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By M. F. Goudge

Introduction It is only fitting on this occasion of the fiftieth anniversary of the incorporation of the Institute that we should indulge in a bit of retrospection and review the progress that has been made within this period in the various branches of the mining industry- progress that is so closely associated with the members of this Institute. Such a moment of retrospection will enable us better to appreciate the present status of the industry and to perceive more clearly the trends that should guide us in making sound plans for the future. The past half century has been a period of amazing industrial progress in Canada. In this period, the economy of our country has changed from one based chiefly on agriculture and the export of raw materials, to an economy based largely on a well integrated manufacturing industry. In all' o( these major developments, industrial minerals have played an important part and will play an increasingly, important part in the future. By ?industrial minerals? we mean the various non-metallic minerals (exclusive of fuels) as well as the rocks, sands, and clays used for industrial purposes. They are now used so widely and in such large quantities that modern industry could not function without them, and their continued availability at low cost is vital to the industrial future of Canada. The key position occupied by industrial minerals in modern Canadian industry was well illustrated two years ago when a strike occurred in the only Canadian plant producing soda-ash and calcium chloride at a time when those materials were already in short supply and unavailable from other sources. Within a short time of the shutdown of this plant, in which the two principal raw materials are limestone and salt, the great aluminium reduction plants on the Saguenay river were forced to curtail operations because of the lack of soda-ash, essential to the process of extracting aluminium from its ore. Automobile production, already harassed by a shortage of steel, was further hampered when glass for windshields and windows could not be supplied because the glass industry was slowed down almost to a standstill for want of soda-ash. Soap became almost unobtainable both to the housewife and to industrial users, because soda-ash is required in its manufacture. As a consequence of the soap shortage, the production o synthetic rubber at Sarnia was threatened because soap in large quantities is essential to the polymerization process. Motorists on gravelled highways all over Eastern Canada drove through clouds of dust because calcium chloride, used for dust laying, was not to be had. There were other cases of dislocation of industry related to the shutdown of this particular plant, but the above illustrates the wide ramifications of industrial minerals in modern industry. However, it is extremely doubtful if many Canadian citizens realized that these apparently unrelated happenings were connected in any way with limestone and salt.

Jan 1, 1948

By W. H. Hannay

Introduction The subject matter of this paper will be treated under two heads: (1) experimental work and the development of the purification system, and (2) the operation of the commercial plant. During 1927-28, a two-ton slag-retreating plant was in operation at the smelter for experimental purposes. Details of this operation and of the commercial plant are presented in a paper by G. E. Murray, read before the Annual General Meeting of the Institute in April, 1933 (1). A point which has considerable bearing on the subject of the present paper, and which was not emphasized by Mr. Murray, is the concentration of volatile impurities in the zinc oxide fume produced. The result of the operation of the slag fuming furnace is largely to confine in a closed circuit all the minor constituents of the Sullivan concentrates, both lead and zinc. They pass into the feed of the zinc fuming furnace, with the result that all impurities which volatilize-such as arsenic, antimony, tin, fluorine, etc.-report in the zinc oxide product. The accompanying condensed flow-sheet (Figure 1) will illustrate this. The only outlet for impurities which is not shown is the small tonnage which passes the Cottrell plants. The flow-sheet would indicate the possibility of building up a prohibitive concentration of cathodic impurities in the oxide leaching plant feed. However, after three years' continuous operation this has not occurred. Should this condition arise at some future date, discard of some tonnage of blast furnace slag is indicated. In Mr. Murray's paper, the much greater flexibility of blast furnace operation, due to the slag fuming furnace, is stressed, particularly as to the lead content of the slag. The requirements of our lead refinery call for a bullion containing about 0.70 percent antimony.

Jan 1, 1934

By Stopford Brunton

For many years it has been accepted as axiomatic that the greater number of 'veins' or 'leads' in the gold districts of Nova Scotia are of the 'interbedded' type. The corollary to this hypothesis is that the vein or lead will have a continuous hanging-wall of one kind of rock, and a continuous footwall of the same or another kind of rock; but the essential point is that the foot and hanging walls are, according to this theory, both continuous and of uniform composition throughout; and that the vein or lead conforms to the bedding of the adjacent strata. With regard to the deposition of the gold in the rocks, the probability is that the key of the problem is contained in a statement by E. R. Faribault, of the Geological Survey of Canada: "The combined effect of cleavage, jointing, and stratification is to cause the rocks, especially the quartzites, to break into rhombohedral blocks". It is essential to comprehend that the rocks of the Province are no doubt folded into anticlines and synclines; but also it must be fully realized that the gold deposits and pay-shoots do not depend so much upon these as upon the fractures resulting from the disturbance caused by the intrusion of granite masses, and controlled by the combined effect of cleavage, jointing, and stratification. These fractures would form the channels through which the ore-bearing vapours and solutions would rise, and at the junctions of these fractures, where the fracturing was greatest, the easiest passages would be afforded to the ore carriers, with the result that the ore-shoots would be found at or near the intersections of fractures. It is a significant fact that in at least thirteen different districts throughout the Province, operators have at various times remarked upon the occurrence of rich ore at the intersection of 'leads,' 'veins,' 'beds,' etc.

Jan 1, 1928

By Jr. Watts, B. K. Cantrell, K. L. Bickel, J. F. McDonald

"A field trial was conducted at an underground gold mine to evaluate diesel fuel derived from soybean oil (soy-methyl-esters or “biodiesel”) as an alternative to commercial, low-sulphur, number 2 diesel fuel (D2). A 2.7 m3, 18-ton load-haul-dump (LHD) unit, powered by a naturally aspirated, indirect injection (pre-chamber), 100 kW diesel engine was used as the test vehicle. The LHD was equipped with a diesel oxidation catalyst. The LHD operated satisfactorily on the biodiesel fuel. Operators observed a slight decrease in power and an absence of black smoke.Diesel particulate matter (DPM) concentrations were monitored for a six-week period while the LHD was operated with either the biodiesel fuel or the D2 fuel. DPM concentrations were measured in the mining section’s clean air intake, exhaust and on the LHD. Reduction in DPM emissions was determined from the measured difference in DPM concentrations between the clean air intake and the exhaust. The biodiesel fuel reduced energyspecific DPM emissions approximately 75%, from 3.6 ± 1.8 g/kW-hr to 0.86 ± 0.27 g/kWhr. Time-weighted average DPM exposure, measured near the LHD operator, was reduced from 0.67 ± 0.13 mg/sm3 to 0.28 ± 0.12 mg/sm3, or approximately 58%, when the biodiesel fuel was used. IntroductionDiesel exhaust consists of noxious gases and diesel particulate matter (DPM). Recent attention has focussed on the potential carcinogenicity of DPM and the potential health impact on miners. The National Institute for Occupational Safety and Health (NIOSH) recommended that whole diesel exhaust be regarded as a “potential occupational carcinogen”, and that reductions in workplace exposure would reduce cancer risks (NIOSH, 1988). The International Agency for Research on Cancer (IARC) declared that “diesel engine exhaust is probably carcinogenic to humans” (IARC, 1989)."

Jan 1, 1997

By N. V. Mel'nikov

This paper discusses the reserves of oil, natural gas and coal in the USSR, with particular attention to the future role to be played by coal in supplying the energy fuel resources of the country.

Jan 1, 1972

By W. C. Whittaker

COMPLETED in November, 1943, at a cost of over $1,500,000, Elk River colliery of the Crow's Nest Pass Coal Company, Limited, has been laid out and equipped for an ultimate annual production of 1,000,000 tons and replaces the recently closed Coal Creek plant, which has been operated by the Company for the past forty-five years. The project has involved the opening of mines in three seams, the construction of a complete set of colliery buildings, including a modern preparation plant of 360 tons per hour capacity, and the laying out of the necessary yard tracks and spur connecting the new development with the Company-owned Morrissey, Fernie and Michel railway, which, in turn, connects with the Canadian Pacific railway at Fernie. The colliery is three and a half miles east of Fernie, B.C., near the southern end of the Crow's Nest coal field, which contains the largest and most important body of coal in the Province of British Columbia. The coal-bearing horizon is the Kootenay formation, present in the form of a syncline covering an area of 230 square miles. Most of the coal seams occur in the lower 2,000 feet of the formation, the covering beds being largely coarse sandstones and conglomerates of great thickness, the presence of which accounts largely for the preservation of the coal measures. James McEvoy, in the report of the Geological Survey of Canada for the year 1900, states that the basin appears to contain a fairly constant coal content of nearly 172 feet in 23 seams of a thickness of one foot or over. Coal has been mined in the Fernie district since 1897 and the first shipments were made from Coal Creek colliery in the following year, over the then newly constructed British Columbia Southern railway. Since that time, a total of over 16,000,000 tons of coal has been produced, an average of 350,000 tons per year. The7ears of peak production were 1910, 1912, and 1913, with an all-time high of 924,000 tons in 1913. The lowest output in the history of Coal Creek was that for the year 1933, when only 60,340 tons were produced, the colliery being closed for some months. Present production from Elk River colliery averages 1,150 tons per day, the output being considerably less than it could be were sufficient man-power available.

Jan 1, 1944

By A. F. Matheson

The St. John Del Rey Mining Company, Limited, is an English company owning 150 square miles -of mining lands near Belo Horizonte, Minas Geraes, Brazil. The area is 2,300 to 5,000 feet above sea level, with a pleasant and healthy climate. Bedrock is Precambrian. The Nova Lima series of metamorphosed sediments and some volcanics is overlain uncomfortably by the Minas series of quartzites, itabirites. etc. Batholithic granite and gneiss cut both series and basic dykes cut all these rocks. There are important deposits of gold, iron, and manganese on the Company's holdings, as well as occurrences of arsenic, antimony, cobalt, nickel, dolomite, day, quartz, -ochre, bauxite, kyanite, and asbestos. Except for gold and consequent recovery of arsenic, all the other materials are relatively unexploited. The Company operates the Morro Velho gold mine and the Espirito Santo and Raposos gold mine. The Morro Velho mine was purchased in 1834 for £56,000. To the end of 1952 it had produced 7,000,000 troy ounces of gold from 15,000,000 short tons of ore. The ore z?ones are replacement deposits in a sinuous siliceous dolomitic rock locally termed "lapa seca," and plunge east, near surface at 45 °, at 8,000 feet at 15°. The ore minerals are pyrrhotite, arsenopyrite, pyrite, and chalcopyrite. Gold is finely distributed and almost nowhere visible. Ore reserves at the end of 1952 were estimated at 5.5 million short tons grading 0.39 oz. gold per ton. Chances exist for new ore within the mine area. The Espirito Santo and Reposos mine, in folded banded iron formation, has mineralization similar to Morro Velho but sulphides are less abundant. The mine to a depth of 2,500 feet has estimated ore reserves of 1.5 million tons of an average grade of 0.28 oz. gold per ton. New ore may be expected both laterally and at depth. To the end -of 1952, the ?Company had paid dividends of almost £4,- 600,000, largely earned from the operation of the gold mines.

Jan 1, 1956

By J. S. Roper

"IntroductionSNOW LAKE is situated in northern Manitoba at latitude 54° 55 and longitude 100°, 400 miles northwesterly of Winnipeg, 80 miles northeast of The Pas, 80 miles east of Flin Flon. A 38-mile road from Wekusko, on the Hudson's Bay railway, serves the community.The mine is located in and close to the southern edge of the Precambrian Shield in typical low-relief muskeg and lake country.The Howe Sound Exploration Company, Limited optioned the property from Nor Acme Gold Mines, Limited, after preliminary diamond drilling had outlined two orebodies of low-grade arsenical gold ore.Following the examination and study of geological data and of 50,000 feet of diamond-drill core, and metallurgical tests made during 1942 to 1945, a decision was made to develop the mine and build a 2 ,000-ton mill concurrently. This development has been described by G. C. Lipsey in a paper entitled The Development of a Mining Operation from Diamond-Drill Data which was published in the August. 1952, issue of Mining Engineering.Geological Features of the OrebodiesThe orebodies at Snow Lake occur in volcanic rocks of acid to basic composition and, to a lesser extent, in intrusive hornblendite. The hornblendite is a massive, uniform, .coarse-textured rock except in the immediate vicinity of the ore zone, where it becomes sheared and carbonatized. The acid volcanics have been converted to quartz-garnet-biotite gneiss, and the basic volcanics to amphibolite gneiss. Orebodies have been formed by the replacement of all three rock types."

Jan 1, 1955

By Mingxia Liu, Hao Li, Qi Liu

"Laboratory batch flotation tests were carried out on fine (-20 µm) hematite to investigate the non-polar oil’s influences when sodium oleate, octyl hydroxamic acid, or oleyl hydroxamic acid were used as a collector. Batch flotation tests were performed with artificial mixed minerals (hematite:quartz = 1:1) under natural pH condition and kerosene was utilized as the model oil. The experimental results showed that kerosene emulsion behaved differently when used in conjunction with the three collectors. Kerosene helped improve the flotation when sodium oleate or oleyl hydroxamic acid was used as a collector. Nevertheless, it reduced concentrate weight yield, grade and recovery to a noticeable extent when octyl hydroxamic acid was used as a collector, especially at low dosages. In addition, single hematite batch flotation kinetics tests coupled with water recovery measurement were carried out to study the role of kerosene at different collector dosages. It was observed that water drainage and the resulting froth destabilization by kerosene was dominant at low collector dosages, especially in the flotation using octyl hydroxamic acid. At higher collector dosages, the water drainage and froth destabilization effect by kerosene was possibly counter-balanced by the higher hematite hydrophobicity and bubble surface tension gradient, which led to more stable froth layer.INTRODUCTION The minerals industry is facing a steady decline in ore grade, compounded by increasing complexity of mineral dissemination. As a result, the ore has to be ground sufficiently fine to have a suitable degree of mineral liberation, which produces large percentages of fine and ultrafine particles outside of optimal size range for ore dressing. Due to the unique characteristics of fine particles, i.e., small mass, high specific surface area, and problems such as increased solubility of complex minerals (Finkelstein, 1997; Finkelstein & Allison, 1976; Fornasiero & Ralston, 2005), high reagent consumption, fast surface oxidation in the case of sulfides (Collins & Read, 1971; Klassen & Mokrousov, 1963), severe particle entrainment (Subrahmanyam & Forssberg, 1988; Warren, 1984), low flotation rates (Glembotsky, 1953; Philippoff, 1952; Ye & Miller, 1988), slime coating (T. K. Mitchell et al., 2005; Parsonage, 1984), etc., flotation performance of these finely ground ores is very poor in terms of low concentrate grade and recovery."

Jan 1, 2017

By W. B. Burchall

Introduction In presenting this paper the author wishes to state that the opinions here given represent only his personal views. A general survey of the subject has been attempted, but such deductions as may have been drawn are not necessarily endorsed by the Company with which he is associated. The aeroplane as an instrument of transport is yet a novelty, for it is only twenty-five years since man first flew. This statement, by itself, may be very deceptive, for compared with the steam locomotive or even the auto-mobile, this infant in industry has made some remarkable showings. The 'actual performance' speed-curve of aircraft plotted over a ten-year period is rising faster than the 'expectancy' speed-curve of 1924 indicated, and it should be noted that, today, the possibilities of 600 miles per hour provoke less scepticism than did the prophecies of 400 miles per hour only a decade ago. Commencing with the remarkable achievement of raising one man into the air, aircraft with an all-up weight of 14 tons are now in daily use on the British airways, and recently a non-stop flight of 5,340 miles was accomplished in an aeroplane, without refuelling. More true than ever is the statement that the records of yesterday are commonplace tomorrow, for new ideas are today seized on and exploited to the utmost once the period of scepticism and doubt has been overcome. In fact, so many new ideas have been brought forward, during the past few years, and applied successfully in our economic life, that one may well ask if today we are not a little too impatient, too exacting in demands, forgetting that real worth-while progress -is attained by no short-cuts.

Jan 1, 1933

By R. A. Wyman, F. E. Hanes

THE demand for high-quality aggregate is increasing in all phases of the construction industry and in all organizations associated with road building in Canada. The production of aggregate in Canada has increased almost continuously since the end of the war and has quadrupled since 1948. Increases during the past fifteen years can be accounted for by the expansion in all types of construction, particularly that of roads and highways. Total construction in 1959, based on preliminary estimates, has been valued at $7 billion, and an increase fore-cast for 1960 indicates optimism on the •construction horizon (1). Cement produced in Canada in 1959 amounted to 6.3 million tons. This is more than 2.5 times the 1948 production. Increased cement production indicates an increased use of concrete, and thus an increased need for aggregate. Natural sand and gravel deposits are gradually being depleted.

Jan 1, 1962

By A. Warczok, C. M. Diaz, A. Bergman, T. Utigard, M. Barati

The world wide consumption of energy is steadily increasing and by 2030 it is forecasted to grow by another 50%, leading to mounting political and economic pressures. For any pyrometallurgical operation, it is therefore paramount to investigate and implement methods to decrease the use of energy. In the pyrometallurgical processing of steel, copper, nickel and other high temperature metals, a large amount of energy is lost in hot off-gases, molten slags, mattes and molten metals. Most of this energy is generally lost during the cooling and solidification steps with very little focus on energy recovery or reuse. In this paper we will quantify how much energy is contained in the various slag streams, then review previous attempts and methods employed to recover some of this energy, and finally evaluate some novel technologies that could potentially be employed.

Jan 1, 2011

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017

By Torsten Zeller

Due to the increasing worldwide demand for raw materials and the resulting rise in commodity prices more expensive processing that is able to utilize complex ores becomes economically viable. This and increasing ecological awareness is why the interest in recycling and urban mining is steadily growing in Germany. In addition to that; landfills do also contain elements, which were not targeted over the period, when they were being accumulated. Examples are rare earths, indium, gallium, cadmium, arsenic, selenium and tellurium. Also copper, zinc and lead, the target components of ancient mining, can be obtained due to more effective processing and smelting technologies. Funding by the German Federal Ministry for Education and Research, entitled "r³ ? Strategic Metals and Minerals ? Innovative Technologies for Resource Efficiency" also indicates the high level of strategic interest. It is against this background that the research project "Exploitation of the Raw Material Potential of Mining and Metallurgical Tips in Respect of Sustainability as Exemplified in the West Harz Mountains (ROBEHA)" has been implemented. A major concern of this project is the possible transfer of results to landfills in other areas. Therefore the development of an expert system based on the innovative processing methods and a method manual for urban mining are the central components of the investigation. This will provide an important contribution to the cost optimization of ensuing urban mining projects. To ensure the success of landfill mining projects it is necessary to record the composition and quality of the deposits accurately. Also the environmental impact caused by landfill mining and changes in the natural and cultural landscape will be considered in a multicriteria evaluation method. Depending on their origin the tips are divided into the categories mining, processing, and smelting. The content of a landfill and thus the economic potential in terms of urban mining is dependent on the type and composition of the deposits (host rock, gangue, and ore mineral), the available processing and smelting technology, and the target components at the time of mining. Zinc, for example, was not been processed until the 19th century, when it gained attention as being material of economic importance. After such knowledge about a landfill is obtained the decision for further investigations can be made. For a total of 158 landfills in the Harz Mountains, both the volume and the approximate contents of copper, zinc, and lead has been estimated for the different types of tips within past research projects. Based on the prices of the London Metal Exchange (LME) and a euro/dollar exchange rate of 0.76 (as of 03/05/2012) and assuming a minimum density of ? ? 1.5 t/m³ a average value of 1.6 billion ? in copper, zinc, and lead can be obtained. Although only these three metals are considered in this first estimate, it demonstrates the potential of landfill mining and the need for further research. KEYWORDS Urban Mining,

Aug 1, 2013

By John Vergunst

"This paper traces the development of Ontario 's cap lamp standard. Over the years, numerous Coroner's Juries investigating fatal mine accidents have made recommendations with respect to underground lighting. As well, recommendations to improve mine lighting have been made by two Commissions, investigating mine safety in Ontario.During the past few years, the performance of any cap lamp worn by miners involved in serious accidents, have been measured by the Mining Heal/h and Safety Branch. Large variations in light output were found between and among cap lamp types. These variations have been attributed to the lack of quality control on the bulbs, design of the cap lamp head piece and in some cases, poor maintenance.In 1986, a series of underground tests were conducted to establish the minimum light output from cap lamps required to visually identify loose ground. The results of these tests indicated that a cap lamp should produce a minimum peak illuminance of 1500 lux measured at 1.2 metres from the light source. On May 30, 1987, Ontario became the first province in Canada to legislate the minimum amount of light required to visually assess ground conditions. INTRODUCTIONPoor lighting has been identified as a factor which can contribute to mining accidents. Over the past decade, several Coroner's Juries as a result of inquests into mining fatalities, have recommended improved lighting in mines.The Joint Federal-Provincial Inquiry Commission into Safety of Mines and Mining Plants in Ontario, was appointed to report upon the adequacy of existing arrangements and practice s that may affect safety. This Commission completed their report in April 1981, and recommended that inadequate lighting be investigated as a possible cause of all reportable underground accidents, and that a comprehensive research programinto mine lighting be undertaken.In response to the first recommendation, the Mining Health and Safety Branch of the Ministry of Labour, hereafter referred to as the Branch, initiated a program to measure lighting levels in all fatal accident investigations where inadequate lighting was a possible factor."

Jan 1, 1989

By S. W. Marcuson, P. J. Mackey

The 1973 Oil Embargo and succeeding disruptions in supply had a profound effect on energy costs and consumption patterns in the developed world. This was especially true in the USA where post World War II growth, fueled by low-cost imported oil, left the country dependent on uninterrupted oil shipments from the volatile Middle East. In this atmosphere, Professor H.H. Kellogg of Columbia University, convinced of the necessity of good environmental stewardship by the writings of the era’s leading environmentalists, developed a methodology for evaluating energy and process efficiency of metallurgical processes and wrote a series of papers describing and applying the techniques. One of these, "Energy Use in Sulfide Smelting of Copper" is recognized as a seminal work which both described the state of energy usage in copper smelting in the mid-1970’s and portended future developments. The background to these papers is examined and the current and past Cu-Ni matte smelting practices in Canada are examined in the context of the results. Data from early 20th century publications describing reverberatory and blast furnace operation is employed to show that energy consumption for much of the century was several multiples higher than that calculated for best reverberatory operation in the 1970’s.

Jan 1, 2015

By D. T. Pritchard

"Introduction""No accounting system is very good, and all of them are infinitely variable*.”The purpose of this chapter is to discuss those facets of a typical accounting system which are most commonly encountered by operating managers in mineral processing plants. However, before concentrating in any detail on these it is important to understand the broad purposes and basic techniques of any accounting system in any major business.The three broad purposes of an Accounting System are:- Administering, controlling, and recording the flow of cash in and out of the business. Cash is, of course, converted into other assets (or stores of value) such as inventory, plant and equipment, etc. These assets also have to be administered, controlled and recorded.- Internal reporting to Management for information, for control, and for use in making business plans and decisions. - External reporting to stockholders, government, lenders and other outside parties.In this chapter we shall organize our discussion of accounting practice in mineral processing plants around these three purposes of accounting and focus in some detail on specific practices and techniques with which operating personnel will be routinely involved. This chapter is divided into the following: Accounting Basics; Administration, Control and Recording of Cash Flows; Internal Reporting; Planning and Budgeting; Cost Control; and External Reporting."

Jan 1, 1989

By K. Cybulski

Coal dust explosions still remain the main hazard in the coal mining sector, notwithstanding their relatively wide recognition compared to other hazards and the development of effective methods of prevention. Coal dust explosions are still the cause of numerous catastrophes, often leading to fatalities. Fortunately, they rarely occur, and it is for this reason that their hazardous impact is often underestimated. This problem in Poland is being exclusively solved by the Central Mining Institute, Experimental Mine Barbara. Here, basic research on the phenomenon of coal dust explosions and prevention methods is carried out, as well as investigations into the causes and circumstances of past accidents. After 15 years of no coal dust explosion accidents in Poland (1987?2002), a few coal dust explosions have recently occurred, with tragic consequences. These events have taken place not only in hard coal mines, where the presence of dangerous coal dust is the result of common production cycle, and safety measures against coal dust explosions are subject to specific regulations, but also in coal-fired power plants. This is of special concern because prior to 1987, such accidents had been been reported only for coal mines and not for coal-fired power plants. In recent years, two dust explosions occurred in Polish power facilities: the Dolna Odra and Turow power plants. In both cases, coal dust explosions occurred in the fuel supply system, but biomass dust was also involved. The explosions caused significant damage to the systems and buildings. This paper gives description and schematics of the regions of catastrophic coal dust explosions that have occurred in recent years in Poland, as well as the results of post-accident investigations, presenting the coal dust explosion hazard at the accident scene The results specify in detail the state of safety measures against coal dust explosions in light of the relevant regulations in force, including amount of deposited coal dust, content of incombustible matter in coal dust, free moisture content in coal dust, state of coal dust explosion safety zones, and state of explosion barriers. The conclusions from the site inspection and post-accident investigations presented enable us to determine locations of explosion initiation, probable ignition sources, range of explosion flames, and explosion barrier performance. A complete elimination of coal dust explosion hazard at the site of dust deposition is practically impossible to achieve. Similarly, a total elimination of ignition source, which may be related to the occurrence of other natural hazards, equipment malfunction or human errors, is impossible. The examples of tragic events that took place in Polish coal mines and coal-fired power plants highlight shortcomings and mistakes made in terms of assessment and prevention measures taken against the coal dust explosion hazard.

Aug 1, 2013

By S. Steinlechner, S. Wegscheider

"In the past, the metallurgical industry was most of the time dedicated on their main commodity, recovering base metals like zinc, copper or lead but leaving other valuable side elements in the generated residues. As a result, these accompanying minor elements, like gold, silver, indium or also PGMs can be found in the dumps of the corresponding industry. Because of political unrest, strikes, economic reasons or decreasing primary resources leading to a high supply risk, also those mentioned minor elements moved into the focus of the recycling industry. Therefore, beside the base metals, first of all the recovery of those minor metals would be of high interest contributing to the economic viability of recycling processes, although they occur in much smaller quantities in materials. In this context, residues from zinc industry, like leaching residues or precipitation residues show high potential to carry silver as well as indium next to lead and zinc. Therefore, the paper summarizes carried out thermochemical calculations investigating a possible recovery of silver as well as indium by volatilization and the influence of zinc and lead on this process. Based on these theoretical investigations with HSC, trials in lab scale were done verifying the obtained results.INTRODUCTIONHuge amounts of iron precipitate, mainly jarosite get landfilled every year although there is a high content of valuable metals in this residue beside iron. Nevertheless, jarosite has to be dumped due to the presence of contaminating heavy metals. The accumulation of these residues takes up massive land on the one hand but also causes a series of environmental problems in ecosystems on the other. Moreover, some toxic ingredients such as arsenic and cadmium can be dissolved in rain water and are therefore harmful to the health of the aquatic systems. (Erdem & Özverdi, 2011; ÖzverdI & Erdem, 2010) Approximately 0.5 t of dry jarosite accumulate in the production of 1 t of zinc by the hydrometallurgical zinc-winning route (Svens, 2010). Jarosite is a precipitation residue formed during the iron removal. In general, the iron already exists in the zinc ore which is why zinc ferrite builds up during the roasting step of the zinc ore. Zinc ferrite is only soluble in strongly acidic solutions and during the hot acid leaching step it gets dissolved while zinc and iron enter the solution. It is necessary to get rid of the iron because otherwise it would deposit on the cathode first due to its precious character which would be harmful in the zinc-winning electrolysis. Nevertheless successful investigations were done by adding chlorine to the jarosite to recover silver. These findings leads to another residue which occurs in huge amounts – electric arc furnace dust (abbreviated with EAFD) from the iron and steel industry. In 2013 the annual electric steel production reached about 451 million tons. Around 15-20 kg of EAFD is produced per ton of steel in an electric arc furnace (EAF), creating approximately up to 9 million tons of dust per year. (Grabda, Oleszek, Shibata, & Nakamura, 2014; World Steel Association) Next to elements like zinc, lead and iron, chlorine and fluorine are present in this dust. While galvanized steel plates in the scrap act as a source for zinc, casting powders, flame retardants and synthetic coatings are responsible for the chlorine and fluorine contents in the dust."

Jan 1, 2016

By M. Reda

Inorganic oxidizing agents of the type MeOx-z such as Chromate, Vanadate, Tungstate, and Molybdate... etc. are widely used as corrosion inhibitor. In non acidic solution these oxidizing agent are reduced on the surface of the meta, according to OX + m e + p H20 Red + n OH" In which y = (n-m)/m. The purpose of this publication is to show that for many metals the value of y for any oxidizing agent determines the possibility of that oxidizing agent being an inhibitor or activator for the corrosion process. The inhibition efficiency for other ions such as Pertecnetate and Tellurate which have not been extensively studied can be predicted. A mathematical, equation was derived to express the relationship among the concentration of oxidizing agent, degree of retardation of the corrosion process I cord cor ° (ratio of corrosion current in the solution containing inhibitor to the base solution) , ionic strength of the solution and the coefficient y. The validity of y and the mathematical, equation were verified by many experimental, works on various metals such as zinc, aluminum and steel. Al, the above research works are based on the published research works of Prof. Mikhailoviskii (from 1979 til, 1998) from the Russian Academy of Science.

Jan 1, 2010