Search Documents

By C. R. Julian

THE large pyrites ore-bodies, the underground mining of which is to be described, are situated at Rio Tinto in the Province of Huelva in Southern Spain. The situation of the different ore-bodies with relation to one another is shown in Figure 1. It will be seen on the plan that the strike of the ore-bodies is approximately east and west. The geology of the district has been very fully described by Dr. D. Williams (1), so that for the purposes of this paper it will be sufficient to give briefly the salient features o each of the two larger ore-bodies which are being mined by underground methods at the present time. (a) San Dionisio.-This ore-body is the largest single deposit in Rio Tinto, having on its upper levels a length of 3,500 ft. On the upper levels the average width is approximately 200ft. but in places on the lower levels there is a width of 900ft. of un broken pyrites. Diamond-drill holes, without running out of ore, show the ore-body to persist to a depth of at least 1,600 ft. The ore-body in the upper part lies between slate and porphyry walls, but in depth is enclosed in porphyry walls. (b) South Lode.-Faulting is considered to be responsible for the break in the solid ore between South Lode and San Dionisio. On the upper levels, the South Lode ore-body has an unbroken length of 4,000 ft. The massive pyrites has a maximum width of 300ft. and an average of about 100 ft. Ore has been proved to a depth of 1,000 ft., at which depth the ore-body is much reduced both in length and breadth. This ore-body, to the depth at which it has been proved, lies entirely between slate and porphyry walls. The South Lode and the San Dionisio ore-bodies are mined both by open-cast and by underground methods. There is evidence that these mines have been exploited intermittently during the last 3,000 years; but, as is to be expected, no records are available of the tonnage mined prior to the time of purchase by the present company.

Jan 1, 1940

By Somasundaran P., M. Vasudevan, Z. Dai, D. R. Nagaraj, T. Bhambani, P. Patra

Historically, efficient beneficiation of ultramafic ores has been challenging, partly due to a lack of clear scientific understanding of the effects of Mg silicates, particularly fibrous serpentines, on selective Ni recovery. Recent research at Columbia-Cytec as a part of a Vale JDP project has led to new insights into the mechanistic aspects of the adverse effects of Mg silicates. Our research has provided strong evidence to support the hypothesis that the adverse effects of Mg silicates are mediated through their large influence on pulp rheological properties, far more than any other pathway. The severity of the effect of Mg silicates is predominantly dependent on the aspect ratios of Mg silicates. For example, the pulp viscosity increases dramatically with increase in the fibrous nature of the gangue mineral leading to poor Ni separation. Various ways by which the suspension rheology affects flotation sub-processes, with implications for remedy are discussed. The insights and results have served to develop (or construct) a phenomenological model to adequately explain all of the ore flotation data, particularly the Mg silicate transport to the froth phase and the concentrate.

Jan 1, 2011

By G. Beckstead, L. Gormely, R. Zimmer, K. Hanneman, B. Nethery

As part of the EIS and permitting activities for the Pogo Mine in Alaska, a risk assessment study for the water management plan was carried out. The basis for the study was a site water volume and contaminant balance model. Probabilistic modeling was carried out using the @Risk Monte Carlo simulation package to investigate the frequency, quantity, and quality of discharges under varying assumptions. The results were used in discussions with regulatory officials as part of the permitting process for the project. The simulation allows probabilistic modeling of key environmental parameters based on input frequency distributions involving both quality and quantity of flow. When combined with predictions of water treatment plant capacities and removal efficiency, this was very useful for defining the likelihood of important regulatory outcomes. Based on the model, certain project modifications were made. Using the simulation as a basis, ongoing dialog with regulators led to consensus that all potential risks have been considered and mitigated for the Pogo Mine according to their likelihood and severity, and that regulatory requirements would be achieved. The paper describes the model and some of the applications for which it was used.

Jan 1, 2005

By Cheryl L. Allen

Increasing energy costs associated with mining have become an issue that must be addressed by industry to ensure sustainable production. As underground mine ventilation systems account for 40% to 50% of a mine?s total energy requirement, initiatives to maximize their efficiency have been introduced worldwide. A control method known as Ventilation-On-Demand (VOD), which adjusts the ventilation system by responding to the activities of mine personnel and air quality, has been commissioned at Vale?s Coleman Mine. This initiative is an effort to reduce energy consumption, maximize efficiency of the ventilation system while ensuring air quality. There are five control strategies that can be executed with the VOD control system in place at Coleman Mine: Manual real time control Time-of-Day Scheduling Event-based control Environmental control Activity Based Control/Tagging This paper describes the system, control strategies and impact on energy consumption and flexibility of airflow distribution as applied at Vale?s Coleman Mine.

May 1, 2011

By G. M. Behrend

"The mining and processing of mineral ores is a very old industry which is steeped in tradition. Rising demand for metals has recently forced the exploitation of lower-grade orebodies which require extensive beneficiation. The high capital expenditures involved, together with market pressures for high-quality concentrates and pellets, have forced the development of new process technologies which are heavily dependent on automatic process control. Development of suitable instrumentation has been rapid and it is being applied to mining processes today with a high degree of sophistication. The drive for higher efficiency and profitability goes on and has reached a level at which modern digital computers appear to be the only answer. However, the efficient application of a digital process computer is extremely complicated and is therefore approached by the mining industry with considerable hesitation.Some of the benefits promised by the digital computer can be obtained today by other means, which are more manageable and can provide immediate payoff. The result would be a building-block system which would utilize the digital process computer as its final component, to perform true plant optimization, free from routine chores."

Jan 1, 1971

By F. W. Gray

A GEOLOGICAL study seeking to determine, for economic purposes, the value of the Sydney coalfield as a source of coal supply. Limitations of the coalfield come under two main heads: (a) Areal extent of the undersea coalfield. (b) The distance from shore at which coal can be mined at a cost of production permitting its profitable sale. Conclusions reached are that the areal extent of seams below the Phalen seam is of. small economic importance, and that non-persistence of these seams in full thickness and quality in the undersea extension of the coalfield will put an end to profitable mining before any limitations connected with distance from the shore-line become operative. With respect to the Phalen seam, non-persistence or deterioration of the seam will become effective in the western part of the coalfield, and less certainly in the eastern part of the coalfield, before operation of limitations by distance from shore. In the central portion of the coalfield, the seam probably persists in commercially workable thickness and quality to beyond the limit of mining set by distance from the shore-line. With respect to the seams above the Phalen seam between the Mountain fault on the extreme western boundary of the coalfield and the assumed termination of the deposition area on the eastern extremity of the field near South Head of Morien, there appear to be only such limitations as arise from engineering approach, distance from shore, sufficiency of strata cover between the sea-floor and the upper coal seams, and quality of the coal (with certain reservations as to the continuity of the upper seams under Sydney harbour and in the Sydney Mines-Little Bras d'Or district). Some of these seams have fragmentary land outcroppings from which their persistence seaward is assumed, and there may be other and still higher seams in the strata column which are entirely submarine.

Jan 1, 1941

By P. Reyes

The start up and operational optimization of the No. 3 Oxygen Plant at the Caletones Copper Smelter of the Codelco - Chile El Teniente Division is summarized. In addition, the economic impact of such optimization on the production cost of oxygen and others aspects associated to the operational robustness as well is detailed.

Jan 1, 2007

By Guojun Wang, Zejun Chen, Wenchang Liu

Al/Mg/Ti laminated metal composite sheet (LMCS) can combine the merits of each of metal components, and obtain excellent performances. It incorporates the advantages of high strength, light weight, easy melt and atomization, and good space adaptability to substitute for the bumper Al sheet of Whipple shield structure for space debris shield. The Al/Mg/Ti LMCS was fabricated by hot roll bonding technology in a certain sequence. The manufacturing process and parameters were analyzed and studied, including the first rolling reduction, roll boding temperature and stacking structure of each metal. The microstructure of dissimilar metals and bonding interface were characterized and analyzed. The optimized manufacturing procedures and parameters were presented based on the microstructure and mechanical properties of LMCS. The research results offer some guides and references for controlling the shape of bonding interface, optimizing the annealing process, improving the mechanical properties of Al/Mg/Ti LMCS.

Jan 1, 2015

By M. Maley, S. Burling, R. Ring

ABSTRACT The numerous global uranium deposits vary significantly in mineralogy, grade, and textural characteristics; therefore, information from traditional (or conventional) sources on the fundamentals of leaching uranium and gangue minerals is not always applicable when studying particular ores. Empirical studies can be effective in understanding leach systems and can lead to improvements in process design but there remains a lack of fundamental understanding necessary for ongoing process optimization as ore bodies continue to vary. ANSTO Minerals has undertaken a work program to address several fundamental questions about uranium leaching, including the unexpected impact for some ore types of leaching at high oxidation potential.

Jan 1, 2012

By Dharmendr Kumar, Pradip, Sivakumar Subramanian, Beena Rai, Venugopal Tammishetti

The separation efficiency in a mineral processing plant is generally assessed and reported in terms of elemental assays constituting the minerals of interest. However, different minerals comprising of same elements behave differently under similar process conditions. Thus, it is imperative to track the mineral composition thank elemental composition of different streams in a processing plant. The availability of automated mineral analyzers such as QEMSCAN and TESCAN in recent times has made it possible. However, due to the high cost and expertise required, their adaptation in day to day monitoring of operations is not yet a common place. X-ray diffraction (XRD) profile fitting (Rietveld Refinement) is another technique which can provide estimates of mineral proportions in a sample. The results of Rietveld Refinement however are affected by coating of fines on coarse particles, method of sample preparation, particle size distribution of sample, elemental substitution in mineral crystal lattice. In the present work, we propose a simple and efficient method for quantitative estimation of minerals in iron ores using elemental assays and thermo-gravimetry analysis data. The minerals (hematite, goethite, gibbsite, kaolin and quartz) are identified using powder XRD analysis. It is also observed that goethite contains Al substitution in the crystal lattice. The samples were analyzed for %Fe, %Al2O3 and %Silica using chemical analysis. The measured Loss on Ignition (LOI) in the sample is contributed from goethite, gibbsite and kaolinite phases. LOI from gibbsite and goethite occur in temperature range 250–350°C and LOI from kaolinite occur in temperature range 400–700°C. According, LOI are determined in two different temperature ranges that are 100–400°C and 400–850°C. We have used the data to successfully determine the mineral compositions of iron ore samples. We have also employed a data reconciliation algorithm on the calculated data for further improvement and consistency of our results. Our method is very convenient for quick estimation of mineral proportions in a sample. The proposed method can also be used for quantitative phase estimation in bauxite ores and red muds.

Jan 1, 2016

By P. M. STILES

Acquired in 1957, the limestone quarry of Ideal Basic Industries on Texada Island north of Vancouver has become a major supplier of high purity limestone and construction stone. Crushed limestone products are shipped by barge to various destinations along the B.C. and northern U.S. coasts.

Jan 1, 1984

By L H. Warren

The types of equipment available for generating a plasma have been reviewed. The efficiency and potential of the plasma generating equipment used in performing extractive metallurgical reactions have been determined. A general classification of the reactions that might be per-formed in a plasma has been proposed. Experimental work done on extractive metallurgical plasma reactions, heat transfer between the plasma and solids, and the quench of the products of plasma reaction has been summarized. From the preliminary results it appears that the high-intensity are or the transpiration-cooled anode plasma torch offer the most promising areas for further research. C ONSIDERABLE world-wide research effort is currently being devoted to the development of processing technologies which employ the new high-temperature generating devices that have appeared over the past few years. The plasma flames produced by these devices offer the potential for subjecting materials to any single gas or mixture of gases at temperatures up to 20,000°K. With these conditions available, many reactions in extractive metallurgy,

Jan 1, 1965

By E. L. Bruce

EUROPEAN Russia is mainly a great plain, the average elevation of which is only 600 feet above sea level and the maximum elevation less than 1,200 feet (Figure 1). The main divide between the Arctic ocean and the Black sea and Caspian sea is an indistinguishable topographic feature from which the Dneiper and Don rivers flow southward to the Black sea and the Volga river to the Caspian. The valleys of these rivers are but little below the general level (Figure 2). To the south, this great, rolling plain is broken by a low ridge of Precambrian gneisses and intrusive rocks. The Crimea is an upland from which the descent to the Black Sea coast is precipitous (Figure 3). The Ukrainian Soviet Socialist Republic occupies the southern part of the plain. It is the southwestern unit of the Union, bordered by Rumania and Poland on the west and by the Crimean Soviet Socialist Republic on the south.

Jan 1, 1938

By Mauro Torres, Gabriel Zarate

"AngloAmerican used the extractant M5640 at Mantos Blancos and Mantoverde and uses PT5050MD at Los Bronces Division, which are aldoxime and modifier blends. In the first case, the modifier is the esther TXIB, while in the second case is the tridecanol TDA. It is a well-known fact that the extractant degrades while the modifier does not and with time the oxime/modifier ratio can change significantly, depending on the operating conditions of each plant.In order to evaluate the effect of this varying modifier content in the plant organic, especially in the organic losses, a complete metallurgical test work program was conducted at laboratory and pilot plant scale by Flomin SNF, a new extractant supplier. Results showed that the addition of an aldoxime without the modifier did not affect the chemical performance of the extractant, but there was a significant decrease in the viscosity and density of the organic.Based on the results obtained in the metallurgical program, it was decided to run plant scale tests at the SX plants of Mantos Blancos and Mantoverde. In these tests, instead of adding extractant to maintain the organic inventory, CuPROMEX 3406 which is an unmodified aldoxime was added until the original oxime/modifier ratio was reached. This was obtained after 6 months of operation and since then both plants are running with the extractant CuPROMEX 3302 both supplied by Flomin SNF.In the case of Los Bronces, the pilot plant work was completed and it is programmed to run similar plant scale tests. In this case, the oxime/modifier ratio increased and TDA will be added until reaching the original ratio.The plant results obtained at Mantoverde and Mantos Blancos, together with the pilot plant test results obtained at Los Bronces, are discussed in this paper."

Jan 1, 2016

By R. W. Hodder

"Archean lode gold deposits of both vein and chemical sedimentary types typically have major enrichments of certain rare elements, including Au, Ag, As, Sb, B, W, Se, Te and Bi, coupled with low or negative enrichments of the more abundant and mobile base metals, Cu, Pb and Zn. On the other hand, in massive base metal sulphide deposits Au, Ag, Cu, Zn and in some instances Pb are all enriched by a factor of 200 to 2000 t:'Jf'1pared to background and there is no large separation of gold relative to the base metals.The fluids from which gold was precipitated in veins were at temperatures of 320 to 480°C, at lithostatic pressure, had significant C02, and Na """" K; whereas the fluids which generated base metal deposits were at 250-300°C, at hydrostatic pressure, had C02 < < H20 and Na > > K.Many lode gold deposits are characterized by K, C02 and Si additions to their enveloping rocks, whereas base metal deposits typically have a fixation of Fe, Mg, Si and S in footwall rocks. Lode gold deposits may also have a relatively large halo of low-temperature oxidative, sadie spilitization in enclosing volcanic rocks, where seawater has later streamed into cooling stocks or flows that have initially acted to focus gold mineralizing fluids along thermal contraction fractures. The submarine environment is one hydrologically appropriate for the mixing of two initially independent hydrothermal systems, and the blending of their separate characteristics. Hence, lode gold and base metal massive sulphide deposits appear to be products of two distinctly different crustal and hydrological regimes. The former involves a high-temperature, high-pressure discharge of fluids which probably were generated during dehydration accompanying burial and progressive accumulation of volcanic-sedimentary sequences, with an additional influence of marine water in the near-sea-floor environment. The latter represents thermally driven convection of ocean water at lower temperatures and under hydrostatic conditions.Auriferous fluid systems with only minor base metal content could plausibly be generated during dehydration accompanying burial and metamorphism, when the water-to-rock ratio is low and halogen availability is limited by crustal abundance (- 60 ppm Cl). These two factors may constrain the uptake of the abundant base metals into fluids, but the solubility of rare elements is not constrained by limited fluid; and preferential uptake of Au along with other rare elements may be promoted if such elements compete more successfully for the limited halogens than the base metals, and/or have an alternative complexing agent such as CO or C()j-."

Jan 1, 1982

By M. Sukhram

This paper presents a technique to determine the direction of velocity in liquid aluminum (Al) by measuring the temperature distribution within a cylindrical rod while it is inserted into the flow. The heating pattern of the rod is a result of the interaction of the thermal fields of the rod with the liquid Al. This interaction freezes aluminum onto the cylinder in a characteristic pattern and as a result the temperature response within the rod also follows a distinctive heating pattern. Monitoring the temperature within the cylindrical rod as a function of spatial and temporal coordinates, the direction of velocity can be inferred. Experimental research work involving liquid Al was conducted at the University of Toronto using the Revolving Liquid Metal Tank (RLMT). The RLMT is a resistance furnace which can hold up to 50kg of liquid Al. In this RLMT tangential velocities up to 0.35m1s can be generated. Experimental data for different superheat and magnitude of velocity demonstrate that the sensor records different heating patterns under different fluid flow conditions. Using the transient temperature information, the direction of velocity of the molten Al flow field can be detected.

Jan 1, 2011

By J. D. McFarlane, V. Robinson

"The paper begins with a brief account of the naturarly occurring resources of gypsum and anhydrite and a discussion of their relative value and utility as sources of sulphur. The fundamental chemistry of recovering sul-phur values from calcium sulphate is discussed. (a) Thermal decomposition -discussed as impracticable; (b) Reduction to calcium sulphide; (i) Total Reduction-The chemistry is outlined and the Dorr-Oliver and Bureau of Mines processes mentioned. The Elcor process is mentioned and certain deductions made from available information.(ii) Partial Reduction-This is stated as the basis of the only proven process, namely ""The Cement -Sulphuric Acid Process."" The possibility of recovering lime is mentioned as an aside, but dismissed for lack of commercial application. The history of the cement -sulphuric acid process is covered briefly and a list of plants in commercial operation included. A brief elementary account of the basic chemistry of cement production is followed by a discussion on raw materials and fuels. A short account of the flow scheme of a typical plant, with notes on the operating peculiarities, precedes an account of product quality. The latest developments which enable by-product gypsum to be used as a raw material are discussed, with an indication of how the flow scheme is modified. A statement of feasible plant capacities is followed by requirements of raw materials, services, labour, etc., and finally some indication is given of capital costs."

Jan 1, 1969

By H. Tudeshki

A great amount of aggregate is utilized in civil engineering applications such as road construction, railway infrastructure, concrete production, etc. Igneous rocks are the preferred raw material due to their high strength and abrasion resistance. Rock quality assurance is a key factor and has great influence on the quality of constructions in civil engineering. One of the major problems encountered by both the producers and users of igneous aggregate rock is the fact that, with the passage of time, some specific rocks lose their strength, up to a complete loss of structure, i.e. disintegrate and degrade. This phenomenon has a great influence on the quality, strength and durability of aggregates. In the last decades, different methods and procedures such as the glycol test, the methylene blue dye test, as well as the Los Angeles test, have been introduced to distinguish rock properties, and to identify these problems. However, as these wet-chemical methods are time consuming, hard to perform, only to be applied to hand-piece samples, requiring special laboratory equipments, and are only possible to be accomplished under laboratory conditions, their application has always been severely limited. To address this widespread quality management problem of the quarry industry, a relatively quick, easy and user-friendly approach is necessary. It calls for a systematic solution with a device that can simply be used in the day-to-day routine of a mine for quality control of the quarry´s daily production. Our research is concentrated on developing a systematic method for early recognition and diagnosis of rock quality, in order to control and manage the quality of the quarry production in advance. Our new approach is based on two rock parameters: magnetic susceptibility and loss on ignition. The measurement of these parameters provides reliable information on the quality of the rock and allows the quality control process to be accomplished and performed at the borehole location. Our new approach has been assessed through extensive field and laboratory studies and has been implemented on the drill-cuttings of a basaltic andesite quarry. The results of the experiments are discussed in detail, including their impact on increasing resources and environmental protection.

Aug 1, 2013

By John J. Laffin

"Nova Scotia Department of Mines and Energy Throughout the history of Nova Scotia, trends in the production and use of its coal resources have resulted in major impacts on the economy and society of the province. Current trends in coal demand locally, nationally and internationally are having and will have an increasing positive effect on Nova Scotia over the next twenty years-in terms of energy supply, job creation and general economic development. Coal for electrical generation is an immediate and key objective of Nova Scotia&apos;s energy plan; and, in the long term, coal-derived fuels will meet the province&apos;s needs for transportation fuels. Demand for metallurgical coal is also expected to increase, especially if the merchant coke plant currently under investigation becomes a reality.Meeting these coal supply and utilization objectives in the face of increasing environmental, social and economic constraints poses a tremendous technical challenge. Work has begun on projects to expand coal production capacity and to adapt new technologies for coal preparation and utilization to the specific needs of Nova Scotia; much more work will be required in the coming decade in order to succesfully tap this resource.IntroductionThe energy problem facing Atlantic Canada has a few unique features not found in the rest of the country. Canada, as a whole, has access to a diverse mix of energy resources, including crude oil, natural gas, coal, hydro and uranium, with the result that crude oil supplies only about 40 per cent of Canada&apos;s primary demand. In contrast, foreign crude oil dominates Atlantic Canada&apos;s energy mix, supplying over 70 per cent of the primary energy demand.This results in important differences in various sectors. Nationally, about 5 per cent of the electricity is generated from oil whereas last year in Nova Scotia approximately 40 per cent of the electricity generated was from imported oil. Residential, commercial and industrial space heating, and industrial process heating in Atlantic Canada was almost 100 percent dependent on foreign oil. This is in sharp contrast to the situation in central and western Canada, which have access to secure domestic natural gas, oil and hydro electricity."

Jan 1, 1982

By Fatemeh Pourakbari, Mohammad Reza Yarahmadi, Abbas Sam

Pyrite is the most abundant sulfide gangue mineral in copper porphyry ores. In spite of addition of lime in large quantities to depress pyrite in flotation, considerable amount of this mineral is reported to concentrate, particularly in rougher and scavenger stages. With the Sarcheshmeh pit advancing to a greater depth and reaching to the hypogene zone, the amounts of pyrite and chalcopyrite in the feed are increased. Hence, a reduction in the copper grade and increase in the sulfur content of the concentrate are observed. In this study the effective factors on the pyrite floatability at the circuit flotation was considered at Sarcheshmeh Mine. Mineralization zones in the pit were firstly identified. Then, sampling points were located using GPS system. On the basis of mineralogical composition and morphology, the ore was categorized into five main classes. In this classification the amount of lead and zinc and also pyrite locking with other minerals were analyzed. The study of polished section indicated that inclusion in pyrite was very frequent in all classes, mostly composed of the floatability of pyrite. Flotation tests were performed on the samples of different classes at pH of 11.8 after conditioning time. It was shown that, pyrite floatability was decreased with a decrease in the lead content of the feed samples except for the second class, while for all classes an increase in zinc content contributed to a decrease in pyrite floatability and recovery. It was found that, the lowest pyrite recovery (1.89%) was corresponding to pyrite–molybdenite dominant mineralization with Zn of 0.33% and the highest recovery (86.89%) corresponding to pyrite vein dominant mineralization with Zn equals to 0.9%.

Jan 1, 2016