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By D. K. Bose, C. K. Gupta, K. U. Nair

A new approach to processing an indigenously available low grade molysulfide concentrate by chlorination with elemental chlorine in presence of oxygen is reported. Recovery of nickel and copper values associated with the sulfide concentrate by suitably treating the residue obtained after chlorination is also reported. In the chlorination process, a gaseous mixture of chlorine and oxygen in the volume ratio bf 2:5 has been passed at 1.66 x 10- 5 m3/s for 1800 s over a 0.01 kg batch of molysulfide concentrate at a temperature of 573°K. Most of the molybdenum has been volatilized as molybdenum oxychloride which has subsequently been extracted in water. The molybdenum value from the aqueous solution has been recovered in the form of calcium molybdate (CaO.MoO3) by treatment with calcium chloride (CaCI2). In an alternative processing scheme, the molybdenum rich solution has been treated with an oxidizing agent (K2S20f.J) and allowed to boil to recover a major portion of the molybdenum value in the form of molybdic oxide (MOOS). The spent charge obtained after molysulfide chlorination has been mixed with about 1 wt % sodium chloride and heated at 773K under an oxygen atmosphere. The reacted mass has been water-leached to yield a nickel-copper bearing solution with limited iron. The process liquor appears to be well suited for further processing by known hydrometallurgical recovery processes for nickel and copper. In the conventional process of molybdenum extraction, the molysulfide concentrate (-59% Mo) is first subjected to roasting to produce molybdic oxide. The oxide is then further processed in sequential steps involving vacuum distillation, ammonia leaching, and calcination to higher purity prior to hydrogen reduction to metal. In India there is at present some small tonnage production of molysulfide concentrate from a byproduct recovery plant of the M/s. Uranium Corp. of India Ltd. (M/s UCIL), Bihar. Efforts are being made at this laboratory to process the low grade fraction of the concentrate which contains sulfides of copper, nickel, and iron; quartz; and chlorites. Here, the conventional routes involving roasting and vacuum distillation appear unsuitable to produce an acceptable quality of molybdic oxide at high recoveries. Formation during roasting molybdates of some of the impurities present in the sulfide concentrate make subsequent vacuum distillation less efficient. In view of these problems, in earlier work reported from this laboratory the low grade concentrate has been processed hydrometallurgically to P. produce calcium molybdate. Starting from this molybdenum intermediate, processes have also been developed for the production of molybdenum and ferromolybdenum. Chlorination as an alternative to roasting for metal sulfides has been drawing considerable interest. The high reactivity of chlorine, the relatively low temperature of operation, the suitability of application to low grade resources, the convenience of recovering sulfur in non-polluting form, and the purity of chlorides which are separated by distillation all favor chlorination. In recent years, considerable work has been reported on the chlorination of common metal sulfides. In the field of molybdenum extraction from its sulfide resource, use of chlorination technology has been rather limited. Senderoff and Labrie3 were the first to chlorinate molysulfide concentrate with elemental chlorine at about 823°K to molybdenum pentachloride for use in the electrolytic preparation of molybdenum. The only other reported work, by Haver, Uchida and Wong, involved reaction between molysulfide and chlorine at 673°K to recover sulfur. The reaction products were, however, identified as molybdenum pentachloride and sulfur monochloride.

Jan 1, 1979

"In the conceptual stages of engineering, benchmarking and empirical ratios are commonly the only references for estimating the production rate of greenfield projects. For underground mining projects, the lack of similar cases often makes the comparison difficult due to each project’s unique geology, rock quality or other singular characteristic. This paper discusses an analytical alternative for determining the maximum achievable production rate for underground stoping mining by modeling production as a continuous process. The results show that long-term maximum capacity depends exclusively on the achievable development rate and the development intensity of the design. In operations constrained by backfill, the development rate could be limited by the backfilling rate. Extraction rate and stope size only have impacts on capacity estimates during the ramp-up period.These findings allow shaping of the maximum capacity profile of a project. They can be used as a tool for quick assessment of conceptual capacities, and sensitivities of mining rates. Benchmarking tests compared favorably with projects, mines in operation and scheduling exercises. IntroductionA key consideration in the value proposition of a mining project is its capacity or production rate (Tatman, 2001). At a conceptual level, it is common practice to refer to empirical references (Taylor, 1986; Long, 2009), rules of thumb (de la Vergne, 2014), benchmark ing studies or consultant experience to estimate or validate a target value. There is, however, a lack of analytical methodology to guide an early estimate of the maximum capacity.Araneda and Gaete (2004) presented an interesting mathematical approach to estimate the capacity of panel caving mines. Using a continuous model, they confirmed that the mine capacity is essentially determined by the rate of area incorporation, in terms of area per period, and ore column height. This simple relationship has been confirmed by multiple detailed scheduling works"

May 1, 2016

By AIME AIME

PURSUANT to a recommendation made by the Section delegates at their conference at the Annual Meeting of the A.I.M.E. last February, the Directors, at their meeting on March 15, 1944, appointed a committee charged with the duty of investigating the present status of licensing and registration of engineers, and to make a report on the whole subject for the information of the mining fraternity. The committee consisted of E. W. Ellis, chairman, H. D. Keiser, Henry T. Mudd, J. J. Croston, and Simon Strauss. Messrs. Keiser and Strauss were unable to assist in the work of the committee, and Mr. Mudd was forced to resign in July, his place being taken by A. F. Greaves-Walker. Able assistance was given the committee by T. Keith Legare, executive secretary of the National Council of State Boards of Engineering Examiners, and by Ed. ward Larson, executive secretary of the National Society of Professional Engineers. The accompanying somewhat condensed version of the report of Mr. Ellis's committee, dated Oct. 15, 1944, is confined to facts rather than to recommendations. The "Model Law" to which reference is made was first drafted by repre¬sentatives of six national engineering societies in 1911. It has since been amended many times, the latest version dated June 1943 is recommended to the State Licensing Boards as a pattern for formulating or amending state laws. A copy of the "Model Law" in pamphlet form will be sent to any member on request from A.I.M.E. headquarters while the supply lasts. The report:

Jan 1, 1945

By Bin Zhu, Mingmei Zhu, Hong Zhou, Xiaofei Dou, Bin Xie, Yu Wang, Tiancheng Lin

In this study, the formation of 2CaO·SiO2 and 3CaO·P2O5 solid solution (nC2S-C3P) in hot metal dephosphorization process is discussed. The variations of CaO and SiO2 mass, both in nC2S-C3P solid solution phase and liquid slag phase with increasing P2O5 mass in CaO-SiO2-FetO-P2O5 slags were calculated using Factsage software. CaO-SiO2-FeOt-P2O5 slag containing up to 18 % P2O5 was melted at 1823 K then cooled to 1673 K. The contents of CaO and SiO2 both in the solid solution phase and liquid slag phase of quenched samples were observed and analyzed by SEM/EDS. Both the calculated and experimental results show that the contents of CaO and SiO2 in the solid solution phase decreased, just opposite in the liquid slag phase, with increasing P2O5 content in the slags. Formation mechanism of nC2S-C3P solid solution in the slags was derived based on the ionic structure theory of molten slag. The SiO4 4- in the nC2S-C3P solid solution can be replaced by PO4 3- in the liquid phase resulting in the increasing of free Ca2+ and SiO4 4- in liquid phase.

Jan 1, 2015

By L. Muñoz, L. Steffen, W. Vilas

The emission of particulate material is one of the several parameters related to environmental control in mining operations near communities. Blasting is an event that generates and leaves a large amount of dust in suspension, which can cause discomfort to communities, generating complaints that can compromise the operational continuity of the mine. The proper management of these environmental impacts is a key factor to ensure a good relationship with the neighborhoods, making a responsible mining in harmony with the environment, giving sustainability to the mining business in the medium and long term. The main goal of this work is to present different techniques and technologies applied in a large-scale open pit mine in Brazil, with operations close to a community, to minimize the emissions of particulate material into the atmosphere. For this, different technical solutions were implemented. First, a non-conventional blasting technique was introduced that incorporates special charging and timing configurations, generating a first upper layer that serves as a blanket to contain a second, higher-energy lower layer. An optimal stemming was also defined in order to minimize ejections and maximize cratering, using the scaled depth of burial theory as well as video and fragmentation analysis. In addition, changes were made in the timing between decks (to guarantee a minimum time between layers) and between holes (changing the initiation point opposite to the free face). Finally, additional measures such as humidification of the bench, use of a wind vane to identify wind direction and the construction of a physical barrier between the mine and the community were implemented as additional mitigation measures. By applying the above techniques together, in some specific zones of the mine, it was possible to considerably reduce the ejections generated by blasting versus conventional blasting without the above measures, which was demonstrated in the field with dual blasts trials. Additionally, it was possible to achieve a vibration reduction in the community of ~30%. This work demonstrates how, by applying these technical solutions, it was possible to minimize the dust and vibrations generated by blasting allowing this operation to do sustainable mining

Jan 1, 2024

By Rollien R. Wells

The Bureau of Mines was created in 1910 by an act of Congress and subsequently directed to: "...conduct inquiries and scientific and technologic investigations concerning mining, and the preparation, treatment, and utilization of mineral substances with a view to improving health conditions, and increasing safety, efficiency, economic development, and conserving resources through the prevention of waste ..." Under this broad charter, the Bureau's responsibilities have changed and grown from an almost exclusive concern with coal and coal mine safety to the present emphasis on a full spectrum of mineral producing and consuming problems. In the past 30 years, the domestic consumption of coal, oil, gas, metals, and industrial minerals has more than quadrupled, in parallel with the rapid and enormous growth in industrial production. Of the scores of metals and nonmetals essential to the Nation's progress and security, many are scarce and difficult to wrest from domestic sources. Reserves of some ores are dwindling. Available ore resources are becoming leaner and more difficult to treat. In recognition of this many faceted problem, the Bureau has engaged in a continuing quest for new and improved technology to enable economic exploitation of marginal minerals and fuels, to find substitutes for minerals in short supply, and to create better materials to meet the expanding and diverse requirements of the growing economy. The current central concern of the Bureau is focused on meeting projected fuel, metal, and mineral demands at the lowest real cost by recovery from available resources by new and improved technology that minimizes waste, hazards, and social and environmental problems.

Jan 1, 1970

By Robert L. Lagace

The attention of this group was focussed on four through-the-earth communication systems that are presently of high interest to the U.S. Bureau of Mines; four systems for providing operational/emergency communications on the working sections of coal mines, indeed up to the very face of the section. The systems are: uplink-data, downlink-voice, sidelink-call alert coded page, sidelink-roof bolt voice page. Each of these systems makes use of the mine overburden as the signal transmission medium, as opposed to the guiding wires, cables, and tunnels treated by the operational communications working group. Each of these systems satisfies one or more of the Bureau's objectives for mine communications systems; namely • reliable links for monitoring the mine environment under both operational and emergency conditions. • reliable links for communicating with miners during emergencies. • special links for increasing the efficiency of day-to-day operations of the mine. Each of these systems has been successfully demonstrated on a limited experimental basis, and prototypes of all these systems are installed and operating in the USBM experimental mine in Bruceton, Pa. Each of these systems must now be optimized regarding its performance, and engineered for practical routine application to the working sections of actual operating coal mines, particularly those of the room and pillar type. This optimization and engineering must take place subject to the principal constraints listed by Howard E. Parkinson in his Workshop paper entitled, "Objectives and Constraints of Through-the-Earth Electromagnetic Communications Systems'' and enumerated below. • Depth of Mine Overburden • Overburden Conductivity • Electromagnetic Noise In and Above Mines • Limited In-Mine Electrical Energy (Stationary or Man Carried) During an Emergency • Intrinsic Safety for In-Mine Equipment • Practical and Rugged Equipment for Use Under Both operational/Emergency conditions • Severe Weight Limitations for Man Carried Equipment • Reasonably Low Costs Especially for Man Carried Equipment Part II of this paper provides a brief description of each system, while Part III summarizes the present status of developments related to these systems and some recommendations for future work needed to advance these systems to the practical application stage.

Jan 1, 1973

By David A. Summers, Clark R. Barker, Marian Mazurkiewicz

In May 1975 the U.S. Bureau of Mines contracted with the University of Missouri-Rolla, Rock Mechanics and Explosives Research Center to develop a Hydrominer modification to a longwall shearer unit, wherein the rotating pick-laced drums and connecting gear drives are replaced by a water jet cutting ahead.1 The concept of the water jet cutting head is based on using the high localized energy of the water jets to isolate a slice of coal by cutting a slot under, at the back of, and at the top of the web. The plow blade of the head then advances into the cut and wedges the coal cantilever over onto the conveyor (Fig. 1).

Jan 4, 1978

By H. C. Gatos, A. D. Kurtz

WITH the growing interest in the mechanism of self-diffusion of metals, the study of accurate and convenient methods for determining self-diffu-sion coefficients appears highly desirable. It was with this objective in mind that the present investigation was undertaken. Gatos and Azzam1 employed an autoradiographic technique for measuring self-diffusion coefficients of gold. This method involved sectioning of the specimen through the diffusion zone and recording the radioactivity directly on a photographic film. Because of the very short range of the emitted ß rays in gold, the activity recorded on the film was essentially the true surface activity. With proper choice of the sectioning angle, sufficient resolution could be obtained and the entire concentration-distance curve recorded in one measurement. For the boundary conditions of the experiment, where an infinitesimally thin layer of radioactive material diffuses in positive and negative directions into the end faces of a rod of infinite length, the solution of the diffusion equation is C/Cn = 1/v4pDt exp (-x2/4Dt) where C is the concentration of diffusing element (photographic density in this case), C,, is the constant (depending upon amount of radioactive material), x is the diffusion distance, D is the diffusion coefficient, and t is the time. Thus, by plotting the logarithm of the concentration vs the square of the diffusion distance, a straight line results and the slope contains the diffusion coefficient. In this manner, the self-diffusion coefficient of gold can be obtained as a function of temperature. In the present investigation the results reported by Gatos and Azzam1 have been verified, and the autoradiographic technique has been further developed and applied for the determination of the self-diffusion coefficient of gold at a number of temperatures. Furthermore, the energy of activation for the self-diffusion of gold has been conveniently determined. . Experimental Techniques Preparation of Specimens: The inert gold of high purity was received in the form of a rod from which cylinders were cut and machined to a diameter of 0.500 in. The specimens were annealed to a suitably large grain size and the faces were surface ground prior to the deposition of the radioactive layer. The radioactive isotope Au198 was chosen. It was produced in the Brookhaven pile by means of the reaction Au197 + n ? Au108. It decays by ß emission (0.96 mev) to Hg108 with the subsequent emission of a y ray (0.41 mev). 70Au 108 ? 80Hg 108 + -1e°. The half life of the Au108 is 2.7 days so that a strict time schedule had to be maintained in order to secure sufficient activity until the end of the experiments. For this reason, initial activities as high as 10,000 millicuries per gram were used. The gold arrived in the form of foil and was evaporated onto one face of each gold specimen cylinder to a thickness of about 100A. A sandwich-type specimen was formed by welding two such cylinders together. Evaporation of Gold: The gold was evaporated under vacuum from heated tantalum strips which were bent in such a way as to limit the solid angle through which the gold was allowed to vaporize, thus insuring a more efficient utilization of the gold. The specimens rested on flat brass rings which had an inner diameter of 0.475 in. The entire specimen-holding assembly could be manipulated from outside the vacuum system by means of a magnet which attracted a slug of soft iron attached to the assembly. By evaporating inert gold on glass slides under conditions identical to those employed for the radioactive gold, it was found that the thickness of the films was about 100A. Welding: The welding was performed by hot pressing in a stainless steel cylinder. The inside of the cylinder was threaded and fitted for two plugs. The specimens to be welded were placed in the middle of the cylinder and two pressing disks, one at each end, were inserted to avoid shearing stresses as the plugs were tightened. Mica disks were placed between the pressing disks and the specimens to prevent them from welding. The plugs were then tightened with a hand wrench and the entire unit was placed in an argon stream for about an hour to remove the oxygen. The unit was then inserted in the center of an argon atmosphere furnace maintained at about 700°C and left there for about an hour. Because of the difference in the temperature coefficient of expansion of the two metals, as the temperature rose. the pressure on the specimen-rollple increased and a weld resulted Welding was generally satisfactory under the conditions described.

Jan 1, 1955

By E. H. Jr. Dix

IN selecting the subject, "Acceleration of the Rate of Corrosion by High Constant Stresses," for the 1940 Institute of Metals Division Lec-ture, I have been influenced by its highly theoretical and speculative nature as well as by the great practical importance of the correct inter-pretation and appraisal of the engineering significance of the phenomenon. I lay no claim to originality in talking on this topic, since it has been the subject of discussion for over a quarter of a century. However, as our technical thinking advances, old phenomena take on new and more significant aspects. In our studies at the Aluminum Research Labora-tories, we have encountered many perplexing and seemingly contradictory results and have been fascinated by the problem of dovetailing all of the many pieces of information to make a complete picture. I hope that in the brief period of this lecture I may share with you some of the enjoy-ment we have had in attempting to meet this challenge to metallur-gical science. The emphasis generally has been placed on the spontaneous failure by cracking of a metal under the combined action of high stress and corrosion, hence the present-day use of the terms "stress corrosion" or "stress corrosion cracking." The older term "season cracking," applied more specifically to copper-base alloys, includes, by inference, the element of time. For the purpose of the discussion today I will use "stress corro-sion" to cover broadly the effect of stress in accelerating the rate of corrosion of metals. To stay within the limits of allotted time the dis-cussion will cover the effect of high static stresses rather than repeated or dynamic stresses, which would take us into the related field of corro-sion-fatigue. The subject is particularly appropriate for an Institute of Metals Division Lecture because much the same phenomenon has been observed in almost all metal systems. Thus, in addition to the season cracking of brass may also be mentioned the "caustic embrittlement" of steel boiler

Jan 1, 1940

By J. E. Gould, H. J. Hand

Many independent studies are being made on slag-metal relationships in the open-hearth furnace, and these studies cannot help but result in an ultimate improvement in the quality of open-hearth steel of both the open and killed types. In maintaining quality control at the National Tube Company's plant, emphasis has been placed on an evaluation of the iron oxide content of the steel in as quantitative a manner as possible, in order that the most desirable level of oxidation might be obtained for a given type of steel, and to secure a more precise basis for final de-oxidation. In the past, various methods were used for estimating FeO content of the metal at tap to ensure uniform and thorough deoxidation of killed steel, avoiding overdeoxidation to minimize the amount of inclusions present and to make as sound a steel as possible. For the open-type steels, such control involves obtaining the necessary level of oxidation for the most suitable action of the steel in the molds to provide good surface quality and cross section for the specific grade involved. While rapid analytical methods are available for determination of FeO in the liquid metal, such methods are still not sufficiently rapid for routine control on the open-hearth floor, nor do such analyses provide information as to what causes high or low FeO values. The method of sampling can still be considered a problem in view of the variability encountered in taking simultaneous duplicate tests. With the accurate rapid methods now available for determining carbon in the metal, estimating slag basicity and obtaining temperatures of liquid metal, it was believed possible to determine the influence of the various furnace reactions in establishiug the state of oxidation at a given time. Simultaneous slag and metal tests were used in this analysis, aided by statistical methods, to determine the factors that affect the metal FeO, and also to make a quantitative evaluation of these factors. Data obtained are from actual iurnace operations, the metal test being of the I spoon, Herty type, and taken in duplicate. Metal temperatures were taken with the open-tube bath pyrometer developed by the Research Laboratory of the United States I Steel Corporation. This method of taking open-hearth metal temperature was invented by Collins and Oseland,l and was developed into its present form by L. 0. Sordahl,2 of the Research Laboratory. The instrument and its mode of operation have been fully described by Sordahl and Sosman in three publications.3,4,5 lag components were obtained by chemical analysis. Data were taken from four 165-net-ton furnaces during the working period of the heat. Recognizing that additions of ore affect the metal FeO. no tests were included within 30 min. after ore additions. In all, 65 tests (48 heats) were used in this study.

Jan 1, 1942

By J. E. Gould, H. J. Hand

Many independent studies are being made on slag-metal relationships in the open-hearth furnace, and these studies cannot help but result in an ultimate improvement in the quality of open-hearth steel of both the open and killed types. In maintaining quality control at the National Tube Company's plant, emphasis has been placed on an evaluation of the iron oxide content of the steel in as quantitative a manner as possible, in order that the most desirable level of oxidation might be obtained for a given type of steel, and to secure a more precise basis for final de-oxidation. In the past, various methods were used for estimating FeO content of the metal at tap to ensure uniform and thorough deoxidation of killed steel, avoiding overdeoxidation to minimize the amount of inclusions present and to make as sound a steel as possible. For the open-type steels, such control involves obtaining the necessary level of oxidation for the most suitable action of the steel in the molds to provide good surface quality and cross section for the specific grade involved. While rapid analytical methods are available for determination of FeO in the liquid metal, such methods are still not sufficiently rapid for routine control on the open-hearth floor, nor do such analyses provide information as to what causes high or low FeO values. The method of sampling can still be considered a problem in view of the variability encountered in taking simultaneous duplicate tests. With the accurate rapid methods now available for determining carbon in the metal, estimating slag basicity and obtaining temperatures of liquid metal, it was believed possible to determine the influence of the various furnace reactions in establishiug the state of oxidation at a given time. Simultaneous slag and metal tests were used in this analysis, aided by statistical methods, to determine the factors that affect the metal FeO, and also to make a quantitative evaluation of these factors. Data obtained are from actual iurnace operations, the metal test being of the I spoon, Herty type, and taken in duplicate. Metal temperatures were taken with the open-tube bath pyrometer developed by the Research Laboratory of the United States I Steel Corporation. This method of taking open-hearth metal temperature was invented by Collins and Oseland,l and was developed into its present form by L. 0. Sordahl,2 of the Research Laboratory. The instrument and its mode of operation have been fully described by Sordahl and Sosman in three publications.3,4,5 lag components were obtained by chemical analysis. Data were taken from four 165-net-ton furnaces during the working period of the heat. Recognizing that additions of ore affect the metal FeO. no tests were included within 30 min. after ore additions. In all, 65 tests (48 heats) were used in this study.

Jan 1, 1942

By Y. I. Yang, Y. -B. Tang, D. -J. Ma

Chlorine-containing minerals are commonly present in coal. Associated minerals such as pyrite can undergo exothermic reactions. Consequently, it is of great significance to study the effect of inorganic chloride on the spontaneous combustion of coal. In this study, the effects of five inorganic chlorides (sodium chloride, magnesium chloride, potassium chloride, calcium chloride, and zinc chloride) on the spontaneous oxidation of coal were investigated. Analysis of the gaseous products of coal oxidization at low temperatures (323K to 453K) showed that the presence of inorganic chlorine in coal markedly decreases O2 consumption and the generation of CO and CO2. Samples of raw coal and chlorine-loaded coal were oxidized for 36 hours under the same experimental conditions. Infrared diffuse reflectance spectroscopy results showed that inorganic chloride can inhibit the oxidative decomposition of some functional structure components (methyl, methylene, methine, and hydroxy) in the coal. The influence of inorganic chloride on the oxidation characteristics of the functional groups in coal during spontaneous combustion was investigated using benzyl alcohol and 1-phenylpropanol as model compounds, which were tested under the same experimental conditions as the coal samples. The oxygen consumption of model compounds with and without the addition of inorganic chloride further suggested that inorganic chloride may hinder the oxygenolysis of these structures during low-temperature oxidation. This phenomenon can be attributed to the radical reaction from the perspective of radical chemistry. It can therefore be concluded that inorganic chlorides play an inhibitory role in the spontaneous combustion of coal.

Jan 1, 2015

The main factors which influence disposal of mine waste under New Zealand conditions are identified and discussed: namely, geological conditions which produce soft weather-sensitive waste, wet and cold winters which affect productivity in such waste, elevated seismicity which affects stability and the need for water rights which involve public participation. The waste disposal scheme for the Martha Hill Project is described, thereby illustrating how these factors influence the planning of a current mine strippings and tailings disposal scheme.

Jan 1, 1986

By Chuck Edwards

"The development of two large, high-grade uranium projects has been proposed for northern Saskatchewan. The projects are now under review by a joint federal/provincial panel. The McArthur River project is owned by the McArthur River joint venture (Cameco Corporation 53.991 %, Uranerz Exploration and Mining Limited 29.775%, Cogema Resources Inc. 16.234%) and operated by Cameco. Cameco proposes to mill the McArthur River ore at the existing Key Lake mill. The Cigar Lake project is owned by the Cigar Lake joint venture (Cameco Corporation 48.75%, Cogema Resources Inc. 36.375%, Idemitsu Uranium Exploration Canada Ltd. 12.875%, Korea Electric Power Corporation 2.000%). The Cigar Lake joint venture proposes that Cameco operate the Cigar Lake mine for the owners, and that Cogema mill the ore at their McClean Lake mill, now under construction. Proposed systems provide safe mining and ore handling, and allow the milling of McArthur River ore at Key Lake and Cigar Lake ore at McClean Lake. This avoids the disturbance of new sites for milling and tailings disposal.The McArthur River and Cigar Lake deposits are the largest known high-grade uranium deposits in the world. The ore grades at McArthur River and Cigar Lake are at least 100 times those that are mined elsewhere. It is proposed to mine these deposits using remote underground mining methods, to crush and grind the ore underground, to pump a thickened ore slurry to surface, and to transport it in special containers by truck to the mills.During all mining and processing stages the ore is fully contained. Radon emission is controlled by positive ventilation of all process vessels, with the process ventilation backed up by the primary mine ventilation system. Radiation is controlled by heavy steel pipe and vessel walls, concrete walls and sometimes lead sheeting."

Jan 1, 1997

By Healy T. W, Dixon D. R

The present study 'of pure ZnS and NiS and ZnS (marmatite) by detailed electrokinetic methods has shown that by careful control of experimental parameters much new' information on sulphide-water interfaces can be obtained. Time-dependent processes of alteration of sulphide surfaces are foHowed by electrokinetic methods and indicate that the isoelectric point of the surface depends on elemental sulphur coverage, oxidation product coverage, and the conditions which promote or minimize such reaotions in the presence and absence of activator.

Jan 1, 1977

By J. O. Jones

[Willis Mountain in southeastern Buckingham County is one of several kyanite deposits its central Virginia. It is composed principally of kyanite resulting from metamorphism of siliceous sedimentary beds rich in alumina. The mountain, which trends north-south, is 2 miles long and is topped by a narrow ridge with sleep rugged sides rising to an altitude of 1,160 feet and projecting 500 fast shove the surrounding countryside. Bureau Mines engineers examiner Willis Mountain early in 1949, when bonded concentrations of coarsely crystalline kyanite were observed in the kyanite-quartzite on the northern end of the mountain and in loose boulders on the eastern slope. Commencing in late July 1949, the investigations continued on the Long Mountain segment for 11 months, ended in June 1950. A total of 600 samples from 32 diamond-drill holes, aggregating 3,876 feet of drilling, and from 255 feet of sampling in 3 trenches was assayed for kyanite and ferric oxide.]

Jan 1, 1954

By J. H. Morris, G. M. Steed

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Oxygen isotope analysis indicates that quartz, carbonates and muscovite could all have formed in near-isotopic equilibrium with the mildly saline H2O-CO2 ore fluid at 330 degrees C. Calculated values for O, C and S in the ore fluids imply derivation from a deep, homogeneous source region and are consistent with formation either as a direct or an indirect result of igneous processes. Values for delta-O18 plot a little outside the accepted magmatic range, but have almost certainly been modified by exchange reactions with wall rocks. These reactions were also the most likely cause of deposition of the ore constituents. The chemical and isotopic character of the fluid was similar to that in many Archaean and later mesothermal auriferous vein systems, especially the Mother Lode region of California. If the Southern Uplands-Longford Down accretionary complex conceals an Ordovician arc, the tectonic setting was also broadly comparable

Jun 19, 1905

The objectives of this paper are two-fold. First, it will show what problems can arise when single estimated values are substituted for a distribution of values when evaluating an open pit mine project in the face of uncertainty. Secondly, it will show how the ability to deal with uncertainty and risk in mine project evaluation can have a significant impact on the ownersÆ and stakeholdersÆ investment decision-making. Here a new mine evaluation framework, the integrated valuation/ optimisation framework (named IVOF), is introduced as an alternative tool for mine project evaluation where uncertainty and risk are incorporated in the evaluation process.

Jan 1, 2009

By S. B. Kim, J. Hong, K. Park, W. Kim, H. Kim, Y. Han, J. Choi

"For the first time, the influence of stearyl trimethyl ammonium chloride (STAC) as a collector, on the flotation behavior of lepidolite (Uljin, South Korea) was systematically examined in Denver Sub-A cells. Flotation tests were carried out by varying amount of STAC (50–200 g/ton), feed size (-65, -100, -150, and -200 mesh), and solution pH. The impeller speed of 1000 rpm, flotation time of 10 min and AF-65 (a frother) of 250 mL/ton were invariably applied. In order to complement flotation experiments, zeta potential measurements and XRD analysis were conducted. XRD results showed that the ores were mainly composed of lepidolite, muscovite, quartz, calcite and albite. In addition, zeta potential results showed that isoelectric points were about 2.5, 2.3, and 9.7 for quartz, albite, and calcite, respectively, and lepidolite was determined to be less than 2. Overall, the results of 3-stage flotation showed that Li2O grade and recovery tended to increase with increasing STAC dosage and decreasing feed size. In addition, Li2O grade increased with decreasing pH. The results were explained by the extent of the interaction between STAC and each mineral.INTRODUCTION A great number of potential applications of lithium are being developed currently by the thermonuclear fusion power generation industry(1,2) as well as by the battery and fuel cell industry(3). Even though lithium is mainly consumed in the form of lithium metal and some lithium compounds, about 10% of total lithium production is consumed directly as mineral concentrates by the ceramic industry for the manufacture of special ceramics and mica based glass-ceramics(4). Granitic pegmatites normally contain feldspars, quartz, and mica in addition to lithium-bearing minerals such as spodumene (LiAl(SiO3)2), petalite (LiAlSi4O10), and lepidolite (KLi2Al(Al,Si)3O10(F,OH)2). The amount and grade of metallic minerals tend to gradually decrease and become lower, leading to the increase in the price of base metal or metallic compound(5). Accordingly, recent studies have been extensively devoted to developing the technique to improve the grade of metallic minerals from low grade metallic ores(6,7). Nevertheless, studies regarding the improvement of Li grade from lepidolite ores are very scarce. Lepidolite is a phyllosilicate mineral of the mica group and is often associated with other minerals such as calcite, muscovite, feldspar, and quartz, which need to be separated for lepidolite enrichment(8). Many studies have reported the flotation techniques for separating calcite, muscovite, feldspar, and/or quartz from various targeting minerals(9-11); however, there has been no attempt to investigate physico-chemical properties of lepidolite and its separation from such types of gangue minerals through flotation. Hence, in this study, for the first time, flotation has been carried out for the quaternary ammonium salts (stearyl trimethyl ammonium chloride (STAC, (CH3)3CH3(CH2)16NCl))-lepidolite system based on only the electrokinetic property of minerals that consist of lepidolite ores without adding any depressant to get an initial insight on its flotation behavior. The experimental variables that influence the lepidolite flotation such as amount of collectors, feed size and solution pH have been also examined."

Jan 1, 2015