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By Andreas Oberrauner

Content ? What is? an introduction ? Crushing technology ? Conveying in pits ? Pit-exiting strategies ? Mine Planning in IPCC ? Summary/Conclusions EHS slide ? Sandvik?s objective is zero harm to our people, the environment we work in, our customers and our suppliers ? Current EHS-figures will be added in August! Who is this? Andreas Oberrauner ? Born in Austria ? Living in Cologne (Ger) ? Mining Engineer ? Montanuniversitaet Leoben (Austria) 2000-2005 ? PhD on Mineral Processing 2008-2012 ? Sandvik Mine Planning Department ? Main task: Provide practical and efficient solutions for mining-challenges

Aug 1, 2013

By David Morley

This paper considers the ideal truck-excavator combination, defined as the combination resulting in the lowest direct unit cost, in consideration of multiple haul scenarios characterized by different haul distances, material and equipment availability. Through the application of Monte Carlo simulation, selected for its unique ability to handle the uncertainty of activity durations, the ?four to six passes? loading rule is shown to not correlate with the selection of the minimum cost fleet. Additionally, through the results of the simulation it is determined that the haul truck capacity has a greater effect on the overall efficiency of the system than does the excavator capacity. As a result, in order to arrive at efficient operations, the entire earthmoving system must be viewed as whole, namely, considering haulers together with excavators, as opposed to the popular method of first selecting a loading unit and then selecting a hauler obeying the ?four to six passes? loading rule. Furthermore, truck utilization and excavator utilization exhibit an inverse relationship and neither directly correlates with the overall efficiency of the earthmoving operation. The following conclusions are drawn: first, with limited financial resources, it is more valuable to increase hauling unit size before increasing loading unit size and second, predefined rules or generalizations, not based on evidence, potentially eliminate optimal truck excavator combinations from being considered.

Aug 1, 2013

By C. D. Shackelford, J. F. Muñoz, M. Vauclin, P. Rengifo, A. Suazo

The results of a field-scale study involving in situ leaching of copper ore tailings using sulphuric acid as the leaching agent, injection wells to introduce the leaching solution and extraction wells to recover the copper-enriched pregnant leaching solution are presented. The study was performed at an abandoned tailings disposal site using a battery of injection and extraction wells. The medium was characterized through the determinations of physical, chemical, mineralogical, and hydro-dispersive properties based on laboratory and field tests, including a tritium tracer test, a pumping test, particle size analyses, and hydraulic conductivity tests. Numerous horizontal strata with different hydraulic conductivities were identified. A previously developed model was used to simulate the leaching of copper ore tailings. Although the study confirms the feasibility of using in situ leaching for recovery of residual copper from tailings deposits, the efficiency of the technology depends significantly on the medium stratigraphy and hydraulic conductivity.

Jan 1, 2001

By Jeffrey L. Pagnutti

Train derailment can lead to loss of capital, damage to the environment, and loss of life. Machinery condition monitoring techniques can be used to develop a structural health monitoring system for railway track to detect faults at the incipient stage, before catastrophic failure occurs. This study uses vibration measurements from a novel material haulage unit to develop a decision support system for railway track maintenance. A variety of feature sets and classifiers were compared to determine the optimal configuration for fault detection. The results highlight the shortcomings and advantages of certain methods and describe the process in which the optimal result was obtained. The Parzen data descriptor paired with a refined statistical feature set performed the task of fault detection with less than five percent false positive and false negative classification error. Overall, the outcome of these experiments indicated that condition monitoring of railway systems is a promising approach for fault detection and has the potential to avoid catastrophic failure.

May 1, 2013

By Anna M. Ferrero

Stability condition of underground excavations have to be assessed to guarantee safe operations within the quarrying working areas. This objective requires a reliable assessment of the rock mass natural state of stress and of the stress redistribution induced by the excavations. This goal is often complicated by difficult geological conditions induced by tectonic stresses, complex topographies and large and irregular excavation geometries. Consequently, the acting state of stress needs to be measured by specific in situ measurement devices. This work refers on an in situ measurements campaign carried out by CSIRO tests in an underground quarry located in the Carrara marble basin. The difficult path carried out for interpretation of the measurements is described in this paper. In particular, the numerical modeling performed using the Boundary Element Method (BEM) first, to study the influence of both surface topography and excavation geometry and then the Distinct Element Method (DEM) to evaluate the influence of rock discontinuities in the measurement zone are illustrated in this work. Parametrical analysis of the rock mass mechanical features is also described in order to calibrate the numerical models and analyze the experimental results. The work has been carried out trough several phases, which are: characterization of the rock mass through geostructural surveys: this allowed us to classify the rock mass and determine the mechanical and physical parameters necessary for modeling; on-site measurement of stress levels through the application of over coring techniques; numerical analyses for the simulation of excavation phases, using the Examine3D (BEM) engineering analysis code. comparison between the measured stress levels and those numerically calculated and subsequent calibration of the BEM model; Numerical model of the forecasted excavation based on the calibrated (BEM) model.

May 1, 2009

By M. R. MacIver, M. P. Pawlik

"An image analysis method based on chord length distributions is applied to the batch settling of polyacrylamide flocculated kaolin suspensions. Two features of the interaggregate void space, the void chord length distribution mean and the white-to-black distribution ratio are extracted from an image series obtained over the two hour settling experiments. This approach produces three signal values, from two different probability distributions that can be measured as an indication of underlying sediment bed density and aggregation state. Further work is required on the physical interpretation of the signal, the image acquisition conditions, and the parameter selection methods. It is suggested that this chord length based feature extraction technique may be a useful signal to monitor during batch settling or thickening.INTRODUCTIONFew in situ techniques are available that can be used to directly measure aggregate properties within sediment beds in thickeners or secondary settlers. Typical process variables monitored include rake torque and height, bed level and pressure, feed rate and density, underflow rate and density, settling rate, and overflow turbidity; yet these process variables are only weakly related to process dynamics (Concha et al. 2014). Additional process monitoring signals, based on the direct measurement of aggregate properties could improve solid-liquid separation control and allow the extraction of more detailed information from batch settling experiments.Several optical methods exist for measurement of moving suspensions of aggregated solids in the dilute concentration regime, such as focused beam reflectance measurement (Peng and Williams 1994), and the turbidity fluctuation method (Gregory 1985). In the more concentrated region of a thickener, acoustic backscatter penetration and attenuation measured with an acoustic probe and changes in the underlying solid concentration in the highly concentrated, near-bed region of a thickener as a function of height and time (Hunter et al. 2012). While machine vision for froth monitoring has been thoroughly studied with at least five commercialized technologies (Aldrich et al. 2010), its’ application to the study of thickening has been limited."

Jan 1, 2016

By Lee Barbour

Waste-rock piles from metal mining operations are comprised of large surface deposits of unsaturated, coarse-grained soil and rock. The unsaturated condition and heterogeneous, coarsegrained nature of these deposits make them difficult to monitor or characterize. Key parameters that must be evaluated include; volume-mass relationships (e.g. water content, air content, porosity, density, degree of saturation, grain-size), transport properties (e.g. air-permeability, gas diffusion, hydraulic conductivity), geochemistry (e.g. solids, gas, and fluid phases) and soilatmospheric fluxes (water and gas). This paper describes some of the techniques that have been developed to characterize waste rock piles for uranium mines in Northern Saskatchewan. For each technique, the method of measurement is described, and preliminary field data are presented and discussed.

Nov 1, 2002

By M. W. Grabinsky

Better in situ performance data is required in order to advance the rational geomechanical design of cemented paste backfill systems. A few in situ test programs have been conducted, but these have suffered from too few measurement locations within the stope and have not used enough different types of transducers to fully capture the information of significance. In this paper the important geomechanical design aspects are listed, the underlying physical phenomena are described, and some previous in situ measurement efforts are reviewed. A new approach to in situ measurement campaigns is then described including measurement techniques, locations, and the logistical aspects of mobilizing transducers in an active mining environment. A work-in-progress is used to illustrate the principles and concepts involved.

May 1, 2007

By M. W. Grabinsky, B. D. Thompson

ABSTRACT: Use of cemented paste backfill (CPB) offers economic and environmental advantages over other backfill methods. However, many operations have limited knowledge of how their CPB behaves in situ. Therefore, to avoid over-pressuring containment barricades, backfilling strategies necessarily tend to be conservative. In situ monitoring at Barrick Gold Corporation’s Williams Mine and Inmet Mining Corporation’s Cayeli Mine has been conducted and factors controlling barricade pressures are demonstrated, including rise rates, binder content, stope geometry, and tailings properties. The application of barricade pressure monitoring on a stope-by-stope basis can increase backfilling efficiency and, thus, reduce stope cycle times, while maintaining optimal safety.

Jan 1, 2011

By C. Gravel, A. Fathi, P. Rivard, G. Ballivy, Z. Moradian, M. Quirion

Numerous schemes have been proposed in the past to evaluate the shear strength of rock discontinuities based on in situ and laboratory testing. Due to scale effects, in situ testing is the most reliable way to assess the shear strength parameters. However, practical reasons often impede this kind of testing. This is unfortunate because advances in theoretical rock mechanics are still dependant on qualitative experimental works. This paper presents a mobile high capacity shear apparatus developed for in situ direct shear testing of discontinuities along with testing methodology. The apparatus has the advantage of being simple, although of high capacity, and can be moved to different site locations for other tests. The in situ test was performed on a natural rock outcrop of schist with subvertical schistosity. A concrete block 50 x 50 cm with a base layer of high strength mortar was cast on the rock surface. Prior to the test, the concrete block was lifted and repositioned to have an unbonded joint but with interlocking asperities. The shear load was applied perpendicularly to the schistosity direction. The test was conducted in a constant normal load (CNL) condition. Both normal and shear loads were applied manually. The instrumentation consisted of two load cells for shear and normal loading, eight displacement laser extensometers for shear, normal, and lateral displacements and fourteen acoustic emission sensors for monitoring evolution of asperities’ degradation during the test. The friction angle obtained is 72° for the peak and 58° for the residual. The high values of friction angle indicates that first-order roughness and good interlocking of the joint surfaces can result in high shear strength parameter values in a rock generally regarded to have low values.

Jan 1, 2015

By Weiren Lin

The Mw 9.0 Tohoku-Oki, Japan earthquake occurred on 11 March 2011 produced a maximum coseismic slip of >50 m near the Japan Trench. To investigate why the plate boundary fault between the subducting Pacific Plate and overriding North American Plate which caused the earthquake had such unprecedented large coseismic displacement and slipped to the trench, Integrated Ocean Drilling Program Expedition 343 called Japan Trench Fast Drilling Project (JFAST) drilled three boreholes at Site C0019 through the earthquake fault about one year after the earthquake. Borehole C0019B dedicated to loggingwhile- drilling (LWD) penetrated ~850 meters below seafloor (mbsf) at a water depth of approximately 6890 m. The plate boundary fault is located at ~820 mbsf in the borehole and has been identified as the slip zone during the Tohoku-Oki earthquake. Borehole wall resistivity images obtained from LWD show that drilling induced borehole breakouts are available in a wide depth range above the fault but are not available below the fault. Breakouts are reliable indicators of the orientations of current maximum and minimum horizontal stresses and can also be used to constrain the horizontal maximum and minimum stress magnitudes. As results of breakout analyses, the maximum horizontal stress orientation highly varied in the upper part of the borehole, but has a clear preferred orientation in a northwest – southeast direction in the deeper part just above the fault. This orientation is approximately parallel to the direction of the Pacific Plate subduction. Stress magnitude constraints indicate that the post-earthquake stress states in the hanging wall are either in or close to the normal faulting stress regime. By inferring the pre-earthquake stress state and comparing with the constrained post-earthquake stress state, a significant coseismic stress change was interpreted. The stress change suggests an active slip of the frontal plate-interface consistent with coseismic fault weakening and a nearly total stress drop.

Jan 1, 2015

By K. U. Kainer, A. Stark, D. Tolnai, M. Hehenberger, C. L. Mendis, N. Schell, N. Hort

Samples of an as extruded Mg-6Zn-0.6Zr-0.4Ag-0.2-Ca (wt.%) alloy was compressed at room temperature and at 250°C. The in situ deformation tests were performed at the P07 (HEMS) beamline of PETRA III, DESY, with a modified DIL 805 A/D dilatometer with to Kapton windows on the sides and the induction coil opened for the beam to transmit the sample. The deformation rate was 10-3 s-1 the samples were deformed to failure. The diffraction patterns were recorded every 3 s with a Perkin Elmer 1621 Flat Panel Detector. The results reveal that different deformation mechanisms are activated during compression at a given strain value. At room temperature twinning is the dominant deformation mechanism, while at elevated temperature dynamic recrystallization occurs while the contribution of twinning to deformation is significantly reduced. The compressed samples were further investigated with conventional metallography and SEM-EBSD to determine the volume fraction, the type of twinning and the strain retained within the grains. The parallel testing of pure Mg samples under the same conditions allows comparison of the compression behaviour of the ZKQX alloy with Mg.

Jan 1, 2014

By Malcolm Scoble, Jean-Marc Robert, Luciano Piciacchia

"An approach to the in situ testing of mine backfills is outlined. It has been developed to provide a measure of the effective strength and stiffness of such materials after placement in stopes. This paper is based upon recent field studies undertaken at five Quebec mines. Details of the selected instrumentation, supporting equipment and testing procedures are reviewed. The mechanical behaviour of the backfills is reported and related to their physical properties. This approach represents an economical, simple and reliable means to assess the mechanical characteristics of backfill materials as an aid to both mine design and placement quality control. IntroductionDevelopments in backfill and mining method technology are creating a pressing need to develop effective techniques for characterizing the physical and mechanical properties of backfill in situ, rather than relying on traditional laboratory testing. The development of bulk mining methods is creating the requirement to more fully understand the nature of exposed fill faces to design for stability in pillar recovery operations. Other backfill technological developments currently receiving widespread attention are high density placement and the use of alternative additives to Portland cement. In Canada, U.S.A. and South Africa attention is also being placed on employing backfill to alleviate rockburst hazards(1,2.3l. In situ testing offers the potential to measure the geomechanical properties of backfill once placed in stopes , in order to assess its actual role in pillar recovery and ground support. Similarly, it offers the ability to provide some quality control during backfill placement. This role is seen as becoming increasingly important with the growing recognition of the need to pay greater attention to the mode of placement, which governs segregation and variation in the properties actually achieved by the backfill after placement."

Jan 1, 1987

By Joseph Hirschi, Behrooz Abbasi, Harrold Gurley, Yoginder P. Chugh

"The research goal was to assess if analytical tool/s can be developed to quantify displacements around a geological fault as longwall face moves toward it and past it. A company was faced with crossing a 2-3 m (6-10 ft.) normal up-thrown fault in the development entries and the face while mining a 375 m (1,200 ft.) wide longwall face. A field monitoring and numerical modeling study was performed to develop data. Field measurements consisted of roof-to-floor convergence and rectangular rosettes in the immediate roof. Numerical modeling consisted of constructing a 3-D structural model using the FLAC3D software with the fault plane incorporated as ubiquitous joint. Based on analyses and field observations data, the coal company was informed of impending movements along the fault plane and likely impacts on the development entries. Additional stiff supports were installed in head gate entries around the stage loader and equipment about 60 m (200 ft.) outby of the longwall face (solid). As the longwall face approached the fault, predicted displacements were documented and manifested by severe loading on the installed supports.BACKGROUND AND STUDY OVERVIEWThis paper summarizes results of a cooperative study aimed at improving longwall mining operations in Illinois. More specifically, the study focused on: 1) In-mine measurements in development entries while mining ahead of and behind a faulted zone, 2) Making observations on stability of pillars and entries while mining through the fault, and 3) Developing simplified analytical structural models using FLAC3D to assess if predictive techniques can be developed to plan mining operations through fault zone. Available data on geometry of the fault with estimates of the cohesion and frictional parameters were used for modeling."

Jan 1, 2015

By G. C. Weatherly, L Beitelman, M Gray, M. W. Bates, R Hadden

"A program of evaluation of in-mould electromagnetic stirring on the product of a straight-mould, billet continuous casting machine has been carried out. The effects on macrostructure, surface and internal quality, chemistry segregation and mechanical properties on carbon, low-alloy and resulphurized, free-machining steel billets and rolled bars are discussed. Operational aspects as a result of in-mould stirring are highlightedIntroductionA development program on electromagnetic stirring (EMS) in the mould of a continuous caster was started by Ferrco Engineering Limited in 1979, with the first experimental device being developed and installed at Lake Ontario Steel Company. As a result of these initial trials, new designs of in-mould EMS systems have been developed and are currently being used in continuous casters in North America and Europe. The rapid progress which has been made is in large measure due to the fruitful cooperation which has existed between the various parties, including Ferrco, the EMS equipment manufacturer, several operating plants and the University of Toronto.A brief review of some of the basic ' principles of electromagnetic stirring action on solidifying metal, and the landmarks of this process development, will explain the philosophy of this cooperation.From casting practice, it is well known that an equiaxed dendritic structure provides better' material properties than a columnar dendritic structure. Homogeneity of the equiaxed structure leads to better control of material properties, such as strength and ductility. Therefore, many efforts are being made to obtain this structure in continuous casting.The extent of the equiaxed zone is determined to a large degree by convective flow in the liquid. Fluid flow can fragment dendrites in the columnar zone, which then act as nuclei for grains in the equiaxed zone farther down the sump. This process is referred to as dendrite or grain multiplication."

Jan 1, 1982

By R. D. Clark, Heinz Althoff

"The advantages and disadvantages of a mobile crushing plant with a belt conveyor system compared to a stationary crushing plant with haulage by heavy trucks are described. The capital expenditure and operational expenses are compared and the individual cost factors are explained.Every open-pit mine or quarry, however, is different and has to be assessed and analyzed individually in order to find the optimum and most economical solution. Due to the high truck haulage costs, many open-pit mines tend to the more economical solution with mobile crushing plants and continuous belt conveyor operation. IntroductionFor the material haulage within an open-pit mine the heavy truck is the most flexible means of transportation. However, due to the high fuel consumption, wear and labour costs, it is also the most expensive one. Therefore, many open-pit mines are looking for alternative solutions for the material transport A mobile belt conveyor system is most likely to meet the requirements because it is efficient and economical with regard to the power consumption. The material , however, has to be crushed at the mining face to lumps which are suitable for conveyor operation. For this purpose a mobile crushing plant is required.In some open-pit mines the crusher is also used to crush the material to lumps of smaller particle sizes in order to save crushing costs in the preparation plant.Although a cost comparison between a system with stationary crusher and truck haulage and a system with mobile crusher and belt conveyors favours in most cases the belt conveyor system, up till now only a few open-pit mines and quarries benefit world-wide from the advantages of the mobile crushing plant with continuous belt conveyor operation."

Jan 1, 1986

By Robert J. McCarthy

Many technologies have been adopted over the last half century for the haulage of material from open pit mining operations. Some of the technologies utilized include rail, off-highway trucks, conveyors, and slurry pipelines - each having its unique application and benefits. Over time, truck haulage has become the primary means of surface mine material movement, though recently it has been plagued by problems of tire shortages, high diesel fuel costs, labour shortages, and carbon emissions. This paper focuses on In-Pit Crushing and Conveying (IPCC) as a competitor to truck haulage which has the potential to solve many of these problems. An overview of the available technology is presented along with measures required to overcome perceptional if not physical barriers to implementing this technology in modern open pit mines.

May 1, 2011

By Mohamed Ourriban, Stéphanie Somot, Éric Proulx, Jean-Sébastien Marois, Marjolaine Drouin, Paul Blatter, Ahmed Bouajila, Claude Gagnon

"The mining industry has to face increasing restrictions concerning the use of fresh water in Québec and throughout the world. Increasing recirculated water usage could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have a negative impact on mineral processing operations, thereby limiting the incentive for sustainable development initiatives. As a first step into selecting and testing remediation strategies, one of which being blending local waters, a mapping of process water quality (inorganic and organic fractions) allowed to locate zones in an industrial case study where fresh water is introduced into the circuit and to detect dissolution and precipitation zones. A complementary hydro-geochemical modeling study on water blends was also performed showing encouraging results towards the objectives of the project.INTRODUCTION The industry has to face increasing restrictions on the use of fresh water in Québec (Quebec Government, 2009) and throughout the world (Brown, 2003; UNESCO, 2006). The cost for the use of fresh water and for water management is highly variable and case-dependent (from 0.2 to up to 7 million dollars/year according to available private estimations, excluding the capital expenditure). It may be, or may become, significant for any plant; thus, risk assessment is of concern here. Using recirculated water could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have some positive and negative impacts on mineral processing operations (Janssen, 2003; Johnson, 2003; Rao and Finch, 1989). Negative impacts could limit the incentive for sustainable development initiatives. Water management strategies at mineral processing sites are supported both by a strategic plan and a water management plan. The strategic plan includes legal aspects, investment costs, potential benefits and various risk levels (Corder and Moran, 2006; Côte et al, 2006; Evans et al., 2006; MacIntosh and Merritt, 2003; McLellan et al., 2008; Merritt and MacIntosh, 2006; Robinson and Keddie, 2006; van Beers et al., 2007a; van Beers et al., 2007b; van Berkel, 2007). In practice, the strategic plan evaluates technical possibilities and costs of various scenarios, such as for example: bringing fresh water to the plant or recirculating waters, or using blends of both. Two important factors to consider in order to enhance the future production efficiency and to minimise risks are: the durability and the stability of the resource, both from quality and quantity points of view."

Jan 1, 2012

By D. R. Reeves

This paper describes the geophysical Jogging of coal that is being carried out for the National Coal Board in the United Kingdom. An explanation of the technique is given and results are presented showing estimations of seam thickness to within ±0.5 in. and ash content to accuracies of ±2.5 per cent. The basic method of interpretation is outlined and some conclusions regarding the conditions of roof and floor material which may be deduced from the logs are explained. An indication of future developments in this field, including the identification of coal type and moisture content, is given.

Jan 1, 1971

The principles and utility of in-situ coal gasification are discussed, and a first field test conducted by the Alberta Research Council in 1976 near Forestburg, Alberta, is described. The test was carried out in a 12-ft subbituminous coal seam under 60 feet of cover. Within this seam, a 30 by 60-foot block , containing approximately 650 tons of coal, was delineated by four injection/production holes which were oriented to take advantage of the natural fracture system in the coal. Linkage between holes was established by reverse combustion and gasification was accomplished by injecting air into the ignited coal. No steam was injected but operating pressures were adjusted to utilize formation waters for partial carbon -steam gasification. The coal gasification runs lasted six weeks and gasified an estimated 900 tons of coal ,' during sustained periods of gasification, a fuel gas with heating values of between 110 and 150 Btu/scf was obtained. Plans are now being developed for excavating the test site and inspecting the subsurface cavities created by gasification.

Jan 1, 1977