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By Geir Martin Haarberg

Modern electrolysis technologies can provide possibilities for developing sustainable processes in terms of energy and environment. Laboratory experiments were carried out to study electrodeposition of iron from molten salts and aqueous solutions using an inert oxygen evolving anode to eliminate the emissions of CO2. The possibilities of molten salt electrorefining of metallurgical grade silicon to produce solar grade silicon were also investigated. Electrochemical techniques were used to study the electrochemical behaviour of dissolved iron, silicon, and titanium species. Bulk electrolysis was carried out to deposit pure iron, silicon, and titanium. The quality of the deposits was studied by SEM/EDS and XRD analyses. Calculations based on laboratory studies indicate that great improvements in terms of reduced energy consum

Jan 1, 2010

By Ting Lu, Gerard Laman

"This document compares the systems of coal classification described under ASTM standards used in Canada to GB standards used in China. A preliminary connection of metallurgical coal classes was set up between the two classifications. In GB classification system, there are nine metallurgical coal groups, namely PS, SM, JM, FM, ½ ZN, RN, 1/3 JM, and QM used in coal blending for coke production. PS coal is almost equivalent to the Low Volatile Bituminous coal; SM, JM, and FM coal groups fall into Low to Medium Volatile Bituminous range; ½ ZN, RN, 1/3 JM, and QM are equivalent to bituminous coal with medium to high volatile matters; QF contains higher volatile bituminous coal compared with High Volatile Bituminous coal. The caking properties commonly used in respective country are also compared in this document. These properties include free swelling index (FSI) and maximum fluidity used in Canada, as well as caking index (GR.I.), and the maximum plastic layer thickness (Y) mainly employed in China. It has been observed that the log of the maximum fluidity has a stronger correlation with the caking index than the Y values. Metallurgical coal processing strategy and typical coking coal product qualities are briefly discussed in the last section of this paper. Currently there is a trend to use heavy medium cyclone in both countries. In Canada the conventional two-product cyclone technology is the preferred practice; whereas in China the three-product heavy medium cyclone arrangement is widely used.INTRODUCTION Coal can be simply classified by applications into two categories: i) thermal coal used to provide heat energy in combustion, and ii) metallurgical coal which is converted to coke, in a carbonization process, and used mainly in the iron and steel industry. Metallurgical coal contains even higher heating values than thermal coal. In addition, it presents unique plastic properties during carbonization which in turn produces a porous solid, high in carbon referred to as coke. Coke is one of the most important raw materials in the iron and steel industry."

Jan 1, 2012

By B. A. Comley

Over the past few decades a great deal of effort has gone into characterizing the effects of frother type and concentration in flotation using a variety of two-phase techniques. Whilst useful and informative, this research still does not assist in the selection of suitable frothers for three-phase industrial-scale froths. This paper investigates the effects of frother type and concentration in a three-phase industrial froth. The objective was to determine if progress could be made in terms of understanding the behavior of frothers in flotation and understanding how they affect the sub-processes occurring in the pulp and froth phases and, ultimately, the metallurgical performance of a flotation cell.

Jan 1, 2007

The distribution or the userul minerals or Tasmania is so closely connected with the geological structure of the island that it will be convenient to briefly recapitulate the principal ract or its geological history, before describing the ore and other deposits. In many cases these present features which are very puzzling in the absence of knowledge of the structure of the districts in which they are found and in all cases it is of benefit to mining engineers to be acquainted with the main facts of the geological·history of the regions in which they have to carry on operations. Moreover, in speculating as to the origin of lodes and other deposits, we have constantly to rerer to the crumplings or the earth's crust by mountain-making movements, and to the igneous rocks which have been thrust throngh the other strata, to explain the origin or the lode fissures, and this discussion cannot be carried on without knowledge of local geology.The oldest rock yet met with in Tasmania are of Archooan age, and consist of highly crystalline quartzites and micaceous schist. They are most extensively developed towards the western side ot the island, forming a belt parallel to the West Coast from South-West Cape to Cradle fountain; but they also crop out here and there to the west and northward of this belt, where the covering strata or later age have been denuded away. Though not seen in situ in the eastern part of the colony, the abundance or pebbles derived from this formation in the conglomerates of the coal measures shows that it must in those day have formed land surfaces there also, and makes it likely that the archooan strata exist at no great depth: below many of the beds of later age now occupying the surface. Lying unconfortably upon these highly metamorphic strata we find next an extensive series of subcrystalline metamorphic conglomerates, grits, sandstones, slates, and limestones,of Cambro-Silurian age. These are well seen in the Gordou River Basin, along the West Coast Range, aloug the North Coast, and in the goldfields of the north-eastern portion of the colony. They are much broken by later intrusive rocks, and covered by younger rormations, but the series is spread more or less over the whole island.

By R. B. Krog

As part of its mining health and safety research program, the National Institute for Occupational Safety and Health (NIOSH) conducted a longwall methane emission and mining time study at a mine operating in the Pittsburgh Coalbed to access the methane emission consequences of mining a longer face. The methane emission contributors from the mining of a longwall face are: 1) gas released from the coal broken by the shearer, 2) gas emitted from the coal on the face conveyor, 3) gas emitted from the coal transported on the belt, and 4) background gas emitted from the coal face and from the adjoining ribs. Based on the results of the study, a set of site-specific mathematical formulas and constants were developed to characterize each of the four longwall emission contributors. The mathematical formulas were then applied to longer longwall face mining scenarios to predict the methane emissions from these faces.

Jan 1, 2006

By Guowen Dong, Qiyong Li, Qiang Li, Tiejun Chen, Zhihong Wu, Junying Wan

In order to search for a more economical and effective roasting additive for extracting vanadium from stone coal and solve the question of the disposal of PVC waste, PVC waste was proposed as a novel roasting additive to enhance extraction of vanadium from stone coal and realize the comprehensive utilization of resources. By adding this roasting additive, the leaching rate of vanadium reached 94.5% under the conditions that the PVC waste addition was 10 wt%, the roasting temperature was 800 °C, the roasting time was 1 h, the sulfuric acid concentration was 15 vol%, the liquid-to-solid ratio was 1.5 cm3 /g, the leaching temperature was 95 °C, and leaching time was 4 h, which increased by 8.4% compared with that of blank roasting. The thermodynamics calculation showed that the decomposition reaction of mica was performed easier with the participation of HCl produced by pyrolysis of PVC. Meanwhile, The SEM-EDS and aperture test analyses demonstrated that more cracks and voids appeared in the roasted sample by roasting with PVC waste, which could facilitate the release and extraction of vanadium. Additionally, the TG-DSC analyses indicated that PVC could provide large amounts of heat for the roasting process to promote the decarbonization and roasting efficiency of stone coal because of its high calorific value.

By Guowen Dong, Qiyong Li, Qiang Li, Tiejun Chen, Zhihong Wu, Junying Wan

In order to search for a more economical and effective roasting additive for extracting vanadium from stone coal and solve the question of the disposal of PVC waste, PVC waste was proposed as a novel roasting additive to enhance extraction of vanadium from stone coal and realize the comprehensive utilization of resources. By adding this roasting additive, the leaching rate of vanadium reached 94.5% under the conditions that the PVC waste addition was 10 wt%, the roasting temperature was 800 °C, the roasting time was 1 h, the sulfuric acid concentration was 15 vol%, the liquid-to-solid ratio was 1.5 cm3 /g, the leaching temperature was 95 °C, and leaching time was 4 h, which increased by 8.4% compared with that of blank roasting. The thermodynamics calculation showed that the decomposition reaction of mica was performed easier with the participation of HCl produced by pyrolysis of PVC. Meanwhile, The SEM-EDS and aperture test analyses demonstrated that more cracks and voids appeared in the roasted sample by roasting with PVC waste, which could facilitate the release and extraction of vanadium. Additionally, the TG-DSC analyses indicated that PVC could provide large amounts of heat for the roasting process to promote the decarbonization and roasting efficiency of stone coal because of its high calorific value.

By Jim Clark

Tunnel boring machine (TBM) tunneling is an ever-increasing prospect for underground construction, and, with each new tunnel bored, there are unknown elements. When boring through the earth, even extensive geotechnical baseline reports can miss fault lines, water inflows, squeezing ground, rock bursting and other types of extreme conditions. This article draws on the consider-able field service experience within Robbins to analyze successful methods of dealing with the most challenging conditions encountered. Many tunnel projects are located in areas with relatively poor access along the tunnel alignment and bored under extremely high overburden. These two factors often result in limited geological information. It would be reason-able to state that the deeper the tunnel, the greater the lev-el of uncertainties. When faced with these uncertainties everyone involved with the project including the owner, the contractor and the machine supplier must be prepared to tackle geological surprises. This article describes the problematic geological conditions and associated difficulties faced on three separate projects and the measures that were taken to overcome these difficulties.

By L. Xinghua

Limonite is a general term for a group of amorphous iron oxide and iron hydroxide materials. It is considered as one of the very refractory iron ore types due to its wide variation in chemical composition, iron content, moisture content and easily sliming in the course of comminution. Iron grade of test sample is 25.48%, the iron minerals are mainly limonite; and the gangue minerals consist of quartz and feldspar in majority, secondarily silicate minerals. In this test work, high intensity magnetic separation (HIMS)-cationic reverse flotation and magnetic roasting-low intensity magnetic separation (LIMS) tests were conducted on limonite ore. The test results show that the concentrate with iron grade of 50.97% and recovery of 68.50% can be obtained by HIMS-cationic reverse flotation technique; while using magnetic roasting-LIMS technique, the better concentrate indexes of iron grade of 60.36% and recovery of 89.71% are achieved, and the iron grade of tailing is only 4.42%. Therefore, the magnetic roasting-LIMS technique is a better suitable method for beneficiation of low-grade limonite ore. Keywords: Low-grade limonite; Mineralogy; HIMS; Cationic reverse flotation; Magnetic roasting; LIMS

Feb 27, 2013

By Paul Downing

A typical day for a blasting company includes what seems to be an infinite list of tasks dealing with numbers. Whether determining the exact amount of explosives material in inventory, the number of holes in the shot, the exact distance from the blast site to the nearest exposure, or the capacity of bulk hoppers, the accuracy of numbers is key to ensuring the safety of the public, property and personnel.

Jan 1, 2008

The trend for using larger equipment in open pit mining to achieve cost effectiveness raises the question about the optimum economic point of scale in the current world of globalization. The present paper treats this question through the prism of a new methodology of assessing the impact of the size of production equipment on the economic outcomes of coal mining ventures. The methodology incorporates a production scheduling optimization model that implements both principles of mine planning, coal quality optimization and waste deferment. The implementation of the waste deferment principle dealing with the spatial and time aspects of the mine sequence arrangement allows the adequate modeling of the optimality of production equipment scale through the use of mine investment parameters, such as, purchase and ownership costs and discounted cash flows analysis. A case study is provided to illustrate the applicability of the new methodology.

Jan 1, 2004

By Sigmund Black

Ingersoll-Rand Research, T n c and the Lee-Norse Co. built a Bureau of Mines sponsored, special deep cutting continuous miner under this contract to study the effects of rotational speed and depth of cut on airborne respirable dust. After preliminary tests indicated and later verified that deep cutting - low rotational speed reduces airborne respirable dust, a series of underground tests were performed (9 combinations of rotational speed and depth of cut at 45° bit angle and 4" bit spacing). Additional data was obtained on specific energy, coal sizing and noise. The conclusions reached from the tests results were; a) deep cutting reduces airborne respirable dust generated and specific energy needed to cut coal., b) the greater majority of the decrease occurs in going from 1" to 2" depth of cut, c) lowering rotational speed has a particularly sizable effect of reducing the amount of dust at the operator's location, d) no significant relationship was found for either noise level or coal sizing to rotational speed or depth of cut. Recommendations include. a)) use of specific energy as an indicator of the change in dust level correlating to changes in cutting parameters, b) mine operators should acquire new deep cutting machines., since retrofitting would be selective.

Jan 1, 1977

Jan 1, 1988

By J. Kruttschnitt

This paper, describing the mining operations at Mount Isa Mines, is one of a series covering mining methods and costs being published by the United States Bureau of Mines. The Mount Isa property has been in operation since June 1931; during this period operations have changed from the production and treatment of carbonate ores to the mining, milling, and smelting of sulphide ores. This change involved revision of ore-extraction methods. Stoping methods have been designed to apply to parallel lodes ranging from 10 to over 100 feet in width and dipping at 50° to 60°. The hardness and strength of the ore and enclosing wall rocks, together with the strength and thickness of the country rock between lodes, have permitted the selection of a sublevel stoping method for mining the sulphide ores.

Jan 1, 1937

By C. J. Allen, L. Battiston

"Introduction It has long been recognized by the hot-dip galvanizing industry that the characteristics of the galvanized coating can be influenced significantly by steel and pro cessing variables. Probably the variable of most concern to galvan izers today is steel chemistry. More specifically, the problem is the excessive reactivity of continuously-cast, silicon-bearing steels. In the past, structural steels processed by general galvanizers were in the low-to-medium ca rbon category and contained silicon at either low impurity levels (as with rimmed steels), or less than approximately 0.10% (as with semi-killed steels). The structures of the coatings produced on such steels are characterized by dense, compact layers of delta and zeta iron-zinc alloy phases and a distinct outer layer of eta zinc, which usually imparts a bright shiny appearance to the coating. The presence of silicon in steel, above the so-called semi-killed levels, is known to cause marked stru ctural changes in galvanized coatings. Such coatings are characterized by a relatively thin delta layer, a thick , coarse zeta layer and frequently an absence of the eta layer. The eta phase, comprising zinc which is carried out of the bath during withdrawal of the work, can be consumed by the continuation of the coating reactions until its temperature drops to the solidification point. This results in a dull grey and often mottled surface instead of the usually bright metallic appearance. These galvanized coatings are usually much thicker than coating specifications requ ire and they are usually more brittle and have poor adhesion to the steel. In service, these coatings tend to develop a rust-like discolouration. With the wider use of continuous casting by the steel producers and the associated additions of silicon in this process, the problem is becoming more important and receiving greater attention from the galvanizing industry ."

Jan 1, 1987

By Otto Ruhl

The zinc-lead ore reserves of the Tri-State district of Kansas, Missouri, and Oklahoma, as of December 31, 1947, are estimated at a total of 66,100,000 tons of crude ore containing 2.18 percent metallic zinc and 0.38 percent metallic lead. The Bureau of Mines began estimating the reserves in October 1945 and completed the' work December 31, 1947. A total of 38,900 acres of land representing approximately 5 percent of the area of the district is covered in this report. The work was confined for the most part to properties developed or partly developed by drilling and underground workings, and to acreage sufficiently drilled out to indicate ore of enough tonnage to make a commercial undertaking. The acreage in which ore reserves exist is widely distributed in all three States. A map of the Tri-State area is shown in figure 1. The remaining 95 percent of the area is not necessarily nonproductive but represents, possibilities for future exploration and development of additional mineral resources when and if economic conditions or national necessity encourage such work. Of the total reserves, 41 percent are in Missouri, 38 percent in Kansas, and 21 percent in Oklahoma.

Jan 1, 1949

By Mark Colwell

As per most other earth science engineering problems, the underground coal geotechnical environment and the way in which roof and rib support interacts with the rock mass are complex issues. While the problem should not be oversimplified (i.e., the dominant failure mechanisms or critical data input parameters should not be ignored), without question judicious simplification is at the heart of all good engineering design. Engineers play a vital role in supplying the world with solutions and products; however it is crucial that engineers make practical and readily useable contributions. One way to ensure this is to employ simplification in the engineering process.

By M. W. Von Bernewitz, W. J. Sharwood

So far as is known , there is no complete bibliography on sampling, therefore , this one should be of value . In it are nearly eleven hundred references , some dating back 30 years , on sampling at mines , mills , smelters , power plants , pumping stations and refineries . For convenience , there are included a few references to methods for sampling such materials as leather belting in mills , salt impregnated soils , and mine waters . All the important technical journals , - including some in foreign countries- and engineering society publications , also mining and metallurgical text - books , have been studied for anything concerning sampling , and while it is not claimed that every important reference has been listed , the bibliography is fairly complete . The arrangement is alphabetical by authors ' names , and the references are numbered serially in the crder that they appear in the bibliography . Anonyous references are listed under the name of the journal in which they appear , and are numbered like the references bearing an author's name . Patents are grouped in their numerical order , without index nu.bers . Under the heading , " U.S. Bureau of Mines Publications " , are listed all publications of the bureau that deal with sampling . While the serial number is omitted , these same references , of course , have serial numbers where they appear in the list arranged alphabetically by authors .

Mar 1, 1922

By Albert H. Fay

The first data compiled by the Bureau of Mines relating to coal- mine accidents in the United States were published in Bulletin 69," in which the total fatalities by years and States were tabulated from 1896 to 1912. Since the publication of Bulletin 69, further research has been conducted, with the result that the bureau is now able to publish for the first time all of the fatal accidents described in the State inspectors' reports by States, causes, and calendar years, from the beginning of inspection service to date. For the anthracite mines of Pennsylvania, there is a continuous record since 1870; the records of the Pennsylvania bituminous mines are continuous from 1877, and, with the exception of one year, the Ohio records are complete from 1874 to date. In fact, the records of all of the States, with few exceptions, are complete; and incomplete data for any year may generally be attributed to the fact that no report was published during that year. The magnitude of the coal-mining industry in the United States is such that too much stress can not be placed on the need of safeguard- ing the three-quarters of a million men employed. Although the figures given herein show an appalling record for past years, they are not published for the purpose of proclaiming the high fatality rate of the past. They are a record of experience covering a period of 45 years, showing causes and results of many accidents in the coal mines of the United States. They represent a diagnosis of the hazard of the mining industry, pointing out the principal physical causes of accidents, and make available a body of uniform facts that will serve as a basis of preventive measures for use in future operations. It is with these great purposes in view that the Bureau of Mines presents the classified data in this report. Classification and study of mine accidents on the basis of number of persons killed is common and very old, but fails to throw enough light upon the problem involved. Many serious accidents in mines have no fatal results, hence in a tabulation of fatalities they are overlooked and the real hazard of the industry is not made clear. An accident does not necessarily include an injury that may result therefrom. Such accidents as the breaking of a hoisting cable, an explosion of powder, gas, or dust, a runaway car or motor are all serious. Although no loss of life results, they should be recorded, investigated, and studied to prevent their repetition. No accurate data for the United States are available showing how far the personal element as related to the miner and his co-worker, the mine foreman, or to the superintendent and others in authority, contributes to accidents. Many accidents are due to inexperience on the part of the miner, his failure to heed orders, a misunderstanding of instructions and last, but not least, carelessness of himself or his fellow worker. A foreman or superintendent may fail to give proper warning regarding the conditions of certain parts of the mine; he may not have inspected certain rooms or entries on the day of a mine accident; the mine may not be properly equipped, or the operator may neglect to comply with the inspector's recommendations. There is, therefore, a personal element on the part of both the operator and the miner that must be considered. Legislation and the enactment of compensation laws will make the operator realize the seriousness of the mine-accident situation, when fatalities and injuries are to be paid for in legal tender of the realm. The miner must be educated and made to realize the dangers he encounters; he must learn that self-preservation and the safety of his fellow workmen should receive his first attention; he should cooperate with his employer, his asso- ciates, and the State mine inspector to the end that the mine hazard may be reduced to a minimum. "Cooperation for safety" should be the watchwords of the operator, miner, State inspectors, and all others in any way interested in the mining industry.

Jan 1, 1916

Electricity will play a major part in providing energy services in the 21st century. Ecologically Sustainable Development (ESD), that is accommodating the needs of the present without compromising the needs of future generations, will provide a focus for optimising the use of electrical energy. Environmental externalities may redefine the cost structure of electricity. Strong corporate environmental management will ensure that current environmental objectives are met and that future ones, identified by the ESD process and environmental externalities accounting, can be developed and implemented by receptive business managers. This paper addresses the current environmental issues of electricity production. It outlines a management strategy for the SECV becoming a community leader in protecting the environment. ESD is discussed in terms of using non-renewable resources wisely, extending their availability and putting in place mechanisms which ensure their ultimate substitution by renewable resources and conservation. The paper explores options for dealing with costing environmental externalities, particularly in relation to greenhouse emissions.

Jan 1, 1992