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By Amila Sandaruwan Ratnayake, T. Dilmi. U. Wijewardhana, H. C. S. Subasinghe

The value addition potential of ilmenite was examined using several characterization techniques. Raw ilmenite is composed of 93.65 wt.% of FeOTiO2, 3.55 wt.% of SiO2, 1.22 wt.% of Al2O3, and the remainder being other minor oxides. Ilmenite and powdered carbonized coconut shells were mixed in the weight ratio of 4:1. A separate fraction of the same mixture was added with powdered seashells in the weight ratio of 4:1:0.5. Six fractions of each mixture were distinctly milled from 1 to 6 h in a planetary ball mill. XRD spectra (broadened and diminished reflections of ilmenite) and FTIR observations (Ti―O―Cbonding) of milled samples indicate the possible incorporation of carbon into the ilmenite structure. Any clues of an occurrence of new rutile peaks were not observed in XRD spectra of milled samples. Consequently, the carbothermic reduction has not been initiated during mechanical activation. In this case, samples powdered for 6 h in a mill were isothermally annealed for 2 h under normal airflow at temperatures of 800 °C, 1000 °C, and 1200 °C, respectively. According to the X-ray diffractograms, the annealing temperatures of 1000 °C and 1200 °C exhibited almost similar trends with rutile (R), pseudobrookite (PB) and elemental iron (F), and a very few ilmenite (I) peaks. Consequently, 6 h of milling and 1000 °C annealing were concluded as the optimum conditions for the carbothermic reduction. Moreover, this study indicated seashells as a potential rate raiser for the carbothermic reduction of ilmenite at 800 °C. Therefore, this process is applicable to upgrade ilmenite into a mixture of synthetic rutile and elemental iron.

Mar 29, 2021

By Galen H. Clevenger

Although there are exceptions, oxidized silver ores containing the higher oxides of manganese are generally refractory to hydrometallurgical methods of treatment. When these ores are of high enough grade they can be smelted; indeed, some rather low-grade ores of this type have been smelted at a profit because of their fluxing value. In the past, when these ores could not be smelted, they either were not treated or were treated at low efficiency, generally by cyanidation. The need for thorough investigation of the problem was therefore evident for some time before the writers began their research. The problem of treating manganese-silver ores seems to have been recognized first about 35 years ago by C. W. Goodale in applying pan amalgamation at Tombstone, Ariz. He attributed the low extraction of silver to the fouling of the mercury by manganese rather than to the presence of a refractory compound of manganese and silver. Although definite knowledge as to the cause of the poor extraction of silver was lacking, a more or less effective preliminary treatment, that is, a chloridizing roast, was applied.

Jan 1, 1925

By Ali Hasham

Reduction rates of FeO in CaO-SiO2-Al2O3 slags by Fe-C melts have been investigated experimentally at 1723 K. The rates were estimated using experimentally determined CO(g) evolution rates. Flash X-ray images were employed to visualize the behavior of the melt-slag interface during the reactions. The influence of melt interface was examined by conducting two types of experiments - (i) dropping one (or several) Fe-C droplet(s) weighing 2 g into the molten slag bath, and (ii) dropping a small amount (10-30 g) of slag onto a Fe-C melt weighing 400 g. The rates from both types of experiments were compared and analyzed to determine the rate limiting steps. It was established that neither the carbon transport in the Fe-C melt, nor the transport of gas species in the gas film adjacent to Fe-C melt was responsible in limiting the reaction rate. It is possible that the slag phase mass transport may be controlling the initial reduction rate in the droplet experiments. However, a, different mechanism was responsible in limiting the reduction reaction when the overall %C in the droplets fell to about 2-3.

Jan 1, 1992

By F. F. Netzeband

This report relates to the sulfur industry of seven States--Arkansas, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas--and is part of a national study of the sulfur industry by the Bureau of Mines. Markets as used in this report are divided into two components for individual analysis-- (1) supplier markets which include regional Frasch and byproduct sulfur producers and (2) consumer markets which include processors and manufacturers requiring sulfur in their operations The term sulfur as used in this report includes brimstone, native sulfur, elemental sulfur, or sulfur equivalents.

Jan 1, 1964

By Ruddle R. W.

The slags produced in copper smelting are largely composed of silica and ferrous oxide and may therefore be regarded as essentially ferrous silicates. A fair amount of information is available on the constitutions of the liquid slags used in copper smelting and, in this connection, the large volume of work being carried out on steelmaking slags should be helpful. Constitutional diagrams are available for most of the principal systems involved (SiO2-FeO; SiO2-FeO-Al2O 3; SiO2-FeO-CaO; SiO2-FeO- MgO; and SiO2-FeO-CaO-Al2O3) and these show that additions of Al2O3 and CaO reduce the freezing points of SiO2-FeO slags but that additions of MgO increase the freezing point. A certain amount of information is available on the thermodynamics of slags, but much further work on this subject is required. Modern theories of the constitution of liquid slags deny the existence of molecular compounds but consider that liquid slags are mixtures of various ions such as, Fe2+. O2- and SiO4(4-). Little appears to be known of the reactions between matte and minor constituents dissolved in the slag

Jan 1, 1953

By S. K. Samal, B. Mishra, M. K. Mohanty, S. C. Mishra

Steelmaking industries consume the majority of chromium and manganese ferroalloys to impart several properties in steel and also for other purposes. The quality of ore governs the process kinetics as well as the process economy of the ferroalloy industry. The present study demonstrates the thermal transformation behavior of chromite and manganese ores with varying compositions. Simultaneous thermal analysis (DTA/TG) is employed for such ore samples where the transformation of mineral phases is correlated with the thermogram characteristics and quantified. Phase, microstructure, and compositional analysis results of individual ores corroborated with thermal analysis are in good agreement. Chromite samples are ferruginous with goethite and gibbsite contents, whereas manganese ores vary in composition and also exhibit multiple and/or overlapping transformations.

Jan 21, 2021

By H. J. H. Pieterse

Agitation requirements in oxidation autoclaves can vary widely depending on the mineralogy of the feed material and the specific process selected. Before selecting an agitation system it is important that the client specify the desired throughput, mineralogy, chemistry, kinetics, compartments, overall retention time, and the desired oxygen utilization. In selecting the agitation system, the factors mentioned above as well as oxygen solubility, oxygen mass transfer coefficients, and specific power are evaluated. Much research effort has been directed toward open tank systems for fermentation and oxidation processes. However, for high pressure autoclave oxidation processes little information is available. In this review the author's experience in the autoclave industry and some of the available literature are utilized to compare the installed power per unit volume with some of the methods proposed for open tank oxidation. Equations that appear to give results close to that experienced in the industry have been identified. Further work is required in this area to develop a higher degree of confidence in the ability to predict the power required for any given case.

Jan 1, 2004

By Jamal Rostami, Asok Ray, Samer S. Saab Jr., Wenpeng Liu

Ground instability, such as roof or rib failures, is one of the most serious and frequent safety hazards that occur in underground mining, tunneling, and underground construction. The ground-related parameters and features of interest, in assessing roof or rib failures, are location, frequency, and orientation of the joints, voids, as well as rock-strength. These parameters are the main components of rock mass characterization that offers effective strategies for ground support, which, in turn, allow one to mitigate the risks related to ground instability. The main objective of this study is to determine the location of joints and classify rock-strengths by analyzing the drilling data recorded from an instrumented roof bolter while drilling for rock bolt installation during the operational cycle. For this purpose, computer programs based on updated pattern recognition algorithms were developed for joint-detection and classification of rock types to offer an estimated strength. This paper briefly introduces ongoing research on joint detection, especially for joints with an aperture less than 0.125in (3.175mm), by employing an instrumented roof bolter in controlled environments. To improve the capability and precision of joint detection programs in detecting the joints from the drilling data and reducing the number of false alarms, many laboratory tests with various simulated joints and rock-strengths were carried out at a J.H. Fletcher & Co. facility. This paper reviews testing procedures, data analysis, updated algorithms used for joint detection, and discusses the latest round of testing in samples with simulated joints at various angles along the borehole.

Jan 1, 2017

By James S. Browning

The Bureau of Mines conducted laboratory batch and small-scale continuous selective flotation tests of barite-fluorspar ores from two deposits near Marion, Ky., to determine the technical feasibility of recovering commercial grade fluorspar and barite concentrates. The lignin sulfonate-sodium fluoride method of floating the fluorspar successfully produced acid-grade fluorspar concentrates. Flotation of the barite from the fluorspar tailing using petroleum sulfonate collector yielded concentrates suitable for use in compounding oil-well drilling mud. The fluorspar and barite recoveries were about 82 and 85 percent, respectively.

Jan 1, 1963

By Claude Bodeving

The present steel economy drastically increases the financial strain on blast furnace operators. As a consequence, the importance of reliable cast floor operations is increasing drastically, which has a direct influence on the required clay mass and tapping equipment performances. When using modern high performance clay masses, pneumatic taphole drilling machines quickly reach their performance limits, which has made fully hydraulic drill hammers a standard in modern cast house operation. Besides the well-established hydraulic TMT hammers with high impact energy, an alternative version with lower impact energy, but high impact frequency was developed by TMT in the past, in order to achieve improved taphole protection. TMT’s recent research has shown that the drilling requirements inflicted by the taphole condition change over the taphole length, which has triggered the development of a new hammer, capable of switching between a high impact frequency mode and a high impact energy mode.

Aug 17, 2017

By R. Macleod, G. G. Bursey, T. R. C. Aston, J. E. Gale

In 1991 the problems of water inflow at the mine were addressed by a three-phase study. A three-dimensional finite-element computer code, CFEST (Coupled Fluid, Energy and Solute Transport), was used to model the system of groundwater flow around the mine, allowing assessment of the nature of the hydrological regime and of the various recharge mechanisms and sources of inflow. A regional (111 km2) model was used to simulate conditions of low to average mine inflow and provide boundary conditions for the subsequent local (16.8 km2) model. The regional model produced inflows of 0.26 m3/s and the local model 0.25 m3/s. With the use of constant head conditions to simulate a saturated flood plain along the Gays River and on doubling the rate of surface recharge, the local model produced a maximum mine inflow of 0.255 m3/s, in contrast to a measured peak mine inflow of 0.37 m3/s. The discrepancy suggests that during periods of high river level surface water gains access to features with high permeability, such as sinkholes, that may be connected directly or indirectly to the mine workings. Improved simulation of high inflow conditions can probably be achieved by determining the hydraulic conductivity of the river-bed and flood-plain sediments and modelling known sinkholes as discrete units. Possibilities for controlling the amount of inflow to the mine include sealing the flood plain with dykes, checking regularly for new sinkholes, which should be filled and capped, maintaining adequate mine drainage, and monitoring well levels and pressures on a continuous basis.

Jan 12, 1993

By A. González

Arsenic is one of the main contaminants present in Chilean copper concentrates and its abatement represents a challenge for the process metallurgy, particularly under the strong environmental requirements in the global community. The possibility to form ferric arsenate directly from a gas phase by means of a heterogeneous reaction between an arsenic gas bearing and iron oxide was studied at laboratory scale. A thermodynamical analysis for the system Fe-As-O-S has been initially made, in order to obtain the stability conditions for the ferric arsenate or other FexAs2O2 type compounds. Experiments were made using an hematite sample suspended in a thermogravimetric device. AS4O6 gas generated from solid AS203 that was passed through the iron oxide sample and its instantaneous weight change was recorded directly. A kinetic study for the AS4O6 volatilization was made to control the gas composition. A chemical control between 300 and 600°C with an apparent activation energy of around 14 Kcal/mol As2O3 was determined. The samples after the reactions were chemically and XRD analysed. Arsenates detected corresponds to complex compounds. Results shows a dependence on temperature and oxygen content in the gas phase. The kinetics for iron arsenates formation is slow, reaching an arsenic capture of 6% after 80 minutes of reaction when an oxygen content of 50% is fed continuously at 800°C and 3,56% As in the gas. Experiences made at the same temperature but under higher oxygen content in a closed reactor, allowed arsenic capture close to 60%. For higher temperatures the capture is considerably lower.

Jan 1, 2003

By Charles L. Kimbell

The final 26 tables of this chapter, tables 14-39, extend and expand the statistical series on production that was started in the 1963 edition of the "Area Reports: International" volume of the "Minerals Yearbook" and that was subsequently updated and expanded in the 1965 and 1967-88 editions. In this year's edition, for the first time, a column has been added to each of these tables providing a 5 year average for 1985-89, inclusive. This should provide a clearer picture more rapidly of the role of each major producer over the 5-year period. The listing order of major producers, however, continues to be, as in past years, in descending order of rank in the year of review, 1989. With the inclusion of silver and uranium oxide in the 1988 edition of this chapter, this group of tables now includes each of the crude minerals that ranked from 1st to 19th in 1983 in terms of value of their output (as well as four others of lesser rank). These 23 crude mineral commodities accounted for 93% of the estimated value of world crude mineral of world crude mineral production in 1983. In addition, world output of five key down-stream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil are included because of their significance as products.

Jan 1, 1992

[United States Page 837 Europe Page 881 Canada Page 876 Africa Page 883 Mexico Page 878 Middle East Page 884 West Indies Page 879 Asia Page 884 Central America Page 879 AustraliaPage 885 South America Page879 Pacific Ocean Area Page 886]

Jan 1, 1961

TRE ? worldwide leader in InSAR ? Spinoff of Polytechnic University of Milan ? Numerous patents for cutting edge technology (e.g. SqueeSAR?, PSInSAR?) ? Focus solely on InSAR with over 13 years experience ? ISO 9001 quality certification ? Powerful scalable parallel processor to handle all jobs What can InSAR provide for mining? An advanced suite of tools for monitoring ground deformation over mine sites: ? Deformation maps ? A dense network of measurement points ? Time series ? Cross sections of surface profile evolution

Aug 1, 2013

By Alejandro Freyre Belliki

El presente trabajo describe las causas del abandono de mineral, las razones de su recuperación de las antiguas explotaciones, así como el estudio de las técnicas más adecuadas para realizar dicha operación. Entre las causas del abandono de mineral tenemos: la variación de precios de metales, calidad y complejidad del mineral, seguridad, derrumbes y el método de explotación. También se mencionan los casos de recuperación de materiales útiles como rellenos antiguos, mineral "in situ", derrumbes y minerales dejados en mantos. Finalmente, se evalúa la posibilidad de hallar reservas recuperables y por ende, examinar la factibilidad de su recuperación. Asi también, las zonas recuperables son generalmente las más altas, ya que la aplicación de métodós con relleno hidráulico tomado directamente de los relaves de la Planta, debe considerar la diferencia de nivel entre ella y los tajeos re-explotables.

Aug 20, 1965

By Gordon T. McKenna

"Syncrude Canada Ltd. is developing new concepts in lease-closure landscape design for its Oil Sands Leases 17 and 22 in northeastern Alberta. Closure planning is becoming an integral part of the planning cycles and of the lease operation. By incorporating closure planning into the day-to-day operation, the company will achieve acceptable lease closure in an economical manner. Ultimately, Syncrude will achieve lower operating costs through innovation in mine planning and a reduction in residual liabilities.New concepts being evaluated for lease-closure landscape design include: designing for closure, use of landforms and natural analogs, self-armouring bouldery ground, robustness in design, landform grading, terrain analysis of reclaimed land, geotechnical hazard assessments, choices in closure design timeframes, passive maintenance, determining post-closure monitoring goals, engineering tailings, engineering other substrates, use of test plots and field demonstrations, geomorphologic monitoring of reclaimed lands, defining closure goals, and visiting other mines. These concepts are being formalized under the new discipline of Landscape Engineering."

Jan 1, 1996

By Willis H. Carrier

PARTICULAR interest in the ventilation of deep mines, especially those in South Africa, has been created by a very complete system of cooling of the world's deepest mine, the Turf shaft of the Robinson Deep in Johannesburg. The writer visited this mine in January, 1936, and again in 1937. During these visits and subsequently, a considerable part of the theory involved in rock cooling in tunnels was developed and this has been checked by practical observations of the rates of rock cooling made within mines. The purpose of this paper is to set forth the method of attack of the mine problem. The cooling or air conditioning of mines by the use of mechanical refrigeration was not wholly new 1-5 when the Robinson Deep installation was made. The first mine to be cooled was the Morro Velho mine, in Brazil. The first installation in this mine was put into operation in December 1920, the refrigerant being ammonia.5 The surface cooling gave considerable benefit but it proved inadequate as greater depths were reached, therefore in 1929 two centrifugal refrigerating machines were installed at the 6000-ft. level. These were used in conjunction with the surface cooling system to furnish additional cooling at the lower levels. This later installation used Carrene as a refrigerant. This nonflammable refrigerant, having a boiling point of 104º at sea level, insured reasonable safety, since all parts of the machine operated at subatmospheric pressure. Very favorable reports have been received on the effectiveness of this installation, but no recent data are available. An interesting feature of that plant is that the condenser water is cooled by spraying it into the exhaust air from the mine at the base of the ventilation upcast, which permits the water to be cooled within a few degrees of the wet-bulb temperature of the air entering the upcast, and the only water that has to be supplied for condensing purposes is that lost by evaporation, or about 0.5 per cent of the volume circulating through the condenser. This plan affords an ideal means for the removal of the heat load from the refrigerating system, and of course also from the mine itself. In many mines, however, especially those in South Africa, there is no

Jan 1, 1938

By V M. Silva, P A. A Martins, V O. Matthew, A L. S Fonseca, E B. Cunha, A J. D Ferrari, E M. S Silva, A C. Silva, D R. T Vilela

The Anglo American phosphate mine is located in the Brazilian state of Goiás and possesses one of Brazil’s most important phosphate rock deposits, with the site being the country’s second largest producer of phosphate rock concentrate. Despite the site having been in operation since 1979, the mining team only started using explosives in 2004 when rocks with greater hardness started to appear in the mine’s geological profile. Rock excavation was previously performed mechanically. Until 2013, only rocks with high hardness were blasted, this following the standard drilling grid that was defined in 2004 without any changes in the blast parameters. The aim of this paper is to show how fragmentation optimisation has yielded positive results at all stages of the production chain, from the mine to the mill passing through an impact hammer crusher, a rod mill and ball mill, operating in close circuit with hydrocyclones.While incorporating the mine to mill holistic approach during the operational integration, the focus was on defining the blasting domains and respective optimal fragmentation and measuring the benefits of blasting in terms of reduction in energy and grinding media consumed in the comminution processes. In the first stage, the blasting team made changes to the blasting parameters and assessed the effects of these changes on fragmentation using computer software and on-site measurements. This generated a database that made it possible to divide the mine into blasting domains. For the second stage, teams from the plant, geology, mine planning and operation departments jointly made comparisons between the performance when processing stockpiles, which only included high hardness blasted ore (20–30 per cent of blasted ore). Changing the drilling grid’s size from 3.0 m × 3.8 m to 2.0 m × 2.6 m for high hardness rock with the presence of silicates resulted in a 40 per cent reduction in the P80 for the blasted material (from 459 to 278 mm), while changing the grid from 3.0 m × 3.8 m to 2.6 m × 3.2 m for high hardness rock without the presence of silicates generated a reduction of 25 per cent (from 270 to 204 mm). There were gains observed from the measurements at the mineral processing plant in terms of specific energy spent on comminution and on the consumption of grinding bodies in the rod mill. There was a measured reduction of circulating load during secondary grinding and a reduction in slime generation.CITATION:Silva, A C, Martins, P A A, Silva, E M S, Fonseca, A L S, Ferrari, A J D, Cunha, E B, Silva, V M, Matthew, V O and Vilela, D R T, 2015. Fragmentation optimisation – adopting mine to mill for reducing costs and increasing productivity, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 363–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Taiping Lou

The effects of slag composition, additive agents, and heat treatment conditions on the perovskite (CaO ? TiO2) crystal morphology, the precipitation behavior, the crystal growth and the volume fraction (VF) in the Ti-bearing blast furnace slags were investigated. The morphology of perovskite is dispersed dendriform in molten slags. The crystal growth mechanism of the remelting of fine dendrites and the coarsening of larger grains exists throughout the solidification of molten slags. With the temperature decrease, the VF was increased and Perovskite transformed from fine dendrites to coarsening ones or equiaxed grains. The lower cooling rate can increase the VF and coarsen the grain obviously, while higher cooling rate will decrease the VF and reduce the average equivalent diameter (AED) of Perovskite. When .increasing the content of CaO and Fe20}, the VF can increase obviosly. However, high basicity will give rise to the increasing of viscosity of slag, which result in the reducing of the AED. The experimental results showed that additive CaF2 and MnO can efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promote growth.

Jan 1, 2000