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By Chul Soo Park, Juhyung Lee, Duhyun Baek

"In this study the preliminary design of suction pile as the supporting system of the concrete floating structures was performed at the offshore pilot project area in Korea. The suction pile of the floating structures has to satisfy the lateral resistance against external force evaluated from the marine and structure conditions, as well as the penetration ability according to the soil and seepage conditions. In the design, the required penetration depths for lateral resistance were evaluated with different diameters of cylindrical steel suction pile, and the design suction pressures at each penetrating depths were assessed through the comparison of penetration forces and penetration-resistances. Finally, the optimal dimension of suction pile for the pilot project area was proposed.IntroductionInterests in sea spaces have rapidly increased around the world due to limitations in use of lands. Such increase has resulted in construction of numerous marine structures aimed at expanding the use of sea spaces and developing marine resources. South Korea also needs to secure construction technologies for floating infrastructures on its relatively deep seas. Foundations for floating structures consist of anchors and mooring systems rather than driven piles or cast-in-place piles, due to limitations in equipment operation or economic feasibility. Anchors and foundations used on the sea include drag anchors and suction piles, but the suction piles are more widely used for reasons regarding uncertainties of calculation of bearing capacity and construction. Large-diameter suction piles are generally used to utilize fully their penetration ability, which is proportionate to the square of the foundation diameter, and the length-diameter ratio (L/D) does not exceed 6 (Randolph et al., 2005; Andersen et al., 2005). Recently, a design and construction technology using group suction piles consisting of medium-diameter suction piles and concrete pile caps is being developed as an alternative to the conventional large-diameter mono suction piles. In addition, pilot projects involving the group suction piles of mediumdiameter are currently being reviewed for the southwest coast area in Korea. In this study, therefore, preliminary design for installation of medium-diameter mono suction piles as the supporting system of the concrete floating structures was performed, and suction pressures, penetration forces and resistances, and lateral loading capacity with diameters were reviewed."

Jan 1, 2017

By Philip J. Bangerter, Chris Twigge-Molecey

Design for safety is critical to metallurgical plants, due to the inherently dangerous nature of their processes. Two significant areas of concern are: 1. preventing catastrophic process failures that cause damage or injury; and 2. operational safety that directly affects those working in or living near the plant. Process safety involves human behaviour, but the designer can eliminate or control hazards by engineering approaches, and control impacts through the design of the operating procedures. The tools available to guide safe facility design include bowtie analysis, hazard analysis, and hazard and operability studies. Clean plant design principles can guide the design process to address in-plant occupational health and safety issues. Auditing and review is a key part of the overall design process.

Jan 1, 2015

By Paolo M. Brion, Z. Bade Sozer

"The Bypass Tunnel has high head conditions ranging from a minimum of 600 feet (183 m) under the Hudson River to a maximum of 875 feet (267 m) on the west side. The ground cover ranges from 425 feet to 900 feet (130 to 274 m). A two-pass lining is designed for the Bypass Tunnel. The bolted, gasketed precast segments carry the temporary hydrostatic and permanent ground loads. After the tunnel is put into service, the design assumes that the final lining, which varies from reinforced concrete to reinforced concrete with steel interliner, will carry the permanent hydrostatic loads. The design head for the segments is assumed at 775 feet (236 m), and the internal operating pressure head is around 1,200 feet (366 m). This paper discusses the design hydrostatic head and different load conditions considered for the segments, the load sharing between the segments and final lining, and the means employed to control water and hydrostatic pressure. PROJECT BACKGROUND The Rondout-West Branch Tunnel (RWBT), a segment of the Delaware Aqueduct, was built from 1937 to 1944 and provides about 50% of New York City’s total water supply. Monitoring and tunnel operations have shown that the RWBT is leaking up to 35 million gallons per day (MGD) (132.5 million L/day). In particular, two locations have been identified as areas of concern: Roseton and Wawarsing, as shown in Figure 1. The Wawarsing reach of the aqueduct will be repaired with an extensive grouting program when the RWBT is unwatered. However, because of the extensive nature of the leakage in the Roseton area, a Bypass Tunnel will be constructed to divert the flow around this area."

Jan 1, 2016

By E Claridge

There are a number of major infrastructure tunnelling projects currently underway or proposed in New Zealand, including construction of new road and rail facilities and the refurbishment of existing road tunnels. These new projects have triggered a rethink of traditional practices in underground fire and life safety and local regulation.While there is a current surge in activity, tunnels have been a signifi cant part of New Zealand’s transport infrastructure for over a century. Despite this background, the new projects commonly face challenges that are symptoms of a national regulatory environment that has aspects that are inappropriate for underground environments. There are inconsistencies in local regional regulation and an absence of national guidance and standards relating to tunnel design. Historically, New Zealand has looked across the Tasman for guidance. Although recent overseas tunnel designs present learning opportunities, the adoption of international best practice and standards may not necessarily address local expectations or needs.This paper explores a number of specific matters affecting the design of road and rail tunnels in the New Zealand context, namely; the Building Regulations and associated local consenting processes and parties, and the responsibilities and needs of the New Zealand Fire Service.The discussion highlights the importance of a collaborative approach involving the designer, asset owner, regulators, emergency services, and other parties, and ensuring up-front clarity in design responsibility and ownership of residual risk.

Mar 8, 2011

By Brennan Lang

Why Seal Tunnels? ?Restore groundwater levels to pre-mining conditions. ?Saturate rock mass to reduce acid rock drainage. ?Reduce discharge flow to the environment. ?Reduce or regulate flows to a water treatment plant.

May 1, 2002

The King River Power Development on the West Coast of Tasmania has involved the storage of the waters of the King River in the new Lake Burbury and their diversion through a 7 km tunnel to a 144 MW power station. The last kilometre of this tunnel descends through 160 m under a ridge before emerging from the bank of the King River at the power station site. The decreasing cover over the tunnel as it approaches the power station meant that a steel lining was required in the last few hundred metres of the tunnel. This paper describes the geotechnical investigations which were carried out to establish the necessary length of the steel lining.

Jan 1, 1993

By Caciola Jr. Joseph J., Nidal M. AbiSaab

"Thanks in great part to the geology of the New York City Metropolitan area, mini-caissons are a popular choice for deep foundations. These drilled elements are readily available, easy to install with minimal impact on adjacent structures, and can be designed with large compressive and tensile capacities. Despite the frequency with which they are employed, the engineering design community is divided over several of the underlying principles governing the design of mini-caissons. This paper seeks to draw attention to several of these issues in an effort to encourage further research and discussion, namely: (1) how the allowable stresses have changed for the NYC Building Code over time, (2) the inconsistent load transfer mechanisms considered for geotechnical capacity, and (3) the role of the permanent steel casing towards structural capacities of mini-caissons.INTRODUCTIONIn the local construction nomenclature, mini-caissons are drilled deep foundation elements which derive their capacity from a socket in rock. A permanent steel casing (commonly between 7- and 24-inches in diameter) aides the drilling through overburden soils to the top of bedrock. Afterwards, an uncased rock socket is drilled into the bedrock and the inside of the casing and rock socket is inspected by means of portable video equipment. After inspection, the interior of the socket and casing is filled with steel reinforcement and concrete or grout. The casing-soil interface is generally ignored for axial design purposes and the full geotechnical compressive or tensile capacity is assumed to be generated in the rock socket. Figure 1 shows a typical mini-caisson cross section.Mini-caissons have been used for decades in the New York City area for a number of reasons. They have historically been proven to develop high axial capacities in the city’s metamorphic rock (Tamaro et. al. 2000), often exceeding 300- to 500-tons. Additionally, their method of installation (drilling) is generally able to bypass layers of dense Glacial Till, boulders, and manmade fill which would interfere with the installation of other pile types (e.g. driven piles, auger cast piles). Further they are able to extend to depths exceeding 50-ft to reach bedrock underlying a site, making them a useful tool in areas where rock is relatively deep or varied in elevation. Drilled casing installation also results in fewer vibrations and disturbances to adjacent structures and can occur in areas of restricted access (a constant concern for any project in a dense urban environment such as NYC)."

Jan 1, 2016

By R. Plassart, F. Laigle

"As a powerhouse, a transformer or a valve chamber, large underground caverns are a major element of hydropower plant. On the contrary to galleries and shafts which are linear and long underground structures, large caverns are designed with often complex geometries and large spans. Moreover, as these caverns are generally located on the foot of the hydraulic scheme, the high overburden is often responsible of a high stress state. Thanks to current experiences in France and around the world, the Hydro Engineering Centre (CIH) of EDF has defined great principles in the design of caverns leading to a more general methodology. The project of Tehri in India is an example of difficult ground, with in the same time a high overburden, a ductile material and an important schistosity. These physical realities are attempted to be approached in numerical modelling thanks to a constitutive law with softening behaviour and an oriented criterion integrated in the continuum model. As a result, a flexible support is advised, based on a high density bolt system and a thin lay of shotcrete. This methodology has been developed in the case of Gilboa in Israel, except the schistosity which has not been observed in situ. At last, the example of Gavet (France) illustrates a discontinuous case of numerical modelling for a good quality but fractured rock mass.PRINCIPES ET METHODES DE CONCEPTION DE GRANDES CAVERNESHYDROELECTRIQUES SOUTERRAINESRESUME Les grandes cavernes souterraines abritant les turbines, les transformateurs et certaines vannes sont des ouvrages majeurs dans les aménagements hydroélectriques. A la différence des galeries et des puits qui présentent de longs linéaires, les grandes cavernes sont des structures à la géométrie souvent complexe et avec des portées conséquentes. De plus, ces cavernes étant généralement situées en pied du circuit hydraulique, la grande couverture rocheuse peut se traduire par un état de contraintes important. Forte de ses expériences récentes en France et dans le monde, le Centre d’Ingénierie Hydraulique d’EDF a identifié de grands principes de conception des cavernes permettant l’élaboration d’une méthodologie plus générale. Le projet de Tehri en Inde est un exemple de terrain difficile, présentant à la fois une forte couverture, un matériau ductile et une schistosité marquée. Ces réalités physiques sont approchées au mieux grâce à la prise en compte dans les modélisations numériques d’une loi de comportement radoucissante avec un critère orienté intégré dans un modèle continu. Les résultats ont conduit à privilégier un soutènement souple basé sur un boulonnage systématique relativement dense associé à une fine couche de béton projeté. Cette méthodologie a ensuite été reprise pour le projet de Gilboa en Israël, exception faite de la schistosité puisque non observée sur site. L’exemple de Gavet (France) enfin permet d’illustrer un cas de modélisation numérique discontinue d’un massif rocheux de bonne qualité mais fracturé."

Jan 1, 2015

By Phillip E. Glogowski, N. Catherine Bazan-Arias

Steel foundations can be designed to cross-sectional configurations ranging from triangular and square to other multi-side shapes. Adding lateral extensions (hereby called wings) along the length of the steel stem can increase the foundation’s uplift, torsional and lateral load capacities. DiGioia Gray staff developed a methodology for the optimal design for multi-facetted, winged deep steel foundations. A finite element (FE) model is used to represent the steel components and the nonlinear subsurface behavior. The geometry of the foundation can be complex; thus, an optimal design needs to be fine-tuned to the specific site conditions. We created a pre-processor tool to generate the FE model including varying values for the number and size of wings, depths of embedment, reveal/stickup heights, top plate geometries, and subsurface profiles. The analytical model has been partially validated through full-scale testing and the methodology has been applied to two installed projects to date.

Sep 8, 2021

By James J. Bryja, Thomas M. Barczak, Dennis R. Dolinar, Joe Bower, Thomas P. Mucha

Maintaining ground stability in the gate roads, particularly the tailgate, has always been critical to the success of longwall mining, both in terms of safety and productivity. Several new support technologies have been developed in recent years to replace conventional wood and concrete cribbing for secondary roof support. Since their performance characteristics are unique, the best practices that have been developed with conventional wood cribbing may not be applicable for these alternative support technologies. Therefore, with so many options to consider and the importance of achieving adequate ground control at minimal cost, the trial and error approach to longwall gate road support is no longer prudent. This paper discusses a design methodology for standing secondary tailgate supports. This design technique requires in-mine measurements of tailgate support loading and convergence to establish a tailgate ground, reaction behavior based on the support and strata interaction. The methodology uses the performance characteristics generated in the National Institute of Occupational Safety and Health (MOSH) Mine Roof Simulator (MRS) to match the stiffness and load characteristics of various supports to the measured ground reaction behavior. It can be used to determine the appropriate -- application of alternative roof support systems or to design in- mine trials such that a fair and equitable comparison of different support systems can be made. A case study if the methodology at a western Pennsylvania mine site is presented in the paper, including a comparison of four alternative support technologies to conventional wood and concrete cribbing historically used at this particular mine.

By Thomas P. Mucho, Thomas M. Barczak, Dennis R. Dolinar

Maintaining ground stability in the gate roads, particularly the tailgate, has always been critical to the success of longwall mining, both in terms of safety and productivity. Several new support technologies have been developed in recent years to replace conventional wood and concrete cribbing for secondary roof support. Since their performance characteristics are unique, the best practices that have been developed with conventional wood cribbing may not be applicable for these alternative support technologies. Therefore, with so many options to consider and the importance of achieving adequate ground control at minimal cost, the trial-and-error approach to longwall gate road support is no longer prudent. This paper discusses a design methodology for standing secondary tailgate supports. This design technique requires in-mine measurements of tailgate support loading and convergence to establish a tailgate ground reaction behavior based on support and strata interaction. The methodology uses the performance characteristics generated in the National Institute of Occupational Safety and Health's (NIOSH) Mine Roof Simulator (MRS) to match the stiffness and load characteristics of various supports to the measured ground reaction behavior. It can be used to determine the appropriate application of alternative roof support systems or to design in-mine trials so that a fair and equitable comparison of different support systems can be made. A case study of the methodology at a western Pennsylvania mine site is presented in the paper, including a comparison of four alternative support technologies to the conventional wood and concrete cribbing historically used at this particular mine.

Jan 10, 2000

By Xiaoting Li, Richard Adasiak, Benjamin Mirabile

Pumpable J-Crib stopping walls and Jennmar high-strength (HS) stopping panel walls are widely used for resisting high-ventilation air pressures and roof support in underground mines due to their installation efficiency, convergence allowance, and better performance than traditional concrete block stopping walls. Based on the different entry dimensions and required maximum ventilation air pressures of up to 36-in. water gauge, 24-, 27-, 30-, and 36-in.-diameter pumpable J-Crib stopping walls, or 18- to 30-in. thick Jennmar HS stopping panel walls can be designed, and their support capacities and convergence allowances are evaluated for better roof control. Pumpable J-Crib stopping walls consist of 0.187-in.-diameter steel wire reinforced, JCrib material-filled bags, and non-wire-reinforced filler bags in between. Jennmar HS stopping panel walls consist of two, 20-gauge (0.04-in.-thick), galvanized, cold-formed steel panels with J-Seal materials pumped in between. Based on the fundamental structural design principles and specifications of ACI 318-19(22), the compression and flexural strength, and shear resistance of the walls can be checked to be compliant with the codes and specifications following the load and resistance factor design (LRFD) method. Specifically, the 0.187- in.-diameter steel wires in the pumpable J-Crib walls and 20-gauge steel panels in the HS stopping walls are integral parts of the walls and are considered to effectively confine the J-Crib or J-Seal materials. These steel elements play a significant role in reinforcing and improving the strength or support capacity of the stopping walls from a structural design perspective. Because of the high ductility of low-density J-Crib/J-Seal materials and steel elements, these walls are good at accommodating or absorbing the roof convergence (≥5% entry height), which cannot be matched by a traditional concrete block stopping wall (Figure 1). Based on the successful design and application of these stopping walls in different mines for improving roof stability and avoiding the air leakage, the authors have formulated the design methodology and verified independently by the finite element analysis (FEA) simulation technique. This design methodology combines the fundamental structural design principles with specific wall dimensions and material properties, facilitating mine engineers and government agencies to understand the in-depth working mechanism of these stopping walls.

Jul 1, 2023

By S. Dubnewych, S. Kieffer, M. T. McRae, R. R. Redd

The seismic vulnerability of the existing outlet tower at Lake Mathews reservoir, located in Riverside County, California, necessitated the design of a new outlet facility to assure serviceability of the facility following a major earthquake. The components of the proposed facility include: a new outlet tower; a shaft; a new outlet tunnel; an approach channel that will be excavated underwater; and two short tunnels that will connect the new outlet tunnel to the existing outlet tunnel via the shaft. As the new facilities will be constructed while the reservoir is in operation, a cofferdam will be constructed around the site of the new outlet tower. The design for the underground facilities used a combination of empirical methods; limit equilibrium analyses, including displacement-based pseudo-static analyses for dynamic loading conditions; and numerical analyses. This paper outlines the design methodology used to develop an innovative design for the facilities which can be constructed within the time frame required by the operational schedule of the reservoir and existing outlet facility.

Jan 1, 1999

By B. Sivarama Sarma, Biswabikash Rout

"Seepage control has to be achieved with plastic concrete cut-off diaphragm walls in dam structures. Materials selected for construction of cut-off walls must be durable, impermeable and have stiffness comparable to the surrounding soil.Plastic concrete provides a feasible and economical solution for construction of durable and impermeable cut off walls for dam structures. Plastic concrete wall should not be understood as a concrete wall with similar mechanical properties of concrete used in buildings, piles and spillways sections. Though it consists of the same materials as those of conventional concrete it has the major differences in end product due to predominant addition of bentonite slurry in the mix with very high water cement ratio. This makes the hardened concrete with very low compressive strength less than 5MPa and high failure deformations after the peak load.This technical paper examines a case study, the typical specifications on demand for construction and the issues corresponding to misunderstanding of the material as a structural grade concrete material. Conclusions were drawn based on a few project site quality data and trial mix experimental data. The anomalies in specifications on demand for construction of curtain wall in a dam structure were removed with modifications.INTRODUCTIONDiaphragm walls which are constructed in trenches made of plastic concrete basically serve the function of seepage control under confined measures. They should have the ability to sustain and undergo large plastic strains as compared to conventional concrete. The three basic mechanical properties of plastic concrete cut-off walls are to have least permeability, minimum strength to retain its shape and ability to undergo large deformations under confined loading conditions. The constituents of plastic concrete are cement, bentonite, coarse and fine aggregates, chemical additives to improve flow of concrete and sometimes to retard the setting time and water."

Jan 1, 2017

By Rodrigo Ladrón, Gonzalo Rund, Gonzalo Montes-Atenas

Modelling ore comminution processes have been a highly fruitful scientific topic. The models have been proved to be largely dependent on the selected comminution technology. Among them, semiautogenous (SAG) mill technology has been widespread implemented in plants but no complete understanding of the mechanisms involved in the process is available. Tracing back in history, SAG models considered only some granulometric cut sizes such as the t10 and attempted to relate these parameters with the energy involved in the impact between particles. Other models evolved towards incorporating physical properties of the material being ground and the mill operating conditions. These material properties have assisted to obtain a more comprehensive description of the breakage mechanisms; nevertheless, the gathering of all known parameters still have not delivered a model able to describe the process. This may be a result of emergent properties or phenomena originated from interactions inside the process which are hard to predict turning the size reduction operation into a complex system. Cellular automata provide one answer to describe complex systems by following simple rules. The aim of this research work is to establish the preliminary rules of thumbs enabling the implementation of cellular automata able to predict the particle size distribution at the exit of a SAG mill. The methodology involved developing a simple 2D model of a ROM sample. Plant data from two mine sites were correctly described by a set of three rules: two rules describing the particle reduction and one rule associated with material transport across the mill. Further analysis related with expanding this model to 3D and its impact on the liberation of valuable material is also discussed.

Jan 1, 2014

By S. K. Kawatra, H. J. Haselhuhn

"Thickening is used during two primary mineral processing operations: water removal and desliming. During water removal, the pulp density is increased through the injection of flocculants. These flocs settle and create a dense pulp while clarified water is removed through the overflow. During desliming, fine particles are removed through the overflow. Desliming can also be used as a mineral separation process known as selective flocculation-dispersion, where valuable minerals are flocculated and gangue minerals remain dispersed and exit through the overflow.There are many ways to analyze thickener performance on a laboratory scale, but these analyses often do not correlate well with full-scale performance. Some pilot-scale systems have been designed using a semicontinuous approach, but the amount of material required to perform their tests can make semicontinuous pilot thickeners impractical for most applications. This paper focuses on the design and optimization of a continuous pilot-scale deslime thickener that requires minimal material to operate. The design, optimization strategy, and an example study of reagent selection are demonstrated. IntroductionMany laboratory methods have been employed to size and optimize thickener performance. The most common of these include the Coe and Clevenger method and methods derived from the Kynch theory of sedimentation. The Coe and Clevenger method was developed in 1916 and was proven for slurries that do not require flocculation to settle. This method proposed that the settling rate of the pulp is only a function of the solids concentration. It is executed by creating slurries of several different concentrations of solids and performing bench-scale settling tests in graduated cylinders. For each concentration, a thickener unit area can be determined using the following equation (Coe and Clevenger, 1916; Laros, Slottee and Baczek, 2002):"

Jan 1, 2017

By K. D. Luxbacher, J. T. Davis

"A wind tunnel was designed to examine air flow, heat transfer and layering near an active fire at a working face. This tunnel simulates an active entry in an underground coal mine including an attached cross-cut of similar dimensions. A steel rectangular duct 1 ft. (0.305 m) tall, 3 ft. (0.914 m) wide and 10 ft. (3.05 m) long composes the main body of the tunnel and represents a mine entry. Air flow is generated by an exhausting centrifugal fan attached to one end of the crosscut. This fan was sized to supply air velocities based on Froude scaling. A 6 in. (15.25 cm) propane burner is used to simulate fires of various heat release rates at the working face. Thermocouples are used to map heat layering in the tunnel. Ports are installed for the introduction of tracer gases into and from sampling the system. Barometric, differential pressure, and temperature sensors are also included to monitor environmental conditions. Details about the design and testing of the system are presented including an overview of how the tunnel was scaled to accurately represent fire and flow phenomena. Finally, the proposed use of the tunnel for better understanding of mine fire phenomena and prevention is given. INTRODUCTION Fires in underground mines have been a concern since the dawn of mining. While technological advancements, regulations and best practices have improved both fire detection and firefighting techniques, mine fires continue to represent high risk events. From 2006 through 2015, fires accounted for 1.06% of fatalities in underground coal mines and 0.85 percent of fatalities in all underground mines in the United States (U.S. Department of Labor, 2006 to 2015). In addition to the risk of loss of life, mine fires can cause millions of dollars in equipment damages and lost production revenue. Extensive research has been conducted on how fires occur and spread in underground mines. In addition to testing conducted by government agencies such as the Mine Safety and Health Administration (MSHA) and the National Institute for Safety and Health (NIOSH) (e.g.(Liming, 2006), researchers like Verakis and Dalzell (Verakis, 1988) and Lowndes, et. al. (Lowndes, 2004) have furthered this field by studying ignitions and propagation of conveyor belt fires. While the studies of belt fires in mines are extensive, studies focused on fires at the working face are few in number. The particularly confined space and limited access to a working face, coupled with less robust, temporary ventilation controls create a unique environment that warrants special attention. Separate from studies on mine fires, the use of tracer gases to characterize flow patterns in normal mining ventilation is well established. In 1982, Timko and Thimons (Timko, 1982) outlined current and future applications of sulfur hexafluoride (SF6). However, little experimentation has been conducted to study specifically how tracer gases might be used to evaluate active mine fires and the fires’ effect on the surrounding mine environment (e.g.(Lindsay, 2014). In order to better understand the dynamics of smoke layering from a fire in an enclosed space, a small-scale apparatus was designed to map smoke layering and to examine other aspects of fire behavior at a working face. In addition to studying smoke flow around an active fire, experiments will be conducted using tracer gases in order to determine how they might be used to evaluate an underground fire."

Jan 1, 2017

By J. A. Marshall

"INTRODUCTION The purpose of this paper is to investigate the potential for use of UAVs in underground mines and present a prototype design for a novel autorotating UAV platform for underground 3D data collection. The mining industry has recently shown increased interest in the use of unmanned aerial vehicles (UAVs) to assist in everyday operations [20, 11, 4]. Above ground, small UAVs are in some cases a more efficient, inexpensive, and safer alternative to manned aircrafts currently used for photography, inspection and security [6, 10]. For example, attaching camera, infrared and LiDAR payloads, UAVs can provide a low-cost method of obtaining highly accurate 3D photogrammetric data and aerial photography. UAVs are now commonly used in open pit mining operations for applications that include stockpile surveying, 3D pit modelling, facilities management, accident reporting, progress monitoring, and environmental assessment [11]. There are numerous companies offering UAV services for mining applications; e.g., UAV Geomatics, Leica Geosystems, Sky Futures, SenseFly and FlyTerra, to name just a few. Common services include stockpile and open pit volume computations, environmental assessment, aerial mapping and photogrammetry. Although the aforementioned services are thosemost commonly provided by UAV surveying companies, they may also add value to other daily mining operations. For instance, SenseFly offers pre and post-blast monitoring in order to identify the presence of misfires and wall damage. This data can also be used to reconcile the blast results with expected results. GEM Systems offers a UAV equipped with a magnetometer for mineral exploration surveys. Companies such as Barrick have even used UAVs for solids modelling at tailings dams and stability monitoring [11]. UAVs in mining have so far been mostly limited to surface applications. Harsh underground environments pose many obstacles for flying UAVs. The confined space, dampness, reduced visibility, air movement, and lack of control signal propagation hinders most operators from being able to fly a drone underground. It may be that truly practical uses for UAVs underground will require either autonomous or semi-autonomous flight capabilities. Although there are many difficulties with flying underground, the potential benefits from a working system could greatly improve mining operations. The potential benefits of deploying UAV platforms underground include access to unreachable and dangerous locations and removing personnel from unsafe situations. These benefits have the potential to greatly improve mine monitoring and mine safety. Research has shown that current UAV technologies exist that allow for autonomous indoor flight. Extensive research has been done to develop UAV systems that are capable of performing on-board simultaneous localization and mapping (SLAM), which can allow them to navigate and map a foreign environment autonomously [5, 7, 1, 13]. Grzonka [7] successfully used an open hardware quadrotor to autonomously navigate and map an office building. The research outlines the localization, mapping, path planning, height estimation and control of the autonomous quadrotor. Other research has been done that exploits autonomous UAVs for search and rescue. Kassecker [9] proposed a software and hardware framework for a quadrotor capable of indoor and outdoor urban search and rescue and Rudol [19] developed a system for human body detection and geolocalization using an autonomous UAV.The use of autonomous UAVs in search and rescue has the potential to improve situational awareness and surveillance for a rescue team. Similar research has been done that uses autonomous UAVs for indoor exploration. Pravitra [15] outlined a strategy for autonomous exploration of miniature air vehicles (MAVs) within indoor environments and Rudol [19] developed a method for using an unmanned ground vehicle (UGV) and a UAV for cooperative indoor exploration. These studies show that aut"

Jan 1, 2017

By Eduardo Lozano, Vilem Petr

The use of explosives brings countless benefits to our everyday lives in areas such as mining, oil and gas exploration, demolition, and avalanche control. However, because of the potential destructive power of explosives, strict safety procedures must be an integral part of any explosives operation.

Jan 1, 2017

By Lucie Spencer, Craig Butterworth

"This paper presents the design of a raft enhanced pile group recently constructed for a hotel development in Perth, WA. At the time of construction in 2016 the hotel was the tallest prefabricated hotel in Australia.The structure covers the entire 12 m by 32 m development footprint, located in an inner city environment, and directly surrounded by existing structures. The small site and lack of space required innovative thinking in terms of the substructure design.The ground conditions comprise a layer of medium dense sand underlain by variable layers of stiff clay, silts and sands. Groundwater was around 1.5 m below ground level.The substructure design was carried out on the basis of a raft enhanced pile group. This allowed the use of much shorter piles than a conventional pile solution, thereby permitting the adoption of CFA piling techniques. This also allowed the raft thickness to be reduced to such that the substructure works were maintained above the groundwater level.The design was carried out in general accordance with the Australian Standard AS 2159 and using conventional piled raft design techniques involving iteration between elastic soil settlement software and structural analysis software until spring reactions were obtained with convergence of the two models. Following this springs were introduced to model piles in the structure.Due to the variable nature of the ground and resulting uncertainty in pile base capacity it was not considered appropriate to design the system as a pile assisted raft with piles loaded beyond their ultimate geotechnical design strength. As a result, all piles were designed based on a maximum load maintained within the elastic response region, with the majority of the load taken by the piles. However, the combined capacity of the raft and the piles allowed for a saving in pile lengths and numbers of around 40%, when compared to a conventional pile group designed in accordance with the Australian Standard AS 2159.The raft slab was monitored during construction in order to check the actual displacements against the design displacements. At the end of construction, the settlements were found to be within 2 mm of the design values.INTRODUCTIONThe Wellington Street area of Perth in the CBD is undergoing recent regeneration which includes the King’s Square development, Perth Arena and the Wellington Street Bus Station. The proposed hotel development is close to the recent developments on a Lot previously occupied by a low rise development. Due to the small size and constrained nature of the site, the substructure design for the tower needed to take into account available space and the impact of the works on adjacent properties. This paper presents reasoning for the choice of substructure design, details of the design methodology adopted, results from limited post construction monitoring and potential improvements that could be considered for similar future developments."

Jan 1, 1900