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The Effect of Mineral Liberation on the Floatabilities of Pyrite, Arsenopyrite and Arsenian Pyrite for Carlin Trend Ores

Sep 13, 2010

By Victor Benavente

La lixiviación es un proceso hidrometalúrgico que permite obtener el cobre de los minerales que lo contienen, aplicando una disolución de ácido sulfúrico, agua y agentes oxidantes. Este proceso consiste en que los minerales son sensibles al ataque de soluciones ácidas y oxidantes. En ese sentido, el objetivo del texto fue determinar la respuesta de los sulfuros secundarios de cobre a la lixiviación ácida y oxidante utilizando cloruro de sodio como portador de cloruro al sistema de lixiviación. El desarrollo de las pruebas y la ejecución de las mismas, definiió el proceso de lixiviación para minerales sulfurados de Minera Pampa de Cobre.

Sep 12, 2011

By David M. Jurich, Randy J. Essex, Alex de Aboitiz

An Automated People Mover (APM) transit system is planned for the growing Phoenix Sky Harbor International Airport. The APM will improve passenger movements between the terminals, and provide a link to parking facilities, a new rental car facility, and the planned metro Light Rail. The underground works will include shallow twin bored tunnels, taxiway crossings, and underground stations constructed beneath critical airport facilities. Challenging soft ground conditions will require extensive underpinning and ground improvements. Design is underway, and construction is scheduled to begin in 2007 with project completion in 2015. The owner’s planned delivery method for the APM Project will be Construction Manager at Risk (CMAR) with a Guaranteed Maximum Price.

Jan 1, 2005

By Larry Mirabelli, David Lilly

In 1777, the French naturalist, Georges Louis Leclerc, Compte de Buffon developed a statistical technique to estimate the width between two parallel lines by randomly throwing a needle at the two lines and counting the number of times the needle intersected one of the two lines. By knowing the length of the needle, the distance between the parallel lines could be estimated. This analysis was named the “Buffon’s Needle Problem”.

Jan 1, 2008

By R. Pelton, Z. Dai, S. Yang

ABSTRACT Hydrophobic polystyrene nanoparticles were evaluated as potential flotation collectors for pentlandite. The flotation of hydrophilic glass beads demonstrated the nanoparticles’ ability to induce flotation. Deposition of nanoparticles on glass surfaces increased the contact angle and enhanced adhesion of the beads to air bubbles. High flotation recoveries were achieved when 5–10% of the bead surfaces were covered with nanoparticles. Surface functionalization—the addition of vinylimidazole to polystyrene nanoparticle surfaces—caused the nanoparticles to selectively deposit onto pentlandite surfaces in the presence of Mg-Si slimes. Ongoing work includes attempts to identify specific applications where nanoparticle collectors might be cost effective. _ KEYWORDS Flotation, Nanoparticle collector, Coverage

Jan 1, 2014

By Tom Dettweiler, Robina Sharpe, Wright. Michael

The International Seabed Authority and a number of countries have or are in the process of developing environmental impact assessment guidelines and legislation for seafloor mineral development. The formal decision to grant a project an environmental permit is based on an environmental and social impact assessment (ESIA), culminating in an environmental impact statement (EIS). The EIS needs to be supported by sufficient data upon which an assessment of impacts can be made and mitigation measures developed. Given the remote locations of many seafloor prospects, collection of sufficient environmental data to inform an EIS is often a difficult, expensive and lengthy process.

Sep 1, 2014

By J. Egan

The recovery of gold by ore leaching is influenced by the size of the particles and the chemical environment. Within the experimental error associated to the testing of gold ore, results of a series of leaching tests conducted with natural ores rather than monosized samples confirm that gold dissolution increases with decreasing ore particle size. The tests also indicate that the dissolution of gold in the ore within a size interval is weakly affected by the intensity of the size reduction method.

Feb 27, 2013

By Diler Katircioglu-Bayel, Oner Yusuf Toraman, Safak Gokhan Ozkan

One of the most energy-intensive processes for producing submicron range calcite is stirred media mill. In the present work, numerous operating parameters such as solid mass fraction, grinding media size, media filling ratio, and grinding time have been investigated using a vertical type stirred media mill. The results are evaluated on the basis of mean particle size, specific surface area, and specific energy consumption. After conducting this study, optimum experimental conditions found to be as 70% media filling ratio, 25% solid mass fraction, 1 mm grinding media size, and 120 min grinding time. Besides, energy savings up to 22% were achieved with the choice of proper media size.

By John A. Owsiany

The effect of longwall mining on streams and shallow aquifers has been the subject of numerous research studies for more than twenty years. As a result of these studies, it has become common to consider an overburden thickness of 400 feet as the lower limit at which longwall mining methods may be used with little or no effect on hydrologic systems. This paper presents the results of a study documenting the response of a large high order stream to shallow cover undermining by longwall methods in the northern Appalachian coalfield. The field site is located in a narrow stream valley where the overburden, composed primarily of limestone and sandstone units interbedded with shales and siltstones, ranges in thickness from 340 to 285 feet above the main bench of the Pittsburgh coal seam. Streamflow monitoring and monitor well measurements indicate that no significant loss zones or water table lowering resulted from undermining the stream or the adjacent valley bottom area. Additionally, hydrographs for shallow near-stream wells exhibit fluctuations related to natural seasonal variations, which are nearly identical to those observed in a non-undermined control well in the same watershed. Environmental factors affecting streamflow were monitored through the use of a control stream in an adjacent non-undermined watershed to differentiate between natural and mining induced changes in flow.

Jan 1, 2001

By L. D. van Dyk

The extraction of iron and lead from their oxides with a volatile organic ligand such as acetylacetone in the gas phase offers potential advantages of lower energy consumption, recycling of the extractant, recovery of pure metals, and a reduced environmental impact compared with conventional extraction processes. The influence of reaction temperature, ligand flow rate, and metal oxide levels on the extraction and rates of reaction of iron and lead from single metal oxide (synthetic haematite (Fe2O3) and synthetic massicot (PbO)) systems in a fluidized bed was studied. It was found that at the investigated acetylacetone flow rates, the influence of mass transfer was limited, but that the reaction suffered from reactant starvation. When the metal load increased the effect of starvation on the rate of reaction also increased. The reaction kinetics increased with an increase in temperature for both systems. At low metal oxide concentrations more that 80 per cent of the iron and lead could be extracted from their respective metal oxides after only four hours.

Jan 1, 2012

By H North, J Barringer, S McNeill, D Pairman

Models of ground surface elevation, slope, aspect, curvature, roughness, deformation, as well as other features are gathered together in the term Digital Terrain Model (DTM). DTMs can be generated from a wide range of technologies such as ground surveying, aerial and satellite imagery, including both active and passive sensors. Some elevation derived parameters, such as roughness and slope, can be measured directly using innovative active sensor technology and smart processing, rather than via traditional processing of elevation information. Such models are used as part of a visual interpretation process, and increasingly for computer-assisted analysis using visualisation technology. There is an ever-increasing demand for DTM information to be used in the mineral exploration and mining industry, and consistent pressure from industry to develop models of higher spatial resolution, higher accuracy, and better overall reliability, regardless of the world-wide location of interest. This presentation will survey the range of techniques available for DTM generation, including active (LIDAR, SAR interferometry and differential interferometry) and passive (optical or SAR stereo) methods, as well as interpolation methods (contour or structure interpolation), and the economic placement of these various techniques in the local and regional context. The research issue oftrue-ground elevation models and slopes is also addressed, using LIDAR and SAR polarimetry as signpost technologies. Particular emphasis will be given to the strengths and limitations of new data sources that will, over the next few years, make the acquisition of elevation models of remote regions of the world inexpensive and relatively accurate.

Jan 1, 2000

CONTENTSSummary.Introduction.Location and Geology.Historical and Exploitation.Part 1. Washability Characteristics of the Liddell.Seam.Foybrook Open Cut, Top Bench.Sampling.Size and Ash Distribution.Washability Data.Washery Separations.Part 2. Washability Characteristics of the LiddellSeam.Foybrook Open Cut, Bottom Bench.Sampling.Size and Ash Distribution.Washability Data.Washery Separations.Acknowledgments.References.INTRODUCTIONThe washability characteristics, size-range and chemical analyses of the screening from the Liddell Seam are matters of growing interest in view of the increased exploitation of this seam over the last few years, and also since the Newdell Coal preparation plant of the New South Wales Mining Company Proprietary Limited, utilizing magnetite heavy media separation, commenced...

Jan 1, 1954

New GSP Trade Status Approved.--President Carter, by Executive Order effective March 30, has approved Generalized System of Preference treatment for imports of nonferrous metal products and other imports from Ecuador, Indonesia, Zimbabwe, Uganda, and Venezuela. As of May 2, Afghanistan and Ethiopia will be taken off GSP status. Under the Generalized System of Preferences, certain imports from developing countries are provided duty-free treatment. A country can lose its GSP status if its shipments of the product exceed $41.9 million or more than 50% of total U.S. imports during the preceding year. However, the President can waive the 50% rule in cases where total U.S. imports of an item in 1979 were less than $1 million. Certain nonferrous imports from Mexico, Peru, Chile, and Zambia are already covered by GSP. Hearings April 10 on International Tin Agreement.--The Fifth International Tin Agreement of which the United States is a signatory, which entered into force on July 1, 1976, will expire on June 30, 1981. A negotiating conference for a Sixth International Tin Agreement will be held under auspices of the United Nations at Geneva from April 14 to May 16, 1980.

Jan 1, 1980

By Ramdane Bahar

"Abstract The design foundations can be performed using Menard pressuremeter rules that require a limit pressure and a pressuremeter modulus. In recent years, another trend of interpretation of this test is appeared. It consists of identifying the rheological soil parameters using analytical or numerical methods and then used to evaluate the bearing capacity and settlement of soil foundations using numerical software. This paper deals with the bearing capacity and settlement predictions of bored piles using two approaches. The first one is the method called ""Pressident"" which is a numerical program developed to analyse pressuremeter tests taking into account the Duncan and Chang model. The second approach is the method developed by Bahar and Olivari based on the generalised elastoplastic Prager’s model with the Von Mises criterion which is suitable to describe the behaviour of saturated clays under undrained conditions. The pressuremeter data, collected on various research and consulting projects are used to explore the relationship between limit pressure and undrained shear strength obtained by the two methods. Numerical calculations, by FLAC2D software taking into account the rheological parameters derived from these two methods, are performed in order to predict the behaviour of a single bored pile subjected to an axial vertical load. The predictions are comparedto the measured data.IntroductionThe Menard Pressuremeter test has been used extensively to measure in situ soil properties and for the design deep foundations in Algeria. These tests are an useful and economical way for obtaining reliable in situ properties of soils and provide the measurement of in situ stress-strain response of soils. From this test, the design foundations can be performed using pressuremeter rules that require a limit pressure, pl, and a pressuremeter modulus, EM. These two parameters are derived from the pressuremeter curve or deduced from existing correlations with undrained cohesion and internal angle friction (Ménard, 1957; Amar and Jézéquel, 1972), and are used to evaluate the bearing capacity of soil foundations and the expected settlements. But, they can also help to identify usual soil parameters required by simple constitutive models for soils in numerical calculations."

Jan 1, 2014

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher production rates and a resultant reduction in production cost. The Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO) funded by the Canadian Mining Industry Research Organization (CAMIRO) has developed a methodology for safe rapid drift development within the underground metalliferrous mining industry in Canada According to industry survey, about 36% of drift development cycle time is spent on support installation. MIRARCO has developed a methodology for safe rapid drift development based on minimizing time spent on support installation. The methodology includes a critical review of the rockmass classification systems, examination of current support practices in the mining industry and civil tunneling, review of rapid drift development practice in South Africa, introduction of risk hazard procedures to account for material property variability and the development of a WIZARD as a quick decision-making tool for the implementation of the procedures. A comprehensive field data collection procedure was put in place and data collected from various mines to verify and calibrate the support selection rationale. The findings of the research programme resulted in the development of an improved rockmass classification system and showed that construction effects have drastic influence on support levels but is often not accounted for in assessing support levels. Stress effects and structurally controlled failures are the other important factors to take into account in rapid drift development. Three support classes were established for safe rapid drift development as No Systematic Support, Light Support and Strong Support. The support levels took into account cost, rate of installation and safety based on compatibility with ground characteristics. This paper describes the methodology for safe rapid drifting within the underground metalliferrous mining industry in Canada and highlights the key issues and major drivers behind their continued development at the Geomechanics Research Centre within MIRARCO.

May 1, 2004

By James Ransford Dankwah

This work investigates the effect of waste plastics addition on the reduction of iron oxide by sawdust. Composite pellets of iron oxide containing sawdust (SD), high density polyethylene (HDPE) and blends of SD/HDPE were fired under argon in a horizontal tube furnace at temperatures between 1300 and 1500 °C. Reduced samples were weighed after 10 minutes of reduction and the extent of reduction was calculated from the measured oxygen contents of the compact. The results showed improved extent of reduction when SD was blended with HDPE. The highest extent of reduction was achieved at SD:HDPE ratio of 2:3.

Jan 1, 2014

By Maurice Bottiau

The recent evolution of the piling market clearly shows a growing demand for screw piles with soil displacement. The recently developed Omega Screw pile ful-fill these new expectations, combining the advantages of vibration-free systems and the behaviour of a displacement pile. The paper describes recent experience and new applications with this very promissing pile. Full-scale load tests were carried out in different countries as U.K. or Sweden. A very attractive and innovative piled embankment is also described, using geogrids in order to transfer the loads from the superstructure to non-reinforced Omega-piles.

Jan 1, 1996

The Estonia Mine, operated by Eesti Energia Kaevandused AS (EEK), the mining division of the Estonian Government's energy company, Eesti Energia AS, is a large room and pillar mine located in Eastern Estonia. It supplied approximately 4.9 Mt/a of oil shale in financial year ending 2010, which is used for electricity and shale oil generation. Due to the Estonian climate and the power station's need for a dry product, Estonia Mine has developed a planning system where short-term demands of the power stations dictate the schedule. Such an arrangement requires maximising flexibility and consequently the mine only operated for 199 days in 2010.The footprint plays a key role in achieving mass mining rates as the 12 km + 12 km lease area allows the mine to split into mining districts that act independently of each other and maximise the number of work areas available. Coupled with this, the geology of the mine is relatively homogenous over the mining lease, simplifying the mine design and production methods.During the last five years, EEK has commissioned a comprehensive conveyor network. Consequently, material handling only requires loaders to dump oil shale direct from the production face onto a chain conveyor that feeds the conveyor network that ultimately supplies the enrichment plant. Dewatering is also of critical importance, with 90 Mm3 of water discharged annually. EEK uses large trenches up to 3.5 m deep and 1.2 m wide to channel groundwater. Track mounted mechanical saws are used to cut slots in the floor, to control overbreak in blasting these trenches.EEK has introduced Salzgitter Machinenbau GB 280S auger drills that drill three 280 mm diameter holes simultaneously. This has improved void hole drilling times and reduced the drilling required for each face, reducing the overall production cycle time. Blasting activities have also been decoupled from other mining activities negating the need for firing times through the use of small independent firings, required to control vibrations.

Dec 6, 2010

By Roberts W. P H, Chant R. A

Investigation of the "whole-rock" major element geochemistry of the Broken Hill lodes and of the rocks immediately enclosing them has been carried out on the full lengths of 19 diamond drill cores transecting B lode,A lode, No. 1 lens and Lead lode in The Zinc Corporation Ltd.-New Broken Hill Consolidated Limited, at the southern end of the line of lode.It appears that the abundances of all of the principal "non-sulphide components" - Si02, AI2O3, Ti02, CaO, MgO, MnO, K2O, TiO2 and P203 - are closely tied to the incidence of sulphide. The well-known direct relationship of calcium and manganese with the incidence of sulphide is confirmed, and to this is now added the pairing sulpnide-phosphate, which is particularly welldeveloped in the zinc lodes. It is also now shown that there is a clear inverse relationship between sulphide on one hand and AI2O3, Ti02 , MgO, and K2O on the other.Total Fe-which is an important constituent of both sulphide and non-sulphide-appears to occur in essentially similar amounts in ore and enclosing materials. The incidence of Na20, while generally depressed in ore, issomewhat erratic and equivocal. Si02 and sulphide usually show a highly systematic inverse relationship-a feature stemming inevitably from their being by far the two most abundant, and hence two co-dominant, materials ofthe ores.These features of elemental abundance are interpreted in the context of seaflooor hydrothermal ore deposition to give some insight into the amount and nature of detrital and of chemical sedimentation, the formation and accumulation of different clay minerals, the chemical and physical characteristics of the bottom waters, and the reasons for the comparative paucity of iron in the Broken Hill lode.

Jan 1, 1978

By T. Gupta, T. Ghosh

Rare earth elements (REEs) and their compounds are essential in a multitude of mundane and sophisticated applications such as renewable energy technologies, catalysts, medicine, and defense applications. The global supply deficit could be attributed to the destabilization of REE market that has, as a result, incentivized indigenous production of REEs. Cost-effective and environmentally benign opportunities are being explored for the production of REEs from non-conventional mineral sources including coal and coal by-products to stabilize the supply chain. Coal from Healy coal mine and Wishbone Hill deposits in Alaska have been quantified for REEs and were found to possess elevated total REE concentrations as compared to world average levels (60– 70 ppm). The objective of the study was to concentrate the REEs in the froth phase by froth-flotation of the fine size fraction (< 75 μm). A Box-Behnken design of experiment was employed to ascertain the main and interaction effects of operational parameters on response variable by analyzing 3D response surfaces. Experiments were carried out to maximize REE recovery and concentration by modeling and optimization of three operating variables (frother dosage, pulp density (% solids), and collector dosage). Based on the results, the optimum flotation conditions for maximum recovery at an elevated concentration of REEs in the froth fraction was obtained at 4.2% solids and 32.7 ppm of frother dosage for Healy sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic relationship between the input and response variable was found to be independent of collector dosage suggesting good surface hydrophobicity and floatability of the two coal samples.