 75 and 90%. The study not only defined the Indicated Mineral Resource resultant from the 2016 drill program, but also provided drill hole targeting criteria for subsequent drill programs aiming to convert Inferred to Indicated Mineral Resources. A subsequent geostatistical drill hole spacing study on the Arrow Deposit was completed by Clayton V. Deutsch with Resource Modeling Solutions in December 2018 to define Measured Mineral Resource spacing in support of the 2019 drill campaign. The study resulted in a drill hole spacing of 9 to 17 m to be within 15% of predicted for monthly and quarterly production volumes using an accepted industry probabilistic tolerance of 90%.

Jan 1, 2020

By Jerry C. Tien, Yingjiazi Cao

"Coal spontaneous combustion (SponCom) is a natural phenomenon in underground operations, which can either happen naturally or be triggered by human activities. For underground operations, espe-cially in coal, SponCom can happen frequently as a result of air leakage, although its incubation period may vary depends on types of coal and surrounding environment, resulting in uncertainty in control. In China, most of the underground coal operations now use longwall mining method because of its superior safety, high productivity and efficiency. With an increased popularity, there is also an increasing necessity to study spontaneous combustion, its occurrence and management. There have been many theoretical analysis and experimental studies over the past half century hoping to understand the occurrence of coal combustion and its control measures to better understand the occurrence and to design controlling measures to limit the dam-age it causes. In this paper, research on coal spontaneous combustion fundamentals from these three aspects will be reviewed, gaps highlighted and possible directions for future studies. INTRODUCTION The history of anthropic development is the history of human's energy utilization progress. From the first usage of fire, people have been continuingly seeking energy resources on earth. Coal, as an abundant, economic and convenient source of fuel quickly became indispensable and made significant contribution to economic growth worldwide. With technology and societal development, people are becoming more and more coal-dependent, but at the same time, problems of fossil fuel combustion came into sight. In global coal mining industry, spontaneous combustion has now presented one of the most challenging safety issues, it is also believed that it has contributed significantly toward the climate change. It is essential that more effort be invested to examine the cause of SponCom and its control measures. Coal SponCom is a complex process, with both physical and chemical inter-actions among various interrelated factors such as local airflow distribution, ventilation pressure, methane emissions (if any), and physical surroundings underground. With the advent of powerful computers, simulation techniques and af-fordable modelling packages in recent years, significant advances have been made in understanding sponta-neous combustion. But because of the complex nature of combustion and varying underground conditions, there are still areas that need further examining. This paper will focus on illustrating the current research of coal spontaneous combustion and addressing research gaps and future study areas."

Jan 1, 2019

By N. Gharib, F. Hassani, P. Nekoovaght

"Novel rock breakage techniques are becoming more viable and attractive to industry. Microwave energy, as a thermal energy capable of inducing micro cracks through differential heating (therefore expansion) is a technology gaining considerable attention in mineral processing and ore comminution applications. Recently, the use of microwave radiation has been evaluated as a possible avenue for terrestrial and extra-terrestrial drilling applications as well as full face tunneling or rock breaking machines. As part of an overall research on use of microwave in rock breaking systems, the influence of microwave energy on the mechanical properties of common hard rock types as basalt has been investigated. The results revealed that microwave energy irradiation imposes micro and macro cracks to the surface of the rock being irradiated. In explosive free tunneling applications using TBM, jointed and cracked surface of rock eases the cutting process and increases penetration rate. The experimental setups have been simulated with the help of a multi-physics numerical modeling and the results have been compared with practical experiment. The wave propagation of microwave has been simulated and the distances where the power intensity is higher are identified. Experimental and simulation results underlined the potential impact of the use of microwave energy in underground or surface excavation applications such as mining and tunneling. This will also contribute economically when mine-to-mill operation is fully considered to improve the efficiency of rock crusher stages. INTRODUCTIONDuring hard rock breakage (i.e., separation of a piece of a rock from its parent deposit) in mining and civil applications, the performance of mechanical equipment such as tunnel boring machines (TBMs) is limited by high levels of bit wear and maintenance. Preweakening natural rock prior to breaking it by machine is one approach to lower bit wear and maintenance costs. Some preweakening methods apply heat directly or indirectly. For example, flame torch-assisted TBMs (Lauriello et al., 1974; Resource Technology, 1984) have been deemed economical in terms of equipment, but their feasibility is limited by high fuel consumption. Microwave energy could offer several advantages over the flame torch method: it does not produce emissions or increase fuel consumption (electricity source is available on the machine), and is easy to control (quick power on and off)."

Jan 1, 2015

By E. Mohammadi Zahrani

In this study, Mg-doped fluorapatite (Mg-FA) nanopowders were prepared through a sol-gel, technique and characterized. Designated degree of Mg2+ ions incorporation into the apatite structure was indicated by the x value in the general formula of (Ca10-xMgx (PO4)6F2), where x=0, 0.25, 0.5, 0.75, and 1. XRD, AAS, FTIR and TEM techniques were utilized to characterize the synthesized nanopowders. In vitro bioactivity of the powders was evaluated in simulated body fluid. Powders had a crystallite size less than 100 nm. It was concluded that Mg-substitution could alter bioactivity and dissolution behaviour of Mg-FA. These two parameters were proportional to magnesium content of the powders.

Jan 1, 2010