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By Martin J. Pedley

The use of soil nailing has grown steadily in the UK over the last 15 years and it has recently become more popular in the Republic of Ireland. This paper presents three soil nailing temporary works case histories where the technique has been used to support steep excavations in difficult ground conditions. It demonstrates the effectiveness of soil nailing when applied in appropriate conditions. Details of design methods and construction techniques are described and those aspects of soil nailing that will benefit from further study and development are identified.

Jan 1, 2000

By Mike D. J Bonneau, Malcom Jr Ford

Rietspruit Opencast Services was one of the first opencast coal mines to successfully employ cast blasting to aid in the burden removal operation. Initial work on cast blasting began at the mine in 1980 and has developed to a stage where approximately 26% of the total burden material is cast to a point where handling by draglines is no longer required.

Jan 1, 1991

By WU Jian-hui

Keywords: metallic material, precursor synthesis, precipitation, nickel, fibrillar powder The composition and morphology of the precursor of fibrillar nanocrystalline nickel powder prepared by oxalate precipitation are characterized by XRD,IR and SEM analysis, and the effects of temperature, nickel concentration, pH, surfactant and drying process on the morphology and the dispersion of the precursor are investigated. By the experiment results, the fibrillar precursor is a complicated nickel salt. The precursor prepared in the of 60~70°C,0.6~0.8 mol/L nickel ion, pH=8.4~8.6 and with addition of PVP surfactant is well dispersive and in fiber form. The powder dried by azeotropic distillation is dispersive.

Jan 1, 2005

By Jodi Roberts, Curtis Deredin, Jean-Guy Paulin

"Since the establishment of the Six Sigma quality improvement program in 2001, several projects have been successfully carried out in the copper-lead, zinc, copper separation, lead upgrading and bulk flotation circuits in the Brunswick Concentrator.This paper provides an update on the process improvement initiatives that have taken place since 2004 using the Six Sigma methodology:•,The recirculation of warm water to the flotation circuit (to save on energy costs)•,Installation of a heat recovery tower to recuperate the heat lost from the zinc dryers•,Installation of an extra row of cleaner-scavenger cells for the copper-lead circuit for extra capacity, and a new reagent scheme for the copper separation circuit that have increased copper and lead recoveries.INTRODUCTIONThe Brunswick Mine Concentrator (Xstrata Zinc Canada) is located near Bathurst, New Brunswick and is one of the world’s largest lead/zinc mines. Milling of ore commenced in 1964 from the No. 12 orebody, with an expansion in 1966 to accommodate ore from the No. 6 open pit mine. The concentrator utilizes selective flotation to produce zinc, lead, copper, and bulk lead/zinc concentrates. The ore is a complex massive sulphide, consisting of approximately 20% valuable minerals, 60% pyrite and 20% silicates.Figures 1, 2, and 3 illustrate the historical annual average metallurgical performance and process improvements achieved at Brunswick Mine for the zinc, lead and copper concentrate products. The objective is to continuously direct metallurgical performance towards increasing grades and recoveries while minimizing operating costs."

Jan 1, 2008

By Peter Richards, Alexander Lewis-Gray, Mark Davies, Nicholas Katsikaros

"Gekko Systems developed the Gekko Resin Exchange Column (G-REX) in order to optimise the recovery of gold in complex leach-to-electrowinning processes, as an intermediate step using a highly gold-selective resin to isolate contaminant metals. The AuRIX®100 resin produced by Purolite is licensed exclusively to Gekko, with the G-REX column designed specifically for this resin (Lewis-Gray et al, 2015). Operational experience has been gained at the CGT Ballarat Gold Plant in near continuous operation since 2008, treating unclarified concentrate leach solution. The extension of the technology to higher throughputs and more complex chemistry is discussed.Aurix®100 ResinAuRIX®100 resin is a cross-linked polystyrene alkaline resin developed by Henkel (Virnig et al, 1996). The resin beads are off-white in colour, spherical, with a nominal size of 100% +600µm. This resin is highly selective for gold and silver over many metals, by way of extracting precious metal cyanide complexes from leach solutions with a pH less than 11.5. The higher end of the pH scale produces best selectivity according to the order of preference: Au > Ag > Hg > Zn > Ni > Cu > Co > Fe. Purolite produces the resin and Gekko Systems maintains licensing of AuRIX®100 resin for use in its G-REX column as part of its unique suite of gravity gold handling equipment.Significant cost savings over carbon-in-solution (CIS) systems are realised with AURIX®100 resin, of around 4% to 12% in capital savings and 27% to 40% in operating costs (Virnig et al, 2004). Allied to this is that AuRIX®100 resin is not susceptible to fouling, that is, the resin does not load with inorganic salts or organic compounds which would affect the loading and extraction of precious metals. To counter any potential for fouling by inorganic salts, in service a dilute acid wash is carried out periodically on the resin to unblock resin pores."

Jan 1, 2016

By David G. Winter

The first test pile for the carrier pier and south wharf at NAVSTA Puget Sound was driven on December 27, 1989, and the final pile was tested on February 26, 1990. Implementation and modification of the test pile program were done by the owners (WESTDIV and ROICC-Everett), the engineers (ABAM and Hart Crowser), and the contractor and his subcontractor (General Manson Joint Venture and GRL). The site is located as shown on Figure 1. SUMMARY OF THE SOIL CONDITIONS A soil profile along the pier is shown as Figure 2. The soil units can be generalized as follows: ? Upper Silts - Fill, sandy silt, and clayey silt extending from the mudline to an elevation of about -80 feet; ? Intermediate Sand - A medium dense to very dense silty sand unit which is about 30 feet thick near the shore, but thins and disappears offshore; ? Lower Silts - Sandy silts and clayey silts in a medium stiff to stiff condition; ? Deep Sand - A very dense overconsolidated sandy soil encountered at an elevation of about -145 feet.

Jan 1, 1990

By Qingwei Wang

Heavy metal-containing wastewater from hydrometallurgical processes of lead-zinc was treated by biologics in a 200 m3/h industrial scale experiment. The result shows that Zn concentration declined from 50.28 mg/L~240.81 mg/L to 0.21 mg/L~1.98 mg/L, Pb from 1.00 mg/L~13.47 mg/L to 0.083 mg/L~0.71 mg/L, Cu from 0.24 mg/L~2.38 mg/L to 0.059 mg/L~0.40 mg/L, Cd from 2.12 mg/L~23.47 mg/L to 0.011 mg/L~0.071 mg/L and As from 0.50 mg/L~6.00 mg/L to 0.005 mg/L~0.10 mg/L. The concentrations of the above heavy metals in the treated water were lower than that in Integrated Wastewater Discharge Standard (GB8978~1996) in China. Furthermore, the treated wastewater was recycled and reused in smelter plant. Zinc content in hydrolytic sludge reached up to 34.04%, which indicates that this sludge can be used to recover valuable metals.

Jan 1, 2010

By S. F. Fu

The Charkhan Salt Lake area of the Chaidamu Basin in West China is characterized by soft super-saline soils with very high contents of soluble salts. From the engineering point of view, these saline soils are saturated, liquid-plastic and moderately to highly compressible lean silty clay and clayey silt. In the natural state, their allowable bearing capacity is only 60-80 kPa. As to the saturated lean silty clay, liquifaction in case of an earthquake of intensity 7 on the Modified Mercalli scale is considered likely. In order to improve the geotechnicai properties of the saline soils, stone colomn stabilization by means of vibroflotation was performed. As the geotechnicai properties of the soils are closely linked with the amount and composition of the soluble salt content, saline water with chemical content similar to that of the saline soils was used as flush fluid in the course of hole-making and column-forming, with a view to keeping unaltered the amount and composition of the salts in the soils and thereby precluding reduction in or loss of their strength. Systematic monitoring on the behavior of the foundation soils before and after the treatment and comparison of the numerical data thus acquired have shown good technical results, testifying to the effectiveness of stabilization of soft superealine soils by vibroflotation. As a result of the treatment, the allowable bearing capacity was increased one to two fold, accompanied by elimination of the liquefaction potential.

Jan 1, 2010

By James S. Graham

Specifications for treated round wood piling are presented for the engineers consideration. Included in the text are background information, technical committees, Chellis, quality, treatment, static and dynamic stresses, accessories, and existing codes and standards. The specifications are also available using Word Perfect on 3.5 or 5.25 inch size disks provided by the National Timber Piling Council. Note: DFI recommended wording is wood, head, and toe, instead of timber, butt, and tip.

Jan 1, 1992

By Holger Witthaus

There is more than a century of experience in multiple seam mining in Germany. In several mines up to 20 seams had been excavated within the last decades. Due to the nature of the deposit and the history of technical development the older panels cause a complex stress distribution for the lower seams and the current longwalls in descending order of mining. The depth of the longwalls reaches up to 4000 ft. This causes a maximum vertical stress that reaches between 30 and appr. 60 MPa. To handle these conditions several support systems are applied for roadway heading. A central knowledge management system for ground control is used for design and dimensioning of support within the DSK. This paper gives an overview to the nature of German multiple seam mining and the solutions in matters of panel layout and support design. It describes the full lifecycle for roadways in the seam starting with the geological and geotechnical evaluation, the basics of roadway deformation in great depth, the development of planning tools and standards for German coal mines, the range of alternative of support systems and roadheading techniques, as well as the reinforcement measures and the processing of support at the T-junction of the face entry. This paper uses exemplary descriptions that are consolidated in a specialized reference book ?Gebirgsbeherrschung von Flözstrecken? ? ?Ground Control in Roadways? which summarizes the standards of ground control based on the development of the past 25 years in German coal mines.

Jan 1, 2007

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,500 tons of ore per day with an average gold grade of 0.34 opt. The mine has a large horizontal extent of 2,500 feet by 500 feet and a vertical extent of 20 to 200 feet. Based on the characteristics of the ore bodies, a long-hole stope and cut-and-fill mining methods are used at the deposits which are divided into several mining zones. Cemented rock fill (CRF) is used as the backfill in the open stope. CRF design includes the aggregate design, the ratio of cement and fly ash design, and strengths for the long-hole stope and cut-and-fill. In the aggregate design, the particle size distribution is one of the most influential aggregate characteristics in determining how it will perform as a basic backfill material. Gradation helps determine durability, porosity, cement and water requirements, strength, and shrinkage. To cut the backfill cost, fly ash usually is added into the binder to replace some part of cement. However, adding fly ash can affect the strength of the backfill. The reasonable percentage of fly ash is also important for making a good and low cost backfill. Based on the different mining method, the different backfill with different strength is designed. A systematic quality control procedure for aggregate and backfill is followed. After four yeas application, CRF system in Leeville achieved very good results.

Jan 1, 2011

By M. Gous

Keywords: Pyrometallurgy, Namakwa Sands, ilmenite, DC arc furnace, titania slag, pig iron Namakwa Sands is a heavy minerals mining and beneficiation business in the Anglo Base Metals Division, and operates along the West Coast of South Africa. The business encompasses mining, mineral concentration, separation, and smelting operations. The smelting process comprises the carbonaceous reduction of ilmenite to produce titania slag with a TiO2 content of 86%, and iron with a carbon content of 2.5%. The Namakwa Sands smelter, situated near the Saldanha Bay harbour, commenced smelting operations in 1994, when a 25 MW DC arc furnace was commissioned. The smelting operations were expanded in 1999, with the commissioning of a second 35 MW DC arc furnace. Despite the fact that ilmenite smelting poses a technical challenge in terms of the high temperatures required, the physical characteristics of the slag, the constraints placed on the feedstock, and the tight product specifications, Namakwa Sands has continually increased slag production since 1995. High furnace feed-on utilisation and furnace stability, complemented by continuous improvement drives, will be the vehicle to drive performance in the short term, with longer-term performance enhancements due to strategic process development.

Jan 1, 2006

By Antonio Nieto

According to the analysis of surface powered haulage accidents involving off-highway haul trucks in openpit mining, the U.S. Mine Safety and Health Administration (MSHA), reported 1,300 fatal accidents from 1990 to 2005. Of these, 163 were considered off-highway truck haulage accidents, and at least 23 involved collisions of an off-highway truck with a neighboring vehicle or a worker on foot (Nieto and Dagdelen, 2006). In general, an average of 18 nonfatal accidents and three fatal accidents occurred in openpit mining per year when equipment backed over the edge of an embankment, stockpile or dump point (Fessak, et al., 2003). The specific problems that need to be solved can be determined by carefully studying the accidents involving haulage trucks (Marrara, et al., 2004). Solutions to haulage truck safety must consider the human factors affecting each task even when engineering solutions seem most appropriate. In surface haulage, human performance becomes a critical issue because of the unusual demand the vehicle?s places on their human operators: ? Roadways and working areas change frequently in mining operations. ? The sheer mass of mining equipment such as trucks requires control inputs (e.g., braking) far in advance of the desired action. ? Rough roads, loading and unloading impacts can subject the driver to dangerous shocks and vibration. ? Visibility is sharply curtailed by the bulk of the vehicle generating large blind spots. All of the above issues can be attributed partially to the lack of visibility (Pyles et al., 2003). Driver visibility and communications are key issues to reduce mining truck accidents. Analysis of fatalities and injuries involving mining equipment demonstrates the need to develop new intervention and control strategies to mitigate the risks associated with mining equipment operation. Ongoing development of these and other new strategies is required to achieve a reduction of injury in the mining industry

Jan 2, 2010

By W. K. Katoto

The Tailings Leach Plant (TLP) of the Zambia Consolidated Copper Mines Ltd at Nchanga was commissioned in 1974 as the world's first largest successfully operated agitation leach SX-EW plant for copper production. The design, development and operation of the plant soon after commissioning termed as TLP stage II has been described by Holmes et al (1). In the initial phase the plant was designed to treat approximately 25,000 tonnes per day of current flotation tailings from the Nchanga Concentrator operations, and had a design capacity to produce 75,000 tonnes per annum of copper. Further expansion took place in 1986, and TLP stage III was successfully commissioned to treat an additional 20,000 -25,000 tonnes per day of large reserves (over 135m tonnes) of reclaimed tailings stockpiled since the early 1930's in four paddock type tailings dams (T01 to T04). The salient feature of TLP stage III expansion described by S K Mwenechanya et al (2 -3) was the installation of the world's largest Horizontal Belt Filter Plant with 26 filters each of 80 m2 filtration area.

Jan 1, 1996

By S Hapugoda, J R. Manuel, M J. Peterson, A Poliakov, E Donskoi

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Aug 12, 2013

By R. Katzenbach, M. Vogler, U. Adamietz

Abstract The design of deep excavation pits in rock mass is dependent as well on the mechanical properties of the rock mass as for example the orientation and the type of discontinuities like bedding planes, joints and fissures, the length of the discontinuities (persistence), the grade of weathering, the strength of rock mass, and the shear strength in the discontinuities, etc., and also on the respective boundary conditions specific for the project, and here especially the geometrical boundary conditions. The basic mutual influences and interactions between these boundary conditions are explained and exemplary presented at an excavation pit with a depth of 18,5 m, situated at a slope with a surface near groundwater table. Résumé La planification des excavations profondes dépend aussi bien de la qualité mécanique du roc, par exemple la location de la texture de la surface de moindre résistance, le degré de rupture, le degré de décomposition, la dureté du roc et la résistance limitée au cisaillement de la texture de la surface de moindre résistance que des conditions limitées spécifiques pour le projet, ici en particulier des conditions limitées géométriques. Les influences et interactions essentielles et mutuelles entre les conditions limitées isolées seront expliquées et présentées à l’aide d’une excavation 18,5 m de profondeur, située sur une pente où le niveau des eaux souterraines est près de la surface. Kurzfassung Die Planung tiefer Baugruben im Fels hängt sowohl von den mechanischen Eigenschaften des Fels wie z.B. der räumlichen Lage des Trennflächengefüges, dem Durchtrennungsgrad, dem Verwitterungsgrad, der Gesteinsfestigkeit sowie der Scherfestigkeit des Trennflächengefüges als auch von den projektspezifischen Randbedingungen hier insbesondere von den geometrischen Randbedingungen ab. Die wesentlichen gegenseitigen Einflüsse und Interaktionen zwischen den einzelnen Randbedingungen werden aufgezeigt und an einer 18,5 m tiefen Baugrube in Hanglage mit oberflächennahem Grundwasser vorgestellt.

Jan 1, 2003

By Hendri Silaen, Charles Leatemia, Monang Napitupulu, John Kamarea, Arwin Edijanto, Riza Hasan, Avesiena Primadiansyah

The Deep Mill Level Zone (DMLZ) is the fourth panel cave mine in the East Ertsberg Skarn System, (EESS) which lies 500 m below the producing Deep Ore Zone (DOZ) mine and up to 1,700 m below the surface. The interaction between the DMLZ and DOZ is occurring as the DMLZ cave grows vertically toward the DOZ footprint. During this process, a rapid change in the global mine system stress is anticipated. This change is forecasted to drive substantial changes in the magnitude and direction of principal stresses in the DMLZ and DOZ mines at PT Freeport Indonesia. These changes will bring the mine system closer to the ultimate capacity of the excavations and can result in significant impacts to mine stability if not managed. Critical to this management, is understanding cave growth and locations, as well as how these changes will impact stress conditions.

Apr 26, 2022

By Jacob Chacko

The Izmit Bay bridge, a 3-km-long suspension bridge crossing of Izmit Bay, Turkey is planned to be constructed in one of the most seismically active places in the world. The site, which has the potential to experience significant earthquakes associated with the relative motion accommodated on the North Anatolian Fault, is underlain by deep deposits of soft soils, and areas of unstable and liquefiable soils. Characterizing the seismotectonic setting, foundation soil conditions, potential fault locations, as well as other geohazards was a critical component for the project concessionaire to finance the project and obtain meaningful bids for bridge design and construction. Given the Build Operate Transfer (BOT) funding mechanism, executing this work in the least possible time was critical to the concessionaire?s financing scheme. Fugro was retained to provide geotechnical, geological, and seismological evaluations for the project region, and to generate data for contractors to develop reliable designs and bids. The uncertainties in these data made it difficult for the BOT concessionaire to finance the project and tender Bridge design and construction. The investment in an early and comprehensive site characterization program to evaluate and quantify those uncertainties allowed the concessionaire to save schedule, provide a robust bid basis to bridge contractors, and persuade banks to finance what was perceived to be a relatively high risk project.

Jan 1, 2011

By David R. Ziegler

The concept and facts concerning "threshold blast damage" are not considered "general knowledge". Perhaps because of a lack of knowledge, understanding, and experience of blasting effects, property owners and lay-persons may attribute a wide range of common cosmetic conditions to "blasting damage".

Jan 1, 1997

By W. J. Schlitt

The development of forced aeration as an approach to enhancing copper sulfide leaching is traced from its earliest development up to present day operations using this technology. Both large-scale field tests and commercial operations are covered. The historical portion is preceded by an introductory discussion of the role of air (oxygen) in sulfide leaching. Sufficient aeration may be achieved via naturally induced convective airflow. However, cases are identified where this is insufficient, leading to retardation of the sulfide leach rate. For these situations, forced aeration may be beneficial. The historical portion of the paper focuses on the major field tests that have been conducted in Montana, Nevada and Utah, along with commercial operations in the United States, Australia, Chile and Peru. The paper concludes with some general comments about the applicability of forced aeration, which are based on the information developed to-date.

Jan 1, 2006