Search Documents

Project developent proceeds by increasingly detailed studies addressing overall project returns through an analysis of the substance, risks and costs associated with the following elements: ò Reserves ò Mining ò Processing ò Infrastructure ò Environmental Impact ò Product Market Computer-based expertise has a potential to ò Capture perishable expertise, making this available for shared access and so reducing the cost of human experience ò Consolidate know-how for optimising process operations, bringing consistency of judgement and advice to decision- making by making the rules, facts and preferences explicit ò Allow assignment of the basis and authority of decisions, so experts can pass routine expertise down the line, freeing their time to generate more. ò Force a review of expertise when creating the knowledge base.

Jan 1, 1989

By Oscar Concha

El presente texto describe la exploración, geología, controles estructurales, mineralización y los tipos de alteración hidrotermal del yacimiento minero Cuajone, situado al sur de la Cordillera Occidental de los Andes y en el flanco Andino de Moquegua. En 1937, se inicia su exploración a través de una campaña exploratorla de la empresa Cerro de Pasco, donde se determina la zona como un proyecto potencial de cobre porfirítico de baja ley. Posteriormente en 1942, se inicia la primera campaña de perforación diamantina exploratoria y en 1969, se inicia la etapa de construcción y desbroce de material para preparar la mina. De otro lado, se ha desarrollado un modelo de la evolución del yacimiento desde las rocas preminerales del Grupo Toquepala, de las cuales la andesita basáltica fue una gran receptora de la mineralización de cobre originada por la intrusión de un primer pulso de latita porfirítica.

Apr 26, 1999

By A. Farnoud

Thousands of miners, construction workers, and truck drivers are exposed to diesel exhaust particles. Diesel Particulate Matter (DPM) is a probable human carcinogen and stringent occupational and environmental standards have been established or are planned worldwide. Modifications in fuels and diesel engine designs have reduced emissions, but may not be enough to comply with the tightest standards. Post-combustion aftertreatment devices are likely necessary for many engine operators. However, even the most common and well studied aftertreatment devices fail from time to time. The objective of this study was to design, construct, and test an electrostatic aftertreatment device to treat DPM. An electrostatic precipitator (ESP) was designed and constructed to capture DPM from diesel exhaust, and different configurations were tested to optimize its performance. DPM was produced by a 6 kW diesel-powered electric generator and directed to the ESP through a short section of galvanized steel pipe after the muffler. Number and mass removal efficiencies were measured with a condensation particle counter (CPC) and by sampling through a stainless steel cassette and collecting the DPM on Teflon filters. Particle size distributions were measured with and without control using a 6-stage cascade impactor. The experiments were performed with the engine running at idle and also at medium load. The results show that our first generation ESP provides 60 percent mass removal efficiency, and up to 80 percent number removal efficiency. Power consumption was generally low, about 20 to 30 watts, to achieve these levels of performance.

Jan 1, 2009

By E. Chin

The only economically significant mineral exploited in Banglades - during 1981 was natural gas. Nitrogenous fertilizer production was important to the agricultural sector and was totally dependent on the natural gas for fuel and raw material. Domestic cement plants were also fu pled by natural gas. The flat river-delta terrain for most of Bangladesh makes the potential for discovering major mineral deposits poor. No large deposits of metal ores have been found and only in the small hilly southeastern section of the country is there even much chance of finding any. Heavy mineral sand deposits may eventually be exploited along the Chittagong coastline. There is a good potential for crude oil discoveries. The Bangladesh economy has been heavi¬ly subsidized by billions of dollars of foreign aid since the country's inception. A World Bank report recommended total aid needs of over $2.6 billion in fiscal year (FY) 1980-81. It received commitments for barely over one-half that amount.

Jan 1, 1983

By K. Severin, B. Flanigan, P. Marion

“Plutonic-related” gold deposits in Interior and SW Alaska (Tintina Gold Belt) vary significantly in size, grade, vein/deposit morphology, depth of emplacement, distance from causative pluton and metal association. Metal associations such as Au-Bi and Au-As-(Sb-Hg) are a good empirical indicator of depth of emplacement and distance from causative pluton and have been used successfully in exploration. Results from a variety of analytical techniques also suggest a phenomenological cause for these metal associations, e.g. gold and bismuth have linked metallogenesis at high temperatures and thus are best correlated at deposits that are deep and/or close to causative intrusions.

Jan 1, 2000

By D. Scott Scovira, Ruilin Yang

Blast vibration in the highwall from a cast blast in open pit mines or in the hanging walls from a stope blast in underground mines is a common concern. Vibration in such cases is a typical near-field situation where the distance from a blasthole to a point of interest varies significantly compared to the distance between the blast as a whole and the point of interest. Most existing blast vibration models are designed for far-field vibration using a single seed wave to represent all blastholes within a blast and do not simulate wave shape change over the distance.

Jan 1, 2010

Exerting the Advantages of National Key Discipline, Outstanding the Training of Engineering Capability, Cultivating Talent to be with Innovation Ability

Sep 13, 2010

By J. Cayouette

In 1995, Louvicourt mine started one of the first paste backfill operations in Canada. From 500 000 t in 1995, the annual paste backfill tonnage produced reached 800 000 t in 1999. The maximum throughput of the surface plant (including binders) is 3500 tpd with a final density of 75% to 76% solids which gives a slump of 15 cm to 17 cm. Following the start-up of the paste backfill plant, the backfill strength performance levels were well below the pilot plant’s predictions. The introduction of ferrous slag, laboratory tests on various binder ratios with or without additives, and the desliming of the tailings enabled us to optimize the mix and operation costs. Primary and secondary stopes are filled respectively with a paste containing 4.5% and 2% binders in a mixture of 20% cement to 80% ferrous slag. In certain stopes, the binder ratio may vary from 2% to 7%, but always in a ratio of 80/20. Six years after start-up, or 4.5 Mt of paste backfill later, this paper discusses the present operation and the major changes that have occurred over the years to optimize both the operation and the paste fill quality.

Jan 1, 2003

By Stewart A. Silling, Dale S. Preece

The two key results of rock blasting are fragmentation and movement of geomaterials. Movement/flow of the blasted rock is often referred to as heave. Modeling the movement of full scale blasting is now possible with 3D distinct element models and parallel processing.

Jan 1, 2016

By Christophe Thiébaut

Keywords: Pyrochemistry, Salts Treatment, Distillation The pyrochemical purification of metal generates spent salts. When this metal is an actinide such as plutonium, the slags cannot be discarded and are thus disposed in nuclear facility. In order to handle with these slags, the decision has been taken to reduce stored quantities. The development of a pyrochemical treatment is in progress in the CEA Valduc centre. The feed salt, typically composed of various Pu and Am species contained into monovalent or divalent chloride matrix, is first oxidized to convert the actinides into oxides. Then the chlorides are separated from the actinide oxides by vacuum distillation. Temperatures higher than 750°C for monochloride salts mixture NaCl/KCl and higher than 1100°C for divalent CaCl2 base salts, are required to produce an industrial flow of vaporization. Inactive qualification of the process for NaCl/KCl base salt has been carried out with lanthanide surrogates. Then, a pilot equipment, called distillator has been designed and built for production-scale distillation of NaCl/KCl and CaCl2 oxidized plutonium salts. Industrial flows of vaporization have been obtained with this pilot equipment : about 4 g/cm²/h for NaCl/KCl at 800?900°C and 1 Pa, and more than 1,5 g/cm²/h for CaCl2 base salts between 1000?1200°C at 0.1 Pa. The last step, now in progress, is the integration of the distillator into a glove box.

Jan 1, 2005

By Richard S. Dennis

Acid recovery employs ion exchange (I-X) resin as separation media for inorganic acids from dissolved metallic salts by physical adsorption and without the use of chemicals. This technology has been used for years on spent etching and plating liquors to recover acid for reuse in the bath and to reduce waste acid neutralization costs. It is also used for electrolyte treatment to facilitate valuable metal recovery via acidity reduction. TETRA's ccrxr'" I-X contactor has been used successfully for acid separation from its metallic salt counterpart in a simple, continuous operating mode using strong base anion resins. Efficient separation is enhanced by acid reconcentration to nearly its original strength or as high as 14-20%. Continuous treatment also recovers heat to the tankhouse or bath and improves metal quality due to consistent acid quality. Conventional fixed bed ion exchange (I-X) systems are impractical for acid recovery because of complex control design and large resin inventories needed to process very low liquid-to-resin treatment ratios associated with strong acid concentrations.

Jan 1, 1996

By Y. F. Liang

Fe-6.5wt.%Si alloy has excellent soft magnetic properties compared with conventional silicon steel. It is very brittle at room temperature due to appearance of ordered phases, like B2 and DO3. In this paper, we investigate the effect of ordering on cold workability of this alloy. Methods of rapid quenching and hot rolling were utilized. It is found that rapid quenching and proper heat treatment of the hot rolled sheet could decrease the degree of order due to the very high solidification rate and high cooling rate. The rapid quenched sheet and hot rolled sheet after proper heat treatment could be cold rolled without crack. Microstructure, phase ordering, micro hardness, and cold rolling properties were investigated by Optical Microscope, X-ray Diffraction, Micro Hardness Indenter and Four-high Mill.

Jan 1, 2009

By Tatsunori Matsumoto

In order to investigate the variation of the load-displacement relations of piles in a site, vertical load tests were carried out on 25 small diameter steel pipe piles. Out of 25 piles, 15 piles were close-ended pipe piles attached with a blade at the pile toe and 10 piles were open-ended pipe piles. To carry out these load tests in a short period, two types of rapid load test methods, Spring hammer load test and Falling mass load test, were employed. The load tests of all piles were completed in two days with 180 blows in total. In order to estimate a static load-displacement of a pile, non-linear damping method was used. It is shown from the test results that the performance of the pipe piles such as the ultimate pile resistance and the initial pile head stiffness is improved by re-driving.

Jan 1, 2006

Mining men and State officials in their efforts to make mining safer are confronted from time to time with various complicated questions. In recent gears these questions have tended to increase with the use of mechanical appliances. Twenty-five years ago electricity had been used but little in mires; today there is practically no other means of transmitting power employed in American mines, except that in metal mines compressed air is used, chiefly for drilling and for operating small portable hoists. In coal mines there has been a great increase in mechanization, which tends to concentrate the work of production in small areas and to increase the local difficulties of ventilation; also, it has intensified locally the hazard from coal dust as well as firedamp in bituminous and subbituminous mines. The answers to the questions that arise are not always obvious, as is shown by the fact that even able, experienced men differ in their opinions of the best, way to overcome a particular mining hazard. The difficulty of .solving the problems is also demonstrated by the varying provisions in mine-safety rules, both in official regulations and in the rules of those mining companies that are endeavoring to do more than follow the letter of the law. Such differences of opinion as to the best way of meeting a difficult situation are often found within the same mining organization, and, similarly, varying opinions are held by different members of the Bureau of Mines staff.

Jan 1, 1937

Large scale fluid extraction from the Latrobe Group in the Gippsland Basin is occurring as a result of offshore petroleum production and coal mine dewatering in the Latrobe Valley. Groundwater extraction in the Latrobe Valley exceeds recharge and is causing an expanding area of declining hydraulic head in the Latrobe Group, and regional land subsidence which is well documented. Recently the government water sector completed the installation of a network of Latrobe Group monitoring bores in the remainder of the onshore part of the Gippsland Basin. The bores situated along the coastal area show a steady decline in hydraulic head of about 1 m/year which can be attributed mainly to petroleum production.

Jan 1, 1992

By J. D. Miller, C. L. Lin

Appropriate software and hardware necessary to adapt a x-ray CT analyzer for determination of coal washability has recently been developed and sucessfully tested for well characterized samples under laboratory conditions. Evaluation of the CT-based analyzer under simulated on-line conditions is also presented to verify the on-line capabilities of the newly developed x-ray CT analyzer for the control of coarse coal cleaning circuits. The investigation shows that the data obtained from CT washability analyses compare favorably with experimental sink-float data. Further, image frequency was considered to evaluate the CT-Based coal washability analyzer for simulated on-line conditions. Specifically the number of observations (image spacing) needed for accurate sampling and the total time required to perform the calculations for a representative data set were determined.

Jan 1, 2001

By Jan E. Nesset, Antonio DiFeo, James A. Finch, Jose Hernandez-Aguilar, Cesar O. Gomez

"The gas dispersion measurement sensors and methodology developed by the mineral processing group at McGill University have to-date been employed at a number of plants in Canada, Australia, the U.S., South Africa and South America. In some cases the measurements have been directly linked with metallurgical performance while in others the gas dispersion surveys on their own have proved very useful in understanding the behaviour of the flotation cells. In addition to reviewing the current state of the gas dispersion measurement technology, the paper will present a series of case studies from the various plants and will show how this technology brings a remarkable new level of understanding to flotation behaviour. The influence of the bubble size distribution on recovery and grade are emphasized in the paper.INTRODUCTIONBackgroundThe advent of new sensors to characterize gas dispersion parameters in flotation cells is a development that is long overdue. While the chemistry of flotation has been studied since the early 1900’s, it is only now that the significance of bubble size distribution, gas rate and gas holdup can be meaningfully measured in-plant with robust and precise sensors. Early researchers, like T.A. Rickard (1916) recognized the importance of understanding the role of air and bubbles in flotation when he wrote in 1916 “we know that the key to the flotation process is to be found not in the oil, the acid, or the apparatus, but in the bubbles. The man who understands the mystery of a soap bubble has mastered the chief mystery of flotation”. In his 1999 review paper on The Froth Flotation Century D.W. Fuerstenau laments the fact that due to their “inert nature”, bubbles have never received their due attention from researchers who tended to focus on the chemical, physical, surface and colloidal aspects, rather than the physics of the process. It is perhaps fitting that now, 100 years after the inception of industrial flotation practice at Broken Hill, Australia, researchers and industry have turned their attention toward the importance of truly understanding the role of bubbles in flotation."

Jan 1, 2005

By P. D. R. Maltby

"With the narrow vein structure of Nova Scotia gold deposits, selective mining is rarely possible and mill heads will be too low (below 0.10 oz per ton of gold) to support a conventional mill of up to 1000 ton per day capacity at present gold prices. The recent operation of a small 100 t.p.d. mill at Cochrane Hill using fine grinding - leaching - filtration supported this assertion. Milling costs exceeded $25.00/ton of feed mainly due to high capital, labour and maintenance costs.Accordingly, since 1981, efforts have been directed towards the development of a cheap gold extraction process in terms of both capital and operating costs. The main criteria is to produce gold below US $200 per oz including all administration, mining and process stages. This paper describes such a process development for Cochrane Hill. LOCATION AND HISTORY OF THE PROPERTYThe Cochrane Hill property is located about 8 miles North of Sherbrooke, N.S. on highway No. 7. Sherbrooke is about 180 miles east of Halifax. Gold was originally discovered at Cochrane Hill in the 1860's. Early work consisted of trenching. In the 1930's a small shaft was sunk to about 80 feet and some tonnage treated using a stamp mill with gravity concentration of gold.Northumberland Mines Ltd. acquired a 70% interest in the property in 1977. Subsequent drilling indicated a potential zone of gold mineralization with a drill-indicated tonnage of one million tons having a grade of 0.07 ounces per ton of gold (all high assays cut to 1 oz) down to a depth of 300 feet recoverable by open pit mining methods. In broad terms, the goldbearing zone is about 50 feet wide and 800 feet long and dips at about 70°."

Jan 1, 1984

By R. Sullivan, K. Joiner, B. Emery, M. de Vries, F. A. Stober, L. R. Nelson, J. M. A. Geldenhuis

Keywords: Pyrometallurgy, smelting, converting, furnace design, furnace retrofit, high-intensity smelting, copper coolers, plate coolers, waffle coolers, tap-blocks, lower sidewall air-cooling, wall hold-down system, platinum group metals, ferroalloys, ferrochrome, ferrocobalt, ilmenite smelting, ironmaking, operational readiness, operational support The paper describes the development of furnace designs by Hatch in conjunction with the smelting plants in Africa to meet the intense process requirements in certain applications; continued improvement in operating efficiency through increased throughput from existing crucibles; and improvement in campaign life and furnace integrity. The era of Hatch in Africa has seen the doubling of furnace power in retrofit projects using existing crucibles to developing the highest intensity immersed electrode operations in the world. This has resulted in minimized OPEX and CAPEX per unit of production. Through the continued development of its cooling, binding and furnace power supply technologies and working with the experienced and knowledgeable personnel at the smelting facilities in Africa, Hatch has managed to meet the challenges of ever increasing furnace process requirements associated with increased power density and superheats prevalent in the operations. In addition to developing furnace crucible designs, Hatch has also intensified its ?after sales service and support? with the construction, commissioning and start-up technical assistance and operational readiness and operational support for ramp-up to nameplate capacity and beyond. The key areas of furnace risk associated with high superheat molten material tapping has also seen the development of diagnostic systems to mitigate risks and produce early warning signals for the operators.

Jan 1, 2006

By Ronald M. Hays

The Duluth Gabbro Complex in Northeastern Minnesota possibly contains a significant domestic copper resource and the nation's largest nickel resource. Exploration has discovered large low-grade copper-nickel (Cu-Ni) deposits between Hoyt Lakes and the Boundary Waters Canoe Area (BWCA). The mining and processing of Cu-Ni will have environmental, economic, and social impacts. The purpose of this study is to relate major environmental, economic, and social considerations to various aspects of Cu-Ni extraction. An open pit and two underground (block caving and open stoping with backfilling) models were developed to generate information on the impact of Cu-Ni extraction. Important considerations having environmental, economic, and social impacts (luring various aspects of Cu-Ni extraction are identified and defined. These aspects are exploration, development, mining, beneficiating, smelting, transportation, and termination of operations. Considerations are grouped into the general categories of site, industrial, energy, climatic, resource, water, air emission, waste disposal, employee, tax and royalty, transportation, and community considerations. Cu-Ni extraction in Northeastern Minnesota presents major environmental, economic, and social risks. Decisions are required on trade-offs between adverse and beneficial impacts. The approach used in this study assists in assessing environmental, economic, and social impacts. It will aid in the examination of potential and projected short-term and long-term advantages and disadvantages and will aid in the development of Minnesota's Cu-Ni resource for the maximum benefit to society.

Jan 1, 1974