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Dust emissions from mining, material processing and ship loading operations (fugitive dust sources) are an environmental issue of increasing concern to both government regulators and the community. The main concerns relate to potential amenity, health and environmental impacts from the emissions. Therefore it is imperative that mining/ processing operations, as part of their overall environmental management, reduce fugitive particulate emissions to as low a level as is practicably possible. This technical paper outlines the mechanisms that lead to fugitive particulate emissions, the importance of understanding the exact cause of fugitive emissions, monitoring methods that can be used to quantify the emissions from specific sources, the use of atmospheric dispersion modelling in dust management and innovative dust management strategies including predictive meteorology and proactive management.

Jan 1, 2009

By F. N. F. le Roux

This paper describes the method used for excavating the upper 33m of emergency access shaft E2 for the underground single track tunnel running between Park and Rosebank station of the Gautrain Rapid Rail System. The soil was decomposed shale and diabase from the Witwatersrand Supergroup. The location was in the car park of The Wilds (a public park) in Johannesburg. The method proved very simple and required less complex plant and equipment than normal when excavating the shallow soil sections in shafts. It involves driving steel sheets ahead of the shaft sump into the soils and then excavating inside the ?tub? created by the sheets whilst supporting the sheets above with regularly spaced circular Steel Rings. It is the intent of this paper to discuss the method and design approach to the method. This will be done at the hand of experiences at E2 shaft..

Jan 1, 2009

The Determination of Sound Exposures (DOSES) software was developed by the National Institute for Occupational Safety and Health (NIOSH) specifically for use by mine management and safety personnel. DOSES simplifies the record-keeping and analysis associated with time-motion studies and worker noise exposures, making it easier to identify and solve noise problems. The software relies on a time-motion study that profiles the worker?s daily activities. At the same time, noise measurements are collected with a dosimeter or sound level meter (SLM). Observations about the worker?s location and tasks or other activities are recorded along with times and durations so they can later be matched up with the noise data. After the completion of a time-motion study of the worker?s daily tasks and locations (possible noise sources), which measures the worker?s noise exposures during the recorded events, the information is entered into DOSES. The program then displays information about the worker?s accumulated noise dose over time.

Jan 1, 2009

By C. G. Goncalves

The Gautrain rapid rail link project is currently Africa?s largest infrastructure project connecting South Africa?s major airport (OR Tambo), Johannesburg and Pretoria. Phase one is planned for completion in time for the 2010 FIFA Soccer World Cup and involves 80 km of track and 15 km of underground tunnels. The key shaft sinking blasting issues revolve around maximising advance and improving blasting cycles to meet the tight deadlines as well as environmental control which, in some cases takes place only 15m from the city infrastructure. To achieve success, DetNet South Africa supplied a range of electronic detonator systems to cater for the different blasting applications involved (tunnels, portals, shafts and viaduct foundations). One such product, QuickShot, was used for the first time in a major civil engineering project and has been used in most of the shaft sinking blasts to date. The QuickShot system combines pre-programmed electronic detonators with special on-bench components that enable the user to quickly and easily design the firing sequence solely by using the order of connections. This precludes the user from having to deal in absolute delay times. The connecting system enables benches to be hooked-up speedily by multiple users who have differing levels of experience. This paper provides details of how, after 33 months, the system has been embraced by the project by aiding in maximised advances, improved cycle times and meeting the required environmental constraints.

Jan 1, 2009

By Donald Jonson

Stockholm’s Northern Link, currently Europe’s largest urban road tunnel project, will be about 5 km long from west to east. Running through two separate, mostly parallel tunnels, each with 2-4 lanes, the complex will include numerous entries and exits, as well as a major branch to the north. The total length of tunnel will be 11 km, of which 9 km will be in rock. Over million m3 of rock will be blasted. The Northern Link will open to traffic in 2015. After a 10-year stop to deal with environmental questions regarding Ekoparken, Stockholm’s unique “national city park”, the Northern Link project in the Swedish capital was restarted in the autumn of 2006, with the construction of five works-access tunnels.

Jan 1, 2009

By R. A. Puchner

The location of a decline shaft portal can have far reaching implications if the geotechnical conditions are not suited for safe and cost effective excavation. Ideally the portal should be positioned in an area where the excavation requires minimal support and the portal can be formed in reasonably competent rock. In many cases, however, the shaft is linked to an underground mining plan and the shaft may have to pass through poor ground conditions. Determining the optimal position at which tunnelling can commence i.e. the portal, is critical and requires a thorough geotechnical investigation. Methods used to acquire information for the assessment of the ground conditions are discussed in this paper. Selection of the appropriate methods is dependent on the anticipated ground conditions, the phase of investigation and restrictions due to site access and budget. Non-invasive techniques are often used during preliminary phases and invasive techniques for the detailed investigation. The methods used during each phase of investigation are discussed. Two case studies are then presented to provide examples of the investigative methods used in two different environments. The first being a flat featureless site with thick soils and deeply weathered bedrock, while the second is a mountainous site with differentially weathered rocky outcrops. Based on these cases, it is clear that an understanding of the geology and geomorphology of the site is vital to the final geotechnical assessment. Key words: Decline shaft, boxcut, geology, geomorphology, geotechnical, portal.

Jan 1, 2009

By A. A. Iranzadeh

The performance of a tunnel boring machine (TBM) depends on the efficiency of the cutters, which can be influenced by geological conditions and rock mass properties. In this study, a three-dimensional numerical model, based on a discrete element method, was used to evaluate the effects of joint orientation and its spacing on the fragmentation process by a TBM cutter. Several models were constructed to study the effects of variable orientation; these models incorporated different spacing, variable spacing, different orientations on the fragmentation process, and different sections of the block model. Three parameters, consisting of induced tensile stress, induced shear stress and maximum displacement, were calculated. The stress in each section that forms chips was considered as critical stress; critical joint spacing and orientation in each section were determined. Results show that the critical orientation was in the range of 45 to 60º, where there was a possibility to achieve the maximum penetration rate. The critical joint spacing was 200 mm and, by increasing joint spacing, the value of critical stress decreased significantly. Furthermore, joint orientation could influence more than joint spacing in the rock cutting process.

Jan 1, 2009

By L. M. Anisdahl

Ventiflex is a flexible ventilation duct system with a global market within mine and tunnel ventilation. The system is distributed in a wide range of qualities and dimensions. It is very important that ventilation systems are designed correctly in mines and tunnels. An incorrectly dimensioned system might result in bad air quality and too high costs. The objective of this study has been to assess some important design parameters for ventiflex comprising the friction loss factor for the duct wall itself, as well as the shock loss factors and the leakage factors for the different couplings systems. This has been obtained by carrying out a large scale experimental program on ducts with all the three different couplings: Velcro, zip and steel-ring. Pressure profiles and air flow rates have been measured, and based on these data the different factors have been calculated. The following results have been obtained: A friction factor l = 0,012 (K = 10) for the duct wall, a shock loss factor z = 0,0125 for velcro- and zip couplings, a shock loss factor z = 0,005 for steel-ring couplings, and a leakage factor f* = 0 mm2/m2 for all three coupling types. The latter result proves that no leakage is possible for a correctly installed duct with proper alignment. The results also confirm that ventiflex complies with class S, or better, according to the SIA-norm. However, whether ventiflex should be designed as class S, A or B according to the SIA-norm, depends on the particular application.

Jan 1, 2009

By L. Trivino

Blast-induced damage criterion based on the peak particle velocity has worked reasonably well for estimating building damage. However, the same criterion cannot be used to estimate damage to rock and mine structures such as shaft and tunnel walls. It does not take into account the nature of seismic radiation pattern in the near-field, which is very different than what is obtained at far-off distances. To investigate this phenomenon, a systematic study has been carried out involving single-hole blasts and normal production blasts, with explosive source ranging from nearly point source charges to standard borehole sizes (6-7 m long explosive column), with charge weight varying from 0.5 kg to 30 kg. In the near-field, it is shown that, both P-wave and S-wave take a dominant position compared to the mainly surface waves measured in the far-field. These are shown to depend strongly not only on the length of the explosive column but also the way it is initiated in the borehole (i.e. direct vs. reverse initiation in the borehole) with respect to the target location. The seismic radiation patterns were recorded by high-frequency triaxial accelerometer stations grouted in the rock mass. This study describes the nature of seismic radiation in the near-field from long and short charges, the role of initiation direction and their effect on frequency with respect to sensor locations or target area of interest, and their implication in prediction of blast-induced damage in the near field.

Jan 1, 2009

By R. E. Ray

Compared to conventional fully ducted axial and centrifugal fan systems, jet fans can offer a number of advantages for control of smoke during fire emergencies and dilution of diesel engine exhaust products in vehicular and rail tunnels. The success of jet fan applications is the result of a balance between the temperature de-rating of the fan, buoyancy forces and the installation momentum transfer efficiency. This paper provides a case study of a unique application of vertically-mounted jet fans in ventilation shafts used to provide both emergency ventilation and pollution control for an overbuild created by the construction of a series of commercial high-rise residential buildings over a portion of an existing passenger rail line. A detailed evaluation of a set of shafts for one building is presented, including a discussion of the calculation methods used to estimate the required jet fan capacity and the results of the subsequent numerical analysis using Computational Fluid Dynamics to simulate the performance of the jet fans during train car fire emergencies.

Jan 1, 2009

By Darcey Baker

Quarry Blasting is usually boring, and that is how we like it. By this, boring means routine, straightforward, meat and potatoes blasting. Quarries typically will not utilize cast blasting, coyote tunnels, or any of the other more spectacular blasting techniques – just plain, old day-in and day-out quarry production and possibly overburden blasting. Differences in material characteristics, mining method, equipment availability, and target markets all play a part in determining the blasting procedures employed at any given location. However, variables exist everywhere and with foresight and planning, effects of tangible variables can be minimized. Variables caused by geology, weather, neighbors, or limitations caused by major plant or mobile equipment are, generally speaking, intangible; and leave the operator with finite options to improve or modify blasting procedures.

Jan 1, 2009

By Joshua Hoffman, Braden Lusk, Perry Kyle

With the advent of any new technology comes the necessity of fully understanding the mechanics of that technology. The Shock Tunnel is one such technology that provides a cost effective means of simulating large-scale explosions while requiring a fraction of the explosive and space. Although the technique is known and practiced, the dynamics and mechanics of this technology has yet to be fully understood. A relationship between the energy potential of a given explosive and the energy realized at a set of distances was determined. This data was then compared to the energies realized from the same explosive when utilized in conjunction with a shock tunnel. A relationship between potential and realized energy outputs from explosive based shock tunnels exists and the understanding of this relationship would allow all for predictions to be made to forecast a specific amount of explosive required to produce a desired energy output. This energy output should then be relatable to peak pressures produced via the shock tunnel. Two shock tunnels are currently accessible for this study, the first under the direction of the University of Kentucky, and a second under the direction of the Missouri University of Science and Technology. The two shock tunnels differ in dimensions but share common construction materials. Energy realized from a shock tunnel is hypothesized to be a function of the shock tunnel’s dimensions. This study explores how different geometries affect the shock tunnel’s performance; this exploration is broken down into three phases. Phase 1: Open arena testing in which theoretical energies produced by the detonation of small (<1.0 kg) charges are compared to actual experimental values. Phase 2: Shock Tunnel testing in which realized energies are experimentally recorded for the UK shock tunnel. Phase 3: Analysis of the data to lay down the ground work for producing a pressure-forecasting tool given shock tunnel dimensions and explosive characteristics with the possible detection of avenues for optimization of shock tunnels.

Jan 1, 2009

By Pierre-Louis Migairou

After a period of development and experimentation ranging over 20 years, electronic detonators have now come to maturity and are becoming the first choice in many diverse applications like tunnelling, civil works, demolition works, quarrying, large scale open pit mining and underground mining. This paper demonstrates the versatility of electronic initiation systems by detailing a number of case studies in several applications as different as their geographical locations, and gives specific reasons explaining the popularity of electronics in each case.

Jan 1, 2009

By M. J. Gilbey

London Underground is the oldest and one of the deepest Metros in the world. The temperature of the Underground has been increasing over the last 100 years, mainly as a consequence of increases in train service. Further increases in train service are planned in the coming years to meet the predicted growth in passenger demand. Unabated, the additional service will increase temperatures on the Underground. London Underground Limited (LUL) has therefore set up the Cooling the Tube Programme (CTP) to tackle the issues of thermal conditions on the Underground. Some of LUL?s studies and cooling methods have borrowed experience and techniques from the mining industry; some of methods used or proposed may in turn be of interest to the mining community. This paper presents a background into the sources of heat on the Underground network, the manner in which the heat is presently dissipated, the analysis of future temperatures and criterion and a number of means and methods being used or proposed to cool the network in an environmentally sensitive manner.

Jan 1, 2009

"What can we do in ground engineering to reduce damage to the environment, to repair historic pollution, to reduce our demand on basic resources and to reduce the carbon footprint of our industry? Some developments in geotechnical engineering are already heading in the right direction. These include reductions of ground pollution from grouting, improved dewatering procedures and advances in mix-in-place processes, ground improvement and jet grouting.There is increased interest in certain promising technologies (for example, drilled partial or full displacement piles), but this approach remains for the moment somewhat avant-garde. These piles require substantially greater power to install, and the overall sustainability balance for general application has yet to be shown to be in their favour. They are particularly suited to polluted sites where the problem of dealing with spoil would be costly and where, in the past, driven cast in-situ piles would have been employed. Drilled displacement piles offer some environmental benefit over driven piles in that they cause far less drawdown of potentially contaminated near-surface ground into sensitive, underlying aquifers.There is also great interest in various means of increasing the frictional capacity of bored piles, both conventional auger and continuous flight auger (CFA) piles, by threading or ribbing the soil/pile interface. The increase in adhesion capacity allows reduction in the pile dimensions necessary for a specific load. This obviously leads to less construction waste, but also to less permanent material consumption in the piles and also in the pile caps.The role of ground improvement remains significant for brown land sites and lower capacity foundations. Information technology (IT) has improved the quality assurance of stone column construction, for example. From the sustainability point of view, this is a good news method; here is no cement, no pollution and little obstruction to future redevelopment. We now need to introduce recycled crushed materials instead of natural aggregate as general practice and the technique’s green credentials will be really compelling."

Jan 1, 2009

By Joshua Hoffman, Braden Lusk, Kyle Perry

This study explores how different geometries affect the shock tunnel’s performance and is broken down into three phases. Phase 1: Open arena testing in which theoretical energies produced by the detonation of small (<1.0 kg) charges are compared to actual experimental values. Phase 2: Shock Tunnel testing in which realized energies are experimentally recorded for the UK and S&T shock tunnels. Phase 3: Analysis of the data to begin building a pressure-forecasting tool for the UK shock tunnel given the explosive characteristics, sample size and desired pressure and impulse.

Jan 1, 2009

By I Lourel

In evaluating the installation of an in-pit crushing and conveying (IPCC) system for any mine, a number of options are available for each of the dig side, transport and dump side operations. Some of them are moreappropriate than others; given the pit arrangement, the material being handled and the rates at which it needs to be moved. This paper seeks to document the options that might be employed, and to rank them in terms of their applicability at any mine and their practicality overall, with a view to nominating those that would be most suitable for further study.

Jan 1, 2009

By Raymond W. Henn

The 30th annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, June 22-26, 2009. The field demonstration portion of the course was conducted June 25, at Hayward Baker, Inc.?s yard in Broomfield, CO. The full-scale field demonstration annually presents many different types of drilling equipment being operated as well as various grouting methods being performed under different field conditions. As part of the field demonstration, the class is shown the proportioning, mixing, testing and injection of various cement grout mixes into sand columns under controlled and measured conditions. These sand column demonstrations have been conducted under controlled and measured conditions each year since 1999 as part of the short course. The sand column demonstrations were conducted prior to 1999, but with less quality control and minimal record keeping of the proportioning, mixing, testing, injection pressures and the final permeation results. The goal of the sand column demonstration is to show the students the effect of the water cement ratio and the use of admixture as well as the fineness of the cement, portland versus ultrafine, used has on the engineering properties of the grout and the grout?s vertical permeation through the sand. Test results for the demonstrations conducted in 1999 and for two separate demonstrations, one at the grout course and one at Geo Denver, conducted in 2000 were published in the 2001 proceedings of the Rapid Excavation and Tunneling Conference (RETC) (Henn et al. 2001). The test results for the 2002 and the 2003 demonstrations were published in the 2005 proceeding of the RETC (Henn et al. 2005).

Jan 1, 2009

By Aly M. Mohammad

The 12th and 14th Street Viaducts, which carry Route 139, are located west of the Holland Tunnel in Jersey City, New Jersey. The two viaducts, provide access to and from the Holland Tunnel (which connects New York City and New Jersey) and carry upwards of 50,0000 vehicles per day from Jersey City and New York City to points west. The New Jersey Department of Transportation (NJDOT) selected AECOM to perform design services including rehabilitation and seismic retrofit for the 12th Street and 14th Street Viaducts while maintaining traffic at all times. Building a new parallel bridge just north of the 14th Street Viaduct was essential in avoiding extremely costly traffic delays. Installation of the new foundation, in close proximity to the existing viaduct, required drilling through some of the existing timber piles supporting the bridge. As a result, the existing bridge was required to be reanalyzed for this new foundation configuration. This proposed structure consisted of 8 piers each supported on a single six (6) foot diameter drilled shaft. Currently this portion of the bridge structure has been constructed. The shafts were constructed with rock sockets that were five feet six inches (5?- 6??) in diameter and were extended 11.2 feet (3.4 meters) into rock. A 2300 ton Osterberg Load Test was performed on one production shaft to confirm the capacity of the shaft. The rock socket for the test shaft was in sandstone. This paper will present a description of the design methodology and construction methods adopted for the foundations. In addition, the paper will illustrate the Osterberg Load Test including: equipment used, number and locations of strain gages, and interpretation of results. Additionally, regarding the close proximity of the new foundation, the paper will present the type of equipment used to drill through the existing timber pile foundation while minimizing the impact on the integrity of the existing foundation. We will also present the method of analysis for analyzing the redistribution of load on the remaining piles. The results presented in this paper will assist the design engineer by providing a comparison between the geotechnical design assumptions and the actual measurements obtained by field measurements for this rock formation.

Jan 1, 2009

By M. J. Gilbey

Cross passageways between adjacent tunnels in passenger rail or transit systems may be used during train fire emergencies to evacuate passengers to points of safety in the non-incident tunnel. Rescue trains can be brought into the non-incident tunnel to remove passengers to expedite evacuation times as compared to walking along bench walls to the nearest egress stairs. In cases of multiple train emergencies, the required ventilation capacities can result in high pressure differences between the incident and non-incident tunnels. These pressure differences can make it difficult or impossible for a normal person to open doors of a cross passageway between adjacent tunnels. If opened, the velocity of the airflow through an open cross passageway can reach levels high enough to impede passenger evacuation. This paper describes the analysis of this problem for a sample rail tunnel. A ventilation concept that mitigates the problems of high cross passageway door opening forces and high velocities through open cross passageways is presented.

Jan 1, 2009