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By M. H. Staia

A Venezuelan ilmenite concentrate has been chlorinated at a temperature of 700" C by carbon tetrachloride. In the experimental rig, built at laboratory level, the direct chlorination process yielded a TiCI, recovery of approximately 85% after 280 minutes processing. The partial pressure of carbon tetrachloride was nearly atmospheric (0.94 atm). Product vapors from the reactor were fractionally condensed in a condenser which was maintained at a temperature of 250°C meanwhile TiCl, vapors were condensed in refrigerated coils at a temperature of -20°C. The concentrate used in this investigation was obtained by applying gravitational and magnetic concentration methods to the black sands. The experimental results have shown the need to asses the influence of the weight ratio of ilmenite to carbon tetrachloride on the resultant products. The equilibrium of the heterogeneous system has been calculated taking into account the initial experimental conditions.

Jan 1, 1995

By P. T. Bissert, L. Yan, M. D. Klein

"Federal regulations require that refuge alternatives (RAs) are located within 305-m (1000-ft) of the working face and spaced at one-hour travel distances in the outby area in underground coal mines in the event that miners cannot escape during a disaster. The Mine Safety and Health Administration mandates that RAs provide safe shelter and livable conditions for a minimum of 96 hours while maintaining the apparent temperature (AT) below 35°C (95°F). The National Institute for Occupational Safety and Health used a validated thermal simulation model to examine the mechanisms of heat loss from the RA to the ambient mine and the effect of mine strata composition on the final internal dry bulb temperature (DBT) for mobile tent-type RAs. The results of these studies show that most of the heat loss from the RA to the ambient mine is due to radiation (51%) and conduction (31%). Three mine width/height configurations and three mine strata compositions were examined. The final DBT inside the RA after 96 hours varied less than 1°C (1.8°F) for the three mine width/height configurations and less than 2°C (3.6°F) for the three mine strata compositions. INTRODUCTION Following a mine disaster, workers will try to escape the mine. If their escape is futile, they can take shelter in a refuge alternative (RA). In 2008, the Mine Safety and Health Administration (MSHA) mandated RAs in mines to ensure that a safe and livable shelter is provided for a minimum of 96 hours, and that the apparent temperature (AT) does not exceed 35°C (95°F) inside the RA [1]. An ongoing concern with RAs is the potential to exceed this limit. The temperature rise inside an RA is due to the metabolic heat released by the occupants as well as heat released by the carbon dioxide scrubbing system. The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type training unit RA in its Safety Research Coal Mine (SRCM) to investigate heat buildup in RAs. The 10-person capacity for the tested RA is based on 1.4 m2 (15 ft2) of floor space per miner. NIOSH-developed simulated miners, which are heat input devices that generate both sensible and latent heat, were used to represent the metabolic heat generation of an average miner (117 W) for testing in the SRCM. It was found that the number of occupants in an RA may need to be reduced based on the ambient mine temperature, which varies from mine to mine [2]. To further research temperature rise inside an RA, ThermoAnalytics, Inc. (TAI) was contracted by NIOSH to perform thermal simulations of the tested 10-person mobile tent-type RA. TAI developed a thermal model of the SRCM using RadTherm software, which incorporates a human thermal model (HTM) to represent the equivalent metabolic heat loss of a miner within the RA’s enclosed environment. The thermal model was previously validated by comparing simulation results with test results [3]. During a mine disaster in which miners would have to take shelter in an RA, mine ventilation may not be available. As such, mine ventilation was off for both the testing in the SRCM as well as in the simulations. This paper discusses the heat loss mechanisms and the effects of mine strata composition and mine width and height associated with a ten-person tent-type RA."

Jan 1, 2016

By Patzen Wu, Chao-Ming Tsai, Shaw-Chii Wu, Yuan Lin

INTRODUCTION The development of nuclear industry in Taiwan requires an increasing supply of uranium. Uranium recovery from phosphate ores, becomes an important item of the R & D programs. Many countries have already started such a program. USA has set up an industrial-scale production plant; South Africa, Israel, Morocco and other countries have also engaged in the development of extraction technology of uranium from phosphate ores and started setting up the production plant. In Taiwan, a feasibility study of establishing the production plant was started in 1977. A pilot plant was completed, tested, and operated in 1979. The main source material. - phosphate ores is obtained from China Phosphate Company. The annual yield of the pilot plant has been planned to be one ton of ammonium diuranate (ADU). The Health Physics Division of Institute of Nuclear Energy Research (INER), Atomic Energy Council of Republic of China (ROC AEC), is responsible for the radiation safety control of the plant. The purpose of the radiation safety control is to collect radiation safety information of the plant of this type, to evaluate possible radiation hazards to the personnel, and to analyze the radiation safety of the immediate environment adjacent to the plant. Furthermore, the information and experience obtained are used as the basis for applying radiation safety control to the production plant. The main emphases of the radiation safety control are therefore the arrangement of radiation safety control areas and the collection and evaluation of the health physics data. This report includes the past one and half years' experiences of the radiation safety control of the pilot plant, the planning of the production plant with an annual yield of 10 ton ADU, and considerations given in improving the radiation safety control of the production plant. PILOT PLANT AND ITS OPERATION PROCESS The pilot plant occupies an area of 350 m2 and is a two-story rectangular building. Exits are provided by a front and a rear door. An additional small door at the central right side of the building is connected to the maintenance area located outside the main building. The interior of the building is divided into interconnected offices, laboratories and process area (Figs. 1 and 2). A stairway to the process area of the second floor is located in the central part of the first floor. The second floor offices are accessible by the additional front and rear stairways. The main process area of the first floor is furnished with plastic floor, and the second floor with poriferous iron-grid floor. The building is not furnished with centralized air-conditioning system. Individual air conditioners are, however, available to some laboratories. Because the back door of the building is frequently open, the product storage room is provided with a blower to maintain good ventilation. Natural uranium contents of phosphoric acid solution vary in the range from 0.07 to 0.11 kg/m3. The process consists mainly of the uranium concentration cycle and the purification cycle. A flow diagram of the process is shown in Fig. 3. CONSIDERATIONS GIVEN FOR RADIATION SAFETY CONTROL AND THE ESTABLISHMENT OF RADIATION CONTROLLED AREAS The radiation safety control of the pilot plant is carried out on the basis of the considerations listed below:1,2 1) Since the wet process is adopted, and the flow of the radioactive material is confined to closed pipes and containers, air contamination is therefore not too much of concern. 2) The concentrations of radioactive material of the whole process are mostly less than 10 ppm. An exception is the final ADU product after precipitation and centrifugal separation, which contains up to 50% natural uranium. It is therefore necessary to apply radiation safety control to the process area where

Jan 1, 1981

By Chuanfu Zhang, Jinliang Wang

"Brickless reaction shaft is the latest progress for flash smelting furnace. However, there are many factors influence the melting point of the freeze slag inside brickless reaction shaft, and their variational regularities are not obvious, thus, it is difficult for conventional methods to analyze accurately the complex data. In this research, the experiment data of slag melting point were processed based on optimal discrimination plane. For this method, two orthogonal vectors were firstly built up based on the Fisher's criterion, and then the experiment data were projected onto the two vectors, thus, two-dimensional feature vectors were extracted as criteria to determine the factors effect degree on the slag melting point. Results show that the CaO content is the greatest factor to the melting point of the freeze slag inside brickless reaction shaft, the content of Fe3O4, SiO2, Cu2 O and MgO is the second, and the FeO content is the last.IntroductionBrickless reaction shaft is the latest progress of flash smelting furnace reaction shaft. To research the influence factors on the slag melting point inside the brickless reaction shaft is significant to form freeze slag with compact structure, good heat insulation, certain intensity, appropriate thickness and reasonable distribution, to extend furnace life, to reduce energy consumption, and to promote safe production.However, due to the complex components, there are many factors influence the melting points of the freeze slag inside brickless reaction shaft, and their variational regularities are not obvious. Therefore, it is difficult for conventional methods, such as variance analysis, data fitting, etc., to analyze accurately the complex experiment data.Pattern recognition can easily classify information, even if there are many influencing factors. For pattern recognition, there are some sub-disciplines such as discriminant analysis, feature extraction, error estimation, cluster analysis (together sometimes called statistical pattern recognition), grammatical inference, parsing and matching (sometimes called syntactical and structural pattern recognition) [1, 2]."

Jan 1, 2012

By R. G. Diale, H. R. Chauke, T. M. Ledwaba, P. E. Ngoepe

FeCo alloys play an important role in soft magnetic materials with a wide range of technological applications due to their high saturation magnetization and Curie temperature. However, these alloys have low ductility at room temperature. The ductility can be improved by the ternary addition of elements such as V. A density functional theory supercell approach was used to generate B2 Fe50Co50-xVx (0 ≤ x ≤ 50) structures and the properties were evaluated at different atomic percentage compositions to determine the ductility at room temperature. The structures were fully optimized to obtain better equilibrium ground-state properties such as lattice parameters and thermodynamic properties for both binary and ternary systems. The stability of Fe50Co50- xVx was evaluated from the heats of formation, elastic properties, and phonon dispersion curves. Furthermore, magnetic strength was evaluated from magnetic moments. It was found that all structures are thermodynamically stable due to the negative heats of formation. The calculated Pugh’s ratio and Poisson’s ratio confirm that alloying with V effectively improved the ductility. It was also found that Fe50Co50-xVx showed a positive shear modulus for the entire concentration range investigated, in agreement with phonon dispersion curves. The ternary addition of V to the FeCo system resulted in reduced magnetic strength due to a decrease in magnetic moments. These findings reveal that B2 FeCo-V alloys can be used as components and actuators for the automotive industry.

Jun 10, 2024

By T. W. Lloyd

Accurately predicting coal seam discontinuities is an important part of modern underground coal mining. Conventional methods of coal exploration sometimes fail to identify rapid variations that may seriously impact mining and quality. Radio Imaging Method (RIM), a geophysical approach to mapping longwall panels, has been developed where electromagnetic signals are transmitted and received though the coal block. The amount of signal loss for a given distance, when compared to the coal seam characteristics, identifies anomalous areas. A comparison of RIM predictions with actual geologic conditions encountered during longwall mining demonstrates the accuracy and usefulness of the data.

Jan 1, 1986

This paper deals with the application of table flotation to two unusual mineral dressing problems. Both problems involved the removal of interfering minerals at sizes too coarse to normal froth flotation.The first problem was the removal of arsenical minerals from Broken Hill gravity concentrates without further size reduction. Table flotation without grinding of the original concentrates gave almost complete rejection of the arsenic from the concentrates. A typical test result was a reduction of arsenic in jig concentrate from 0.75% arsenic to 0.007% arsenic.The second problem was to develop a method to produce a high grade calcium carbonate concentrate from coastal dune sands containing about 10% silica and about 80% calcium carbonate. The sands were about 30 mesh British Standard Screen (B.S.S.), and for economic and other reasons it was stipulated that the separation be made without grinding. Again, table flotation gave excellent results. A concentrate was produced containing 99.62% acid soluble material, representing a recovery of 98.69% of the calcium carbonate in the feed with a rejection of 96.44% of the silica.The investigations' were carried out at the Kalgoorlie Metallurgical Laboratory, under the Department of Mines...

Jan 1, 1954

By J. P. Fitzgerald

This paper is an accumulation of information on the geology, mineralogy and mining of the Hectorite clay deposit owned by NL Chemicals (U.S.A.), Inc. The mine is located in San Bernardino County, California approximately 35 miles east of Barstow and 1-1/2 miles south of U.S. Highway 40. The region is known as the Mojave Block which is a region bound by the San Andreas fault zone to the southeast and the Garlock fault zone to the North. The faults of both zones are active, vertical faults along which movements are mainly horizontal. Most of the faults within the Mojave Block are high angle faults which trend northwest. They are considered part of the San Andreas fault system and are a result of the right- lateral movement characteristic of this system. The east-trending faults are also high angle faults, along which movement has displaced rock units vertically. Manix fault is the only mapped fault that shows evidence of left slip which is characteristic of the Garlock sys tem to the North.

Jan 1, 1986

HW Process Technologies, Inc. (HWPT) has developed a patented membrane-based ion fractionation system, which specifically separates copper from gold and silver species in a cyanide matrix. This Engineered Membrane Separation (EMS?) system was pilot demonstrated on the 82,000 liters of pregnant leach solution' (PLS) generated from tailings, via thin layer leaching, at a mine site in Durango State, Mexico. The EMS? recovered ~90% of the gold-silver cyano-complex to a 90% volume permeate (based upon an EMS? feed stream of 100% volume) while rejecting -90% of the copper cyano-complex to a \0% (by volume) concentrate. The EMS? technology combines pore-size specific electro-statically charged membranes with engineered materials of construction and application-specific operational design that reject multi-valent, ionically charged species to the concentrate and transmit mono-valent species through the membrane to the permeate. The 850 ppm Cu PLS contained approximately 0.8 gil free NaCN with, the copper cyano-omplex principally in the CU(CN)3 and CU(CN)4 forms. The gold grade of the PLS was -2 ppm Au. The ~LS calcium concentration at -700 ppm Ca was reduced to ISO ppm.Ca (± 50 ppm) by sodium cycle ion exchange pre-treatrnent prior to EMS? processing.

Jan 1, 1998

By A. S. Macfarlane

This paper describes how knowledge of the orebody morphology and ore morphology can be used to optimize the planning, mining, and metallurgical output from an open pit copper mining operation, such as to significantly increase the stability of the whole value chain process, and increase the reliability and value of the process outputs. In the case under consideration, the orebody contains both copper and cobalt. This in itself provides a challenge, in that the two metals do not occur in consistent ratios across the orebody as a whole. Furthermore, mineralogical differences within the orebody have a significant impact on plant performance in terms of throughput rates, acid consumption, and recoveries. In order to stabilize and optimize the plant performance, it is necessary to firstly have a complete understanding of the geometallurgical factors that affect performance, and then to have a sound knowledge of how these are distributed within the orebody. These models then inform the mine planning strategy that optimizes cash flow and NPV, and also allow the development of a stockpiling strategy that not only stabilizes the plant, but also allows variations in the plant feed according to ore type and grade in volatile price scenarios. Integral to the realization of these opportunities is the establishment of an appropriate measuring, control, and reconciliation system, customized to the optimization objectives. The paper describes how all of these factors and strategies can be integrated to produce optimal value from the orebody through to final dispatched product. It also shows the significant value that can be released through such an approach.

Jan 1, 2014

By Randy Clarkson

"Free gold particles occur in many base metal and precious metal mines throughout the world. Occasionally mine operators are unaware of the presence of free gold particles in their ores because they have not seen free gold hand specimens or at the working face of the mine.Due to the high density and malleability of gold, large circulating loads of free gold particles can build up over time in grinding circuits. This gold is often deposited in unintended traps throughout the mineral processing system.These unidentified free gold deposits represent a serious security risk as well as inaccessible inventory of gold. Deposits of free gold particles often remain undetected by mine management until they are accidentally discovered while repairing mill equipment. The trapping and subsequent release of gold particles can frustrate attempts to calculate accurate metallurgical balances.Nuclear tracers have been used to determine the free gold recovery efficiency of gravity recovery equipment, drills, and sampling equipment (Clarkson, 1994, 1997, 1998, 1999 and Walsh, 1986, 1992). In 1995, the author used radiotracers to locate and eliminate gold traps at La Mine Doyon (Clarkson, 1997). In 1998 and 2001, the author also salted mineral processing circuits at Royal Oak's Pamour Mine in Timmins (Clarkson, 1999) and at Gold Corp’s Red Lake Mine in Ontario with radioactive gold particles.The gamma and X-ray radiation from gold's nuclear isotope (Au198) were detected through steel, in pipes, and in moving equipment with scintillometers. The radiotracers proved to be a safe, rapid and accurate method of identifying gold traps, improving security, determining the recovery efficiency of Knelson gold concentrators and estimating retention times of gold particles in various processes."

Jan 1, 2003

By G. Ergin

The interactions taking place between Al-Mg alloys and the bed media during aluminum filtration are not yet well understood. These interactions were studied using the infiltration technique. The reaction interface was analyzed using different techniques such as SEM and TEM. Only spinel formation was observed at the interface regardless of the type of alumina and contact time. This paper discusses the results of the study.

Jan 1, 2004

By R. Agius, A. Nacu

"Cyanide destruction technologies are implemented at gold and silver operations to comply with the International Cyanide Management Code and meet ever more stringent discharge limits. Currently, the most common chemical cyanide destruction processes used in industry are sulfur dioxide/oxygen, hydrogen peroxide, and Caro’s acid. The cyanide destruction process used at an operation must reliably generate streams of acceptable quality at all times, and depends on numerous factors, including permit discharge requirements, tailings chemistry, location, site-specific climatic conditions and size of the operation. Selecting the most appropriate cyanide destruction process and determining the process design criteria requires accurate laboratory testing. This paper presents and discusses the results of a number of cyanide destruction evaluations that have been conducted to reduce cyanide concentration in process solutions or cyanidation tails. Laboratory testing provides important insights into reagent consumption and other factors required to achieve the target residual weak acid dissociable cyanide (CNWAD) levels.INTRODUCTION Process solutions associated with the extraction of gold and silver contain several forms of cyanide. The most toxic form of cyanide is free cyanide, which can be present as a dissociated cyanide anion (CN-) or gaseous or aqueous HCN. Weak or moderately stable cyanide complexes such as those of zinc, copper and nickel are classified as weak acid dissociable (CNWAD). Although less toxic than free cyanide, weak acid dissociable cyanide complexes are considered “ecologically sensitive” forms of cyanide and are regulated in most jurisdictions. In practice, reported WAD cyanide values comprises both free cyanide and weak acid dissociable cyanide complexes. Cyanide complexes with gold, mercury, cobalt and iron are referred to as strong acid dissociable complexes (CNSAD) and are much more stable, even under mildly acidic conditions. Another term commonly used in cyanide chemistry is total cyanide, which represents all cyanide compounds present in solution. Total cyanide levels in solutions are always equal to or higher than WAD cyanide values and the difference between the two usually indicates the presence of iron-cyanide compounds. Typically in Canada, CNTOTAL levels cannot exceed 1 mg/L in solutions discharged to the environment."

Jan 1, 2017

By Rajesh S. Ransing

An intelligent tool has been developed to analyse the quality of diecast components. The influence of both design and process parameters has been studied in great detail. The tool, based on expert systems related technologies, can identify the causes for the defective castings manufactured. Design related causes such as gate position; gate area, runner design etc. as well as process related causes such as cycle time, cavity filling time and melt temperature are suggested by analysing the data on defective castings for a manufacturing campaign. This intelligent analysis is useful for both design as well as production engineers in the decision making process. All the causes for the occurrence of defects are classified into two categories. The firs category is the 'rootcauses' i.e. the causes which are related to the actual process, material and design parameters and which can be directly monitored. The second category is more abstract in nature and is classified as `metacauses'. These capture the scientific rationale implicit in the cause and defect relationships. This knowledge on causes and defects is represented in the form of a structured graph rather than by a set of rules, which, coupled with forward reasoning and heuristic search techniques results in an elegant and efficient approach. Uncertainties and the degree of relationship among causes and defects are represented by a fuzzy probabilistic model.

Jan 1, 1994

By J. J. Jonas, G. R. Stewart, A. M. Elwazri

Two important parameters for dynamic recrystallization can be derived from the changes in the strain hardening rate: the critical strain for initiation of dynamic recrystallization and the point of maximum softening. In this work, these values are determined from the flow stress-strain data obtained in continuous compression testing in the range 900-1100°C. The resulting strains are used to calculate a kinetic model of dynamic recrystallization for two materials: 304 austenitic stainless steel and a hypereutectoid plain carbon steel. The mechanical parameters used to define the proposed model are confirmed with quantitative metallographic analysis of the recrystallized microstructure.

Jan 1, 2004

By W. P. Shinn

In a paper contributed by W. A. Goodyear, M.E., on "Water Gas as Fuel," read at the Boston Meeting, February, 1883,* the following statenlent was made: "The latest experiments on a scale of some magnitude in our citier, in the way of heating buildings and furnishing power for manufacturing purposes, have been by the distribution of high-presslire steam through pipes laid in the streets. Hilt these experiments (1) have not hitherto been very successful; and when we consider the high cost and (2) the great and unavoidable loss of heat and power, which always accompany the conveyance of high-pressnre steam to any considerable distance in pipes, to say nothing of (3) certain practical difficulties in the management of the pipes themselves, (4) it is evident that all such methods must eventually disappear before a system which can furnish a cheap gas of great heating power, easily distributed wherever wanted, without requiring pipes to stand pressures of 50 to 75 pounds per square inch, and (5) without keeping the whole mass of ground in the streets through which it passes hot, gratis, for a distance of ten or fifteen feet, in all directions around the pipes!' For the purpose of controverting Mr. Goodyear's statements in regard to steam-distribution in cities, I hare numbered the points made in his indictment, my principal object being, not a professional discussion of the technical and theoretical merits of steam vs. watergas, but a simple statement of facts, in regard to the present state of the street system of steam distribntion. Taking Mr. Goodyear's points in their order: 1. Concerning what he terms " These experiments," saying that they " have not hitherto been very successful," I propose to show, that the problem of stearn-distribution has passed beyond the experimental stage, and that its practical solution is highly successful. This will be shown by the facts hereinafter fully set forth. 2. "The great and unavoidable loss of heat and power whicn always accompany the conveyance of high-pressure steam to any con-

Jan 1, 1884

This paper briefly reviews the demise of professional mining education and training in NZ over the past ten years; compares it with the Australian experience; and discusses the immense success experienced by EXITO and the upsurge of competency based education and training we are currently experiencing in the mineral extraction and associated industries. It also looks to the development of a Bachelor in Mining Technology.

Jan 1, 2001

By S. H. Ash

THE INUNDATION of anthracite reserves in the Eastern Middle field of Pennsylvania affects the life of the anthracite industry in this field; it also influences the economic status of people, communities, and industries that depend wholly or in part upon anthracite for their livelihood. The trends of production and of employment in the anthracite-mining industry in this field are downward, and they probably will continue in this direction. The reserves have been depleted to the extent that the end of the active life of the industry as a. major economic factor is approaching. By removing the water in those pools where it can be done economically, the future of this industry may be extended somewhat.

Jan 1, 1950

By K. K. Kelley, L. B. Pankratz, W. W. Weller

The heat capacity of columbium (niobium) carbide (CbC ) was measured over the temperature range from 51 ° to 298 ° K, and the entropy at 298.15° K was evaluated . Also , the heat content above 298.15 ° K of columbium carbide was measured to 1,800 ° K. The results were combined with the known heat of formation at 298.15 ° K to obtain values of the heat and free energy of formation over the temperature range from 298.15 ° K to 2,000 ° K.

Jan 1, 1964

By Tatiana Ravani von Ow, Leandro Bomvisinho

"The size of mills driven by ring-gear or by a gearless solution has significantly increased in the last years. This has created additional challenges for the driven equipment. The requirements for the mechanical devices and the power grid have become more demanding. Controlled soft starting and operation, especially in dual pinion mills, as well as the protection of the equipment has gained importance. The selection of the drive solution for the mill therefore becomes more critical. Besides the classical criteria such as performance, efficiency and capital costs other factors come in the evaluation of the system such as flexibility and optimization of operation, reliability and the ageing of the grinding equipment.Variable speed solutions offer significant advantages over conventional fixed speed drives due to their application specific features and process optimization capabilities, even for ball mills where these are not seen yet as a must.The initial capital costs are higher than some of the direct on-line solutions however the benefits for the operation during the lifetime of the mill generated by the use of converter solutions justify the additional higher investment.INTRODUCTIONThe method of powering mills such as AG, SAG and Ball has a long and technically interesting history. It can be said; almost every decade in the last half century had its own trend. The trend was dominated by the market demand, by the process development and requirement of the mechanical and the electrical technology but mostly by the price of the applied technology.All has started about 50 years ago with mill diameters less than 20 feet driven by fix speed synchronous or wound rotor motors with the power of about 2 MW. Around 10 years later, the mill sizes increased, but the necessary torque could not be transmitted by one pinion therefore dual pinion solutions were developed to power the mills. However, realization of the dual pinion solution was only possible when load could be evenly shared between the two pinions."

Jan 1, 2010