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By E. Cauda, K. Phillips

"Diesel particulate matter (DPM) exposures are a serious occupational health hazard in underground mines. While the complex nature of DPM makes direct analysis difficult, its primary component, elemental carbon (EC), can be used as surrogate. The near real-time FLIR Airtec monitor measures EC mass based on laser extinction. It was developed for use in underground metal/non-metal mines, and calibrated to the NIOSH Method 5040. Its effectiveness has not been demonstrated in coal mines, however, where coal-sourced EC could produce analytical interference. To gain preliminary insights regarding the Airtec’s performance in the presence of coal dust, experiments were conducted in a controlled laboratory chamber. The Airtec EC results consistently underestimated Method 5040 EC for both respirable-sized and submicron coal dusts. While underestimation of coal-sourced EC bodes well for limiting coal interference for DPM measurement, one key reason for the observed trend was non-uniform coal particle deposition on the Airtec filter. This may be problematic in coal mines where DPM and coal dust occur together in the instance that DPM deposition is also non-uniform. INTRODUCTION Diesel particulate matter (DPM) is an occupational health hazard, and underground miners have the potential for relatively high exposures due to their work in confined environments with large diesel equipment (NIOSH, 2011). DPM is heterogenous and complex in terms of its chemical composition (Birch & Cary, 1996; Noll et al., 2006), but elemental (EC) and total carbon (TC) are often used as analytical surrogates (Birch & Noll, 2004; Noll et al, 2015). EC is the solid “soot” component of DPM, whereas TC also includes particulate organic carbon (OC) (Noll et al., 2007). EC and OC can be measured in filter samples using the standard NIOSH Method 5040 (NIOSH, 2003), and summed to obtain TC. In US mines, TC has been adopted as the analytical surrogate for DPM in regulatory activities. In metal/non-metal mines, personal exposures are limited under 30 CFR Part 57. In coal mines, limitations are made on emissions from each piece of equipment (30 CFR Part 72) rather than for personal exposures. This is because coal dust has the potential to interfere with TC measurements in personal samples. In some other countries, and for non-regulatory purposes in the US, EC is also commonly used as a surrogate for DPM in mine monitoring applications [e.g., see AIOSH, 2013). EC generally exhibits a linear correlation with TC (Birch & Cary, 1996; Noll et al., 2006 and 2007) but unlike TC measurements, which are analytically intensive, EC can be determined more simply using a laser absorption/extinction principle on filter samples (Noll et al., 2013)."

Jan 1, 2019

By S. Rash Ahmadi

Welding is highly reliable and efficient metal joining process. In welding the metal adjacent to the weld joint is subjected to severe thermal conditions. As a result, complex changes in metallurgical structure occur in this region. These changes in structure depend on the material and the temperature history experienced. Friction stir welding (FSW) is relatively a new welding process in which, heat is generated by friction between the tool and the workpiece. The amount of heat conducted into the workpiece determines the quality of weld, residual stress and distortion of the workpiece. The objective of the current work is to study the transient temperature in a friction stir welding. So, a three dimensional transient analytical model is used to study the thermal distribution during the welding. Heat input from the tool shoulder alone is considered in the model. The process parameters like axial load, welding speed and tool rotational speed, used in actual FSW process are taken to build the model. This analytical model is very useful for select the optimized affected parameters in friction stir welding. The model illustrates the comprehensive equation including actual affected parameters in FSW and it can be used for different materials. In addition to the above the thermal history finds application in design of welding tools.

Oct 1, 2011

By G. P. Holmes

"Bell Copper is situated (Latitude 55°0''N, Longitude 126°14W) on Newman Peninsula on the east side of Babine Lake at an altitude of 2,450 feet above sea level. The mine site is approximately 170 miles north west of Prince George and 40 miles east of Smithers. Access to the property is by way of 30 miles of paved road to the Village of Granisle on the west shore of Babine Lake and then a further 9 miles of unpaved road to Bell Copper's west dock. The two mile lake crossing is made using a tug and barge. A compressed air bubbler system maintains an ice free channel for the barge during the winter months.Temperatures range from summer maximums of around 32 °C to winter minimums in the region of minus 40°C. Long periods in winter may be spent with temperatures in the range of minus 15""C to minus 28°C. Freezing temperatures usually start in October and last for six months. The lake normally freezes over in mid December and the ice breaks up in mid May. Snow accounts for approximately two t11irds of the annual precipitation of twenty-one inches."

Jan 1, 1976

By G. W. Norval, V. G. Papangelakis, G. A. Moldoveanu

Smelting has been the primary method of treatment for refractory copper sulfide concentrates such as enargite (Cu3AsS4), but the pyrometallurgical processing generates elevated levels of volatile arsenic. The present research investigates a novel hydrometallurgical process of oxidative dissolution of enargite at ambient conditions in the presence of chlorine dioxide (ClO2), a very powerful oxidant generated in solution by the reaction between a strong acid (HCl or H2SO4) and sodium chlorite (NaClO2). The effects of initial oxidant concentration, particle size, agitation speed and temperature on dissolution kinetics and copper extraction were investigated. It was found that a stoichiometric ratio of ClO2:Cu3AsS4 = 9:1 were needed to completely and congruently dissolve the mineral with fast kinetics (<15 minutes) under ambient temperature. The dissolution extent (metal extraction) increases with increasing ClO2 concentration and decreasing particle size of solids, but is not influenced by temperature or agitation speed.

Jan 1, 2014

By J. A. E. Bell

"Inco has shifted part of its traditional extractive research effort at its J..Roy Gordon Research Laboratory in Mississauga toward new, value-added products. Most of the effort is being expended on new Ni powders for batteries and new Ni-coated products which will be produced in Inco&apos;s carbonyl nickel refineries. New products under development are Ni-coated powders, Ni-coated fibres and ultra-fine Ni powders. Other new products for advanced material applications include controlled expansion composites, NiGOLD strip, Thermal barrier coatings on Inco alloys, and plasma coatings.Research and Corporate Strategic ThrustsThe newest strategic thru st of the company is to increase the value of the primary metal products. These new products are to be in addition to any new alloys or downstream alloy fabrication.Historically Inco has had the highest research expenditures in the extractive metallurgy field in North America. This has resulted in many new processes including flash smelting , matte separation, fluid bed roasting, pressure carbonyl refining and cobalt electrowinning which have contributed to establishing Inco as the lowest cost nickel producer. The recession of the 1980s caused a restructuring of Inco research and corporate goals .As shown in Figure I, from 1975-1982, i.e. pre-recession, Inco spent around 33 million dollars per year on research. Some 48070 of that sum was spent in Corporate Laboratories in Sterling Forest in the United States and in the United Kingdom , mostly on alloy associated research. A further 10% was spent on alloy research at the alloy production facilities in Hunting- ton, West Virginia, and Birmingham and Hereford in the United Kingdom. On extractive research, 13% was spent by process technology groups at the plant s, 20% at the pilot plants in Port Colborne and 9% at the J. Roy Gordon Research laboratory.The relative research expenditures (Fig. 2) have decreased so that today they are at the same level as 1975-80. The research as a per cent of sales has been cut from 2.2% to 1.2% of normalized sales. A normalized sale price of $4.00/lb Ni was used in the 1988 figures. This was partly achieved by closing Corporate Laboratories. Most of the essential alloy research was moved to producing plants and total alloy research is now 27%.A new thrust initiated in the 80s was mining research which now accounts for 20% of research expenditures. Over a period of the past five years this research has doubled the mining productivity in Inco. The pilot plant expenditures have been cut in half. One entire research station at Port Colborne was converted into a platinum group metals intermediate refinery. The decrease in pilot plant expenditures has been compensated by full scale plant trials devoted to the S02 abatement program at Sudbury."

Jan 1, 1990

By L. V. Bell

THE object in prospecting is to find ore. With the exception of certain discoveries of more or less accidental nature, intelligent prospecting as conducted today is, whether consciously or not, based upon a process of elimination. In the following discuss on it is proposed to evaluate those factors that enter into the eliminating of certain tracts of ground and, conyersely, the concentrating of attention upon others. The danger of generalizations as to the barrenness of cer.ain areas, without having due regard for all such factors, is emphasized. The fact that our conception as to what areas or rock formations are to be regarded as favourable or unfavourable is, in some measure at least, changing with new discoveries under diverse and unexpected circumstances, adds more point to the discussion. The criticism might be raised that the subject is treated largely from the standpoint of geology, but that may be met by stating that it is, and must continue to remain, precisely from this standpoint that the prospecror directs his activities. Briefly, the geologist may render the greatest service to the prospector in the early steps of selecting (a) the general territory in which to prospect; (b) the area to be intensively prospected; and, finally, (c) those parts of the claim or claims to be prospected in detail. Although certain phases of the discussion will be, in some measure, of general application, we shall here concern ourselves essentially with prospecting in the pre-Cambrian shield. Furthermore, the subject is so large that it has been decided to limit it to a consideration of that portion of the pre-Cambrian rocks in which is situated the mining district of western Quebec, of which the writer can speak with more personal knowledge. This limitation need not, however, seriously detract from whatever merit the discussion may possess, since the deposits concerned cover a fairly wide range of metallic ores, including gold, copper with associated zinc, and, lastly, molybdenum.

Jan 1, 1936

By A. M. Nordale

Let us first trace a line, mentally, across Alaska and Yukon, starting at a point in the west slightly south of the delta of the Yukon river and from there continuing eastward, loosely following the 63rd parallel of latitude until we have passed beyond the eastern border of Yukon. We will make two pronounced digressions southward to include the greater parts of the Iditarod and Tanana River valleys. That visualized line roughly defines the southern boundary of permafrost. North of it lies a vast region, fully three-fourths of the area of the two territories, which includes Seward peninsula, the great Yukon River basin, and the tractless wastes of the Arctic. During some frigorific cycle in the distant geological past, the ground there was frozen to a depth of many hundreds of feet. How deep the frost actually penetrated is not known, but it has been found to exceed three hundred feet in many places. Nature afterwards provided a perfect insulating cover in the form of heavy moss and dense grass, which has protected the ground from the heat of the sun&apos;s rays during the intervening ages. This frozen condition has always been accepted as something indigenous to the North and little thought was given to -it until recently, when the United States Government and, I believe, the Canadian Government, began extensive studies of it, particularly in respect to its effect and bearing on the development of the great oilfields of the Arctic. Within this large region and but a short distance south of the Arctic circle are the three principal producing placer gold fields in the sub-arctic, whose hubs centre at Nome and Fairbanks in Alaska and at Dawson in Yukon Territory. The geological structure and history of the gold-bearing deposits of Dawson and Fairbanks are very similar and probably closely related. They are typical placer deposits produced by stream action during periods of erosion and inundation and subsequently covered with a thick layer of fine, powdery silt mixed with decayed vegetation which, locally, is termed &apos;muck&apos;. The depth of muck varies from less than 10 to more than 250 feet, with the greater depth near the lateral edges of the valleys. The gravel underlying it is medium in size, well rounded, and composed mostly of quartz and schist. The proportion of sand or fines is approximately 40 per cent. No large boulders and little clay are found, for those districts, as well as that of Nome, have not been subjected to glaciation. The most common bed-rock found is either decomposed or hard schist, but infrequently it is slate, quartz, diorite, or a porphyry. The vertical concentration of the gold is invariably on bed-rock and in the lower few feet of gravel which overlie it. The horizontal concentration or paystreak is roughly parallel to the trend of the valley but does not ordinarily coincide with the course of the present stream. The width of the paystreak usually expands from a few feet at the head of a creek to several hundred feet near its mouth.

Jan 1, 1947

By Tom Demorest

SMART is an association of mining companies that meet regularly to coordinate the technology development needed by the mining industry. Since 1995, the member companies and institutions have directed research and influenced the manufacturers and suppliers to improve surface mining technology and services. SMART actively supports learning seminars, collaborative research projects, and user groups. Members of SMART include some of the major surface mining companies in North America and Australia. These companies have recognized the value that collaboration can bring to the needs of individual organizations as well as the global mining industry.

May 1, 2009

"5.1. IntroductionThe sample preparation requirements for bulk analyses of platinum-group elements (PGE) are different from the requirements for ore microscopy and in-situ analyses. It is necessary that the initial sample collection results in as representative a sample as possible for both types of analyses. Ingamells (1980) believes, however, that sampling is always imperfect and that there is no such thing as a truly representative sample. Once collected, the usual low content and irregularly dispersed nature of the PGE require that samples for bulk analyses be made as uniform as possible, whereas in samples for ore microscopy and in-situ analyses the PGE must be concentrated. Because of the generally high specific gravity of platinum-group minerals (PGM), certain precautions must be taken, such as mixing the sample material in the bags prior to opening.5.2. Preparation forBulk Analytical MethodsThe principal factors that determine the size of the sample required for a bulk analysis are grade, heterogeneity and grainsize. Initially, the grade and sample heterogeneity can only be estimated and a sampling methodology is developed with experience. It is essential at all times, however, that the assayers have information about the source of the sample and the purpose for the analysis. Information on the grain-size, which can only be obtained through mineralogical analysis, is also very important for PGE analyses, but, unfortunately, is often ignored.5.2.1. Samples fromUnconsolidated DepositsConcentrations of PGE may occur in eluvial deposits as well as in a large variety of alluvial deposits, including those of fluvial and glaciofluvial origin. These deposits are often difficult to map and sampling is further complicated by the wide range, from sand-size to boulders, of the non-POE-bearing constituents, and by the irregular distribution and shape of the ""pay streaks"". PGE concentrations in unconsolidated deposits are largely composed of resistant Pt-Fe and Os-Ir-Ru alloys (cf. Cabri and Harris, 1975 and Raicevic and Cabri, 1976), thus making comminution to the usual-150 to -200 mesh somewhat unreliable, due to the malleability of these alloys."

Jan 1, 1979

By Z. Zhang

Aluminum boron carbide particulate reinforced composites have found new applications in nuclear industry due to their special capability to capture neutrons, Recently, Alcan successfully developed a liquid metal mixing process to fabricate Al¬B4C metal matrix composite instead of powder metallurgical technology. In the process, titanium is added into the composites to control interactions between boron carbide particulates and aluminum matrix, To understand the effects of titanium on the composites, the solidification microstructure of Al-16%B4C without or with titanium was examined by optical and electron microscopes. The results show that titanium can improve the uniformity of the particulate distribution within aluminum matrix if the titanium content in the composites is more than 0,5%, Furthermore, it is found that the layer with rich titanium on the surface of the particulates can limit the formation of AlB2 type compounds, which may greatly deteriorate the fluidity of the composites, In addition, it is also found that the amount of the reaction products in the composites increases with the increase of holding time. However, the rate of the increase is mitigated by the increase of the content of titanium in the composites. Besides, a procedure was proposed and implemented for the evaluation of uniformity of particulate distribution within aluminum matrix.

Jan 1, 2005

By T. Senga, T. Namihira, S. Terada, S. Owada

"Electrical disintegration (ED) has been well known as a good comminution method to improve liberation of compositional phases because it was reported that electron avalanche could occur preferentially at phase boundary. But the detailed mechanism of the ED has been still not known. This paper describes the results of ED experiments using synthetic binary sample, copper/resin, under the conditions of various distance between electrodes, and discusses the energy distribution in the three kinds of phenomena in the ED process, which are(1) streamer progression in water, (2) electron avalanche in water, and (3) electron avalanche in solid sample, by measuring current and voltage with elapsed time. Then, it has been found that the energy distribution in the phenomenon (1) is quite low and that the distribution in the phenomenon(2) had a considerably large compared with that in the(3), which indicates that the shockwave generated in water could contribute much to the sample breakage.INTRODUCTIONElectrical disintegration (ED) has been well known as a specific comminution technology which enhanced selective breakage at phase boundary and lead to a good liberation among compositional phases1-6),but the detailed mechanism has not been clarified yet. This study describes energy distribution among the phenomena in the ED process by using a synthetic binary sample, copper/resin, the phenomena of which are (1) streamer progression in water, (2) electron avalanche and shockwave generation in water and (3) electron avalanche in solid sample usually at phase boundary. The energy distribution could be calculated from ED experiments and from voltage-current changes between electrodes as a function of elapsed time.SAMPLE AND EXPERIMENTALSampleThe sample used in this paper was a synthetic binary solid of copper/resin as shown in Figure1.Cut and polished pure copper lump was put into silicone mold and melted epoxy resin was poured into it and cooled, then, finally the binary sample was polished and molded in the form of 10 mm * 10 mm * 10 mm."

Jan 1, 2017

By C. Barlow

The White Mesa Mill (WMM) began operating in 1980 as a regional processing mill owned by Energy Fuels Nuclear, Inc. Original mill design was for 656,000 Mtpa of U ore producing 1,250 tpa of U3O8 concentrate. Sustained market downturns delayed facility upgrades during most of the 1980s and 1990s. The new owners of WMM, Denison Mines, elected to advance the regional mill concept in 2007 with the modernization of these facilities. This paper details decisions taken and lessons learned in plant redesign, choice of leading-edge instrumentation, motor controls and process automation, training and some example benefits from process control stabilization.

Aug 1, 2010

By S. W. Henley

"Shaft sinking design is typically driven by what has been successful in the past and the availability of sinking plant. This document considers a project where the sinking design and methodology is unconstrained by conventional thinking and removed from the commonly held belief that a sinking methodology should be developed from available winding plant. Schedule was a key driver for the Project and led to an alternative sinking design that aimed to optimise sinking advance rates by specifying new winders that compliment known sinking plant while providing improved safety, redundancy and flexibility within each part of the sinking cycle. KEYWORDS Consistent, Efficient, Flexible, Improved, Innovative, Optimise, Redundancy, Safety, Schedule INTRODUCTION The project is remotely located in the South Gobi region of Mongolia on a brownfield site and the scope of work included the concurrent blind sinking and concrete lining of two (2) ventilation shafts to an approximate depth of 1,150 m at a finished diameter of 10 m and 11 m respectively. All sinking and lining operations to be completed as in-line activities, (no lining whilst other activities are undertaken). The project was schedule driven with a completion date set for the first quarter (calendar) of 2021 and there were no restrictions imposed on the successful Contractor with respect to their equipment selection. Existing sinking plant already onsite from three previous shaft sinking operations would be made available to the Contractor if required on an as is where is basis Sustained advance rates in excess of 2.4 m per day would be required in order to achieve the completion milestone, therefore the design would have to include contingency and demanded flexibility to account for equipment down time. Previous shafts that had been sunk onsite have utilised a single double drum kibble (bucket) winder (hoist) with a single excavator loading on the shaft floor into a large capacity kibble (bucket). DESIGN Mucking The sinking design centred on the mucking cycle given that this is traditionally the most restrictive part of the sinking cycle and typically accounts for one third of the overall sinking cycle. The Vertical Shaft Mucker (VSM) and/or diesel excavator are commonly used plant for shaft sinking that were under consideration. The use of Cactus Grabs was not considered given the higher risk associated with grab ropes and hoist failures."

Jan 1, 2019

By A. Ingelson, C. Nwapi

"With growing international interest in mineral resources in Central Africa, the importance of transparency in resource development cannot be overemphasized. Without transparency, the region cannot maximize revenues from resources. Although the importance of transparency is beginning to be recognized, many factors can hold back the gains of transparency from resulting in real economic development for the countries involved. This paper reviews current financial, economic, and development literature for Central African countries, with a focus on identifying underlying conditions and specific transactional conditions impacting the effectiveness of transparency in mining development in the region.RÉSUMÉ En raison de l’intérêt international croissant pour les ressources minérales en Afrique centrale, l’importance de la transparence dans le développement des ressources ne peut pas être surestimée. Sans transparence, la région ne peut pas maximiser les revenus tirés de ses ressources. Bien que l’importance de la transparence commence à être reconnue, plusieurs facteurs peuvent freiner les gains acquis de la transparence à produire un véritable développement économique pour les pays touchés. Le présent article analyse la littérature financière, économique et développementale contemporaine pour les pays de l’Afrique centrale, tout en ciblant l’identification des conditions sous-jacentes et les conditions spécifiques transactionnelles qui ont un impact sur l’efficacité de la transparence dans le développement minier de la région."

Jan 1, 2015

"Cobalt refining at Vale Canada (previously known as Inco) has been associated with Ni production. Because certain compounds of both metals carry risks for adverse health endpoints by inhalation exposure, it is critical to understand the aerosol concentrations of specific substances and the metallurgical processes through which they enter the air. Vale Canada has therefore decided to describe the histories of its Ni-related operations and to report industrial hygiene measurements when available. This paper describes electrolytic Co operations carried out at Port Colborne, Ontario (1954–1966), and provides aerosol measurements (1995–2008) for current Co electrowinning operations.RÉSUMÉ L’affinage du cobalt chez Vale Canada (anciennement Inco) a été associé à la production de nickel. Puisque certains composés de ces deux métaux comportent des risques d’effets néfastes pour la santé par exposition à l’inhalation, il est essentiel de comprendre les concentrations en aérosol des substances spécifiques ainsi que les procédés métallurgiques par lesquels ils entrent dans l’air. Vale Canada a donc décidé de décrire les historiques de ses opérations liées au nickel et de divulguer les mesures d’hygiène industrielle lorsqu’elles sont disponibles. Le présent article décrit les opérations électrolytiques effectuées sur le Co à Port Colborne, Ontario (1954–1966), et fournit des mesures de la teneur en aérosol (1995–2008) pour l’extraction électrolytique actuelle du Co."

Jan 1, 2015

By P. Nayak

"Comminution is an energy intensive and expensive process consuming approximately 40-50% of the total processing costs in a mining operation. This process poses an even greater challenge with gold ores due to their low elemental concentration and small particle size. Over 99.9% of the ore fed to the mill is waste which must be removed during the ore processing stage. Preconcentrating the Run of Mine (ROM) ore before feeding the mill will result in significant cost savings. In partnership with Sacré-Davey Engineering, Agnico Eagle Mines Limited identified this opportunity and is currently evaluating the implementation of sorting technology to preconcentrate the ore or upgrade the waste material at its operations. This paper will discuss the steps adopted by Agnico Eagle in the evaluation and installation of sorting technology at its operations. Since the Company has a large portfolio of operations, the first step in the project was to shortlist the operations that had the highest probability for successful application of the technology. Following this, the top three operations were selected for bench scale evaluation. The projects which showed the most economic potential were then considered for detailed evaluation and pilot plant installations. This paper provides an insight into the methodology followed by Agnico Eagle and Sacré-Davey in the evaluation of the technology.INTRODUCTION The benefits of ore sorting technology are being increasingly understood by the mining industry today. The application of ore sorting in gold mining is attractive due to the nature of the mineral distribution. The presence of high value minerals distributed in an extremely small mass of the ROM ore creates a tremendous opportunity for preconcentration with ore sorting. Since Agnico Eagle currently has a portfolio of eight operating mines and numerous development projects and exploration properties, the challenge was to identify the deposits which had the most favourable mineralogy and grade distribution for successful ore sorting. The success of ore sorting is mostly based on the minerals present in the deposit and the grade distribution. The minerals signify the amenability of the deposit for ore sorting and the kind of sensing technology to be used. On the other hand, the grade distribution demonstrates the amount of material that can be rejected without losing value. In order to understand a deposit’s characteristics, it is important to examine the sample’s behaviour with various sensors and then assay it to know its actual value. It is a common practice in the mining industry to document assay value of drill cores and/or material feeding in and out of the mill. However, those VALUES (are insufficient to understand the grade variability on a granular basis. To capture the ore variability in very high resolution and significantly improve the selectivity of the material feeding the mill, it is vital to assay the samples on a rock-by-rock basis, as this is the level of resolution which will be examined by the ore sorter during sorting. A careful and elaborate procedure was followed in evaluating the technology at Agnico Eagle’s operations which is discussed in this paper."

Jan 1, 2019

By J. Cui, Z. Meng, W. Zhao

"The decomposition of rare earth concentrates containing bastnasite and monazite by alkali solutions has been investigated. A slurry of the rare earth concentrate and the alkali solutions was calcined at different temperatures. The impacts of calcination temperature on the decomposition of rare earth minerals, the oxidation of cerium, the deportment of fluorine and phosphorous, and the adaptability of the method to the different grades of rare earth concentrate were all studied. A possible technique for comprehensive recovery is proposed in which the chemical elements such as rare earth, fluorine, phosphorus, calcium, iron and thorium could be recycled or recovered. INTRODUCTIONThe liquid alkali decomposition method is an important technique for the decomposition of mixed rare earth concentrates. The technique is relatively clean compared with the sulfuric acid roasting method. However, its operation is intermittent rather than continuous. The two-step solid-liquid reaction and the subsequent water washing make it not very suitable for mass production and application. An important reason for the disadvantage is that an additional process of ""calcium removal by acid leaching"" is needed for the technique. The content of calcium in Baotou rare earth concentrates is usually 6-12%. The requirement of the current technique is that the content of calcium should be reduced to about 0.2% after the calcium removal process. Otherwise, the decomposition and leaching of rare earth will be affected. Therefore, calcium removal by acid leaching is a necessity before the alkali decomposition process is carried out. Research on different alkali decomposition techniques has been conducted with prior calcium removal by acid leaching (Xu, 1995; Yu, 1993; Han, Li, Chang, Liu & Xu, 1985). There have been some investigations of direct decomposition of the bastnasite (Feng, Pan & Li, 1998; Zhao, Zhang, Yang & Liu, 2002)and monazite (Sun, Li, Li, Su, Zhao & Liu, 1998; Zhou, 2005) by alkali-liquid, however, all studies were carried out in solid-liquid reaction system, and continuous calcination studies have not been reported.This paper investigates the process of direct decomposition of Baotou rare earth concentrates by continuous calcination with concentrated alkali. Using the rotary tubular electric furnace, the mixture of rare earth concentrate and concentrated alkali solution were decomposed continuously. Satisfactory decomposition results were achieved. A method for clean processing and comprehensive resource recovery from Baotou rare earth concentrates is proposed."

Jan 1, 2012

By Stephen G. Mlot

Technical Study Work ?Technical study work enables informed decisions: -Obtain a higher price for a quality asset -Minimize expenditure on a project that won?t provide adequate returns -Optimize expenditure on a project to capitalize on the potential return

May 1, 2013

By Hans Lundberg

Magnetic methods have been used for more than three hundred years in prospecting for magnetic ores. More recently magnetic methods have been used for finding salt domes and studying certain geological formations. A number of instruments have been developed and substantial improvements made as to their sensitiveness and accuracy. Papers and articles written on magnetic methods are generally elaborate and technical, and the average prospector finds it difficult to obtain the necessary information as to how to operate the simple magnetic instruments to the best advantage. The miner&apos;s compass, dip needle, and inclinator are, indeed, very useful instruments and are easy to handle, and a great deal of valuable information can be gained if the instrument is properly operated and the results correctly interpreted. The lack of knowledge of the fundamental principles, however, has caused a great deal of disappointment. Other and more elaborate geophysical methods have recently come into the limelight, and the prospectors seem to have lost a great deal of interest in the dip needle. This is much to be regretted, because magnetic methods have a particular field of use. The present article is an attempt to help the prospector regain interest in the magnetic instruments and to show the use and application of a simple magnetic survey. If the prospector expects some useful help in his work, he must, of course, know the instrument, know how to take the readings, and know how to plot and interpret the observations.

Jan 1, 1929

By W. T. Irvine

Introduction The property of the Britannia Mining and Smelting Company is on the east side of Howe sound, some twenty miles north of-Vancouver. The camp is served by two settlements, one at Britannia Mines townsite, approximately three miles from the water&apos;s edge at an altitude of 2,100 feet, the other at Britannia Beach, on Howe sound. The first discovery of copper ore on the property was made in 1888, but it was not until 1905 that production started. From that year until the end of 1944, production had totalled 732,414,420 pounds of copper and 261,126 ounces of gold from six orebodies, known as the Victoria, Empress, No. 5, Fairview, Bluff, and Jane. No. 8 orebody, with which this paper is concerned, was discovered in 1937 by diamond drilling from the 4100 level, some 300 feet above sea level. Development of this orebody to the end of 1944 had included the sinking of a shaft from the 4000 to the 5250 level, and a limited amount of stoping. This work has delimited the orebody from the 3800 to the 4950 level and has indicated upwards of 1,000,000 tons of copper-zinc-gold ore. It is planned to commence production in the near future, while continuing exploration of the orebody at depth.

Jan 1, 1946