Search Documents

By R. G. Bradburn

"Brenda Mines Limited is a low grade open pit mining and milling operation located near Peachland, British Columbia. The mill was brought into production in late 1969 at a rated capacity of 24,000 tons per day. Tt currently treats an average of 30,000 tons per day of an ore that has an average grade of 0.130% copper and 0.030% molybdenum.Description of Crushing and Grinding CircuitsRun of mine ore is delivered to a primary gyratory crusher. The minus seven inch product is separated into plus and minus one inch fractions on two parallel vibrating screens. The fine product is conveyed directly to the mill fine ore bins, while the coarse fraction is sent to a 45,000 ton stockpile.Material from the stockpile is fed to two standard cone crushers which operate in an open circuit with five secondary vibrating screens. The minus five-eighth inch product from these screens is conveyed to the mill fine ore bins while the coarse fraction is fed to four shorthead cone crushers. These crushers operate in closed circuit with the screens."

Jan 1, 1981

By M. Schwarze

SMS Meer GmbH with its COPPER PLANTS DIVISION produces a full line of systems and machines for the processing of copper. The product range includes: shaft melting furnaces, anode casting lines, horizontal and vertical casting lines, casting and rolling lines for copper wire rod and strip, cold pilger mills, planetary rolling mills as well as tube drawing equipment. The new designed shaft furnaces are the most economic way of copper melting. The CONTILANOD® system with hydraulic shear represents a breakthrough into higher production capacities and improved geometrical accuracy of anodes. The new generation of CONTIROD® lines with individual drives of rolling stands guarantee cost effective production of highest rod quality. A new horizontal continuous casting technology for the production of tube shells as feed stock for the copper tube manufacturing process ? directube® was developed and introduced into production. A first line for continuous vertical strip casting - called VERTICAST® - for higher production rates and improval quality of cold-rollable strips is in the final stage of commissioning. These innovative technologies increase product quality, reduce process costs and help for a wide use of copper in all sectors of life.

Jan 1, 2007

By Eamonn F. Maher

Superconductivity is one of the most remarkable scientific phenomena ever investigated. It is the phenomenon whereby some materials exhibit zero resistance to the passage of an electric current when cooled to low temperatures, and requires a quantum mechanical explanation. Four Nobel prizes in physics have been awarded specifically on the subject of superconductivity, with many more enabled by superconducting technology. For example, particle beams are generated in accelerators and manipulated in ?particle beam lines? in the ?Big Physics? projects around the world eg. at CERN, Geneva, leading to major discoveries in fundamental particle physics. Similarly, at the JET Propulsion laboratory near Oxford, U.K, controlled nuclear fusion has been demonstrated, and magnetic containment of plasmas is key. In the chemical and biological sciences high field NMR spectroscopy has become indispensable for examining organic matter, revealing the mysteries of the workings of cells, genetics, and in the development of new polymers and pharmaceuticals. With all these very advanced uses for superconducting magnets, it is easy to forget that superconductivity is big business, not just a scientific curiosity. MRI (Magnetic Resonance Imaging) superconducting magnets, the key component of high resolution body scanners, use approximately half of the world?s superconducting wire ? the other half being mostly used in accelerator magnets. The MRI market is about 3 billion dollars per annum, and one MRI magnet uses 200km of wire. New applications for superconducting magnets are now appearing including ?Catheter steering?, enabling much shorter timescales for life-saving brain tumour removals and ?Functional MRI?, a whole new area in patient diagnostics. Whilst the use of low temperature superconductors (LTS) is now well established commercially in superconducting magnets and niche electronic applications, the application of LTS in electric power distribution and transport has been very limited to date. It is now more than fifteen years since the so-called High Temperature Superconductor (HTS) materials were discovered: these can be operated at liquid nitrogen temperatures rather than liquid helium temperatures. However, materials processing and scale-up issues have prevented their widespread use, and in particular the required price/performance criteria are only beginning to be reached except in certain niche markets. BSCCO (Bismuth Strontium Calcium Copper Oxide) tapes up to one km long are now readily available, and have been demonstrated in high current cables for power distribution networks, but the general consensus is that 1) it is difficult to reduce the price much further because of the silver matrix required and 2) in applications where coils are required eg. motors, generators, transformers etc the properties of BSCCO are rather poor because of the critical current dependence on magnetic field. Magnetic fields are always associated with coils and windings, and such fields are of course fundamental to the operation of all electrical machines. YBCO (Yttrium Barium Copper Oxide) however, has good characteristics in field and for the last few years there has been intensive research and development costing several tens of millions of dollars worldwide into the scale-up of production of so-called ?coated conductor?. This ?second generation? tape can be produced by any of many different film deposition techniques, with more or less success for short lengths, but as yet it is unavailable in lengths more than a few tens of metres.

Oct 1, 2003

By H. A. Gorrell

Preliminary studies of the potential for the production of warm water (up to perhaps 150°C) have been carried out in the Plains region of Western Canada. Production might be from depths as great as about 5 km . Natural waters in this temperature range are currently being used for space heating in other parts of the world. The geography and stratigraphy of the Prairie Provinces are reviewed in terms of their apparent potential for warm-water production. Temperature, salinity and other data provided by wells drilled by the oil and gas industry are reviewed and problem areas are outlined.

Jan 1, 1979

By P. A. Bahri, D. G. Dixon, T. M. Woodward

A comprehensive mathematical model of the Sherritt-Gordon ammoniacal pressure leaching process at K winana Nickel Refinery has been constructed. The process is comprised of six autoclaves functioning as a three-stage leach circuit, operating over the temperature and pressure ranges of 85-95°C and 750-1000 kPa, respectively. The process chemistry forms a complex series-parallel reaction network, characterised by: (1) the gas-liquid mass transfer and reduction of oxygen, (2) the oxidation of eight distinct minerals, (3) the oxidation of sulphur, and successive reactions involving various intermediately oxidised sulphur species, and (4) the oxidation of Fe(II) to Fe(III), and subsequent precipitation as a hydrated ferric oxide. Material balances were developed for species in all three phases, and an energy balance to account for all reactions and phase conversions. The multiple convolution integral (MCI) statistical reactor model was employed for the scale-up of particle kinetics. The model has been validated against plant data, and simulation results are in agreement with plant performance.

Jan 1, 2005

"The last thirty years have seen enormous changes in all aspects of the gold industry, from the technologies of mining and extracting gold to the role it has played in the fiscal policies of nations. In this time, the market price of gold has increased ten fold and mine production has more than doubled. However, the cost of mining and extracting gold has also increased exponentially, and the industry has struggled with declining ore grades and increasingly refractory ore bodies.With the major economic powers of the world shrugging off the uncertainties of the post cold war era and moving into a period of unprecedented political stability, economic growth and low inflation, gold is also losing its lustre as a hedge against inflation and a backing for national currencies. Consequently, countries that had accumulated and hoarded gold for decades are now disposing of these non-performing assets, resulting in major swings in supply of the metal. Fortunately, this has coincided with the end of communism in many parts of the world and a tentative move to free market economies in most of the developing nations. As a result, people are becoming wealthier, and this is creating more demand for gold, principally in the form of jewelry.On balance, the shift in the role of gold, from one in which a significant portion of new gold production lay dormant in bank vaults as insurance against political or fiscal instability, to one in which most new gold is now freely traded as an industrial commodity, responding to normal market forces of supply and demand, has had a negative impact on the price of gold over the last fifteen years. In that time, the gold price has declined from a peak of $850/oz in 1980 to an average price of about $400 through the rest of the l 980's, to a price of -$320/oz today (1997). In large measure, this has been due to the enormous inventory of gold metal that was held by central government banks in vaults around the world, and which has been dumped on the market as soon as the price has started to trend upwards. Even today, after ten years of fairly steady selling by central banks, about 3 0, 000 tons of gold (or -8 years' supply at the present rate of consumption) is still retained in vaults (Murray et al., 1997).The downward pressure on the price of gold has created exciting opportunities for the development and implementation of new technology. Increasing the efficiency of gold recovery from more and more refractory ore bodies, whilst at the same time lowering production costs, have become critical to survival in this industry. These challenges have been met by the development and implementation of new technologies such as heap leaching, carbon in pulp, resin in pulp and the sulphide ore pre-treatment process of pressure leaching, bacterial leaching and fluid bed roasting. For an industry that saw very little technological change in the first seventy years of the twentieth century, the pace of change over the last thirty years must have seemed bewildering at times."

Jan 1, 1998

By D. Seke, E. Katsande, R. Khumalo, K. Seerane

Palabora Mining Company (PMC) processes a multi-component ore body using a circuit consisting of two AG mills in parallel, closed with vibrating double deck screens and hydrocyclones. The bottom screen undersize feeds the hydrocyclones, but the screen oversize products can be treated in a variety of ways. The top deck screen pebbles can be crushed and then combined with the bottom deck oversize and recycled to the AG mill. Alternatively both the top and bottom deck screen oversize can by-pass the recycle crusher and be recycled directly to the mill. A full tap-off is a configuration when both the top and bottom deck screen oversize streams are stockpiled. The other configuration is when the bottom deck screen oversize is recycled to the mill while the top deck screen oversize is stockpiled - termed partial tap-off. This article reports the findings from the surveys performed to evaluate the performance of the PMC auto mill circuit when operated under the four different configurations discussed. Ore characterisation tests were performed to assess the deportment of the key ore components for the different configuration.

Jan 1, 2012

By L. Voisin, K. Mühlenbrock

A new pyrometallurgical process is proposed for cleaning complex copper matte and for recovering copper from copper scrap containing lead. In the process, a given amount of pig iron is added to the complex material under a reducing condition to produce two or three liquid phases at the equilibrium, depending on the content of sulfur in system, of copper-rich and iron-rich alloys, and matte, respectively. The novel process is proposed based on the experimental results obtained by performing laboratory scale tests in an electrical furnace at 1473 K followed by a quenching method on the final stage. The samples obtained from the experiments were analyzed by using Atomic Absorption Spectroscopy (AAS), Inductively Couple Plasma (ICP) and Carbon Infrared Spectrometry (CIS) techniques. The results were discussed on the basis of the distribution of lead as impurity in the miscibility gap where equilibrated phases coexist. According to the mass balance calculations, the elimination of lead into the iron-rich alloy phase as a harmless and smaller deposit might be feasible and the process proposed for cleaning the complex matte would be promising.

Jan 1, 2014

By E. De Souza

Two comprehensive surveys, which focus upon backfill practices and the economics of backfilling in underground mines in Canada, have been conducted. The two surveys were designed to assess operational practices and costs associated with the wide scope of filling operations that must be met by individual mines, ranging from raw material feed to the preparation plant, through underground backfill transportation, to in-stope product placement. This paper presents the current state of backfill usage in Canada, identifies trends in minefill practices and provides mine operators with an updated database of information upon which they might compare their own practices and costs with present trends throughout the industry.

May 1, 2003

By N. Kolev, M. Poibrenski, I. Nishkov

"The following paper examines the flotation of copper porphyry ores in Assarel concentrator with focus on the reasons for low molybdenum recovery in the final copper concentrate. The copper-porphyry ore of the Assarel deposit is characterized by its variable mineral composition and high clay content, which influence the process efficiency of their concentration. Particle size distribution, chemical and mineralogical analyses have been made on various flotation products showing the distribution of the main elements of interest - copper and molybdenum. It was found that molybdenum is not concentrated into the final copper concentrate as usual in the flotation of copper-molybdenum ores but into the tailings of the copper selective flotation (cleaner tailings). An attempt to explain these results has been made with proposals to improve molybdenum flotation. Low floatability of molybdenite is caused by the ultrafine clay minerals content in both the run-of-mine ore and copper flotation streams. In order to achieve selectivity of copper minerals against pyrite a significant amount of lime is used in the plant leading to higher pH conditions, which could be another possible explanation for the molybdenite depression. The results obtained after the laboratory experiments, showed that it is possible to restore molybdenite floatability using traditional reagents such as diesel, kerosene, etc., and introducing a new polymeric reagent as froth modifier.INTRODUCTIONOne of the main technical difficulties in the area of copper-molybdenum flotation is the selective recovery of both metals, especially the fine (<40 micron) mineral particles. The problem is even more serious when Cu-Mo ore treated contains a lot of natural fine particles, predominantly clays, micas and other gangue minerals. Peng and Zhao (2011) conclude that the mineral processing industry is well aware of the difficulty in treating ores in the presence of clay minerals. Tremolada et al (2010) found that clay minerals have been named as the main problem in ore beneficiation processes due to their small size, which cause a higher viscosity in grinding. In flotation, these clay minerals have natural hydrophobicity or float by entrainment.The impact of clay mineralogy on flotation performance has been reviewed in the literature and the various deleterious roles of clay minerals have been investigated (Bulatovic, Wyslouzil & Kant 1999; Jorjani et al, 2011; Farrokhpay, Bradshaw & Dunn, 2013). It is widely accepted that the actual flotation recovery problem appears to be caused by the properties of these fine particles: small mass (and/or momentum) – high interfacial free energy (Rubio et al., 2007; Farrokhpay, 2011). In most cases, the loss in recovery is found to be insignificant, but the detrimental effect on the concentrate grade is found to be more prominent. The main reasons for the flotation inefficiency are the low probability of bubble-particle collision and adhesion, formation of dense froths and as a result - low process kinetics. A great deal of fine valuable minerals is discarded as slime in flotation due to lack of effective recovery methods."

Jan 1, 2016

By Ruan Chi, Zhenyue Zhang, Zhengyan He

In order to understand what governs the leaching of exchangeable rare earth (RE) and impurities and enhance the RE leaching process, the effects of the concentration of ammonium sulfate, pH and leaching temperature on the migration of RE and aluminum (Al) during the leaching of weathered crust elution-deposited rare earth ore was studied. The elution curves for ammonium ion (NH4 +) were also studied to reduce the consumption of the leaching agent. It was found that a high concentration of leaching agent can enhance the leaching process of RE and Al, reduce the breakthrough volume of NH4 + and more rapidly obtain the equilibrium of NH4 +. However, excessive leaching agent can both increase the cost and the burden on the environment. There is almost no variation on the elution curves of RE and Al in the pH range of 4-8 and control of the pH of the leaching agent can be omitted. It is better for the leaching work to be done in summer since higher temperatures can enhance the RE leaching process and improve the use ratio of ammonium. Using 0.1 mol/L ammonium sulfate for leaching 250 g RE ore, 95.42% RE extraction can be obtained when the volume of leachate is 102.6 mL. At this moment, only 18.17% of NH4 + is used to exchange RE and 49.22% of NH4 + is left in the leachate that can be reused as leaching agent by replenishing ammonium sulfate. The results of our studies can provide theoretical guidance for high efficiency and low consumption exploitation of RE ores.

Jan 1, 2016

By R. W. Seedsman

In 1984 and 1985, two 7.6m diameter TBM tunnels were driven from the Donkin-Morien peninsula in Nova Scotia to access the Harbour coal seam. The design of the ground support was based on identifying zones of rock failure through the application of the Hoek Brown failure criterion and the early use of finite element analyses. In 1992, the mining project was abandoned and the tunnels allowed to flood. Monitoring data from the tunnel was subsequently used as a case study in the development of the concepts of brittle rock behaviour. In 2007, the tunnels were pumped out as part of a feasibility study into the reintroduction of longwall mining into the coalfield. There is a good match between observations of the collapse zones in the roof and sides of the tunnel and a simple elastic analysis using brittle parameters, a spalling limit of 5, and a low independent shear modulus. The brittle analyses form the basis of the design for the resupport of the tunnels.

May 1, 2009

By H. Ito, T. Takasu

Effects of a mechnochemical treatment to oxide Ni ores have been investigated to enhance the extractive ratio of Ni from them in acid leaching process. High intensity grinding by a planetary boll mill showed strong effect to enhance the extractive ratio of Ni, for example , 10% of extractive ratio of Ni in sulfuric acid leaching(0.05mo1/1,at room temperature) increased to more than 90% with 60min. of planetary boll milling. Effects of additives(sulfur and some oxidants) on the mechnochemical treatment have also studied. Sulfur showed almost no effect to enhance the total Ni extractive ratio but increases the selectivity of Ni extraction. More than a half of Ni could be extracted by water when Ni ore was grinded at addition of Na2S207 in the milling treatment. Some effects of mechnocemical treatments to Ni ore are summarized in this paper.

Jan 1, 2005

By D. Asefi

A new method to detect microstructural features such as recovery and recrystallization as well as cold rolling reduction in low carbon steels was developed based on magnetic hysteresis loop measurement. To this aim, a hysteresis loop measuring apparatus, specifically designed and assembled for plate samples was employed. It is shown that maximum field (Hmax) of hysteresis loop, measured at constant maximum flux density (Bmax) of 0.5T, is an adequatemagnetic property to monitor different stages of changing microstructures during annealing.

Oct 1, 2011

By Z. Zhang, X. -G. Chen, F. Breton, A. Arici

"The microstructure of Al-10Si-0.3Mg-0.5Mn alloy with 0.27% Zr and 0.19% V addition was quantitatively analysed and compared to the base material. The addition of Zr and V in the AlSi10Mg alloy exhibit a beneficial effect on the Si modification, resulting in the reduction of the size of eutectic Si particles on both as-cast and T6 conditions. The quantitative image analysis results show that the Zr and V addition and T6 treatment can reduce the size of the intermetallic phases. In addition, the presence of Zr and V is favour to the partial dissolution of the intermetallic phases during the T6 treatment. Different heat treatment procedures were tested to optimize treatment parameters. The mechanical properties of the alloys were evaluated using hardness measurements and tensile tests. The results show that the addition of Zr and V can remarkably improve the mechanical properties on as-cast and T6-treated conditions. The correlation between the microstructure and mechanical properties of the alloys is discussed.INTRODUCTION Al-Si-Mg foundry alloys have been widely used in automotive and aerospace industries due to their high strength-to-weight ratio, heat-treatable capability and excellent castability. The alloying elements such as Cu, Mn, Fe are traditionally added into Al-Si-Mg alloys to improve their mechanical properties (Mohamed, Samuel, Samuel & Doty, 2009). In recent years, the attention has been paid to the effect of the transition elements such as Zr, V, Ti, etc, as minor alloying additives, on the properties of aluminum alloys (Elhadari, Patel, Chen, & Kasprzak, 2011; Kasprzak, Amirkhiz & Niewczas, 2014; Shaha, Czerwinski, Kasprzak, Friedman & Chen, 2015; Shaha, Czerwinski, Kasprzak & Chen, 2014; Mahmudi, Sepehrband, Ghasemi & 2006; Meng, Cui, Zhao & Zuo, 2013). Kasprzak et al., (2014) and Shaha et al., (2015) reported that additions of Zr, V, and Ti in Al-Si-Cu-Mg cast alloys can improve the alloy mechanical properties at high temperature by forming stable intermetallics and precipitates on as-cast and heat treatment conditions. On the other hand, the mechanical properties of near-eutectic and eutectic Al–Si cast alloys depend not only on the chemical composition but also, even more importantly, on microstructural features such as the morphology and size of eutectic silicon and intermetallic particles, which are present on both as-cast and heat treatment conditions (Mohamed et al., 2009). However, there is rather limited information on the effect of Zr and V on the microstructure features and mechanical properties of near-eutectic Al-Si-Mg cast alloys."

Jan 1, 2018

By A. Dahi Taleghani, A. Shojaei

Continuum damage mechanics (CDM) of rocks is studied together with their elastic and plastic behaviors to develop simulation tools for hydraulic fracturing jobs in naturally fractured formations. The model is constituted based upon pressure sensitive inelastic deformation of porous rocks and their damage mechanisms in the cases of drained and undrained conditions. The CDM model is formulated within Fracture mechanics framework. The performance of the developed elastoplastic and CDM models are compared with the available test data of a specific shale play. The hydraulic fractures growth in the reservoir scale is then simulated; in which the effect of fluid viscosity, natural fractures characteristics and differential stresses on induced fracture network is studied. The simulation results are compared with the available solutions in the literature. The developed CDM model outperforms the traditional fracture mechanics approaches by removing stress singularities at the fracture tips and simulation of progressive fractures without any essential need for remeshing.

Jan 1, 2015

By S. Orzecki

The KGHM Copper Refinery Plant, Glogów 1, has operated for 35 years and -increased its capacity almost ten times.Cathode quality, expressed in terms of the total impurity content, has undergone a five-fold improvement. The present refining capacity is equivalent to 240,000 metric tonnes of copper cathode, with a total impurity content of 20 ppm, inclusive of 10 ppm Ag. These accomplishments result from combined implementation of current technological progress in electrolytic refining and KGHM&apos;s own solutions applied to the Glogów Refinery. The quality improvement measures feature both lowering actual current density, despite an increase in nominal current density, and diminishing the role of non-ion mechanisms which transfer impurities to cathodes. The paper contains a detailed discussion of these issues and outlines possible measures aimed at further production and quality improvements.

Jan 1, 2007

By D. Ortiz, J. R. Frias, E. D. Mast, J. J. Fañas

Falconbridge Dominicana (Falcondo) has operated an integrated tpy nickel laterite mine and ferro-nickel processing plant since 1972 in the Dominican Republic. The operation includes mining, a processing plant, an oil refinery, and a power plant. Falcondo has improved process efficiency over the years via modernisation and better understanding of the process. The present business environment of high fuel prices and high nickel prices present a challenge and an opportunity to Falcondo&apos;s operation. This paper gives an update of Falcondo&apos;s process, improvements in energy consumption, factors affecting energy consumption and how Falcondo is facing up to the current business environment.

Jan 1, 2005

By P. Au, P. Patnaik, H. Saari, D. Y. Seo, S. Bulmer

Ti-48Al-2Cr-2Nb-xW (where x = 0, 0.5, and 1 at. %) powders were consolidated by hot isostatic pressing (HIP). The consolidated samples were solution heat treated above the a-transus followed by stepped cooling to room temperature. Selected samples were subsequently aged at 950 °C for up to 72 hours. The post-heat treatment microstructure was examined by optical and electron microscopy. It was found that increasing holding time above the a-transus generated a more homogenous microstructure. Utilizing the stepped cooling sequence, especially with a transition temperature of 1270 °C, massively transformed gamma (Ym) was diminished. Aging caused coarsening of the fully lamellar microstructure in the 0%W and 0.5%W samples while almost no coarsening occurred in the 1 % W sample. Precipitates began to form during aging in samples containing W. The precipitates at the lamellar interfaces are fine and have a needle like shape, while precipitates at the lamellar grain boundaries are coarse and circular in shape. The size and number of the precipitates depend on aging time and the level ofW content.

Jan 1, 2006

By William Hawker, James Vaughan, Jeff Chen, Antony van der Ent

"Nickel agromining utilizes hyperaccumulator plants (“metal crops”) to extract nickel from low-grade soils, a process that yields high-grade nickel bio-ore. This feedstock is further processed into a range of nickel products. The bio-ore is relatively free of impurities that complicate the traditional processing of laterite nickel ores. In this paper, current primary nickel processing routes and proposed nickel bio-ore processing options are summarised. A novel pyro-hydrometallurgical route demonstrated at the laboratory scale is described. This process produces a precipitated nickel hydroxide product and takes advantage of the water-soluble basic compounds in the ash to minimise reagent requirements, thereby making it suitable for small-scale implementation in close proximity to the nickel farm. In this process, nickel is precipitated from the leach solution using the basic ash wash liquor. Leaching nickel from ash generated from open air burning requires strong acid and long residence times to obtain high recoveries due to its complex nature and distribution of nickel in multiple phases. This process can be improved by optimising the ashing process with respect to nickel leachability.INTRODUCTIONHyperaccumulator plants have the unique capacity to ‘biopurify’ and concentrate certain trace elements (e.g. nickel) from the soil into their biomass (Reeves 2003; van der Ent et al., 2015). Cultivating these plants as ‘metal crops’ by periodically harvesting and incinerating their biomass generates a high-grade bio-ore (Chaney et al. 1998; Li et al. 2003). This process is called phytomining or ‘agromining’ which is an emerging technology for extracting nickel from sub-economic resources (van der Ent et al., 2015). Potential near-term applications of the technology include implementation on land ahead of processing of the underlying ore-body (Willis 2015), as a mine-site rehabilitation strategy or as an alternative crop for farmers on land that is not suitable for normal food crops. In the longer term, nickel agromining could provide a significant supplement to the nickel supply chain. Critical to the success of agromining is effective bio-ore processing. Due to the unique chemical composition of this feedstock material, existing processes are not very efficient. Our current research efforts aim to develop new process options that overcome limitations of previously trialled routes. In this paper we summarise conventional nickel process routes and proposed new options for producing agromined nickel."

Jan 1, 2016