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By Brendan Demich, Joseph McGuire, Emily J. Haas

Near misses recorded and reported by workers can provide awarenessto the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, it is unclear what the value of these reports are, if any, and how they influence subsequent actions or controls to reduce on-the-job risks. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. Of those, 167 were valid near misses that occurred at work. Researchers coded the reports using a qualitative 5 × 5 risk matrix. Of the 167 near misses, 19% were deemed low risk, 25% moderate risk, 30% high risk, and 26% critical risk. Several patterns in the near-miss incidents were documented, including classification of incidents and common corrective actions referenced (i.e., elimination/substitution, engineering control or redesign, work process/procedures, and personal protective equipment). The analysis provides insight into ways that risk communication and management programs can be improved to reengage workers and their situational awareness on the job.

By Martin B. Hudson, Andrew K. Cho, Rolff B. Knobel, Les R. Chernauskas, Jonathan L. Ernst

ABSTRACT The Bruce Museum, located in Greenwich, Connecticut, is home to an extensive display of art and natural history exhibitions. A large addition was designed to be constructed adjacent to the museum requiring new spread footings to be installed up to 16.5 feet below the existing foundations. The soil conditions at the site consist of highly variable sand and gravel overlying weathered rock and sound bedrock. The Contract Documents called for traditional foundation underpinning. Traditional underpinning techniques, however, presented two major challenges on this Project; (1) deep underpinning pits would be required involving multiple levels and staging with tieback support and (2) the highly variable soil and bedrock composition and elevations presented uncertainty in the design and construction of the pits. In lieu of traditional underpinning, Geosciences Testing and Research, Inc. (GTR) proposed an “active” soil nail underpinning system. A major reason that the soil nail underpinning option was feasible, related to the fact that the soil nails and facing could be installed slightly in front of the existing footings rather than directly underneath the existing footings. The soil nail wall design involved one to four rows of soil nails with nail positions and wall depth able to be adjusted “on the fly” as excavation progressed depending on the field conditions encountered. To create the “active system,” the soil nails were pre-loaded to mitigate wall deformations that would be associated with a standard passive soil nail wall design. To evaluate the performance of the active soil nail wall and confirm design assumptions, an extensive automated monitoring, on-site testing and inspection program was proposed and executed by GTR to monitor deformations of the wall and the museum in real-time, evaluate and confirm bedrock and soil bond stresses and ensure that each soil nail was pre-loaded and locked off. Careful analysis, planning, and use of the observational method illustrates the importance of collaboration between design and construction personnel and applying engineering judgement throughout construction. The use of the observational method includes the potential for modifying design based on conditions observed. This paper presents a unique case study of the “active” soil nail underpinning system to support and protect sensitive structures, close collaboration between design and construction facilitated by real-time deformation monitoring, and its successful application as a safe and cost-effective alternative to traditional underpinning.

Oct 1, 2022

By BRETTMANN TRACY

Jan 1, 2000

By R McDonough

DTL2 contract C916 was awarded in March 2009 for S$340 M. This contract includes two mass rapid transit (MRT) 1100?m long bored tunnels using two slurry tunnel boring machines (TBMs), with an internal diameter of 5.8?m, two cross passages and 135?m of cut-and-cover tunnels The contract also includes the design and construction of a new underground station including station entrances, subway links, architectural finishes and external landscaping. The station, located at Upper Bukit Timah Road near Jalan Jurong Kechil will also double as a civil defence shelter.The works included significant traffic management in a dense urban area in order to create the working areas whilst keeping the requisite number of traffic lanes. This involved numerous utility diversions and included the removal of a 33-year-old pedestrian overhead bridge (POB) over busy Bukit Timah Road. The station and tunnelling works were completed on time, including a ‘dock and dismantle’ TBM retrieval and subsequent breakthrough of the separating wall.This paper will detail the methods and solutions used to construct the tunnels and stations, with a focus on the requirements for construction of the station to be a civil defence shelter if required. This involved solutions to tying reinforcement and placing concrete to high standards in a restricted space, as well as the incorporation of heavy blast doors and other associated protective measures. The efforts of the management team resulted in the project being awarded first prize in the 2011 Land Transport Authority’s Annual Safety Award Convention and being named winner of the Safety and Health Award Recognition for Projects (SHARP) award at the 2011 Workplace Safety and Health (WSH) Awards. As well, McConnell Dowell won a Green and Gracious Builder Award (Excellent Category) from the Building and Construction Authority (BCA).CITATION:McDonough, R, 2014. Design and construction contract C916 Beauty World Station and Tunnels, Singapore, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 411–418 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M. Mustafa Kahraman, Sean Dessureault, W. Pratt Rogers

Most contemporary mines have considerable amounts of data. Structured and unstructured large data sets are colloquially named big data. Much of the data in mining operations come from a variety of systems, each with different databases and reporting environments. Standard technology deployments create a Bsilo-ification^ of data leading to poor system benefit. Through modern server monitoring and systematic approach, data utilization and value can quantifiably be measured. The Data Utilization and Value Index (DUVI) can quantify business intelligence best practices and user interaction. This study seeks to provide a data management tool to measure data utilization across the process of converting data into action.

Quay Magnesium Limited (QMG) listed on the Australian Stock Exchange in late September 2004 having raised approximately A$30 million with the object of designing, constructing, commissioning and operating a 15 000 tpa magnesium alloy production facility in Nanjing, China. Site construction commenced in February 2005, with installation of all major components completed by the end of October 2005. Hot commissioning was simultaneously commenced with the final stages of installation, leading to the first stage of continuous ingot casting by mid November 2005. Since that time, ramp-up to the name plate capacity has been undertaken. This presentation highlights some of the more significant technical and logistical hurdles that have had to be overcome in order to meet the high quality product specifications required by a range of QMG customers.

Jan 1, 2006

By R Domotor

Brisbane’s Airport Link is Australia’s largest road infrastructure project, worth a total value of A$4.8 billion. The project is using surface and underground blasting to excavate hard volcanic rock, Brisbane Tuff. This paper tells the story of the most challenging and difficult blast of the whole project: the removal of a remnant pillar of rock (approximately 2250 m3) next to a major arterial road and within 100 m of existing infrastructure including a number of heritage listed buildings, residences and privately owned sensitive receivers. The pillar consisted of a hard rock wall (Brisbane Tuff) between 2 m and 6 m thick, 15 m high and 35 m wide; with in situ precast concrete piles embedded within 1 m of the boundary of the pillar. Orica Australia Pty Limited was contracted by Thiess John Holland, to perform the work in this area, including design, modelling, drilling and loading of the explosives, as well as blast clearance and shotfiring. Access to the area was limited so all explosives and equipment, including the 20 t drill rig, had to be lifted in and out by crane. Due to the nature of the blast, with infrastructure 5 m directly in front of the 15 m high face, there was only ever going to be one chance to get this blast right. This was an extremely complex blast which required the use of a number of different types of packaged explosives, as well as special timing techniques only made possible by using electronic initiating systems. This type of blast is high risk, and is more typical of a building demolition in the urban environment. The blast was fired on the 25 September 2010, and was highly successful. The environmental results for vibration and overpressure were well under the imposed limits, and the embedded concrete piles remained undamaged.

Nov 8, 2011

By Randy McMeekin, Chris Twigge-Molecey, J. Peter Blake

The business objectives of a metallurgical project determine targets and constraints, such as the range of products, production capacities, in-service dates, and capital and operating cost parameters. Permitting is usually left to the project team, as are decisions regarding site location, technology, and construction approach. Success requires an orderly methodology, represented in this book by front end loading (FEL) phases: FEL1 examines several alternative approaches; FEL2 ranks and eliminates less economically or technically attractive options; and FEL3 develops the preferred option to the point of major permit completion, with defined scope, schedule, and cost to submit for approval to proceed with implementation in FEL4. Working through FEL1, FEL2, and FEL3, the project definition improves, estimates become more accurate, and project risks are reduced. The project design basis at the end of FEL3 is the control document for project implementation in FEL4.

Jan 1, 2015

By Sigmund J. Andersen, Eva A. Mørtsell, Jostein Røyset, Randi Holmestad, Oddvin Reiso, Yanjun Li, Øyvind Paulsen, Calin D. Marioara

"With the purpose of increasing the extrudability of lean alloys, we reduce levels of the alloying elements Mg and Si in a 6xxx extrusion alloy. To avoid sacrificing strength, we investigate the compensating effect of smaller amounts of lithium and germanium, alone and in combination. Recent studies by atomically resolved high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) together with density functional theory (DFT) calculations have demonstrated that while Li replaces Mg, Ge substitutes Si in the columns in the hardening ß’’-phase. Several studies have shown that Ge replaces Si in other precipitates as well, and that both Li and Ge promote precipitation and can improve macroscopic properties, like strength and thermal stability. The scope of the current work has been to investigate and document the combined effect of the two alloying elements. Of the investigated alloys, the one containing both elements displayed highest hardness, corresponding with a significant increase in precipitate number density. We used HAADF-STEM to determine the extent of Li and Ge in the precipitate structures.INTRODUCTION The two most important alloying agents, with respect to age hardening of the 6xxx alloy series, are Mg and Si. In general, 6xxx alloys are formed into their final shapes by rolling or extrusion, before being age-hardened at elevated temperatures around 180°C. The hardening effect during this stage is due to the formation of metastable, semi-coherent, precipitate needles along the three < 001>Al directions generally following the precipitation sequence (Marioara, Nordmark, Andersen, & Holmestad, 2006): Supersaturated solid solution ? atomic clusters ? Guinier-Preston-zones (pre-ß”) (Edwards, Stiller, Dunlop, & Couper, 1998) (Marioara, Andersen, Jansen, & Zandbergen, 2001) ? ß” (Andersen, et al., 1998) (Hasting, et al., 2009) ? ß’ (Vissers, Huis, Jansen, & H. W. Zandbergen, 2007), U1 (Andersen, Marioara, Vissers, Frøseth, & Zandbergen, 2007), U2 (Andersen, Marioara, Frøseth, Vissers, & Zandbergen, 2005), B’ (Vissers, Marioara, Andersen, & Holmestad, 2008) ? ß, Si (stable)"

Jan 1, 2018

By T. M. Yegulalp

A numerical model is being developed to assess the enhancement of permeability by improved fracture connectivity by micro-hydrofracturing. A generic two-dimensional percolation model has been developed to test the impact of various field conditions on permeability. Field data from Cyprus Minerals&apos; Mineral Park Mine has been used to establish statistical properties of the observed fracture systems. Results of statistical anlyses of the field data and examples of the use of percolation model are presented.

Jan 1, 1995

By Scott King, Norm Patterson, Ruilin Yang

The multiple blasthole fragmentation (MBF) model developed by Orica models the contributions from multiple blastholes to fragmentation at any given point in the rock and simulates a production blast with the actual geometry of the blasted overburden and free faces, explosive loading, multiple decking, and delay timing of each explosive charge. The model has been successfully applied to several open pit mines and quarries around the world, including Canada and the United States. The peak particle velocity (PPV) induced in the rock from the explosive detonation is used in the MBF model as the key parameter relating to the size distribution of the rock fragmentation. Relating the PPV to the rock fragmentation is based on earlier work relating the particle velocity to the dynamic strain in rock. A recent publication further revealed that the PPV is related to the maximum relative displacement that induces three dimensional strain at a point in the rock. The model can explicitly model most of the blast design parameters including explosive properties.

Jan 1, 2018

By D. J. Adams

Cyanide heap leaching is the predominant technology used in processing low-grade gold ores. During closure ora heap leach operation, residual cyanide must be removed from the process and waste solutions, as well as the heap. Biological cyanide oxidation is a proven, economical technology for destroying cyanide in process and waste waters and spent heaps; The use of biological cyanide degradation eliminates the need for toxic or corrosive chemical oxidizers and has- been implemented at full scale at treatment costs usually <$0.50/1,000 gal. The Applied Biosciences biological cyanide destruction (BCND?) process has been demonstrated to effectively treat cyanide, concentrations up to 350 mg/L. Treated process solutions and wastewaters also contained other contaminants such as arsenic, copper, iron, silver. selenium, mercury, nitrate and zinc, much of which was removed in the cyanide degradation process. Under optimal conditions, microorganisms can rapidly oxidize free cyanide in some process solutions from over 250 mg/L down to 0.1 mg/L in 4 to 5 hr. Cyanide is degraded to ammonia and carbon dioxide, with 50%ofthe cyanide carbon liberated as C02. In general, carbon tank based bioreactors degrade cyanide at significantly higher rates than process or wastewater pond configured treatments, which usually degrade cyanide-more rapidly than in heap treatments. Investigation of cell-free enzyme preparations as an alternative to live microbial cyanide degradation shows promise. Advantages of enzymes over live microbes for cyanide degradation include: (I) the ability to tolerate and degrade higher cyanide concentrations (> I ;000 mg/L), (2) nutrients to support live microbial cells are not required, (3) the effects of other toxic contaminants, such as metals, found in mining waters-are eliminated and (4) the potential for greatly increased kinetics.

Jan 1, 1998

By Phil Wilkinson, Sam Whitaker

"The installation of large (XL) diameter monopiles offshore typically requires expensive and specialist plant, equipment and vessels. Due to the increasing size (weight, diameter and length) of the foundations, in order to mitigate installation risk, the use of large diameter drills is becoming an increasing requirement.Project developers often try to avoid drilling operations due to the time associated with the drilling process. This restricts projects in terms of location and it also overlooks the additional engineering benefits drilling can bring to monopile foundation design e.g. reduced foundation material and better fatigue design life.By comparing the lessons learned of three milestone overwater drilling projects; methods of maximising drill speed and decreasing drilling process time is established. Particular emphasis is put on pile internal relief drilling in a process known as Drive-Drill-Drive (DDD).The milestone overwater drilling projects are North Hoyle Offshore Wind Farm (OWF) (2003); Flamanville EPR cooling water outlet shaft (2008); and Gwynt-y-Mor OWF (2014).By evaluating the effect of foundation pile diameter on drilling process times, example foundation installation costs are derived and used to show that incorporating drilling as part of a process may not be cost prohibitive to projectsContinued advances in drill technology, and drilling rates of penetration, combined with an integrated approach to foundation design, challenge whether hammering only is always the optimal solution for XL monopile installation."

Jan 1, 2017

This volume constitutes the final report for the Rescue Subsystem portion of the Coal Mine Rescue and Survival System program conducted by the Westinghouse Electric Corporation under contract to the United States Bureau of Mines (Contract Number H0101262 dated Jung 17, 1970). The program was directed by the Special Systems Department of the Westinghouse, Baltimore, Maryland facility. The basic objectives of the CMRSS program were to develop and test hardware to determine the efficacy of a variety of coal mine rescue and survival concepts and techniques. These concepts were drawn from two major- sources: the Request for Proposal from the Bureau of Mines and the final report on the Mine Rescue and Survival Study conducted by the National Academy of Engineering (NAE).

Jan 1, 1971

By Craig A. Johnson

Cyanide speciation and behavior have been examined at three active heap leach operations, three heaps undergoing rinsing, and three sites with cyanide contaminated groundwater, all in the southwestern U.S. Data from these studies demonstrate that strong cyanometallic complexes of iron and cobalt can play ?an important role in cyanide behavior throughout the lifetimes of heap leach operations. In active circuits, we find evidence that significant amounts of cyanide combine with iron and cobalt to form strong cyanometallic complexes, and that these species can be adsorbed, probably onto iron hydroxides, or precipitated as insoluble cyanometallic compounds. When spent heaps are rinsed, the release of this cyanide is likely controlled by the slow kinetics of desorption from, or dissolution of, solids that have gone largely uncharacterized. We find evidence that strong cyanometallic complexes can give rise to transient free cyanide in some settings by rapid photo dissociation where heap rinse effluent is exposed to sunlight in open channels or translucent sample bottles. Thus, these species can complicate the ,preparation of spent heaps for decommissioning, even where regulatory standards ?are based on weak acid dissociable cyanide. There is a critical need for information on the form and stability of adsorbed and precipitated cyanide in spent ore heaps, on the concentrations of strong cyanometallic complexes in mineral processing effluents -particularly the complexes of cobalt, and on the natural attenuation of iron and cobalt cyanometallic complexes in both surface and subsurface waters.

Jan 1, 1998

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur.

Feb 1, 2020

By Henning Schwarz, Ade Ogunsola, Anas Almousa

"The Riyadh Metro, commissioned by Arriyadh Development Authority “ADA” - the executive arm of The High Commission for the Development of Arriyadh -, forms part of a new public transport-system of Saudi Arabia’s fast growing capital city. The Design & Build project consists of 176 km of Metro Line with 57 km of tunnels. Beyond the Design and Construction, an additional aim of the ADA is to introduce up-to-date methodologies and improve safety in construction projects. A systematic dilapidation survey of buildings and infrastructures was a prerequisite for designing the required instrumentation and monitoring tools. Site investigations required of existing methodologies and the use of geophysical methods for achieving reliable results. Large diameter TBM tunneling is challenging in hot weather conditions and karstic ground. The present paper shows how modern technologies for underground construction are introduced into the local industry and gives an outlook on future projects in the Kingdom of Saudi Arabia. INTRODUCTION Riyadh, the capital city of the Kingdom of Saudi Arabia, is a fast growing city with more than 5.7 million inhabitants. The growth of the city is linked to the recent history of the Kingdom, where some initial milestones from the 1950’s can be highlighted: Revenue generation from the exportation of oil from the Kingdom; downstream investment of oil revenue in the reconstruction and development of the Kingdom; a general plan for the settlement of the Bedouins; the provision of a public electricity network for the city; the opening of the Riyadh - Dammam railway corridor providing a link from the capital to the Eastern Region; the commissioning of Riyadh airport (converted to Riyadh airbase, after the opening of King Khalid International Airport in 1983); and the relocation of ministries and other central government agencies in 1955. In 1974, The High Commission for the Development of Arriyadh was established as the organizational, planning, executive and coordinating body responsible for the development of Riyadh. Arriyadh Development Authority “ADA”, established in 1983 is the High Commission’s executive, technical and administrative arm. The ADA is responsible for implementing the High Commission's organizational, planning, executive and coordinating decisions and missions. The ADA’s president is a member of the High Commission (ADA 2015). One of the remits of the ADA is the preparation and execution of a transport plan for the city of Riyadh."

Jan 1, 2016

By D Blair, T Scutts, L Fergusson

This paper presents a waste rock treatment and rehabilitation program conducted at a metaliferous mine site in northern New South Wales from 2000–2013. It updates findings from 2005 for Program #1 (which examined acidity, leachable metals and tree growth in a control and three treated areas of waste rock) and includes new results for Program #2 (which examined acidity, plant uptake of metals and trace elements and tree growth in a control and four treated areas compared to undisturbed background levels) and Program?#3 (which examined the treatment and revegetation of submerged mine tailings and an exposed tailings beach).Program #1 showed low soil pH in the control area remained unchanged from years 1–14, and soil pH in the limed and capped areas was initially increased but fell back to starting levels within 12 months and remained low for 14 years. In contrast, soil pH in the Terra B area resulted in soil high pH immediately after treatment and increased in years six and 14 without further treatment. Tree height and density in 2005 and again in 2013 indicated acidity in the control, limed and capped areas suppressed tree height and density; however, in the Terra B area, revegetation in 2013 was comparable to undisturbed forest. Outcomes in the control, biosolids and three Terra B areas in Program #2 were similar to those observed in Program #1.Program #3 showed the submerged and exposed tailings initially had low pH and high concentrations of total and leachable metals before treatment, but these became non-leachable after treatment with Terra B. Revegetation was achieved on the tailings beach, with almost uniform colonisation of bulrush and common reed, along with bottlebrush and golden wattle; a variety of reptiles have also been observed on the revegetated tailings beach, along with migrating ducks, spoonbills and grebes.CITATION:Fergusson, L, Blair, D and Scutts, T, ?2014. Treatment and rehabilitation of acidic waste rock and tailings – a 14-year case study, in Proceedings Life-of-Mine 2014 , pp 247–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M. C. Radomsky

Approximately sixty, small, surface coal mines in Pennsylvania participated in a program designed to improve safety performance in the workplace. The method involved the use of safety sampling and observation to assess the safe standards of worker behavior and work conditions. Data were collected through the use of operation-specific, on-site safety records covering seven major occupational units. Workplace events observed (acts and conditions) were assigned a hazard classification; feedback, both immediate and delayed was initiated to improve safety performance. The experiences drawn from this pilot project have proven the need to continue to pursue this behavioral approach; however, a stricter methodology needs to be adopted in the collection and analysis of data.

Jan 1, 1987

By C. Gosselin, M. Rheault, M. Benoit, Y. Bouroubi, V. Sarago

The last three decades have seen significant mining development in northern regions of Canada, where the freeze and thaw cycle of permafrost and the corresponding surface subsidence and heave represent a significant challenge to the design and maintenance of infrastructures. Identifying areas at risk is of great assistance to reduce the impact of this issue. Over the past ten years, Synthetic Aperture Radar Interferometry (InSAR) has been widely used to monitor ground surface deformation. With this technique, changes in phase between two SAR acquisitions are used to detect centimeter to millimeter surface displacements over a large area and with high spatial resolution. InSAR can be used as a tool to assist the siting and design of new infrastructure as well as highlighting the risk to existing structures in areas of unstable terrain. This paper presents the results of a project carried out by Effigis, which made use of SAR interferometry in the context of monitoring terrain and infrastructure stability in a northern mining environment that is affected by permafrost seasonal and long term changes. TerraSAR-X images acquired during two periods, August to November 2012 and March to October 2013, were used to measure the deformations and/or movement of ground surface, infrastructure and stockpiles caused by seasonal changes in permafrost extent in and around a mining site located in Nunavik, Quebec. The results showed that spatial and temporal distributions of surface displacements are in accordance with scientific and terrain knowledge. Some displacements were observed in loose soil areas while, as expected, none were detected in bedrock and rock outcrop areas. The areas most affected by active layer changes showed surface subsidence in the thaw settlement period. This study confirms that SAR interferometry has a great potential for operational applications related to risks induced by surface deformation in mining environments. It shows that this technique can be used to produce reliable maps of surface movement and monitor the vertical displacement of important infrastructure.

Jan 1, 2015