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By Joram M. Amir, Ernst Niederleithinger, Nikolaus Schneider

"Abstract: Diaphragm walls are used to provide a stable and watertight confinement for the construction of tunnels, underground railway stations, deep basements and other structures requiring deep excavations. Water seepage and soil loss through the joints have occurred on several occasions, causing extensive damage. This may have been due to uncontrolled concrete flow between the joints, unexpected geologic conditions or just poor workmanship.Different ways of quality assurance are applied on construction sites. Most of them rely on recording parameters of the construction equipment and conventional concrete quality control. In the frame of the EUREKA/ZIM project DiWaQ we have looked at several ways to perform non-destructive quality control. Some methods are to be applied after excavation before concreting (phase 1); others after the wall is completed (phase 2).For phase 1 we have used two different principles for checking the shape of the excavation, especially the joint to existing panels. A mechanical device which can be adapted to the excavating equipment was developed; field tested and validated on test and construction sites. It is described in detail in another paper in the same volume. A sonar-based device with a 10 mm resolution has shown good performance in the lab, but is still under development.For phase 2 different temperature sensors have been lowered into access holes to monitor the hydration heat developed during concrete curing. The same tubes can also be used to perform electromagnetic and ultrasonic crosshole measurements across or along joints to detect flaws. Especially the ultrasonic method has shown promising results on validation specimen at the BAM test site at Horstwalde, but limitations as well. Success substantially depended on the joint type, flaw size and distance of the sensors to the joint."

Jan 1, 2014

By A Giblett, K Afewu

This paper uses a case study to demonstrate best practices techniques for predicting the contribution of gravity concentration in a gold recovery process flowsheet. The case study was selected as an example of an ore with a marginal gravity gold content, which makes the value of a gravity circuit difficult to quantify. In this instance the value of leveraging a significant knowledgebase of operating gravity circuit performance to support the decision making process was demonstrated. This case study analysis serves as a useful demonstration of best practice methodologies supporting decisions to include or exclude gravity recovery in a gold recovery process flowsheet.CITATION:Giblett, A and Afewu, K, 2015. Do we need a gravity circuit or not? A case study in applying best practice, in Proceedings MetPlant 2015, pp 288–295 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By D. Nag, J. Fernando

Hazelwood Power Mine is one of the largest open pit brown coal mines in Australia. The removal of overburden is the first step in coal winning operation. The primary aim of construction of overburden dump is to provide an effective stable working surface for stacker. The paper discusses site investigation techniques used to determine dump soil properties, stability analysis method using GALENA and GWEDGEM, results of stability analysis. The paper concludes with recommendation for a safe dumping strategy for level 2 stacker dumping.

Jan 1, 2003

By P. N. Lategan

Mining companies are challenged with increased difficulty in delivering capital projects on schedule and within budget. In 2005, PricewaterhouseCoopers global review of major capital projects in the mining industry only 2.5% of projects could be defined as successful when assessed across the four critical dimensions of scope, cost, schedule and business benefits. Thus 97.5% of major mining capital projects were not successful according to the criteria PricewaterhouseCoopers used. Normally if a project fails on all these criteria it indicates scope creep. Scope creep refers to the change in a project's scope after the project work has started. As a result, the projects drift away from their original design, timeline, and budget, and as a consequence destroy business benefits. The major reasons for scope creep are poor change control and the lack of proper front end loading. Change control and front end loading are based on project processes in the planning and monitoring & control process group of the Project Management Body of Knowledge1 (PMBOK). This paper will focus on key factors to consider during project scheduling/planning with special reference to cost and schedule (using Microsoft Project as a tool although the principal is universal)

Jan 1, 2009

By M. England

Keywords: Bi-directional tests, Osterberg cell, O-cell®, static load tests, Timeset® Static load testing, where loads are applied vertically to the top of the pile and often referred to as 'top down testing', has been used for many years and has become a 'standard' test for the world of foundation engineering. The method, although well developed, cannot be used under certain circumstances, magnitude of load being a particular issue. There is a finite limit to the load capacity that can be applied with either kentledge, the use of reaction piles or anchors, and as the loads increase, the costs escalate dramatically. A novel test method seeks to overcome all the associated problems of large scale and restrictive area "top down testing", utilising static load testing techniques. The method requires the foundation element to be divided into two or more sections and these can be loaded axially as required using a portion of the foundation element as a reaction. This paper presents some recent applications and developments in the use and application of the bi-directional testing technique using the Osterberg Cell or O-cell® and outlines some of the many advantages of the system. Recent bi-directional test loads applied to bored piles have mobilised capacities of 279 MN and with flight auger piles up to 25 MN.

Jan 1, 2006

By K. A. Lewandowski

Agglomeration techniques are widely used by industry to form fine particles into larger masses that are easier to handle and process. One area where agglomeration is potentially useful is in heap leaching operations. With-out agglomeration, fine particles travel through the heap, clogging the spaces between the larger particles and resulting in poor leach solution flow. Poor flow of leach solution will result in long leach rates and/or decreased metal recovery. Agglomeration immobilizes the fine particles and therefore improves heap permeability to fluid flow. Additional additives (binders) are needed to prevent agglomerates from breaking up as leaching solution percolates through the heap. Type II Portland cement and lime are two well-known binders used in gold and silver leaching, but these are limited to alkaline leaching environments. Various other products have been tested as binders, including polymers. This paper summarizes the benefits of agglomeration in heap leaching and the results obtained from the testing of several different agglomeration binders in heap leaching operations.

Jan 1, 2009

By Michael Drozd

"The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application.The unit operations are:a. Absorptionb. Desorption (Stripping)c. Acid Washingd. Reactivatione. Carbon Handling (carbon transportation, sizing, dewatering, etc.)Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. These parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability.Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operations in the United States have undertaken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPLCarbon Link is being used to attempt to fashion industry standards so that a common reference point can be established for activated charcoal usage."

Jan 1, 2008

By I. Mihajlovic

This paper investigates a potential method for arsenic removal from copper concentrates using hypochlorite leaching. The problems concerning pyrometallurgical processing of copper concentrates with high arsenic contents are discussed. A possible solution to the problem by leaching of natural enargite crystals with sodium hypochlorite under alkaline oxidizing conditions, with enargite converted into crystalline CuO and the soluble arsenic forming AsO43-, was experimentally investigated and results are presented. Kinetic parameters were calculated for enargite leaching, using a model-free approach. Advanced isoconversional methods were used to investigate the dependence of activation energy (Ea) on reaction rate (a). Keywords Enargite, copper concentrate, isoconversional method, kinetics, activation energy.

Jan 1, 2011

By C. Nexhip, S. Sun

Critical to understanding and controlling phase mixing and separation in metallurgical processes, is the development of reliable experimental techniques to measure interfacial properties of melt systems. A series of experiments has been carried out to determine the effect of oxygen potential on the surface tension of liquid copper. Using an electromagnetic levitation method, a surface tension-oxygen chemical potential adsorption isotherm was produced for the Cu-O system at T 1400 K. The surface tension results show good agreement with the literature values e.g. within 3 per cent for pure copper. The Belton `ideal' adsorption isotherm was applied, and the following equation derived to best fit the experimental data ? =1251-77.5 1n41+ (2.79x105 . pO1/2)](mN.m Using this equation, the surface tension of copper was calculated/predicted as a function of oxygen potential at 1400 K, and showed excellent agreement with the experimental values. This confirmed that the adsorption behaviour of oxygen in liquid copper is ideal. The saturation coverage of oxygen on the surface of liquid copper was determined to be T0 = 6.65 µmoles.m,-2 corresponding to an area per adsorbed oxygen atom of ao ? 25 Å2. These values agree well with those cited in the literature, and our experimental data cover a very wide range of oxygen potential (10-5 to 10-17 atm). Keywords: levitation melting, surface tension, Cu-O alloys, oxygen potential, adsorption isotherm, surface coverage.

Jan 1, 2004

By M. Fan, M. Mankosa, G. Luttrell

"Column and other non-conventional flotation approaches continue to provide benefits where conventional flotation processes have exhibited limited success. This is particularly evident with respect to flotation of ultrafine and coarse particles. Advancements in air sparging technology have provided the ability to produce finer bubbles than previously possible. The generation of finer bubbles coupled with the froth washing capabilities of a flotation column has demonstrated improvements in ultrafine particle recovery while simultaneously producing a high-grade float product. On the other side of the spectrum, the use of these sparging technologies while applying flotation fundamentals to a fluidized-bed reactor has increased the maximum floatable particle size up to and in excess of 3 mm. Benefits of higher recoveries and reduced reagent consumption have resulted from the use of these technologies. An additional benefit includes a reduction in plant grinding requirements. As such, this paper describes the application of Cavitation-Tube sparger technology and fluidized-bed flotation (HydroFloat). A review of data from industrial and pilot-scale applications is also provided.INTRODUCTIONConventional (mechanical) froth flotation is considered the workhorse of the minerals processing industry. This low-cost process makes it possible to selectively recover minerals by exploiting the difference in surface characteristics (e.g., wettability) of the valuable component and the waste material. Unfortunately, the upper particle size limit for flotation rarely exceeds 0.600 mm, and is typically maintained at less than 0.300 mm for most industrial applications. For many commercial base metal plants, the particle size range for optimum recovery is typically between 0.01 and 0.1 mm (Lynch et al., 1981). This finding is not novel. In fact, the effect of particle size on flotation recovery was studied as early as 1931 by Gaudin et al. who showed that coarse (+0.250 mm) and extremely fine particles (-0.010 mm) are more difficult to recover than particles of an intermediate size. The loss of recovery is due to inherent limitations associated with the flotation process, including bubble-particle adhesion and collision, detachment, buoyancy, and transport."

Jan 1, 2010

By Steven C. Borell

For more than a decade, changes have occurred each year that have improved the regulatory and business climate for mining in Alaska. These changes have taken place during Republican and Democratic governorships as well as when the state House of Representatives and Senate were controlled by either party. During some years, the changes have been relatively minor. In others, including the 2003 legislative session, the changes could only be characterized as massive. These improvements have encouraged exploration. This, in turn, has resulted in some major new discoveries. But Alaska is essentially unexplored and tremendous opportunities remain.

Jan 1, 2004

By H. T. Kennedy, S. M. Avasthi

An equation developed for gaseous hydrocarbon mixtures predicts molal volumes with an average absolute deviation of 0.73 percent when applied to 264 natural gas and condensate systems including 2,043 PVT points. Another equation developed for liquid hydrocarbon mixtures predicts molal volumes with an average absolute deviation of 1.12 percent when applied to 346 crude oil systems including 1,759 PVT points. Both equations require composition of the mixture to be expressed as mole fraction of methane through heptanes-plus, hydrogen sulfide, nitrogen and carbon dioxide, together with the characteristics of the heptanes-plus fraction in addition to the temperature and pressure. The equations cover wide ranges of the variables involved, and their accuracy is considerably better than that of other available methods. The equations were differentiated to allow calculation of the coefficients of isothermal compressibility and isobaric thermal expansion. (In this paper the coefficient of isothermal com-pressibility and the coefficient of isobaric thermal expansion will be expressed as compressibility and thermal expansion coefficient, respectively.) Equations to calculate these quantities are presented. INTRODUCTION Calculations of reservoir performance for petroleum reservoirs require accurate knowledge of the volumetric behavior of hydrocarbon mixtures, both liquid and gaseous. Compressibilities are required in transient fluid flow problems, and thermal expansion coefficients are important in thermal methods of production. An accurate laboratory investigation of the PVT behavior of each reservoir fluid encountered would be costly and time consuming. For this reason various correlations for predicting fluid properties have been developed and recorded in recent literature. Correlations have been presented in the form of graphs, tables and equations. Since an increasing number of studies are being conducted with the aid of electronic computers, recent efforts have been directed toward development of correla-tions suitable for computer programming. Application of computers permits the use of more complex correlations which otherwise are not feasible. Moreover, methods for predicting reservoir performance, particularly those based on the compositional material balance, depend upon the capability of accurately expressing the molal volumes and other fluid properties as functions of pressure, temperature and composition. The coefficient of isothermal compressibility c is defined by

Jan 1, 1969

This publication summarizes, for potential contractors and other interested parties, the research, development, and demonstration contract projects programed by the Bureau of Mines for fiscal year 1982 (October 1, 1980 -September 30, 1981) under its Minerals Health and Safety Technology program. Contingencies may require that a significant port ion of the program be deferred into fiscal year 1983. The objective of these projects is to provide an ordered and sequenced series of advances toward the Bureau's overall goal of providing the systems technology required to create a healthier and safer working environment for the Nation's mining and minerals processing workers.

Jan 1, 1981

By P. A. Witt

"Highland Valley Copper is a conventional truck-shovel mining and flotation concentrator operation located 75 km southwest of Kamloops, British Columbia (Fig. 1).The ore is situated within a porphyry copper deposit and is mined at a rate of 135,000 mt/day from two separate open pits. The nearby mill produces concentrates containing 375 million pounds of copper and 5 million pounds of molybdenum metal yearly. In the Valley pit, head grades are roughly 0.40% Cu at a 0.23% Cu equivalent cut-off. The Valley pit strip ratio currently sits at 0.55:1 with waste quantities made up of separate rock and unconsolidated overburden units. From the mill, concentrates are trucked to nearby Ashcroft and then hauled by rail to ocean port facilities in Vancouver. The mine employs 950 people and is planned to operate until 2009. The operation is a partnership between Teck Cominco (63.9%), BHP Billiton (33.6%), and others (2.5%). Management is shared by the two principal owners and directed by a management committee."

Jan 1, 2005

By R. C. Courtney, D. J. Forrester

Modern advances have led to sweep and multibeam bathymetric surveying techniques that yield three-dimensional images of the sea floor and have also produced high-powered personal computers with which to control the data and analyse the results. At Sydney, in Nova Scotia, the topography of the sea floor over the longwall workings was observed before and after mining with a precision echo-sounder in 1987-89, with sweep bathymetry in 1993 and with multibeam bathymetry in 1994-95. The results of the latter programme produced what was probably the first observation of a complete three-dimensional subsidence trough over a longwall panel 2 500 m x 168 m. The subsidence has been quantified to a sufficient degree of accuracy to allow simple trend analysis, which has shown that the pattern and shape of movements are similar to those found elsewhere but with significantly smaller maximum subsidence. A prediction model has been calibrated

Jun 19, 1905

By Robert M. Matyas, P. E. Sperry, Robert J. Smith, A. A. Mathews

INTRODUCTION The first Dispute Review Board (DRB) was utilized on a tunnel project 20 years ago. Increasingly utilized on a wide range of construction projects, DRB's are becoming the norm on tunnel and underground projects. This paper summarizes the growth in this usage, uses observations and experience to establish that barriers to the utilization of DRB's are more perceived than real and that many arguments against the DRB concept are not valid, and notes some of the salient elements that should be considered in practice to optimize DRB effectiveness. The purpose of the paper is to provide an annotated checklist for current and prospective users. The basic concept, structure, and operation of DRB's are described elsewhere and will not be repeated here (ASCE, 1991). DISPUTE REVIEW BOARD USAGE A compilation of Dispute Review Board usage for tunnel and underground projects to January 1994 indicated use on 63 contracts with a cumulative construction value of $3.8 billion and a total of 60 disputes settled. As of that same date, DRB's were planned for another 63 contracts with an estimated construction value of $4.7 billion. (A listing of these 126 projects is available from the authors.) This success and popularity have spread to other civil projects as well as process and building construction. The increase in DRB usage has been exponential. See Figure 1.

Jan 1, 1995

By Mike Cammack, Logan Huppert, Gustavo Azpilcueta

During the summer of 2015, Unisea Inc. sought proposals for the G1 Dock Replacement Project in Dutch Harbor, Alaska. It would be a one year project and construction was scheduled to begin in the spring of 2016. One aspect of the project was the requirement for a layer of armor stone to protect part of the dock. An estimated 30,500 tonnes (37,670 t) of armor stone were needed for the project. The source of rock was the Unisea Quarry due to its proximity to the project and the quality of the stone meeting all the required technical standards.

Jan 1, 2018

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

By R Harding, T Hunt

For the past 120 years, Portland cement manufacture has been undertaken on the shores of the Whangarei Harbour in northern New Zealand. Through a serendipitous conjunction of geo-chemistry, the argillaceous marl found on Limestone Island in the harbour and Tikorangi Hill provides a perfect mix of the various elements required for strong and durable cement. Golden Bay Cement, and its predecessors, have been the guardians and managers of the use of these minerals. As the demands of the concrete industry have increased, so have the needs of the manufacturing process. Careful mapping of the resource at both Portland and Wilsonville Quarries has been undertaken. This has allowed the Company to change the Quarry operation from a purely volume basis to one of selection and blending of constituent minerals. Within the manufacturing process, change has also been introduced. Analytical techniques, using x-ray fluorescence spectrometry, microscopy and the application of modem data collation, has allowed fine tuning of the process. The Company now produces an increasing diverse range of products for both the domestic New Zealand market and exports to various South Pacific countries. This paper discusses the processing of limestone and æcement rockÆ into cement clinker, an intermediate synthetic mineral ground into cement. It examines control and blending regimes, and some methods used in determining process efficiency. An important technique ærediscoveredÆ has been the application of microscopy to clinker.  Examination of the major silicate minerals enables interpretation of the kiln processing and feedback to process operators. It also enables a prediction of indicated performance when ground into cement. Examples this paper give an insight into the use of minerals from Northland in some of the more important construction projects in modem New Zealand.

Jan 1, 1999

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, Mexico, 150 km (95 miles) southwest of Ciudad Juarez (Fig.1). The ore deposit was discovered in 1979 and was placed in production in 1992. The production rate is about 2.4 kt/d (2650 stpd) from an ore reserve of 8.5 Mt (9.3 million st). Grades currently average about 8% zinc, 0.5% lead, 0.2% copper and 50 g/t (1.46 oz/st) silver. Substantial inflows of water into the underground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark is a joint venture with 90% participation by Minas Penoles, SA de CR of Mexico City and 10% participation by Promociones Industriales Banamex, S A de C V (PIB S A) of Mexico City. Anew company, Minera Bismark, SA de CV was formed to operate the property. Cyprus Minerals was a 40% participant in the joint venture but, in early 1993, sold its share to Minas Penoles. The Bismark Mine is one of the largest new underground mining projects built in Mexico during the last 10 years. It is the country's fifth largest underground metal mine and provides about 1 % of the world's zinc supply at about 50 t/a (55,000 stpy). Bismark is a trackless operation with overall productivities of 7.6 t/manshift (8.4 st/manshift). The 2.4-kt/d (2650-stpd) concentrator started up in March 1992.

Jan 1, 1994