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By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

Tellurium (Te) is an important scattered metal. Known as the vitamin of modern industry, national defense and cutting-edge technology, it is the supporting material for new high-technology materials. Currently, its separation and extraction from Te-bearing materials face problems such as long flowsheets and high reagent consumption, giving rise to an urgent need to develop new methods for its recovery.

By M. A. Trevits

Methane gas is an ever-present problem facing the underground coal mining industry. Mine operators are mandated by law to maintain safe concentrations of methane gas within the mine environment. Ventilation is used by all mine operators to reduce gas concentrations. When gas emissions are such that ventilation alone cannot control the gas, methane drainage methods must be applied. In the 1970's, there was a concern that unprecedented gas emissions would be experienced as mine operators began new developments in the deep and gassy Blue Creek and Pocahontas No. 3 Coalbeds. Such concern was well founded as significant gas volumes are being emitted as these mining operations mature. In 1971, the O.S. Bureau of Mines began to tabulate and track the change in mine emissions. These data were extracted from the underground coal mine quarterly air quality-quantity inspections performed by the Mine Safety and Health Administration. At that time, approximately 6,560 Mm Id (231.7 MMcfd) of gas were emitted from 430 underground coal mines. It was determined however, that the mines emitting less than 2,832 m Id (100 Mcfd) contributed only 2.1 percent of the total daily gas flow. In 1988, underground coal mines emitted 8350 Mm Id (294.9 MMcfd) from 487 mines. This report evaluates the changing nature of U.S. mine gas emissions over the last 18 years.

Jan 1, 1993

By R. D. Stewart

Abstract. Induced fluorescent sorting is a means of beneficiating an ore by selective labeling with a reagent combination which fluoresces when activated by ultraviolet light The reagent combination normally consists of a surface active compound and a fluorescent dye. The surfactant adheres selectively to a specific surface and carries the dye with it. Upon activation with ultraviolet light, the labeled pieces, in the size range 1.27 cm to 20 cm (0.5 to 8 in.), are detected during free fall by photosensitive cells and ejected by water jets. Either ore or gangue may be labeled.

Jan 1, 1980

By Bekta? Uz

In this research, geological characteristics of sand quarries around the village, Kemerburgaz Akpinar, are studied and the mineralogical, petrographical, chemical and technological characteristics (such as sieve analysis, relative density, water absorbtion etc.) of the sand samples, obtained from the area are explained. In the general area sand' quarries, being in lacustrine formations belonging to Neogen, the stratigraphic location of the sand occurences take place at high levels of these formations, geologically. All of this pattern, being under 1 mm with a ,particle dimension, it ranges from 0,5 mm in the quantity of 99 % to 0,25 mm in the quantity of 15 relative density is 2,65 g/cm3 ; water absorbtion is 0,9%. Mineralogically, the sand samples contain Quartz (84%), Feldspar (3%), Calcite + Aragonite (10%), Pyroxen+Amphibole (1-2%), Garnet+Tourmaline (0.5%), Olivine (0.1-0.5%). Besides, sand samples contain SiO2 with the quantity of above 90%. Containing Quartz at high levels for mineralogical, petrographical and chemical characteristics, Akpinar sand will be evaluated as silica sand when the carbonate mineral is removed with the method of ore preparation such as leaching.

Jan 1, 2005

By VIVEK KUMAR HIMANSHU, PK SINGH, AK MISHRA, MP ROY, RAVI SHANKAR

Underground blasting has many challenges. The primary aim of blast designers is to optimize drilling and blasting parameters to deal with the associated challenges. Optimizing these parameters is currently based on various rules of thumb, which have many site-specific limitations. Accordingly, computation of these parameters using empirical rock fragmentation predictors can be useful for blast designers. This paper presents the results of work on burden-spacing determination by back-calculation from the empirical Kuz-Ram model for underground stope ring blasting.

By Mark J. Zdunczyk

"The term “aggregate” has a number of definitions depending primarily on the use of the material. Aggregate in some context is sand, gravel, crushed stone, slag or other material of mineral composition used in bituminous and portland cement concrete, mortar, plaster, railroad ballast, filter beds and a variety of other uses where aggregates can be utilized.Of the natural aggregates, crushed stone is widely used for most construction purposes. Crushed stone can be mined from a variety of rock types such as limestone, dolomite (dolostone), granites, and granitic type rocks, basalt, gabbro (trap rock), sandstones, schist, marble, gneiss, quartzite, rhyolite, as well as other rock types. The U.S. Geological Survey (USGS) breaks down the rocks by type sold as follows: limestone, dolomite, marble, calcareous marl, shell, granite, trap rock (basalt, diorite) sandstone/quartzite, slate, volcanic cinder and scoria and miscellaneous stone.In 2015, the USGS estimates that 1.32 Gt (1.45 billion st) of crushed stone were produced in the United States. The volume of crushed stone produced, and the numerous mines that produce it make the crushed stone industry the largest mining industry in the United States. The five leading states for production of crushed stone in 2015 were Texas, Pennsylvania, Missouri, Florida and Ohio. The size of the first two states certainly helps in output because of the large market area. The remaining states benefit from being able to barge along rivers to outside markets in adjoining states. Georgia producers rail large amounts of granitic aggregate to Florida and adjacent states devoid of crushed stone aggregate, especially skid resistant aggregate (aggregate used on the top course of asphalt roads)."

Jul 1, 2016

By D. M. Thayer

Dry magnetic separation of feebly magnetic minerals and wet magnetic separators suitable for highly magnetic minerals have been commercially utilized for a number of years. The beneficiation of magnetic taconite ores by conventional, low intensity magnetic separators in combination with flotation is well established technology (1). However, over the past decade much effort has been expended in developing techniques for the upgrading of feebly magnetic oxidized iron ores (2,5). Such research and development have been stimulated by the limitations of the above-mentioned techniques in application to ores containing fine material; for example, ores requiring fine grinding for liberation or slime-forming ores such as the oxidized taconites or semi-taconites. Wet separation has allowed the reduction of the minim particle size that can be effectively treated from that allowable for high intensity dry magnetic separation. Consequently, the development of high intensity wet magnetic separation methods has received much attention in the search for an effective method to treat the weakly magnetic minerals. Recently Lawver and Hopstock (5) have provided an excellent review of the state of know- ledge of this technology. In addition, a valuable compendium of available laboratory and commercial devices is included. Nonetheless, the feasibility of the use of high intensity magnetic separation in a particular application is largly empirical in nature and requires experimentation to chazacterize the response of a particular ore. The purpose of this paper is to assess the incorporation of high intensity magnetic separation for the beneficiation of a non- sliming specular Michigan hematite. Particular attention is focused on the existence of a lower limit of particle size that can be treated effectively and is inherent in the use of these techniques. Additionally, a rationalization of various models presented in the literature is attempted.

Jan 1, 1979

By Taner Aydogmus

The A$29 billion Chevron-operated Wheatstone Project is one of Australia’s largest resource projects. Located at Ashburton North, 12 kilometers west of Onslow in Western Australia, the project will consist of two Liquefied Natural Gas (LNG) trains with a combined capacity of 8.9 million tons per annum and a domestic gas plant. The LNG Plant will serve the offshore gas fields, which are situated some 250 km off the coast of Onslow in Western Australia. Once operational and on-stream, the Wheatstone Project will contribute to Australia becoming the world’s second largest exporter of LNG. For crossing the environmentally sensitive shore area, a micro-tunnel with an internal diameter of 2 m and approx. 1,242 m in length has been constructed by means of the pipe-jacking method. The micro-tunnel will accommodate a 1.1 m diameter pipeline (trunkline) to deliver gas from the offshore fields LNG Plant. The Wheatstone shore crossing design involves a number of unique challenges owing to its coastal location, where the alignment crosses through a shore area and terminates in a marine environment. This paper provides an overview of the Wheatstone Shore Crossing Project, presents the key features, and discusses the main aspects of the micro-tunneling design.

Jun 13, 2021

By Charles M. Pelanne

Without insulation we could not survive on this planet. This may sound like a self-serving statement but it is a fact. The blanket of air which surrounds us is a very effective insulating blanket, allowing some shortwave solar radiation to warm us during the day while retaining the longer infrared radiation at night. Our life on earth is very much dependent on materials performing an insulating function without being thought of as insulation, clothing, fur, window glass, the ice of an igloo etc. The mechanisms of heat transfer involved in these materials are analogous to those involved in engineered insulations - Engineered insulations are designed for maximum effectiveness for given conditions within the applicable retraints. Engineered insulations are very effective! As an illustration let us consider this graph (Figure 1). It represents: 1. The radiative heat transfer between two 1 foot2 (0.0932) radiantly black surfaces, one at 100F (38C) and the other at the temperature indicated on the bottom scale. This does not include the convective and conductive heat flow of the air, both of which are significant but small in comparison. 2. The heat transfer resulting from the placement of 1 inch (25.4 mm) of insulation [10 pcf (160 kg/m3) ceramic fiber] between these two plates.

Jan 1, 1976

By Ilmar J. Martens

The statistical information and cost data used in this report has been made available by NICKDATA INC. Since 1982, NICKDATA INC. of Toronto, Canada, has produced an annual comprehensive nickel industry cost study. Up to date information on 22 mines, 21 smelters, and 16 nickel refineries representing 30 nickel production operations in 17 countries are included in the computerized cost analysis. The report is compiled from information obtained through regular annual visits to major nickel operations and continuous monitoring of information on all nickel producers. The 1984 report which was completed this summer, reveals drastic changes in the nickel industry cost structures.

Jan 1, 1984

By B. V. Cooper

The word "research" has been used in the title of my presentation somewhat against my better judgement. There are many definitions of the word. But the one I like best comes from Webster's New World Dictionary. It reads: "Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles. ..." I like that. In only 9 words, the definition conveys to me the very essence of what should be going on either in or for the coal industry. Unfortunately, not enough coal-related research is going on. And much of what is being done is, in my view, not really as effective as it might be.

Jan 1, 1983

By Venkata Aneesh

This paper examines the desired blast fragmentation results associated with mining fleet performance at Sidney Quarry of Pike Industries, A CRH Company by reducing cycle times and hauling less oversize material generated from the blast to the crusher to increase the overall plant throughput. We are constrained with blast patterns due to the poorly sorted and fractured seams in the quarry, which is angled at 35° NE and dipping at 80° and runs parallel to the Interstate-95 highway on the east of the quarry boundary about 600 ft, making it challenging to alter the blast patterns for optimal yield. We evaluated multiple relationships between blast patterns in conjunction with loader diggability. Results analyzed include the digging hours, fleet cycle times, and the fragment size with the optimized blast design through 3GSM software to arrive at the optimal yield to maximize the crusher throughput. Our primary objective is to focus on safety with efficient cycle times and clean floors & clean face generation for better operational efficiencies. Secondly, to optimize the crusher yield which is an integral part of quarry operation. Further, this paper provides the utilization of 3GSM blasting techniques in quarry applications with computer vision fragmentation analysis and VizaLogix, a fleet management software to analyze the cycle times sampling.

Feb 1, 2024

By J. MCGUIRE, E. J. Haas, B. Demich

Near misses can enhance awareness of the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, the value of these reports and how they influence subsequent actions or controls to reduce on-the-job risks are unclear. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. The analysis provides insight into ways that risk-communication and management programs can be improved to reengage workers and their situational awareness on the job.

By S. Hicks

This technical note describes an alternative procedure that can be used in linear programming calcula¬tions where the compliance limit of lbs S02/million Btu for the blending coal is subject to change. Dr. Mateer in his technical note titled "Coal blending for sulfur compliance" (ME, September 1994, p. 1103) defined an "excess sulfur" parameter that provides a valid constraint equation for a linear program optimization. The coals used by Dr. Mateer in his examples are shown in Table 1. To create the parameters for the constraint equa¬tions to blend to an SO2 content of 1.2 lbs S02/million Btu; the excess sulfur for Coal A was defined as Sulfur excess%o = 0.5 - 0.6-13,000/10,000 = -0.28 This equation was used to create the constraint equation -0.28A + 0.44B + 1.36C<- 0.0 Another way to create the parameters for the constraint equation is given below. In these equations: ? W is the total weight; ? A, B and C are the fractional proportions of each potential blend stocks; ? Sa, Sb and Sc represent the percent sulfur content of the blend stocks; ? Ha, Hb and He represent the calorific content of the blend stocks in Btu/lb; and ? H and S represent calorific and sulfur contents of the composite blend. The weight of blend to produce one million Btu is [ ]

Jan 1, 1997

By Paul E. Richardson, Edwin E. Maust

Cyclic voltammetry and surface potential (photovoltage) measurements have been carried out on galena electrodes in sodium tetraborate solutions with added HC1 and NaOH to adjust the pH over the range 2 to 13. The first technique shows that the surface species formed on moderate anodic polarization and reduced on subsequent cathodic polarization are the same over the entire pH range. At anodic potentials, a soluble metal species and excess sulfur are formed; at cathodic potentials, sulfur is reduced to a soluble species. More importantly, excess surface sulfur is formed spontaneously under zero current conditions in alkaline solutions. This has been shown to occur on both polished surfaces and on virgin surfaces produced by in situ cleavage under the electrolyte. The photovoltage gives some insight into the charge and potential distribution at the galena surface. This is found to depend on past electrochemical history and the n- or p-type semiconducting character of the electrode and is interpreted in terms of changes in the surface stoichiometry that occur during reduction or oxidation. The effect of surface stoichiometry on subsequent xanthate interactions is discussed.

Jan 1, 1976

By J. Hupka

The limited effectiveness of the original hot water process for recovery of bitumen from certain Utah tar sands containing bitumen of higher viscosity (e.g. Sunnyside, Tar Sand Triangle)1,2 indicated that bitumen viscosity strongly&apos; influences the separation efficiency. In this regard, there should exist a critical value of bitumen viscosity above which the effectiveness of the hot water process decreases significantly. Apparently certain tar sands contain bitumen of such high viscosity that even a digestion temperature of nearly 100°C is insufficient to lower the viscosity below the critical value. In addition it seems that differences in physico-chemical forces which act between sand and bitumen are negligible in comparison to the difference in visco-mechanical forces. Predominantly mechanical forces hold viscous bitumen on the rough surface and in the pores of sand particles, resulting in strong adhesion. This phenomenon is a critical feature in the phase disengagment of oil-wetted domestic tar sands with viscosity control by temperature. Besides increasing the temperature for viscosity control the effectiveness of the original hot water process could be enhanced by control of bitumen viscosity with diluent additions. Strictly speaking this appraoch is the only possibility for heavy bitumen for which the high temperature of digestion does not lower the viscosity sufficiently. As a result of viscosity control by diluent addition the digestion temperature can be lowered which is important from an industrial standpoint. Another important consideration is that effective phase disengagement occurs only when the entire bitumen phase has the same viscosity. This means that some time (penetration time) is necessary for complete and uniform dilution of the bitumen. If the viscosity of bitumen, which is a function of temperature, diluent addition and penetration time, controls the separation efficiency, hot water processing of many different kinds of tar sands should be possible, assuming that the sand phase consists primarily of quartz-type minerals.

Jan 1, 1982

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

"Underground refuge alternatives (RAs) require an air source to supply breathable air to the occupants. This requires pressure relief valves (PRVs) to prevent unsafe pressures from building up within the RA. The Mine Safety and Health Administration (MSHA) mandates that PRVs prevent pressure from exceeding 1.25 kPa (0.18 psi or 5 in H2O), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. Research to date by the National Institute for Occupational Safety and Health (NIOSH) suggests that the design and implementation of PRVs used in RAs has not yet had sufficient performance analysis or technical development. In response to this need, NIOSH tested a variety of PRVs using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork, and various sensors to determine if subject PRVs meet the MSHA requirement. Relief pressures and flow characteristics including opening pressure and flow rate were measured for five different PRVs under a variety of conditions. Subject PRVs included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place (BIP) RAs, and a commercially available valve that was designed for a steel RA and is currently being used in some BIP RAs. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.8 to 6.1 in H2O) and flow rates up to 19.3 m3/min (683 SCFM). INTRODUCTION The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) was enacted in the wake of three mine explosions/fires that claimed 19 lives that year. Intended to help improve underground coal mine accident preparedness, the MINER Act includes provisions that target mine safety issues in areas such as emergency response planning, adoption of new technology, training and education, and mine safety standards enforcement [1]. Section 13 of the MINER Act specifically directed NIOSH to provide for research into the effectiveness and viability of refuge alternatives (RAs) for underground coal mines. This mandate culminated in the 2009 adoption of changes to 30 CFR mining health and safety regulations, requiring underground coal mines to provide mine emergency RAs and associated components, to provide a life-sustaining environment for persons trapped underground. Such RAs can be either self-contained mobile units or built-in-place (BIP) facilities. The regulatory changes also include provisions establishing requirements for Mine Safety and Health Administration (MSHA) approval of RAs and their components, and among these provisions are numerous criteria for providing a safe breathable atmosphere under positive pressure within the RAs. One specific criterion for maintaining a safe RA atmosphere requires the inclusion of an air pressure relief valve that will activate at a maximum of 1.25 kPa (0.18 psi or 5.0 in. H2O), or at a pressure above mine atmospheric pressure in the RA as specified by the manufacturer when the breathable air is supplied by a fan or compressor [2]."

Jan 1, 2017

By R. Venugopal, V. K. Saxena, Veerendra Singh

"Ore morphology plays a vital role during the milling and liberation of minerals. This study was carried out to understand the role of mineral crystallography and mineral interfaces on the milling and liberation processes. Data related to mineral crystallography, Vickers Hardness Number and beneficiation processes were collected from literature, and detailed statistical analysis was conducted to relate these parameters. Review of the crystallographic information of minerals present in ores indicates that molecular weight and cell parameters significantly affect milling and liberation characteristics. Mineral interfaces were classified into the three categories of coherent crystals, semi-coherent and incoherent crystals, and breakage behaviors were studied. The studied cases revealed that these material interfaces control the micropore properties that play a vital role in the initiation of intergranular and intercrystalline fractures which occur in siliceous manganese ores and dolomite as a result of thermal treatment. In contrast, banded hematite jasper and coal exhibited a much more complex fracture pattern due to their coherent interfaces and finer physical associations. This study explains the effect of the various types of interfaces on milling, and the approach can be helpful in developing a methodology to enhance mineral liberation with minimum energy consumption.IntroductionComminution is a vital unit operation in the mineralprocessing, cement-making, power-generation and pharmaceutical industries. Its importance in mineral beneficiation operations is increasing every year as a result of the growing need to exploit lower-grade ore bodies and process reject materials (Blazy et al., 1994; DOE, 2005). Low-grade ores require significant energy during grinding to liberate the valuable minerals, which are further separated from the gangues by various beneficiation methods. Various attempts have been made to enhance mineral liberation during grinding to minimize energy consumption. Most of these studies focused on the analyses of the compression mechanism, chemical additives, thermal treatment, microwave treatment and electric disintegration (Klimpel and Austin, 1982; Norgate and Weller, 1994; Bearman et al., 1997; Kumar et al., 2010; Wang et al., 2011; Singh et al., 2012). However, many of these efforts had limited success, and there is a need to see the problem from a fresh perspective."

Jan 1, 2015

By S. K. MONDAL, K. K. K. SINGH, S. Singh, R. K. TIWARY, S. K. Chaulya, G. C. MONDAL, R. S. Singh, T. B. SINGH

In this work, a comprehensive field study was carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling was conducted to envisage dust concentration due to existing and closed mines in the region. The air quality modeling exercise predicted that particulate-matter levels of PM10 and PM2.5 might increase in the ranges of 3.2 to 23.1 and 2.1 to 8.9 μg/m3, respectively, due to mining activities when some of the closed mines will be operated in the region without controlled emission. The predicted total PM10 and PM2.5 at the selected receptor locations were in the ranges of 86.39 to 194.89 and 34.82 to 99.55 μg/m3, respectively. Adequate measures were suggested to control air pollution from mining activities, and an intelligent dry fog system was designed to suppress dust emission efficiently from mineral processing plants and opencast mines. The developed system has special features for facilitating eco-friendly mining.

Canada is a major producer of chrysotile asbestos. In fact, Canada accounts for approximately one third of the world chrysotile asbestos production. Deposits are mined and the fiber processed in Québec, in British Columbia on the West Coast and in Newfoundland in the Atlantic region. Foremost among the Canadian provinces is obviously Québec. Some 85% of Canadian deliveries come from mines located in the Eastern Townships, a region which lies along the southshore of the St. Lawrence River, between Montreal and Québec City. At the heart of this vast territory, five (5) mining towns make up what is called the Québec asbestos region. Total capacity of the five (5) mining producers of Québec is about 1 366 000 tonnes.

Jan 1, 1981