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By Don Phelps, Dean Brox, Peter Procter, Andy Saltis, Tom Morrison, Jeff Pringle

The Greater Vancouver Water District is currently constructing the Seymour-Capilano Water Filtration Project to enhance the quality of drinking water in the Vancouver metropolitan area. The Seymour-Capilano Water Filtration Project comprises the 1,800 million litres per day Seymour-Capilano Filtration Plant, the 1,080million litres per day Capilano Pumping Station, twin tunnels with associated shafts, and the Capilano Energy Recovery Facility. The twin tunnels will convey raw water under pressure from the Capilano Reservoir to the Seymour Filtration Plant and return treated (filtered) water for distribution. The Twin Tunnels component of the project comprises twin, 3.7 m diameter, 7.2 km TBM bored tunnels, the 180 m deep Seymour Shaft as the main launch shaft, and two 4 m diameter, 268 m deep raise bore exit shafts at Capilano. The Twin Tunnels have been planned as predominantly unlined tunnels sited at depth entirely within granitic bedrock and cross under two major buried glacial valleys of breadths in excess of 1500 metres that are filled with glacial sediments to depths up to 200 metres. The maximum overburden along the tunnel alignment is approximately 400 metres. Comprehensive site investigations and studies were completed during the detailed design stage of the project. The construction of the twin tunnels started in the fall of 2004 and is planned to be completed by mid-2008.

Jan 1, 2005

Of late there have been various papers published on this subject by various authorities, in which certain definite factors influencing slime settlement have been brought forward. As the principles set forth by these writers are of great interest, and have, in most cases, been generally accepted, the author will review them in the hope that by discussion some more knowledge may be brought to bear on many points connected with the subject.The definition of slime at the present time is not a standard one, and varies according to different authorities, some defining slime as ore crushed to such a fineness that it will pass through a screen of standard size, say 150 or 200-mesh, in water (1, 2);others as that part of the finely-crushed material which is in the physical condition which causes it to remain in. suspension in water, and possesses pr?perties which render it almost unleachable (3). Authorities seem divided on this point, but of late American writers seem to prefer the former definition. On the contrary, B L Gardiner describes slime as a mixture of small particles of crushed ore of varying sizes which, when mixed with water, tend...

Jan 1, 1912

A new system for granting access to mineral rights is proposed in the recently released White Paper, ?A Minerals and Mining Policy for South Africa?. Official policy states that ?Government?s long-term objective is for all mineral rights to vest in the State for the benefit of and on behalf of all the people of South Africa?. In order to achieve this objective, government is presently investigating the feasibility of imposing a financial or tax-related disincentive to holding mineral rights. The paper aims to present the pros and cons and to examine the alternatives which will cause minimal disruption to the minerals industry in the period during which mineral rights are transferred to the State. South Africa is a country whose economic and political history is embedded in the development of its mineral resources and has inherited a system which cannot simply be wished away. Hasty or radical decisions will compound the problem, rather than provide a lasting and widely acceptable solution. Mineral rights ownership and its impact on access to mineral deposits are discussed. Taxation as a possible economic disincentive is also evaluated. Finally, the value of mineral resource related information as a prerequisite to mineral policy decisions and as an alternative to mineral rights taxation is emphasized.

Jan 1, 1999

By Mark A. Jirsa

The Biwabik Iron Formation is a ~1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern- most extent by ~1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones?each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact. ©2007 Elsevier Inc. All rights reserved. Keywords: Iron-formation; Mining; Fibrous; Mineralogy; Metamorphism.

Jan 1, 2007

By S W. Robertson, A Vercuil, P Craven

Mintek is currently developing a design approach for the heap leaching of low-grade primary copper sulphide material. Since the leaching of chalcopyrite requires elevated temperatures, the generation and management of heat within the heap is crucial. Furthermore, the precipitation of iron needs to be managed to prevent premature blinding of the heap, and acid consumption needs to be limited to contain cost and limit the dissolution of gangue impurities. Standard column tests using jacketed 1-m and/or 6-m columns do not allow accurate prediction of temperature changes and heat generation in an actual heap. Mintek therefore utilizes a computer model to calculate the energy balance and heat generation with time, based on the measured sulphide oxidation rates in the column. The temperature in the column is then adjusted to reflect the computer-predicted temperature in an actual heap. Using this approach, an overall copper extraction of 70% was achieved in 120 days, using 1-metre columns, when treating an ore blend containing 1.36% chalcopyrite, 0.23% chalcocite, 0.07% covellite, 3.8% pyrite and silicate gangue (92%). The chalcopyrite contribution to the total copper content in the feed was 75%. This was followed by 6-m columns using a similar approach, and the column results will be validated on a 23,000 tonne test heap. Key Words: heap; bioleach; chalcopyrite

Jan 1, 2005

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

Sep 3, 2019

By Alvin J. F

Tin in ores containing 0·025 to 1·5 per cent tin can be determined polarographically by the reduction of the chlorostannite ion at the dropping mercury electrode in 2M hydrochloric acid solution containing 15 per cent ammonium chloride. The tin is separated from interfering elements by distillation as the tetrabromide and collected from the distillate by co-precipitation with aluminium hydroxide. The method can detect 0·01 per cent tin in ore.INTRODUCTIONAn iodimetric method, suitable for routine analysis of titrating tin in concentrations down to 1 per cent, has been available for some years (Low, Weinig, and Schoder, 1939).As concentrations fall below 1 per cent tin, there is increasing difficulty in obtaining a distinct end point due to large amounts of iron and silica normally present after fusion of the ore. Since concentrations of tin down to 0·02 per cent are significant in ore dressing products it was necessary to examine methods to determine such low concentrations, and to adapt these to tin ores containing a wide variety of other minerals.EXPERIMENTALDigestion and separationCassiterite, the principal tin mineral, is refractory but readily attacked by a sodium peroxide flux to yield soluble sodium stannate. In a recognized procedure, a sample of ore is mixed with up to 15 g of sodium peroxide in an iron crucible and swirled over the full heat of a Meker burner for 7 min. The fusion is leached with water and acidified.This solution then contains tin, silica, and other soluble...

Jan 1, 1962

By Masaki Kitazume, Yoshiaki Kikuchi

"Abstract Pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The deep mixing method, an in-situ admixture stabilization method, was developed in 1970s in Japan and the European countries, and has been frequently applied to many construction projects for various improvement purposes such as increasing bearing capacity and horizontal resistance, reducing ground settlement, preventing liquefaction and so on. The design methods, execution procedure and quality control and assurance (QC/QA) of the method are standardized or specified in many countries. These standards, specification and/or technical manual have been a remarkable contribution to spread the techniques throughout the world. The QC/QA is one of the major concerns for clients and engineers who have poor or no experience of the technologies. In order to assure the high quality of deep mixing work in the global market, it is necessary to establish the concept of QC/QA and correlate the output of different procedures. Upon the request by the organizing committee of the DFI-EFFC International Conference on Piling & Deep Foundations, the authors conducted survey of the specifications and standards on the piling and deep mixing technologies in Asian countries. In this manuscript, the results of survey are briefly introduced by comparing these specifications and standards.IntroductionThe pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The design method, execution procedure and quality control and assurance of pile foundations are standardized in many countries based on the accumulate research results, laboratory and field experiences. In Japan, steel pipe piles are mainly constructed by hammer driven in port construction. On the other hand, precast pre-stressed concrete piles or cast-in-place piles are mainly used in on land construction. When precast pre-stressed concrete piles are constructed, piles are usually set by inner excavation method because of preventing noise and vibration problems. More than 50 years ago, noise and vibration problems had not been serious problem in Japan, but around 50 years ago, they became serious and now less noise and vibration construction methods are used for pile construction on land in Japan. In Asian countries, though piles used for construction have a lot of variety, precast pre-stressed piles are commonly used. In this report, execution controls of construction methods of steel pipe piles and precast concrete piles are mainly considered."

Jan 1, 2014

"Increasing demand for timely and accurate information about flotation plant performance requires metal accountants to increase the scope and reporting frequency of plant production. This trend has brought in-process inventory estimation at the forefront of metal accounting issues. Such significant in-process inventories can be locked in diverse process equipment (bins, holding tanks, flotation cells, thickeners, pipeline, etc.) or in stockpiles (ore, concentrates, tailings, etc.). Practice has shown that boldly ignoring these in-process inventories or the errors associated with their estimation lead to unreliable metal balances thereby creating confusion in plant production planning and operational performance assessment. To this extent, the characteristics (physical bounds, spatial heterogeneity and residence time) as well as the available measurements (volume, density, humidity, mass, composition, etc.) of each unit/section found in a generic flotation plant are jointly reviewed with respect to the particular metal accounting issues they present. The daily and monthly metal accounting tasks are then reviewed together with possible methods for obtaining reliable inventory estimates including different procedures for end-of month reconciliation.INTRODUCTION Most of the cost reduction initiatives of the mining industry aim at improving capital efficiency and asset utilization. Among the possible paths through which these goals can be achieved are mine-to-metal optimization, real-time plantwide process control (Hodouin, 2011) and knowledge sharing databases (Bascur & Linares, 2006). However, the successful implementation and subsequent monitoring will ineluctably results in an increased demand for timely and accurate information. This more than often requires metal accountants to increase the scope and reporting frequency of plant metal production. A striking example of such scope expansion is the Minas-Rio iron ore project in Brazil (Anglo American, 2013) having a pipeline route of 525 km between the concentrator and the concentrate shipping area. Several other mining companies have also set an increased frequency for their key performance indicators thereby shrinking the metal accounting period from monthly to weekly and daily. Those concurrent trends have brought in-process inventory estimation at the forefront of metal accounting issues. Indeed, as illustrated in Figure 1, improving trading reactivity requires improvements in production planning which strongly impacts the requirements for reliable metallurgical accounting. Furthermore, practice has shown that boldly ignoring significant in-process inventories or the errors associated with their estimation can lead to unreliable metal balances. In other words, since metal balances are the cornerstones of metal accounting, some of the risks associated with important business decisions are linked to errors associated with in-process inventory measurements."

Jan 1, 2014

By Xuejing Xie, Tianxiang Ren

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). Standardised stream-sediment sampling procedures have been used in mountainous and hilly terrains. Special sampling procedures were developed for application in remote environments, such as high mountains, desert, semi-desert, karst and loess-covered regions. The diversified analytical methods used in more than 20 analytical laboratories participating in the project have been unified into two multi-element, multi-method analytical systems. A unified data monitoring procedure was developed based on primary and secondary standard samples. To date the project has covered about 4 000 000 km2 and the aim is to complete the coverage within the present decade

May 1, 1991

By C E. Davies

At present the source of virgin iron for steel produced in New Zealand is titanomagnetite extracted from titaniferous beachsands. Some of these beachsand deposits contain extractable quantities of ilmenite as well as titanomagnetite and both minerals represent challenging sources of vanadium and titanium products in addition to iron. This study looks at some theoretical aspects of smelting these ores directly with coal rather than with electric power, and takes into consideration the properties of the raw materials, the thermodynamics of possible process routes and the background of the economics involved.

Jan 1, 1980

By D. M. Wagner, G. Biggs, M. Osmundson, C. J. Twaroski

Potential air emission impacts to federal Class I areas from distant sources are receiving increasing scrutiny by federal land managers (FLMs). This paper provides summary results of the impact analyses conducted for FLMs and PSD permitting of a proposed expansion for a taconite processing facility. Results from air quality increment, acid deposition, mercury deposition, and visibility analyses for Class I areas located 50 to 162 km from the facility showed the project would meet the respective regulatory and guideline values for the specific analyses. During the course of the air quality analyses, potential new requirements from the FLMs’ Air Quality Related Values Workgroup (FLAG) efforts and USEPA’s Regional Haze Program were brought into the PSD discussions. The implications for these future guidelines and regulations as they may affect future expansions at other mineral processing facilities are also discussed.

Jan 1, 2001

By Richard Stayner

Suspended seats perform two functions: Reduce effect of occasional large bumps; Reduce more continuous vibration at a lower level. The former needs high damping. The latter needs low damping. For most mobile work machines the inevitable compromise is generally better than a simple cushion seat, because that amplifies vibration at around 4 Hz which is a sensitive frequency for human vertical WBV. Why have standard tests for seat suspensions? • Seat suspensions are non-linear so any measure of performance depends on operating conditions. For comparison these need to be defined. • Seat manufacturers need benchmarks for product development; • Machine makers choose dynamic characteristics appropriate to their products; • Occupational health specialists wish to control operator exposure to Standard tests should be representative, repeatable and reproducible. These requirements are reviewed in relation to the history of seat test standards and the current position. Current position and history The current position is that we have standard tests for seats for agricultural tractors, earthmoving machinery, industrial (fork-lift) trucks. These tests comprise measurement of vibration transmission and of the rate of damping. Current standards developed as the technology developed, starting around 1960: 1. Test on machine driven over standard surface1. 2. Test on shaker reproducing standard surface. 3. Shaker input replaced by representative spectrum2. 4. Human subject replaced by dynamic dummy. (Not yet settled). Are standard tests representative? The development process has gradually moved seat tests further from reality. 4 hr samples of work exposure suggest that seats do not on average provide large reductions of vertical WBV3. For specific magnitudes of vibration they can work well. For low vibration, performance is reduced by friction and for severe vibration by length of travel. Recent work has led to a new test to quantify how a suspension controls over-travel 9.

Jan 6, 2006

By Orlando Gallardo

El presente texto describe la implementación del software ADS (Sistema de Despliegue Activo) a los sistemas de control supervisor de los diferentes procesos del complejo metalúrgico a nivel administrativo -en tanto replica los archivos gráficos y de base de datos. Este servidor además de concentrar en su red de campo redundante data de controladores e instrumentos de campo, puede compartir información con clientes usuarios y clientes de visualización dentro de la planta. En ese sentido, el objetivo es simplificar la producción y uso de datos únicos y garantizar la fiabilidad de estos a tiempo real para todos los niveles de supervisión a nivel administrativo, al tiempo que se planea y optimiza los recursos con la toma de decisiones apropiada.

Sep 24, 2008

Effective gas management in coal mines, as well as proper ventilation design, is very important for maintaining the safety of underground coal miners. Advances in numerical modeling techniques have enabled evaluations of the coal mining environment using advanced grid designs and computed gas distributions through detailed mathematical models. These models help engineers to see the unseen areas of the mine through visualization of the data and ultimately help improve worker safety. This paper summarizes the modeling efforts conducted by NIOSH in the U.S. and CSIRO in Australia to address various gas management issues encountered in longwall mines. The modeling studies involved two of the most widely used grid-based techniques, namely computational fluid dynamics (CFD) and numerical reservoir modeling. This paper discusses the application of these techniques for gob inertization and gas control for spontaneous combustion, pre-mining degasification of coalbeds, gob gas venthole design and performance evaluation in longwalls, and gas management during development mining.

Jan 1, 2009

By R. Raghavaraju

Estimation of the dynamic stress field in terms of its amplitude and decay around a blast hole is a key input parameter in all numerical modeling and blast prediction exercises. However, there is very limited information available in literature on these critical parameters, which would be considered essential in any blast modeling exercise. A laboratory-scale experimental study has been carried out in two different rock types to study at very close range the stress wave decay from a blast hole at distances ranging from 3 to 10 borehole radii. The single–hole blasting experiments employed a centrally located detonating cord (5.3 g/m) in 6 mm(1/4 inch) and 10 mm (3/8 inch) boreholes. The coupling medium employed was air and water, in addition to using a thin-walled copper tube in intimate contact with borehole wall to prevent of penetration of explosion gases into the emerging cracks. The paper describes the nature (amplitude and decay) of the transmitted shock pressure and their evolution in the two rock types for these various experimental conditions, which are present to varying degrees in all blasting operations.

Jan 1, 2014

By Cadia Geology Team

The Cadia Hill Gold Mine, located near Orange in Central Western New South Wales, is owned and operated by Cadia Holdings Pty Ltd, a wholly owned subsidiary of Newcrest Mining Limited. Construction including pre-strip mining occurred from 1996 to 1998. The mine was officially opened in October 1998 following commissioning of the concentrator and mine fleet in June of that year. The Cadia Hill orebody is a porphyry related gold and copper system. The final pit has a strip ratio of approximately 1.3:1.0. Mining is undertaken on 15 metre benches using large capacity diesel hydraulic face shovels at an annualised rate of up to 70 Mtpa. The concentrator is currently rated at 17Mtpa and includes the worldÆs largest single line grinding circuit. The feasibility Mineral Resource was estimated at 352 Mt at 0.63 g/t Au and 0.17 per cent Cu. Initial reserves totalled 200 Mt at 0.74 g/t Au and 0.17 per cent Cu yielding a mine life of approximately 12 years. During the pre-production period mine geology systems were developed to support the operation. By design these systems were intended to add value to the business through minimisation of material miss-classification, provision of accurate and timely production information and mapping and reconciliation as a continuous model improvement tool. Variances that would prove to be material to the life of mine plan were recognised during the first year of production. These included identification of additional ore tonnes, higher copper grades and higher gold recoveries relative to the model. Gold grades and copper recoveries also reconciled favourably. Testwork was undertaken to determine the underlying causes of each variance. Re-modelling was then undertaken to capitalise on those variances. The Cadia Hill Gold Mine life of mine plan was re-evaluated with updated geology, grade, geotechnical, metallurgical and environmental inputs. Operating strategies were also reviewed and revised. Despite application of reduced metal prices in the evaluation, the outcome was one of extended mine life with more metal produced at lower cost. Development of robust mine geology systems, including a pro-active reconciliation process contributed to tangible improvement of the Cadia Hill Gold Mine operation. On-going system development and improvement initiatives are planned to add further value for the future.

Jan 1, 2000

Milling circuits are known to be difficult to control. In order to address these difficulties, it was decided to develop and test a model predictive controller (MPC) for a milling circuit. A milling simulator was written using Microsoft Visual C++ and used to design and test the MPC controller. Due to the large number of tuning parameters in a controller of this type, an optimizing algorithm was written that automatically tunes the controller. Good, robust control was obtained when the controller was tuned using this algorithm. Control was further improved by combining feedback and feed forward control and by using quadratic programming in the MPC algorithm. The movement of the manipulated variables was reduced by using a novel technique that allows the controlled variable to vary within a specified region around the set point. An optimiser controller was also successfully implemented to control the circuit at its maximum throughput.

Jan 1, 2000