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By Brian FitzPatrick, Michael J. Weaver

Everyone has a role in site safety, even consultants. This paper presents a summary of how a geotechnical and environmental consulting firm, with field staff on construction and subsurface explorations sites, engaged their staff and leveraged relationships with contractors to assess the construction related risks to which its staff members are exposed. These findings were then integrated into their technical training materials for both new staff and those needing a refresher, so that safety is discussed at the same time as the technical work and not treated as a separate topic. The paper outlines the process of identifying and evaluating the construction related risks that staff members face and presents examples of how the consultant can engage contractors in the process. By doing this, knowledge can be shared and there is a better mutual understanding of the risks associated with common construction and exploration related field tasks. The work resulted in an increase in staff engagement in safety, a better understanding of the true risks that staff face in the field, better relationships with contractors, and lower safety metrics. HISTORY At Haley & Aldrich, Inc., we renewed our safety journey in May 2012. Like many others, we had concerns over injuries our staff experienced in the three previous years, and a potentially significant utility strike we experienced while excavating a trench. In 2009, 2010 and 2011 we experienced an increase in recordable injuries, including two significant injuries, which caused our Experience Modification Rate (EMR) (see note below), Total Recordable Incident Rate (TRIR), and Days Away-Restricted, and Transferred Rate (DART) to rise significantly. See Fig. 1 for details. This caused us to step back and review our approach to safety, and our “safety culture”. The rise in reportable incidents and injuries also corresponded to the beginning of a growth period for the company.

Jan 1, 2019

Contact Angle Measurements on Lignite Surface

Sep 13, 2010

The growth of "Unit Load-cargo handling technology in world cargo lin- er trades over the last decade has cre- ated a situation in which special pur- pose-vessels (cellular container ships, roll-on/roll-off vehicle deck ships and Lash type vessels) are rapidly replac- ing conventional cargo ships, the principal means previously available for transporting heavy lifts. Consequently heavy lift traffic has tended to accumulate awaiting ship- ment, especially where discharge is required in "off beat" locations. A partial solution to this problem will be provided by new and small but exceptionally versatile ocean going heavy lift carriers now finding their way into world trade routes. These new ships combine extremely high lifting capacity, high manoeuvreability and exceptionally shallow draft with bow and stern Ro/Ro capability. They can handle rolling loads of exceptional size and weighing up to 1,000 tons Each. But the problem is a far larger and more serious but essentially a domestic one. Major industrial pro- jects in Australia will require pro- gressively heavier and larger plant and construction sites are becoming much more inaccessible. Whereas these new ocean going heavy lift carriers have ample capacity to satisfy part of the total transport requirement, there is clear evidence to show that domestic transport resources have little if any potential for increase in capability at the same rate as demand or at the same rate as sea transport facilities. Resolution of the larger problem is within reach but only through a pro- perly co-ordinated approach to future planning for the overall needs of large scale projects on a national basis. This co-ordinated approach must involve Federal and State government transport administrators, railway and highway authorities, shipping and road haulage interests and finally the planners of the projects which require these improved heavy haulage services.

Jan 1, 1973

By Anton Sizo, Alexey Klyashtorin

The Gunnar uranium mine operated from 1953 to 1961 on the shore of Lake Athabasca, in 1964 the site was abandoned, and the mine pit flooded. In 1981, the pit was found to be stratified with a chemocline at ~70 m by a sharp change in conductivity and TDS. The uranium concentration was ~700 μg/l on the surface, 320 μg/l at 50 m, and 2,900 μg/l at 110 m. The Ra-226 concentrations were 0.1, 0.06, 0.12, and 0.4 Bq/l. By 2017, the chemocline was ~60 m deep. The highest uranium concentration was 1150 μg/l and the lowest concentration (220 μg/l) was attributed to the chemocline. In the deeper column, the uranium content varied around 750 μg/l. The uranium distribution down the pit profile was aligned with DO, ORP, and TDS. Ra-226 averaged to ~0.4 Bq/l, Ra-226 and uranium profiles were inversely related with the respective maximum and minimum attributed to the chemocline. The uranium and radium amount accumulated in the pit by 2017 was 3,420 kg and 2,163 GBq, respectively. The uranium and radium apparent accumulation trend estimates to 64 kg/y and 41 MBq/y, respectively. A stable chemocline and no concentration gradients in the other parts of the pit suggest that the contaminants are unlikely to inflow from the bottom opening or outside the pit, but rather are mobilized from the pit walls. The contaminants are not in a steady state, and concentrations of both uranium and radium are likely to increase slowly in the future if no remediation occurs.

Jan 1, 2020

By L. R. Moore

The World Health Organization (WHO) considers contamination from oxyanions, such as selenium and arsenic, a global concern. While their elemental forms are toxic, the aqueous oxyanions are more so. These aqueous forms, which exist at a higher oxidation state, are the most common forms released during mining processes. Many technologies are capable of meeting the governmental discharge criteria for oxyanionic contaminants, but may possess limitations due to redox chemistry as well as the water matrices. An innovative technology was developed that can successfully reduce such aqueous forms generated during mining processes to a level below the discharge criteria. This paper discusses how an understanding of the sensitivities of this novel adsorbent towards these variations in water matrices and redox chemistry can be used to optimize its application.

Feb 27, 2013

The Functional Performance Equation for ball milling circuits provides plant staff with a new means to improve circuit performance. However, successful execution of a plant project, with verifiable circuit processing performance improvements, requires a significant number of accompanying steps beyond the equation alone. In order to identify and articulate all these steps, a study with plant staff from two milling operations and a grinding media supplier was undertaken. ?Task analysis? of improving plant grinding performance was carried out. This analysis called for the development of a number of system components, and ultimately yielded a ?Plant Grinding Circuit Processing Performance Management/Improvement System.?

Feb 23, 2014

Jan 1, 1965

By James R. Hein

Barite and Fe-Mn-oxide deposits that occur along faults in the Southern California Borderland formed by low-temperature hydrothermal processes. The Borderland region consists of block-faulted continental crust within the broad transform boundary of the North American plate. The fault-bounded basins are anoxic and partially filled with hemipelagic and turbidite sediments. Barite was collected from four dredges and a submersible dive (DSV4-355) in the southern California Borderland, and was collected from two sea-cliff sites along the Palos Verdes Headlands near Los Angeles. Barite at these seven locations occurs along strike-slip and basin-margin faults from the shoreline to 1800 m water depth. Submersible observations showed a series of mounds up to 10-m high composed of friable, white barite associated with diffusely venting milky fluid; the mounds support large benthic colonies, including tube worms (Lonsdale, 1979). Barite samples recovered from dredges are brown, green, and white and range from porous, vuggy fragments to massive fragments cut by banded barite veins. Samples from two dredge sites contain fossil worm tubes 1-3 mm in diameter and >10 cm long. All the samples are nearly pure barite, with only minor to trace amounts of other minerals. Chemical analyses show 94-98 wt. % BaSO4, low total rare-earth element (REE) contents (<45 ppm), Sr contents from <2 to 10,000 ppm, and Hg contents up to 1 ppm. Chondrite and shale-normalized REE patterns show light REE enrichments and large positive Eu anomalies. These REE pattern characteristics are typical of marine hydrothermal fluids and minerals. Sulfur isotope ratios (d34SCTD) from +21.6 to +67.4? range from seawater values (+21?) to exceptionally high positive values. Strontium isotope ratios are lower than the modern seawater ratio as well as the seawater ratio that existed at the time of deposition of the host rocks.

Jan 1, 2002

By T O Aspinall

The Australian mineral industry involves a diverse range of expertise and skills. Within that, the mining industry, representing mine planning, mine management and equipment operation, has capital intensive, high productivity equipment and a small but skilled workforce. Continuing education for all personnel in the workforce after formal school courses will be an important contribution towards improving competitiveness. The non-tertiary sector represents a significant proportion of the workforce and requires as much attention as the tertiary educated group. Competency Based Training is now being developed for the mining industry in Australia under the National Training Board and the mining industry is well represented in establishing standards and curriculum. TAFE is a major source of accredited courses but some mining companies are also developing internal courses not necessarily for external accreditation. Articulation of such accredited courses to tertiary mining engineering courses has been considered. The education and training of equipment operators through continuing education requires attention to operating skills, an understanding of the productivity factors under the direct influence of the operator and providing product quality to the customer. The education and training of mining engineers has been widely covered and continuing close involvement of the mining industry is required to ensure well balanced courses in technical and interpersonal skills as well as motivation to continue learning for life. Postgraduate research is a part of continuing education but the mining industry has to continually address the adequate recognition of post-graduate qualifications for the increased technical or management expertise and the development of better analytical and problem solving skills which can be directed towards improving competitiveness. More attention has to be paid to providing adequate financial incentives to attract suitable students, particularly after attaining some experience, and to address their professional career path with a company so they are not significantly disadvantaged by undertaking post-graduate studies. The Chartered Professional Engineer status as provided by The Institution of Engineers, Australia to qualified candidates is being considered by The Australasian Institute of Mining and Metallurgy as a further recognition of a member&apos;s specific expertise and competence in mining and metallurgical engineering. Continuing education plays a major part in the maintenance of the expertise and competence required for a professional engineer to develop and also to retain chartered status. Continuing education will be a significant part of the education and training of all the mining workforce towards improving the competitiveness of the mining industry. The major challenges will be the motivation of all towards lifelong learning and the integration of the various programs towards providing the opportunity for a steady and satisfying career progression.

Jan 1, 1994

By P. O'Connell, J. Lever, C. Clemence

The Bulyanhulu Mine, Tanzania is constantly trialing ideas for improvements in the drill and blast process. The project work has resulted in a large number of choices in explosive type and charging methods being available for blast design. Interestingly, though booster sensitive bulk emulsion had been introduced to the site to reduce dilution, better results were being obtained from reduced charge columns (decoupled columns of poured anfo in 50mm pvc pipe) and pneumatically loaded anfo upholes, which had been traced. In order to compare the explosive type and charge up-methods, an explosives comparison trial was performed.

Jan 1, 2006

By Jaidev Sankar

The dream of constructing the new Second Avenue Subway in New York has finally become reality as the first construction contract package is currently underway. This first contract requires the construction a TBM Launch Box in the middle of Second Avenue from which a Tunnel Boring Machine (TBM) will bore two tunnels south to 63rd Street. This paper will discuss the design of this contract and how construction has progressed including preparation, site constraints, utility construction and com-munity impacts while highlighting the challenges of working in an urban environment. It will also discuss moving forward on this major project outlining the remaining contract packages including their scope and status.

By J. G. Zafiratos

The leaching of a Greek low-grade manganese dioxide ore, not amenable to conventional mineral processing operations, was studied using a mixed culture of Thiobacillus sp. bacteria. The experiments were carried out in specially designed continuously aerated and stirred tank reactors arranged in two-tank series. The first tank of each series was loaded with an elemental sulfur culture suspension while the second was loaded with a manganese ore high density slurry. The bacterial culture had been previously adapted to grow on elemental sulfur and also in the presence of manganese ore and dissolved manganous ion. A two level full factorial design was constructed in order to study the effects of the ferric ion concentration in the leach solution, the "elemental sulfu weight to ore weight" ratio, the ore pulp density and the composition of the dispersed gas. The responses which were investigated included percentage manganese recovery, co-dissolution of iron and manganese dissolution rate. Parameters with constant values throughout the experiments were the leach solution pH, the nutrient medium composition, the dilution rate and the ore and sulfur grain sizes. It was found that the ferric ion concentration was the most significant factor and had a positive effect on the final percentage extraction of manganese from the ore and also on the rate of manganese solubilization from the ore. The effects of the other factors studied are discussed in detail.

Jan 1, 1997

By Wagner Viana Bielefeldt, Felipe Buboltz Ferreira, Antônio Cezar Faria Vilela

The continuous casting machine is one of the most important steel production steps in a melt shop. The tundish, a reservoir between the steelmaking ladle and the mold, has great influence over the steel cleanliness, along with the productivity bid. It must takes into account the quality of the metal and operational safety. Several different variables are related to the tundish process, of inclusionary cleanliness. Some of them are discussed in this paper: the free opening of ladle, tundish inertization, steel temperature in the reservoir and clogging formation, besides a brief topic about castability. Therefore, a critical analysis, with a review from some papers available in literature, is proposed in this study, with its focus on tundish.

Oct 1, 2019

By R. D. Pehlke

The history and present status of continuous casting of steel are reviewed, including a genera 1 description of current processes. Plant layout, process development and elements of machine component design are outlined, and key steps in integration into a stee-1 production system are detailed. Recent productivity advances and improvements in quality are described. Process developments are reviewed, and some future avenues for this technology are considered.

Jan 1, 1985

By L. E. Baker, M. J. Leck

OSIRIS is a continuous monitoring system for respirable dust which has been specifically designed for mining and related industries. By using the latest microprocessor technology, OSIRIS provides a sophisticated dust measuring system which is a cost effective alternative to regular gravimetric sampling. The system is certified intrinsically safe for use underground. Up to eight underground OSIRIS sensors can be controlled and monitored by a single IBM PC computer located at the mine surface. This computer provides continuous and instantaneous information about the dust concentrations at the sites being monitored. Information is available in tabular and graphical form. The paper gives details of proving trials of the OSIRIS system in some UK coal mines. During these trials, adjacent OSIRIS sensors placed on the same underground roadway cross-section gave virtually identical results. Throughout a good correlation was obtained with conventional gravimetric dust samples. The OSIRIS equipment proved both reliable and easy to operate. OSIRIS was designed and developed by the Safety Engineering Laboratory of the UK Health and Safety Executive. It is now available commercially and is being

Jan 1, 1987

By J. H. Daniel

Dust-related respiratory disease remains the major health concern in mining, and health agencies are proposing more stringent standards. The U.S. Bureau of Mines (USBM) is investigating techniques to continuously monitor respirable dust in real-time during the coal or ore extraction process. Continuous monitoring will allow mine operators to evaluate hazardous dust concentrations and adjust the operations to produce less dust. Mine instrumentation applications include machine-mounted and hand-held monitors, personal monitors, and area/environmental monitors. Six dust detection methods have been considered to meet application requirements. These are: light-scattering instruments, a smoke-particle detection technique, correlation of pressure drop across the collection filter with amount of dust deposited, the Tapered-Element Oscillating Microbalance (TEOM) instrument, a method that relates the amount of dust collected on a filter with the vibration of the filter, and beta attenuation measurement of dust. Studies to date have identified the TEOM instrument and the technique of correlating the amount of dust collected with the vibration ofthe filter as having the most promise for success. Development of the machine-mounted monitor is the highest research priority. The application options and progress to date in developing continuous monitoring instrumentation are presented.

Jan 1, 1995

By T. Y. Chong, J. A. Folinsbee

Since milling began in 1909, the PJV Dome mill has been expanded several times, to the current throughput of 11,500 tonnes per day. PJV recovers free gold using crushing and grinding followed by gravity concentration. The remaining gold in the gravity tails is recovered by cyanide leaching followed by Carbon-In -Pulp processing. Prior to 1993, cyanide tailings were impounded in the tailings pond where cyanide was allowed to degrade naturally. Effluent was discharged seasonally during the summer and early autumn to maintain the water balance. In 1993, an Effluent Treatment Plant (ETP) was designed and constructed for the purpose of removing dissolved metals and suspended solids. In 1997, an INCO SO2/Air cyanide destruction process was added to the ETP. Even though the ETP was successful in meeting the cyanide, metals and total suspended solids (TSS) discharge limits, often the treated effluent failed to pass toxicity tests. Following successful laboratory and plant scale testing, the addition of the chelant EDTA (ethylene diamine-tetra-acetic-acid) was commenced in the 1999 operating season. To date, discharged effluent has passed all toxicity tests. This paper describes the evolution of the ETP from its early conception to the various phases of upgrade needed to meet the MISA discharge limits.

Jan 1, 2005

By Jesse R. Jacobson

A large casino complex in Cherokee, North Carolina recently underwent a $633 million expansion that involved substantial foundation challenges. The site is located in a valley on the southern edge of the Great Smoky Mountains National Park, where subsurface conditions typically consist of varying thicknesses of fill overlying alluvium, residuum, partially weathered rock and rock. The fill and alluvium contain cobbles and boulders as large as several feet in diameter. The residuum and partially weathered rock are very thick in some areas, and the depth at which consistently high quality rock is encountered is highly variable. To reduce the foundation costs for the expansion, continuous flight auger (CFA) piles were proposed in lieu of micropiles. CFA piles are not generally used in this geologic environment and concerns regarding their selection included: (1) an uncertainty that CFA piles could be successfully constructed given the difficult conditions and (2) a lack of regional data regarding unit resistance values and load transfer characteristics. To address these concerns, a design-phase test program was undertaken to evaluate pile constructability, develop an understanding of the load transfer behavior, and establish the required pile lengths. The program included soil test borings, shear wave velocity measurements, timed auger probes, instrumented pile load tests and observation of exhumed piles. It was demonstrated that CFA piles could be advanced through the fill, cobble/boulder-laden alluvium, residuum and into the partially weathered rock, albeit with some limitations. Under axial loading, the pile response was very stiff and relatively high unit resistance values were measured. Pile instrumentation allowed for the evaluation and use of design pile lengths shorter than that tested, and the overall reduction in pile lengths yielded a 40 percent reduction in foundation cost. In general, CFA piles were determined to be a suitable, economical foundation alternative.

Jan 1, 2011

By Jouko L. Lehtonen

Sheet pile walls can be sealed watertightly using various methods. The objective of this paper is to introduce a new innovation comprising the use of continuous cement grouting during embedding. The method has been tested on a field test site and installation and permeability features have been observed and analyzed. Installation can be carried out using traditional sheet piling machinery, merely some additional grouting equipment is needed. Installation speed of grouted sheet piles corresponds to that of conventional embedding. The permeability of the tested method is satisfactory in applications where e.g. polluted soil or water has to be isolated from the surrounding environment. In addition, this method can be used for conventional retaining walls where very low permeability is required or for reduction of soil vibration, e.g. close to a railway embankment. The new method to grout simultaneously and continuously during embedding has been developed based on respective innovations on impact driven steel piles.

Jan 1, 2006

By Bo Arvidson

SALA MAGNETICS, INC. is now operating a 15 tph continuous high gradient magnetic separator, the SALA-HGMS® Mark III Carousel, as part of a complete mineral processing pilot plant installed at Sala&apos;s Cambridge headquarters. The Mark III can generate a maximum magnetic field of 18 kG making it possible to process even weakly magnetic, finely ground ores and ore tailings on a continuous basis at the performance level achieved in Sala&apos;s cyclic high gradient magnetic separators. Test results on iron ores, clay, and decoppering of molybdenum concentrate will be discussed. Bench scale tests have been performed on all of these materials using the SALA-HGMS® Model 10-15-20 Cyclic Magnetic Separator. A direct correlation may be made between cyclic and carousel results. Sala&apos;s Mark III Carousel high gradient magnetic separator is designed to permit scale-up to machines capable of processing two hundred (200) tons of ore per hour and more.

Jan 1, 1976