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By E. S. Yan, R. Graley

"The StackCell was developed to overcome the engineering and design challenges that are commonly associated with existing flotation technology such as pneumatic, self-aspirating cells, mechanical cells, and flotation columns. These challenges include high energy consumption, large floorspace requirements, and size. They are most evident when designing systems to process streams containing a high volumetric flow rate coupled with a significant float yield. Unlike many metalliferous and industrial mineral applications, fine coal flotation circuits are typically characterized by feed streams containing a low solids content (<5%, by weight) where up to 85% of the feed can report to the product launder. With input from major engineering houses and end-users, the Eriez Flotation Division (EFD) developed the StackCell technology with the goal of providing an additional flotation option for end-users. This technology was designed specifically to overcome these challenges by providing an efficient method of separation in terms of metallurgy, but also with respect to equipment size, energy consumption, and installed costs. Besides being placed in tandem with existing cells to provide cost-effective supplemental capacity, this technology can be installed in a stand-alone arrangement as recently demonstrated at Patriot Coal’s Kanawha Eagle preparation plant. This manuscript provides an understanding of the underlying fundamentals of this new technology and presents data from Kanawha Eagle in addition to other industrialscale installations.INTRODUCTIONOver the past decade, column flotation has continued to gain acceptance as an alternative method for recovering fine coal due to superior metallurgical performance as compared to mechanical flotation cells. This point has been proven on numerous occasions by comparison of plant flotation data with the release analysis separation curve (Dell et al., 1972). Data from a release analysis test approximates the ultimate flotation response of a coal sample. In North America, a number of investigations have been published that document bottom-line improvements achieved using column cells (Luttrell et al., 1999; Kohmuench et al., 2004; Baumgarth et al., 2005). According to these reports, the benefits are derived from an overall increase in plant yield that can be achieved due to the improved product grade in the flotation circuit. In particular, the application of wash water to a deep froth utilized in column flotation minimizes the nonselective recovery of high-ash ultrafines that are hydraulically entrained in the froth by conventional flotation machines."

Jan 1, 2013

By J. S. Stachulak

Inco Limited operates nine underground mines on the rim of the Sudbury Basin. These operations are situated near the City of Sudbury, 589 km (365 miles) west of Montreal, and 363 km (225 miles) north of Toronto. The ores are mined primarily for nickel and copper, and the principal minerals are pentlandite, chalcopyrite, and pyrrhotite. Total ore production from underground is in excess of 51,000 tons per day. The total volume of fresh air supplied to the nine mines is six million cubic feet per minute. There are 50 main fans in operation at these mines, powered by electric motors totalling 11,200 kw (15,000 hp). The trend in metal mining during recent years towards mechanization and high-tonnage production methods has greatly increased ventilation requirements. The flow of air must quickly dilute and carry away diesel exhaust fumes, dust created by mining operations, and the fumes of the explosives used in blasting. Mechanical ventilation is required to obtain the necessary volume and control, as natural ventilation pressures alone are, for the most part, inadequate and unreliable. In the event of a mine fire or other needs, close control of ventilation is essential. There are two unique heating systems presently in operation at Inco: Creighton Natural Heat Ex- changer and Stobie Ice Stopes.

Jan 1, 1989

By B. K. Slone

The depth at which it becomes more economical to use slope access as opposed to box-cut access for near-surface coal reserves, termed "transition depth," can be established for a given coal property by considering cost estimates for those parameters that determine respective access method. Fourteen parameters that influence access cost were identified and ranges determined. A Transition Depth Formula was developed to permit determination of the better method of accessing a reserve, given such information as highwall slope, road width, total bench width, pit dimensions, road grade, belt component costs, pumping costs, and cost of overburden removal and reclamation. In most cases, in Appalachia, studies indicate that the transition depth ranges between 20 and 30 m.

Jan 1, 1998

By Carlos Campos Junior, Leonardo Soares Chaves, Raul Carretero Hoz, Renato Jacome Costa, Davi Bastos Martins de Oliveira

The Vale’s Serra Sul mine, also known as S11D project, is one of the world’s largest open pit iron ore mines, located in Brazil’s Amazon region. The mine produces around 90 Mt of high-quality iron ore annually. Its unique orebody enabled the S11D project to adopt a truckless mining system with In-Pit Crushing and Conveying (IPCCs) for ore exploitation and waste stripping. The IPCCs system requires crushing the waste, mainly composed by the jaspilite lithology, and is also conveyed to waste deposits several kilometers away from the mine. Due to Amazon’s environmental restrictions, the project was designed with preliminary geological knowledge, leading to the installation of primary crushers not designed for the hardest jaspilite, with uniaxial compressive strength (UCS) up to 500 MPa. This resulted in low waste crushing performance, affecting stripping ratio and threatening future production. A project was developed to improve the fragmentation of the jaspilite, allowing higher waste IPCC production, and reducing the risk to the production due to low performance of waste crushing and conveying. The first challenge was the independence of the geological and the geomechanical models, while only the geological model was considered in blast designs, the geomechanical model describes six waste groups of jaspilite classified according to their strength. A new geological model was then created to incorporate the geomechanical classification, allowing different blasting design according to the rock strength of the jaspilite. The blasting pattern on most compact jaspilite was reduced 27%, from 22m² to 16m² in 9 7/8” diameter holes, with a proposed theoretical reduction of 23% of the P80, from 326mm to 250mm. The second challenge was the implementation of the new design, as this pattern size and the high powder factor (2.9 kg/m3) were paradigms for such a large iron ore mine. The measured results have shown 25% reduction of the P80, the crushing rate was increased by 17% (230t/h), saving around $2.4 million annually in crushing and conveying system maintenance.

Jan 21, 2025

The Pogo Mine, near Delta Junction, Alaska is a 2500 TPD gold operation employing processes including grinding, gravity, rougher flotation, leach, CIP, and E/W. An OCS(Optimizing Control System) expert control system has been implemented on rougher flotation in early 2008. The OCS system communicates with the Plant DCS(Distributed Control System) through OPC(OLE for Process Control) communication. The initial strategy was to control the flotation cell froth level set points to achieve target froth velocities. This strategy was enhanced by controlling both level and air flow setpoints. The flotation cell air and level are adjusted to reach cell pulling rates (froth velocities). The pulling rate setpoints for each cell are determined based on downstream capacity (concentrate surge tank level). The effect of pH and upstream disturbances is also taken into account in adjusting the air and level setpoints. Feed forward compensation is employed down the flotation row to minimize disturbances.

Jan 1, 2009

By S. P. Hansen

Gravity sedimentation is one of the most widely used processes for separating solids from liquids whether it be for ore and mineral processing or for treating municipal sewage or industrial wastes. Investment in sedimentation equipment can represent a significant portion of the total capital costs associated with a processing or treatment facility. In spite of the importance of sedimentation, little attention has been devoted in recent years to improving this equipment by applying the basic principles involved in sedimentation. In the water and waste treatment field, design criteria established one half-century ago is still the accepted standard and in reflection of this lack of progress, sedimentation and thickening equipment has remained virtually unchanged. The primary purpose of this paper is to present and describe a new innovation in gravity sedimentation which has been applied to water and wastewater treatment and could definitely have application in the field of ore and mineral classification. A secondary object is to introduce the mixed media filter which has been widely used to treat municipal drinking supplies, industrial process water and to provide tertiary treatment of sewage and industrial wastes. The tube-type clarifier was developed primarily to be applied in the field of water and waste treatment where it was found that it could be used to considerably reduce the size and cost of clarification facilities. A logical extension of the tube clarifier would be to the area of minerals classification, ore separation, and for treating waste water associated with these activities. In water treatment practice, most clarification processes are followed by a filtration step to provide further polishing of the water prior to use. This paper will also discuss the mixed media filter which is graded from coarse to fine in the direction of filtration and is capable of operating at high filtration rates and with greater applied suspended solids loading than other filter designs while providing a high qualify filtrate.

Jan 1, 1970

By P. Massacci, F. La Marca, G. Bonifazi

Some deposits of inhomogeneous materials, which occur near the surface and are exploitable by open-pit mining, may he characterized in real time prior to mining through groundsurface imagery. If the slice to be stripped is not overly thick, surface texture and color properties may be extrapolated to its entire thickness. Image-analysis techniques for processing ground-surface images acquired in situ or in the laboratory shortly after their acquisition have been developed. These images yield pattern vectors representative of red, green and blue (RGB) color component distributions and hue, saturation and brightness (HSB) texture parameters. The techniques were applied to a sandy ore deposit containing three lithotypes. Geostatistical analysis indicated that the data used to characterize the lithotypes were reliable. The correct recognition of the lithotypes was carried out using a multibarycenter classification algorithm. Such in situ image-analysis procedures provide a means for selecting the ore to be mined, selecting the proper ore-processing method and determining the appropriate blend to he processed. This can be done either before or during mining.

Jan 1, 2000

By Jennifer Riefenberg

Ground control hazards, coal quality, ore reserve estimation, and pollution modeling seem unrelated topics from most mining perspectives. However, geostatistical methods can be used to characterize each of these, and more topics. Exploratory drill core data, and continued drilling and field measurements, can provide a wealth of information related to each of the above areas and are often severely underutilized. Recent studies have led to the development of the Multiple Parameter Mapping (MPM) technology, which utilizes geostatistics and other numerical modeling methods, to generate a "hazard index" map, often from exploratory drill core data. This mapping has been presented for ground control hazards relating roof quality, floor quality, numerically modelled stresses due to mining geometry, and geologic features. A review of the MPM method, future directions with the MPM, and a discussion of using these and other geostatistical methods to quantify coal quality, ore reserve estimation, and pollutant modeling are presented in this paper.

Jan 1, 1996

By James Lett

The role of pre-conditioning in a caving operation has multiple benefits, ranging from assisting with improved caveability, normalising fragmentation and improving draw point hang-up frequency. At Newcrest Mining’s Cadia Operations, both the Ridgeway Deeps block cave the Cadia East Panel Cave have utilised pre-conditioning using hydraulic fracturing. Seismic response data inside and outside the pre-conditioned volume show the benefit of treating the full caving block. Cadia East has further developed pre-conditioning to mitigate developing seismic hazards associated with major structures (fault-slip events) and managing mine-wide seismic hazards in new caving operations where the potential for large damaging seismic events exists due to high stresses and hard competent rockmasses. A case study reviewing the impact of pre-conditioning to mitigate seismic hazard associated with fault slip is presented. Cadia East operation undertook a targeted hydraulic fracturing program and reduced the overall number of large events as an example of the benefits of pre-conditioning. This paper will review the application of Hydraulic Fracturing at Cadia and discuss the geotechnical and seismological parameters of seismic events that occur within and outside of pre-conditioned rockmass volumes to demonstrate the benefits that Hydraulic Fracturing bring to future caving operations.

Apr 26, 2022

By D. R. Torgoson, Th. G. Sahama

"This paper contains some new thermodynamic data for silicates in the series Mg2SiO4-Fe2siO4 and MgSiO3-FeSiO3 and gives the results of a thermodynamic attack on the problems of stability end parageneses.. Although some data are lacking satisfactory agreement with mineralogical and petrological observations is indicated.The use of thermodynamic methods in mineralogy and petrology has been rather limited, because accurate thermal data, especially for the more complicated and more important rock-forming minerals, have been too scanty to permit any systematic application to problems in those fields. It is, nevertheless, a fascinating task to investigate to what extent the mode of occurrence and the stability relations of the minerals and mineral parageneses, as revealed by petrological and mineralogical observations, agree with predictions of thermodynamics. At the present stage of development calorimetric data are needed for most of the abundant silicate minerals.Measurement of the heats of solution in hydrofluoric acid of minerals in the series Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 affords a ready means of obtaining their heats of formation from the oxides. Combination of such data with entropy and heat-capacity values gives a means of obtaining free energies of formation from the oxides, which, in turn, are connected di¬rectly with stability and paragenoses.The two silicates of magnesium, Mg2SiO4 and MgSi03, occur as rock-forming constituents as forsterite and clinoenstatite or enstatite. The orthosilicate (forsterite) forms a series of isomorphic mixtures with ferrous-orthosilicate (fayalite). The continuity of this series, suggested by petrological observations, has boon proved experimentally by Bowon and Shairer.4/ The present work shows that those minerals constitute a series of perfect solid solutions - that is, a series of solid solutions for which heats of formation from the individual pure silicates, Mg2Si04 and Fe2SiO4, aro negligibly small.The metasilicates of magnesium and iron also form an isomorphic series. However, this series differs from the forstorito-fayalite series in the fact that the most iron-rich mixtures, between about En10Fs90 and pure Fs, appear to be unstable with respect to the paragenesis iron-rich olivine plus quartz. The supposed instability of pure FeSiO3 as a crystalline compound, at least at high and at moderate temperatures, is remarkable, as no crystal struc¬tural reason for such instability is apparent. The present work indicates, also, that these minerals form a perfect series of solid solutions and throws additional light on the instability question.In the following, the samples used in this investigation will be described. For each of the natural olivines and orthopyroxenes, with the exception of sample L, a chemical analysis was made of the purified and actually used fraction. All the analytical work was carried cut by Oleg v. Knorring, and the specific gravity determinations, by moans of a pycnomctcr, by Oiva Joensuu, both of the University of Helsinki, Finland. The determinations of the optical properties were made by Mrs. Toini Mikkola, of the Geological Survey of Finland."

Feb 1, 1949

By Cyril Wells, Robert F. Mehl

The diffusion of carbon in gamma iron plays an essential role in many metallurgical processes. In carburizing, in graphitizing, in homogenizing, in the formation of pearlite from austenite, and in other processes, migration of carbon in gamma iron occurs.1&apos;2 A full understanding of the rate at which these processes occur obviously requires a knowledge of the rate of diffusion of carbon. In carburizing, for example, the depth of carbon pentration is determined by the carbon concentration in solid solution at the surface, and by the rate of diffusion inward of the carbon. Until reliable data on the rates of diffusion of carbon are available it is unlikely that a full quantitative description of this process will be obtained. In the formation of pearlite from austenite, the segregation of carbon and alpha iron from the austenite obviously requires the diffusion of carbon; the rate at which pearlite nodules grow is evidently controlled at least in part by the rate of diffusion of carbon; it is unlikely that we shall understand the factors that determine the rate of growth unless data on rates of diffusion of carbon, and the variation of these with composition, grain size, and temperature are available. Accordingly it was decided: (1) to determine, more accurately than hitherto, the diffusion coefficients of carbon in austenite over a wide temperature and a wide concentration range, (2) to study the influence of grain size and impurities on this diffusion coefficient, and (3) to study the effect of manganese and nickel on the rate of diffusion of carbon in the austenite of manganese and nickel steels, respectively; the influence of carbon on the rate of diffusion of manganese and of nickel will be made the subject of later papers. The rate of diffusion of carbon in gamma iron has been studied by Runge3 by Tammann and Schonert4, by Bramley and co-authors,5-14 and

Jan 1, 1940

By Cyril Wells, Robert F. Mehl

The diffusion of carbon in gamma iron plays an essential role in many metallurgical processes. In carburizing, in graphitizing, in homogenizing, in the formation of pearlite from austenite, and in other processes, migration of carbon in gamma iron occurs.1&apos;2 A full understanding of the rate at which these processes occur obviously requires a knowledge of the rate of diffusion of carbon. In carburizing, for example, the depth of carbon pentration is determined by the carbon concentration in solid solution at the surface, and by the rate of diffusion inward of the carbon. Until reliable data on the rates of diffusion of carbon are available it is unlikely that a full quantitative description of this process will be obtained. In the formation of pearlite from austenite, the segregation of carbon and alpha iron from the austenite obviously requires the diffusion of carbon; the rate at which pearlite nodules grow is evidently controlled at least in part by the rate of diffusion of carbon; it is unlikely that we shall understand the factors that determine the rate of growth unless data on rates of diffusion of carbon, and the variation of these with composition, grain size, and temperature are available. Accordingly it was decided: (1) to determine, more accurately than hitherto, the diffusion coefficients of carbon in austenite over a wide temperature and a wide concentration range, (2) to study the influence of grain size and impurities on this diffusion coefficient, and (3) to study the effect of manganese and nickel on the rate of diffusion of carbon in the austenite of manganese and nickel steels, respectively; the influence of carbon on the rate of diffusion of manganese and of nickel will be made the subject of later papers. The rate of diffusion of carbon in gamma iron has been studied by Runge3 by Tammann and Schonert4, by Bramley and co-authors,5-14 and

Jan 1, 1940

By Liu Y

Mathematical modelling of scrubbers in development and longwall operations in underground mines produces useful results. Mathematical modelling on the mounting of scrubbers on longwall supports shows that the number of scrubbers and the air quantity through the scrubber are the two important parameters. Increase in both these parameters results in decrease in dust levels at the tail gate. The critical factors are scrubber efficiency and the ratio of the air through the scrubber/total air quantity.Results of parametric studies conducted to establish factors which have dominant influence on the effectiveness of the scrubbers on dust levels and high gas build-up in the scrubber show that for use of scrubbers in development headings, the order of importance of parameters in relation to dust concentration in the scrubber area is: scrubber efficiency, rate of production, specific dust make/tonne, leakage factor, intake dust concentration, recirculation factor and air quantity through the scrubber.The equations developed for mathematical analysis and the detailed results of modelling provide useful data on recirculation of emitted gas in the use ofscrubbers for dust control.

Jan 1, 1995

By C J. Greet, J Kinal, C Hitchen

Following the successful completion of a marked ball test defining the potential wear benefits the high chrome alloys may offer against forged steel, as well as laboratory test work investigating changes in pulp chemistry and improvements to metallurgical performance, a plant trial was commissioned at NewcrestÆs Ridgeway concentrator. The paper briefly describes these results.Newcrest decided to convert their media charge by the top-up method. To monitor the trial a sampling protocol was put in place whereby the pulp chemistry was monitored before, during and after the purge. The metallurgical shift data was analysed using various statistical methods to determine if the metallurgical performance had improved with the change in grinding media. While the analysis indicated that the metallurgy had improved, not all of the benefits could be assigned to the change in grinding media alone. However, the combination of reduction in media wear and the increases in copper and gold recoveries suggested that it was economically viable to operate with high chrome grinding media.As with many trials of this nature the prevailing economic conditions are fluid and a decision was made to revert back to forged steel grinding media in an effort to reduce operating costs. It was further agreed that Magotteaux could monitor the pulp chemistry and metallurgical changes in this reverse trial to confirm the results observed in the earlier conversion to high chrome grinding media.CITATION:Greet, C J, Hitchen, C and Kinal, J, 2012. Conducting high chrome grinding media trials at NewcrestÆs Ridgeway Concentrator, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 56-64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Li Shibo, C. Halls

The compositions of olivine, pyroxene and chromite from the Proterozoic ultramafic complex are analagous to those of cumulate ultramafic rocks of tholeiitic origin, suggesting that the parent magma may have been tholeiitic rather than komatiitic. The complex contains economically significant Ni-Cu sulphide mineralisation. The high sulphide/silicate ratio is best explained in terms of the segregation of sulphides from a large volume of magma, of which all but the ultramafic cumulate fraction has since been eroded. Platinum-group minerals that have been identified include sperrylite, moncheite, native platinum, froodite, merenskyite, michenerite and Pd-rich pentlandite lamellae exsolved from pyrrhotite. They are characteristically found in close association with chalcopyrite, either along the contacts between hydrosilicate and sulphide grains or in cracks within pentlandite and chalcopyrite, which may also be intergrown with galena. Crystallisation from a Cu-rich residual magmatic liquid also enriched in Pt, Pd, As, Sb, Bi, Te, Zn and Pb is postulated.

Jan 12, 1993

By Do-Hyeong Kim, Jong-Jin Pak, Jung-Mock Jang, Min-Kyu Paek

"Thermodynamic relations among Mn, Al and N in liquid iron were studied by measuring the effect of Mn on the solubility product of AlN in liquid Fe-Mn-Al-N alloys in the temperature range from 1773 to 1873 K. The critical Al and N contents for AlN formation were determined by the metal-nitride-gas equilibration technique over wide ranges of melt composition and temperature. The effects of Mn on N solubility in Fe-Mn and Fe-Mn-Al melts containing Mn up to 26 mass% were separately determined in the same temperature range. The experimental results were thermodynamically analyzed using the Wagner's formalism to estimate the critical Al and N contents for the onset of A1N formation. The validity was checked by the observation of inclusion evolution in Fe-20%Mn-1.5%Al-0.6%C-0.3%Si-0.012%N melt during cooling and solidification.IntroductionRecently, high manganese steels such as Twinning Induced Plasticity (TWIP) steels have been developed as next generation steels because of their high formability as well as excellent strength and ductility.[1•2l In these steel grades, a large amount of Mn (15-20 mass%) and Al (1-2 mass%) are added to liquid steels, and such high Mn and Al concentration bring the great challenges to the steelmaking and casting processes. Mn significantly increases the N solubility in liquid iron and the AlN inclusions can be easily formed at such high Al concentrations due to high affinity of Al and Mn with N in liquid steels. Although the AlN inclusion is known to be a dominating and considered as a detrimental phase for the hot ductility of steels,l3l thermodynamics of AlN formation in high Mn-Al alloyed liquid steels was not well known.Moreover, the melting point of these steels decreases down to near 1623 K as increasing Mn content up to 20 mass%. However, most of thermodynamic data has been measured at the steelmaking temperature around 1873 K. Even at steelmaking temperature, there are huge scatters in thermodynamic interactions of Mn and Al on N in liquid iron. The nitrogen solubility in Fe-Mn alloy melts has been measured using the Sieverts' method[4l and the samplinij method[5-7J in the temperature range of 1813 to 1973 K. In the authors' recent study,[8•9 the N solubility in Fe-Al alloy melts was measured using the sampling method in the temperature range of 1823 to 1973 K. However, the simultaneous effect of Mn and Al at high concentrations on Nin liquid Fe-Mn-Al-N alloys is still not known. Also, there remains uncertainty about the temperature dependence of the interaction parameter of Mn on N in liquid Fe-Mn alloys. Therefore, it is worthwhile to check the temperature dependence of this parameter at a low temperature near the melting point of Fe-Mn alloys. There have been few studies on the characterization of non-metallic"

Jan 1, 2014

By J. G. Lang

"This paper gives an outline of the principles used in E.M. wire rope testing, showing the practical application of the device and its value in industry and in mining operations.It presents: case histories involving deterioration, such as corrosion, peening and broken wires; anomalies indicating conditions peculiar to drum hoists and friction hoists; tests of locked coil ropes; low-frequency testing; and experiments and development."

Jan 1, 1969

By Ching L. Wu, Joseph Penzien

An analytical procedure is presented for evaluating the stresses in linings of bored tunnels caused by kinematic soil-lining interaction. Three cases of interaction as produced by the following conditions are treated: (1) relaxation of in situ soil stresses near a lining following its installation; (2) overburden pressure at the soil surface; and (3) free-field soil response resulting from an earthquake. Non-dimensional formulas and graphs resulting from parametric studies are presented for practical tunnel design applications. The procedure is applied separately to a steel lining and a concrete lining for a site located at the lower end of Market Street in San Francisco through which a BART (Bay Area Rapid Transit)tunnel passes.

Jan 1, 1997

By P. Latostenmaa, O. Forsén, M. Lundström, J. Aromaa

The history of electrolytic copper production in Finland is closely connected with the industrialization of Finland and events of the Second World War. Production of cathode copper by electrowinning from the processing of Outokumpu ore started in 1913 based on the Hybinette nickel process, however due to the poor performance of this process, the plant was closed in 1929. Outokumpu commenced copper smelting at Imatra in eastern Finland in 1936 producing blister copper for refining outside the country. Due to the threating military situation, a new electrolytic copper refinery was built in 1941 at Pori in western Finland to refine the anodes. This was the first electrolytic copper refinery in Finland. It was built with 108 cells having a capacity of 12,000 tonnes/y. In addition, the smelter was relocated to nearby Harjavalta in 1944–1945. To fulfill the war reparations included in the peace treaty with the Soviet Union, a doubling of the smelter capacity was realised, with the Pori refinery capacity increasing to 20,000 tonnes/y in 1946 by adding additional cells. The cornerstone of Finnish metallurgical technology — Outokumpu flash smelting — was invented with the new technology commissioned at Harjavalta in 1949 replacing the electric furnace and providing a further increase in copper output with subsequent enlargement of the refinery. By 1963, the plant consisted of 380 cells with a capacity of 48,000 tonnes/y of cathode copper. The Pori electrolytic copper refinery has operated continuously since 1941. Commencing in 2004 the Pori refinery has been part of the Boliden group of Sweden. The most recent plant upgrade was in 2007 with the installation of permanent cathode technology. In 2017, the production of the Pori refinery was 133,000 tonnes of copper cathode, 2,300 tonnes of nickel sulphate, along with 66 tonnes of silver and 4.6 tonnes of gold. This paper describes these outstanding achievements. INTRODUCTION In 1809 the Kingdom of Sweden was defeated by the Russian Empire in the Finnish War, and Finland was annexed by the Russian Empire as the autonomous Grand Duchy of Finland. Finland’s commercial and industrial interests were developed to serve the Empire’s needs. Finland had raw materials, but at the start of the 20th century Finnish industry was based on the use of wood as raw material and agricultural products. The mining industry was only a few percent of the country’s industrial production.

Jan 1, 2019

By James Warren Andrews, Philip C. Nyberg

The regulation of exposure of underground personnel to radon and its daughter products has significantly changed since the 1950&apos;s. The U.S. Bureau of Mines - Mining Enforcement and Safety Administration (MESA) - Mine Safety and Health Administration (MSHA) sequence of standards and regulations have lowered the maximum allowable occupational exposure and now the new Environmental Protection Agency (EPA) National Emission Standards for Hazardous Air Pollutants, effective in 1990, have further regulated uranium mine emissions. Under the authority of Section 112 of the Clean Air Act (42 U.S.C. 7401), the EPA has set regulations for the control of radon (Rn-222) emissions from underground uranium mines as well as other sources. Since the venting of radon from the mine atmosphere to the outside air is a major component of the miner&apos;s protection, and since this is the first quantitative effort to limit gaseous mine emissions to the environment, it was felt that it would be useful to examine the implementation of the EPA regulation at working mines. The concern was not only for determining compliance with the regulation but also for observing what effect the rule might have on mine air quality and thus on worker exposure. The regulation is stated in terms of the maximum permitted radiation dose to the closest potentially exposed individual, which is calculated from a computer program supplied by EPA and radon emission rates measured by the mine operator. Relative proximity to nearby populations determines the allowable magnitude of mine exhaust ventilation emissions. For some mines this is a serious operational constraint.

Jan 1, 1991