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By A Benedictus, A Butcher, J Wikstr÷m, B Lindblom, E Rutqvist

LKAB is a mining company situated in northern Scandinavia, manufacturing blast furnace- and direct-reduction pellets and sinter fines. Pellet development at LKAB comprises testing at laboratory and pilot scale. The LKAB Experimental Blast Furnace (EBF) is a unique test facility and an important tool in terms of product development and process research. For a better understanding of pellet behaviour in the blast furnace process, LKAB has started to use automated mineralogy for the characterisation and quantification of its iron ore products and pellets. A mineralogical evaluation of iron ore olivine pellets, taken from a test campaign in the EBF, has been performed. The studied materials were samples from excavated pellet layers through the entire EBF at different positions. A large number of iron ore pellets was analysed using a combination of automated mineralogy, using QEMSCAN«, and chemical analysis. Important information about the performance of pellets in the blast furnace process, such as a quantitative description of mineral and iron oxide alterations at different temperatures, Fe-reduction and alkali deposition, was obtained.

Jan 1, 2008

By J. J. Carlson

Studies were carried out to determine whether filtration rate changes observed in an iron ore concentrator were due to variations in particle shape. It was confirmed that ores mined from different locations differed in filtration rates by as much as 60%. However, when image analysis was used to quantify the shapes of the individual particles in the filtration feed, it was found that the particle shapes showed almost no variation, and the shapes did not correlate with the filtration rate. It was also determined that the filtration rate variations were not caused by changes in particle size distribution. These results suggest that the differences in filtration rate are due to factors other than size and shape, such as surface chemistry.

Jan 1, 2008

By E. Kokinou

The main scope of the present study is to investigate the suitability and sensitivity of the magnetic susceptibility as a pollution monitoring tool in urban areas. For this purpose, a municipal park located in the centre of Chania city, which may be affected by traffic and domestic heating pollution, was selected as the study area. In the context of the present work, magnetic susceptibility measurements were conducted in two phases. Surface soil samples were collected in 2006 from the area under investigation and they were analyzed in order to estimate the spatial distribution of the magnetic susceptibility. One year later, mapping of the magnetic susceptibility has been contacted in situ using Bartington MS2D and MS2F sensors. Additionally, soil samples were collected from selected positions in order to compare the values of the magnetic susceptibility with that estimated in 2006 research. Both investigations indicate high values of the magnetic susceptibility around the park near the roads and in a small area inside the park where a café is located.

Jan 1, 2008

By Djavid Mohammad

Over the next several years, the storage capacity of the Metropolitan Water Reclamation District of Greater Chicago?s Tunnel and Reservoir Plan will be increased by 14.8 billion gallons through the addition of two large off-line reservoirs: the McCook and Thornton Reservoirs. The Thornton Reservoir will be constructed at the terminus of Calumet TARP System. The constructed TARP system will be connected to the Thornton Reservoir via connecting tunnels and gates systems. The connecting tunnels will comprise of: an upgradient transition tunnel, steel lined bifurcated tunnel for conveyance and control of flow, downdradient transition tunnel, and energy diffuser at tunnel portal. A large, approximately 250-foot-long, 69-foot-wide, and 40-foot-high, rock cavern will be excavated at an average depth of 320 feet to house the bifurcated tunnel system and associated six large control gates, each 12.5-ft by 28-ft wheel gate. Presented in this article are discussions about the TARP system, the Connecting Tunnels and gates Project, regional rock conditions, evaluation of reservoir?s wall stability for evaluation of tunnel penetration, and design challenges facing during design of the: rock cavern hosting the bifurcated tunnel system and gates and associated tunnels and shaft.

Jan 1, 2008

By Meyer Steinberg

"Some early experiences of a Cooper Union Chemical Engineer on the Manhattan project and his latest studies on CO2 Greenhouse Gas Mitigation Technologies are presented. Mitigating Global Greenhouse effect while maintaining a fossil fuel economy, requires improving the efficiency of conversion and utilization of fossil fuels, use of high hydrogen content fossil fuels, decarbonization of fossil fuels and sequestration of carbon and CO2 applied to all energy consuming sectors of the economy including electric power generation, materials production, transportation and industrial domestic heating. Decarbonization means removal of carbon as C or CO2 either before or after fossil fuel utilization and sequestration means long term disposal of C or CO2. The review will cover the principles of removal and recovery from power plant, stacks, the oceanographic and geological disposal of CO2 and the conversion of CO2 to gaseous and liquid transportation fuels. The global economic aspects of CO2 mitigation technologies are touched upon.IntroductionThis is an odyssey of a chemical engineer. My career started with the production of U235 at the Gaseous Diffusion Plant in Oak Ridge, Tennessee and the production of PU-239 metal at Los Alamos on the Manhattan Project. After 40 years at Brookhaven National Laboratory, I wound up performing studies on CO2 mitigation technologies. The following is a power point presentation on the subject of global warmingThe DOE is proposing to increase its sequestration development program in order to maintain the utilization of our vast resources in coal both for power and for transportation fuel production. Congress is considering steps to promote energy efficiency in attempts to solve not only the CO2 problem, but also the prime problem of energy supply. We will be promoting increases in energy efficiency as time goes on."

Jan 1, 2008

By R M. Tosdal

The Manantial Espejo district (Argentina) hosts a low-sulfidation epithermal Ag (-Au) deposit with a proven and probable reserve of 38 Moz Ag and 0.55 Moz Au. The district lies along the southern rim of the Deseado Massif in the Middle to Late Jurassic Chon Aike Province, a large bimodal igneous province dominated by silicic volcanic rocks that were formed during the initial extension leading to the opening of the South Atlantic Ocean. The district stratigraphy consists of 162 to 161 Ma old rhyodacitic to rhyolitic volcaniclastic rocks of the Chon Aike and La Matilde Formations, followed by 160 to 157 Ma old andesites and dacites of the informally called intermediate formation. The main stage of normal faulting post-dates the volcanic activity and coincides with the formation of the precious metal veins that were dated by 40Ar/39Ar on hydrothermal adularia with ages between 152.8 ¦ 0.8 Ma and 156.6 ¦ 0.8 Ma. Economically important hydrothermal veins show characteristic features of a low-sulfidation epithermal deposit with crustiform and colloform banding, bladed calcite replaced by quartz and abundant adularia. In the Maria Vein, the major orebody of the district, six hydrothermal stages are identified, but only stages one and four contributed metal. Lead isotope ratios in hydrothermal sulfides show a close relationship to ratios in feldspars from the district Chon Aike Formation, suggesting a common source for the Pb and possibly the precious metals in both the magmatic and hydrothermal products, or that the Pb in the hydrothermal veins was derived from the volcanic rocks. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By S. Dinescu

The paper deals with the modeling of longwall shearer cutterhead interaction with the coal, in order to study the influence of different limiting factors of the haulage speed, and the cutting regime ensuring optimal energy consumption A computer simulation model is used to draw-up the torque vs haulage speed and the haulage force vs haulage speed dependence diagrams, for different strength of coal and different degrees of bit wear.

Jan 1, 2008

By Maria I. De Rosa

Analysis of mining equipment fires from 1990 through 1999 reveals that there were 340 large mining equipment fires, resulting in 72 injuries and five fatalities. Many of the fires resulted in the loss of equipment and all posed potential or real risks to the operator. In 97 cases, the fires raged out of control due to engine shut­off failure, even upon activation of the machine fire suppression system, due to the spraying of pressurized hydraulic flu­id and fuel onto hot engine surfaces. In other cases, even after engine shutoff, the fires re-ignited, fueled by the contin­ued flow of flammable fluids remaining in the lines onto the hot engine surfaces. In many of the fires, flammable vapors evolved and penetrated the cab, violently igniting, forcing the operator to exit under very hazardous conditions. The use of emergency evacuation lines in the fuel and hydraulic fluid systems, and methods to reduce or prevent the spraying of pressurized fluids onto hot engine surfaces would greatly improve the chances of successfully suppressing large mining equipment fires. In addition, the use of systems for preventing the ignition of flammable vapors inside the cab, and detecting and suppressing fires originat­ing in the cab, would greatly enhance operator safety. The National Institute for Occupation Safety and Health (NIOSH) recently conducted experiments on meth­ods to reduce the fire hazards associated with large mining equipment. These experiments evaluated the use of cab inerting systems to prevent the ignition of flammable vapors inside the cab and sup­press fires originating in the cab, while maintaining a breathable atmosphere for the operator to bring the equipment to a stop and safely exit the cab.

Jan 1, 2008

By Tsisana Gagnidze

A processing of technogenous wastes, which involve a gold-containing sulphide minerals, is a potential source to supplement the gold reserves. Hence, searching of ecologically safe and economically reasonable methods for processing of gold-containing technogenous wastes is a topical problem. To increase a parameters of gold extraction and to simplify a technology of the processing of above-mentioned wastes of sulphide minerals, an investigations have been carried out in the direction of the use of the method of electrochemical leaching without any preliminary processing of the mineral. It was established experimentally that an introduction of nitrogen containing organic additive into chloride solution favours to reduce a Red/Ox potential of the solution from 0,8÷1,2 V to 0,35÷0,5V, which permits to conduct the process of direct electrochemical leaching at ?soft? oxidation regimes at temperatures 20-300C C without an environmental contamination by molecular chlorine and with a high degree of a gold extraction up to 80-90%.

Jan 1, 2008

By Carla Lupi, Mauro Pasquali

"Photographic technology is based on light sensitivity of silver halides that, because of silver properties, are capable of forming photographic images. Photographic laboratories and hospital departments because of digital photographic systems less use this technology today. Nevertheless recovery of silver is still advantageous because environmental problems related to Ag ions danger to biological system. Many processes have been studied to treat silver containing photographic bath: cementation, chemical precipitation and electrowinning. In this work, after preliminary voltammetric tests, a batch electrometallurgical process has been studied to completely deplete the silver containing photographic fixing baths. The effect, of silver concentration in the electrolyte, varying over the range 0,2-1 g/L, bath stirring and current density ranging from 10 to 500 A/m2 on process yield and deposit quality, has been investigated. Introduction Photographic wastes, electronic scrap and spent catalysts constitute the main sources of materials for silver recycling. Among those silver secondary sources, the photographic discharged material could be still important and useful, even if photographic laboratories and hospital departments, because of digital photographic systems, less use photographic technology. Several processes have been developped in order to recover silver used in the field of photography from both photographic solutions and scrap film paper[1-5]. Fixing solutions are very complex baths but, because of silver position in the electromotive series, electrolysis could represent an advantageous method for silver recovery. Electrolysis produces high purity silver without generating new pollutants, while the fixer can be reused: obviously it is necessary to purge off a portion of this solution in order to avoid the excessive build up of other deleterious compounds into solution. A tested recovery method was constituted by the dissolution of silver from X-ray films with concentrated nitric acid. Internal electrolysis and external electrolysis methods were carried out using a steel electrode as cathode and a copper electrode as anode [6]. Silver recovery from photographic chemical solutions has been also performed in a special cell [7]: the solution is supplied to the bottom of a non-agitated cell having a vertically elongated form and including a central anode enclosed by a cathode. An other study discloses the use of an electrolytic cell comprising at least one anodic compartment and one cathodic compartment: the solution is treated in the cathodic compartment and then recycled in the anodic one [8]. A more recent work proposes the use of zirconium cathode for the recovery of silver from photographic fixing solution [9]: studies carried out by cyclic voltammetry showed that about 98% of total Ag can be recovered with an electrical efficiency close to 92%."

Jan 1, 2008

By Hamid Maleki

Prudent design of coal pillars in any mining system requires an estimation of in-situ pillar strength, overburden lateral load transfer capability, and a failure criterion. Pillar strength is typically determined using one of several different empirical pillar strength formulas. For coal reserves in the U.S., a new pillar design method was proposed based on extensive U.S. field measurements in underground mines (7) which accounted for confinement effects. Field measurements in seven U.S. seams indicated highest strength for some Utah mines where the coal seam developed high confining stresses. Lower strength was measured in structurally controlled seams. This method is expanded here including the data from the weaker tertiary coal measure rocks and lower confinement for pillars with low width-to-height ratios. The determination of how much load a pillar is expected to take is partially dependent on the ability of overburden to transfer load laterally; this is useful for selection of panel width and barrier pillars size in select mining applications where long-term stability is required in conservative designs. In caving mining systems, caving of the strata is influenced by geologic, mining and stress conditions and the released energies influences how the pillars react at loads approaching pillar strengths. Overburden deformation and caving mechanisms are analyzed in this paper in multi-panel extractions to enhance the understanding of load transfer, seismicity and coal bump control in deep western U.S. operations.

Jan 1, 2008

By Q Zhou, Y Ma, J Zhu, R L. Frost, P Yuan

A series of organoclays with different surfactant arrangements were prepared by ion exchange. The resulting organoclays were investigated using a combination of characterisation techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric measurement (TG) and N2 adsorption-desorption. In the present study, the pores within the organoclays were discussed on the basis of the micro- structural parameters, including BET-N2 surface area, pore volume, pore size, surfactant loading and distribution. The results show that both BET-N2 surface area and pore volume decrease from low to high packing density of the surfactant as the average pore size increases. Two basic organoclay models were proposed for hexadecyltrimethyl- ammonium bromide (HDTMAB) modified montmorillonites: 1. the surfactant mainly occupied the clay interlayer, and2. both the clay interlayer space and external surface were modified by surfactant. This study demonstrates that the pore structure of the resulting organoclays has a significant influence on the sorption efficiency and mechanism of p-nitrophenol onto the organoclays.

Jan 1, 2008

By Matthew E. Fowler

The Central Subway will extend the recently completed 8.2-km long Third Street Light Rail line another 2.7 km north through the Union Square shopping district to Chinatown with a concourse-to-concourse connection to the Powell Street BART Station. One mined and two cut-and-cover subway stations are planned. Particular challenges include: tunneling under existing tunnels; variable ground conditions ranging from saturated alluvium to fractured bedrock; a congested urban setting and large-span caverns. This paper gives an overview of the project as it stands midway through the preliminary engineering stage along with a discussion of the rationale and design approaches that are being used to address the construction challenges of restoring light rail service in the most densely developed areas of San Francisco.

Jan 1, 2008

By I KylmSkorpi, H Mansikkaviita

The traditional direct-heated drying process has been replaced by the steam drying process in non-ferrous metal smelters, where steam is available from waste heat boilers. Many recent projects have selected Kumera Steam Dryers in equipping a new production line or modifying an old production line. The industrial performance of the steam dryers has shown significant energy saving and emission reduction. The steam dryers have been operated at high availability and long maintenance interval. As the process principle of Kumera Steam Dryer is different from other equipment, the set-up for steam dryer plants is configured to fit the smelter site and operation conditions to achieve optimal performance. This article discusses the equipment involved in the steam drying process and their combination options.

Jan 1, 2008

By Hélio Wiebeck, Fabio J. Esper, Wildor T. Hennies, Guillermo R. Martín-Cortés, Francisco R. Valenzuela-Díaz

"Natural rubber reinforced commonly with carbon black to produce vulcanized material, turns into a new environmentally friendly nanocomposite when carbon black is replaced by organically modified clays of Brazil. Carbon black is substance derived from the oil refining process with consequent pollution to the environment. Its substitution in this industrial process must contribute to diminish the oil derived products dependence. As the added clays are only a third in weight of the traditionally carbon black added, then, to obtain the same final volume it is necessary to add low cost neutral filler that does not damage the technological characteristics of the final material. This paper presents results using as neutral filler of this type rice husk ashes from industrial wastes. Experiences realized with this nanocomposite material show results of quality and technological characteristics similar or superior to those of the rubber made with carbon black.IntroductionTraditionally rubbers are black or a very dark color. But they can have different appearance when filler of distinct composition of the carbon black is used. The carbon black is substance derived from the oil gotten during the final phases of the mineral fuel treatment with consequent pollution of the environment. Carbon black show nanometric grain sized distribution and a depth black color, because these properties it is also used for computer printers inks production. The substitution of this substance, traditionally used as a reinforced load in the rubber production, will have to contribute in such a way to diminish the dependence of these products as to diminish the pollution of the environment. The present work shows the results of the use of another kind of mineral nanoparticulate material substituting carbon black in the production of some rubber products. This nanoparticulate material is the organic modification of smectite clay treated with some types of ammonium quaternary."

Jan 1, 2008

Toxic gases, mostly carbon monoxide (CO) and nitrous oxides (NOx), are invariably generated by commercial explosives under practical conditions of usage because of oxygen unbalance and non-ideal chemical reaction. Permitted explosives are statutorily required to meet the criteria stipulated by regulatory authority for their toxic fume quality for their safe use in underground coalmines. Solid blasting using P5 explosives contribute around 60% production from Indian underground coal mines. Low pull and yield per blast in solid blasting has been identified as a reason for low production and productivity of Indian underground coal mines. In an effort to improve performance of solid blasting, it was envisaged to apply air decking between suitable P5 explosives using high density polyethylene (HDPE) spacers under a Ministry of Coal, Government of India funded project. A non-deflagrating slurry explosive composition having high air gap sensitivity was specially developed for this purpose, so that air decked cartridges get detonated sympathetically with single priming. However, statutory authority in India apprehended that the use of oxygen negative HDPE spacers can influence the generation of toxic gases. The effect of using HDPE spacers on the generation of toxic gases was studied under simulated laboratory conditions with newly developed as well as with three commercial P5 explosives. The results of studies presented in this paper revealed that the level of carbon monoxide increases linearly and there is no significant effect on the level of oxides of nitrogen due to the use of HDPE spacers with selected explosives. Studies also revealed that this newly developed slurry explosive can be used for air decking up to 15 cm using HDPE spacers of weight not more than 21 g without exceeding the permissible limits for toxic gases.

Jan 1, 2008

By S. Paul Singh

Rock burst is one of the most serious mining hazards, adversely affecting the safety, economy and productivity of mines. It is a sudden manifestation of the release of strain energy stored in the rock mass. At present, there is no universally accepted method for predicting the timing of the rock burst. However, if the seismically hazardous regions in mines can be identified before they are exposed to mining then precautionary measures can be planned before the work begins. A study was conducted in Sudbury Nickel Belt and an approach has been proposed to identify rock burst prone workings on the basis of (a) Rock properties and bursting indices (b) In-situ approaches (c) Geological features (d) Mining conditions (e) Observations during mining operations (f) Comparison and analogy with previous case histories of bursting. This approach will facilitate the judicious application of the burst control techniques to seismically hazardous areas.

Jan 1, 2008

By Verya Nasri

The proposed Second Avenue Subway Project in New York City is approximately 8.5 miles long, up to a depth of 120 feet beneath grade and runs the length of the eastern side of the island of Manhattan from Harlem in the north to the financial district in the south. It will reduce overcrowding and delays on the existing parallel line, improving travel for both city and suburban commuters, and upgrading access to mass transit for residents of the East Side of Manhattan. This subway line will have 16 new stations providing transfers to the existing Metro-North commuter rail service and to New York City Transit subway lines and bus services. The first phase of construction includes two TBM rock tunnels 2.4 miles long and two new large and shallow rock cavern stations with clear span openings ranging from 70 to 100 feet and length in excess of 1000 feet with 615 feet center platform, coupled with low rock cover ranging from 20 feet to 40 feet. The design methodology for these large and shallow rock caverns consists of using well known empirical methods for initial estimate of support requirements and then two and three dimensional continuum and discontinuum analyses for verification of the selected excavation sequence and support system. This paper describes the analysis and design methodologies used for the two large and shallow rock caverns with insight into how to overcome the design complexities and construction challenges of the urban underground.

Jan 1, 2008

Incorrect sampling and measurement operations and misunderstanding the components of variability can cause huge economic losses to the mining industry. The main objective of this paper is to illustrate by means of four historical facts how Codelco has been evolving in those issues since the late 1980s. The El Abra bias, the awareness of the different kind of sampling errors and the role of Francis Pitard, the awareness of weighting errors, and the understanding of the components of nature and process variability are described. It has been a slow but a consistent process. Much progress has been achieved but still there are many opportunities for improvement to transit from the tonnage culture to the productivity culture.

Jan 1, 2008

By Emilia Visileanu, Eftalea Carpus

"The strategy of developing the Romanian textile industry sub-sectors envisages the achieving of certain superior production indices, from a physical and value point of view, in 2010, a quantitative increase of textile wastes by 14% in 2010 as compared to 2000, implicitly. The percentage of the turned-to-profit wastes will have an increasing tendency, from 53.6% in 2000 to 74.7% in 2010. The article synthetically presents the innovative elements of the technology of processing the industry textile wastes.1. Introduction“People will need to re-adopt this sense of rarity that has been forgotten over the last two centuries. Humans need to collect, sort, recover, going back to the old ideal of alchemists: complete the material cycle, turn waste into resource, reduce all forms of predatory behaviour as much as possible”Irrespective of the historical period, geographical positioning, economic power or employed technologies, wastes resulted and will result in a bigger or smaller quantity as long as life and activity on Earth go on. The negative effects of these over the environment factors and implicitly over population health are well known all over the world and not approaching this matter enough may have catastrophic consequences over life. Having in view these aspects, finding solutions for diminishing the general waste quantity and limiting the negative effects of those products is important, by effecting the reusing of the recyclable ones in the production processes as secondary raw materials, and by ecologically treating and storing those than cannot be reused.2. Experiments and researchesThe textile industry affects the environment by the high water, energy and chemical consumption, as well as by the high quantity of wastes that are the result of using an impressive number of chemical substances and technological processes.The development strategy of the Romanian textile industry sub-sectors foresees, for 2010, the achieving of certain higher production indices as compared to 2000, both in terms of materials (as merchandise) and in terms of value, which implicitly leads to a quantitative increase of wastes.The flexible, economic and ecologic technologies which include systems of waste preliminary preparing (cutting, opening) and conventional or non-conventional system of processing the recovered fibres lay at the basis of substantiating the activity of implementing the notion of zero wastes."

Jan 1, 2008