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By David S. Yang

The Cement Deep Soil Mixing (CDSM) method introduces and mixes cementitious materials with in situ soils using hollow-stem rotating shafts equipped with a cutting tool at the tip and mixing paddles above the tip. CDSM generally produces a soil-cement panel consisting of three overlapping soil-cement columns. The soil-cement panel is then extended to form walls, which are effective for excavation support and groundwater control due to the continuity and low permeability of soil-cement walls. Two design approaches could be taken in the application of CDSM for excavation support: 1) single wall design and 2) gravity wall design. The former one is treated as a wall technology and the latter one is treated as a soil stabilization method. This paper will review the CDSM equipment and installation procedures for the construction of these two types of soil-cement walls. Four case examples are used to illustrate the design and application of these two types of soil-cement walls.

Jan 1, 2003

By T. Y. Yunsel

Estimation techniques such as polygonal, triangular prism, trapezoid, isopach maps, and inverse distance methods are often used in ore or industrial minerals deposit evaluation. These techniques do not express the variability of the deposit and do not allow a determination of the reliability of the estimates. However, geostatistical methods can express a measure of the error associated with the estimates, by finding weighting coefficients for a given mining block, and can also help with data configuration that minimizes the error. This work addresses an application study on the quality and reserve characteristics of the cement raw materials of the Adana Cement Factory in Adana, Turkey, based on the spatial distribution and variability of the chemical components (Si02, CaO, A1203, Fe203). The study has been carried out using a geostatistical procedure that is useful for site assessment, characterization, and monitoring situations where data are collected spatially. Directional and omnidirectional experimental variograms of the cement raw material variables showed that neither strong geometric nor severe zonal anisotropy exists in the data. The most evident spatial dependence structure expressing the continuity for omnidirectional experimental variograms were characterized by exponential and spherical variogram models. These models have been used in cross¬-validation analysis, which proved that these models, their parameters, and kriging parameters are applicable for the study area. Quality contour maps of the deposits at given levels underground were estimated using a kriging interpolation technique. Anomalies such as bullseyes and drift were not observed in the maps that were generated. Kriged maps showed the spatial distribution of quality continuity and variability of the deposits. Grade-tonnage curves and total tonnage estimates in the particular grade were determined using ordinary kriging in order to improve the mining operation and planning. Consequently, local uncertainty and the probability of extreme values occurring are tools of prime importance for the mine planning, the optimum mix of raw materials coming from different quarry stopes.

Jan 1, 2012

By M. H. Kline

The Cranberry magnetite deposits occur in pre-Cambrian granite-gneiss, in a belt extending from 3 miles southeast of Cranberry, N. C., to about 6 miles southwest of Magnetic City, Tenn. The belt forms a curve) elongated to the north, approximately 26 miles in length. The Bureau of Mines investigation has been confined to the eastern part of the belt, comprising the area from Fork Mountain, Avery County, N.C., to the Hcupscup Knob prospects in Carter County, Tenn. The deposits were worked at least us early as 1820. The Cranberry Iron & Coal Co. and its successors operated the Cranberry mine intermittently for about 50 years until 1930, when operations were abandoned.

Jan 1, 1948

By J. Mason

In order that the use of continuous mining machines be most economic, the equipment must be operated at rated capacity as much of the time as possible and downtime for repairs kept at a minimum. A large factor influencing any proposals for maintenance programs is the complexity of the machines—often the intricacies of the precision-built equipment requires engineering knowledge byond the scope of mine maintenance personnel. A training program is part of the answer; there are others. In addition to investigating a joint company-manufacturer equipment-design improvement program, Mountaineer Coal Co. has launched a detailed preventive maintenance program to combat extensive downtime often encountered when continuous miners are used. Everyone in the coal industry knows the importance of operating continuous miners at their rated capacity as much of the time as possible. The potential capacity of the miner is such that l-min. delay means from 3 to 8 tons of coal lost. Today's miner is a well designed, precision-built machine, complicated with hydraulic and electrical equipment and complex mechanical assemblies with all possible combinations of gears, levers, and rods. As the machine becomes more complex, the problem of maintenance becomes more acute. The transition from conventional to continuous mining has taken place so rapidly that the mine mechanic has been unable to keep pace. When there is a machine failure, the maintenance man usually employs either the trial-and-error or the play -it-by-ear method of repair, but this represents an expensive proposition. Mine mechanics, maintenance superintendents, and mine managers complain about the complexity of the machines and how difficult it is to keep them running. There is no shortage of skill in the design offices. Machines are designed by good engineers, but for engineers. What's the answer? Better trained maintenance men—better maintenance instruction—better field service. These are all good corrective measures, but the real cure is to provide for the men at the do it level. Designers have got to cooperate with men to simplify maintenance on the increasingly complex machine. The designer must be aware of how his machine can be maintained. Sometimes a simple design change in a bearing, oil seal, or a bushing will correct recurrent breakdowns. Parts such as filters, hydraulic cylinders, hoses, and pivot pins can be better arranged on the machine to make them accessible so that the mine mechanic can easily keep the machine producing. Therefore, to get our maintenance off on the right foot, the program must begin back in the design office, before the machine is delivered to the mine property. Realizing the importance of this aspect, our company set out on a joint company-manufacturer equipment-design improvement program. This is a formal program in which quarterly reports are written covering machine defects, design weakness, and general problems relating to machine maintenance and performance. The manufacturer in turn comments on each and every item appearing in these reports, indicating the action he proposes to take. In addition to the written reply, meetings are scheduled with manufacturer representatives to discuss further the outlined problems. The benefits realized from this organized program are both substantial and far reaching. Good maintenance begins with a good design. The subject of preventive maintenance is not a new one. Volumes have already been written on the subject. It consists primarily of doing the maintenance work when you want to rather than when the machine demands it. However, a preventive maintenance program can be overdone. Theoretically, if carried to ridiculous extreme, all working time could be spent inspecting and repairing the machines and no time would be left for production output. Our goal in maintenance is to maximize running time for all machines, and to prevent or at least minimize production downtime. INSPECTION AND REPORTING The center of any preventive maintenance schedule is regular and systematic inspection, but it must be

Jan 1, 1961

By Ed Beswick

Resource Update Drilling Program ? Pre-feasibility ? Exploration Metallurgy Program ? Grindability ? Metallurgical Optimization ? Hydrometallurgical Options Preliminary Mine Development Design Environmental Permitting Infrastructure Development

May 1, 2008

By C. Crussard, R. Tamhankar

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers accord-ing to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Gerhurd Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Staff Coordinator, James J. Burke THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Past-President; John Chiprnan, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman; Dennis Carney, John Chip-man, J. C. Fulton, J. H. Hollomon, H. H. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and D. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman, F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham, .Jr., Robert F. Hehemonn, R. I. Jaffee, F. E. Jaumot, Jr., Irving R. Kramer, A. J. Lena, Harold Margolin, C. J. McHorgue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alan U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B. King, F. C. Langenberg, W. 0. Philbrook, and T. 0. Winkler. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts... Second class postage paid at New Yark, N. Y., and Ann Arbor, Mich. Volume 212, Number 6.

Jan 1, 1959

By G de Jong, W Sunyoto, K Sari, P Silalahi

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Big Gossan mine is operated by PT Freeport Indonesia and is one of the largest stope-and-fill mining systems in the world. The Big Gossan deposit is a ~200 m wide, 1200 m long and 500 m high steeply north-east-dipping to subvertical skarn body at the Cretaceous-Tertiary Ekmai-Waripi contact. The copper-gold mineralisation, with a 1.3 per cent copper equivalent cut-off grade, occurs mainly proximal to the Ekmai-Waripi contact in the garnet-clinopyroxene prograde skarn at the base of the Tertiary Waripi formation and partly distal to the contact in the tremolite-actinolite retrograde skarn of the Tertiary Waripi formation.The Big Gossan stope mine is designed from 2540 m to 3020 m above sea level. Present active stoping operations occur at level 2540 mL to level 2640 mL and are done in a primary and secondary stoping sequence. The width and length of the stopes is 15 m and 20 m respectively, while the height of the stope varies between 20 m and 40 m, depending on the ground conditions. The stability of the stopes is visualised in the Mathew’s Stope Stability graphs. These graphs and actual Cavity Measurement Scanner measurements on the stope will predict and show the overbreak and underbreak, which affect the reconciliation of the mined stope and also the pillar stability between the primary stopes. Geological factors like major structures, joints, veins and alteration intensity are important factors that correlated with the stability of the Big Gossan stopes.CITATION:Sari, K, de Jong, G, Silalahi, P and Sunyoto, W, 2015. Stope stability at the Big Gossan skarn deposit, Papua, Indonesia, in Proceedings PACRIM 2015 Congress, pp 139–146 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A. Kostin

GIS and multivariate geometric distribution have been used to predict the association of high-level intrusives with hydrothermal alteration related to iron oxide Cu-Au (IOCG) mineralizing systems. Several examples in the Russian northeast are presented in this paper. IOCG ore deposits can have enormous geological resources containing significant reserves of base, precious, and strategic metals, and hence are economically attractive targets for mineral exploration. To date, examples of this type of mineralization have not been reported from the northeastern area of Russia. The Tarinskiy ore cluster, located in Eastern Yakutia, shows brecciated altered rocks with sulphide and iron oxide cement, which is typical for IOCG mineralization of the iron oxide Cu-Au±U type. This cluster was formed near surface and is linked with the Rep- Yuruinskiy pluton. It has potential to host new world-class precious metal deposits in northeastern Russia

Jan 1, 2014

By Lutz Markworth, Wolfram Jaspers, Johannes Kottmann

PNEUFLOT® technology has been applied for the past 20 years in coal, ore and other minerals processing plants. During the last two years this technology has achieved a breakthrough with some 42 units being sold signifying a rising trend. »Humboldt Wedag Coal & Minerals Technology« has performed extensive research and development work over the last five years. The results of which were used to design a new fourth generation aerator. Humboldt Wedag, through its association with EKOF, can offer a holistic solution encompassing both flotation equipment and reagents. It is the only company in the world able to offer such a package. The association with EKOF strengthens the Humboldt Wedag product offering, especially as the company in-troduced pneumatic flotation cells to the South African market in the form of the PNEUFLOT®. Before starting pilot scale test work, a mineralogical analysis has to be carried out to determine the mineral com-position as well as the liberation grade. HW-CMT works together with independent institutes. Different reagent regimes can be tested in laboratory scale. Pilot machines, each packed in a 20? container, are available to carry out extensive test work at customers? processing plants. A group of engineers from HW-CMT is involved in the pilot test work. The flexible pilot machines are designed to cater for coal, ores and other minerals. The small feed rates of 7 ? 12 m³/h only means the pilot machines do not disturb the operation of process plants. Batch tests have to be carried out to determine the numbers of PNEU-FLOT® stages. New applications in iron ore, copper ore, platinum group minerals, rock phosphate and potash were suc-cessfully tested in the last three years. In applications where the feed material is very fine, PNEUFLOT® technology is able to achieve high recoveries with particle sizes where conventional technology failed.

Jan 1, 2007

By A. G. Mayton

Vehicle vibration exposure has been linked to chronic back pain and low back symptoms among agricultural tractor drivers. The objectives of this study by the National Institute for Occupational Safety and Health (NIOSH) were to assess driver whole body vibration (WBV) exposures and recommend interventions to reduce the risk of back related injuries, particularly relative to vehicle jarring/jolting (the transient mechanical shock components of WBV). The methodology included collecting, from two independent samples, ?eld data and health and work history data of farm equipment operators. Data were collected during mowing, raking, baling, chiseling, tilling, and road travel for different model tractors. Spraying using a sprayer and shrub removal with a skid steer loader were also included. Based on ISO 2631 (1985), the American Conference of Governmental Industrial Hygienists, threshold limit values, presents 0.5 m/s2 as the action level recommended by the Commission of European Communities for overall weighted total RMS acceleration (vector sum for axes x, y, and z) [ACGIH, 2006. Threshold limit values and biological exposure indices. Cincinnati, OH]. WBV measured at the operator/seat interface exceeded this action level. The roughest rides and highest vector sum accelerations occurred with small utility tractor mowers (3.3 and 2.8 m/s2) and a skid steer loader (1.7 m/s2). Major ?ndings from health and work history data showed 96% of participants reported having to bend or twist their necks, although 24% reported neck symptoms. Sixty four percent of participating operators reported experiencing back symptoms (e.g., pain, aching, stiffness, etc.). Recommendations included: specifying a seat that ??better?? isolates operators from jars/jolts with new tractor purchases; maintaining the seat/seat suspension and replacing worn or damaged cushions with NIOSH tested viscoelastic foam padding; using larger diameter tires with radial ply instead of bias ply construction, particularly on small utility tractor mowers, to aid in attenuating ride ??roughness??; using a swivel seat to reduce the stress on the neck from bending or twisting; and improving efforts to educate owner/operators of the adverse effects of WBV exposures. Since the data presented in this paper were collected from two independent samples, the authors were unable to draw any correlations or etiological inferences from the study. However, results were compared and contrasted with other studies which included similar vibration measurements in agriculture.

Jan 1, 2008

By L. C. IlsLey, M. W. Von Bernewitz

"Introduction.Several hundred thousand open lights are daily carried in coal mines of the United States, each lamp being a menace to life and property through fire or explosion. They have been responsible for many disasters in the past, and will be again. Flame safety lamps have been available for over a hundred years, but during the last ten years safe and practical electric lamps have been perfected. These have eliminated many of the flame safety lamps, and in a few mines have replaced open flame lamps. But there are still more than twice as many open lamps as electric lamps in our mines, and the open lamps should be discarded in favor of an approved type of electric lamp. There are several electric miners' lamps which have been approved by the Bureau of Mines for safety and efficiency, give good light, and are easily maintained and carried, some flame safety lamps will always be used, hut mostly for detecting gas; although they might be supplanted if some simple, reliable, and cheap gas detector were developed.Explosion Hazards from Open Lights.An open light and gas*** constitute a vicious hazard; while if there be coal dust present in the vicinity the consequences are multiplied many times. An open light and black blasting powder also constitute an explosion hazard, vividly attested by several serious disasters."

Jan 1, 1924

By R. Lombard

"Water is a very important component in the production process at underground coal mines. Current unfavourable economic conditions have forced the coal mining industry to identify and address every possible bottleneck preventing optimal production. An increase in water-related downtime was identified as one of the bottlenecks at Goedehoop Colliery’s Vlaklaagte Shaft. The purpose of this project was to identify the various causes that contributed to the high downtime (501 hours in 2013, which led to a potential profit loss of R12.9 million) and to suggest possible solutions.After a thorough investigation the main causes of water-related downtime were identified as low water pressure and low water flow caused by pipe leakages and bursts. The main root cause for the low water flow and pressure was identified as being the low pressure resistance (1600kPa) of the thin-walled galvanized steel pipes used in the underground inbye water reticulation system. The pipes were selected according to the previous 1000 kPa pressure requirement for the continuous miner. However, the pressure requirement changed to 1500 kPa, which resulted in the pipes being exposed to much higher pressures than designed for.The water reticulation system was reviewed and current and future underground pipe layout and water requirements were determined for the shaft. The time frame in which the water consumption would be the highest was determined to be between 1 January 2014 and 7 September2014. Machine and sprayer specifications were used to determine theater consumption at the shaft. Three different solutions were considered to solve the water-related downtime problem and to ensure the efficient supply of water to the newly open sections. Permanent underground concrete dams, semi-mobile dams, or new pipe columns with a higher pressure resistance of 3200 kPa were considered. A trade-off study (taking into consideration cost, time to completion and ease of implementation, maintenance requirements, safety, and flexibility) was completed to determine which of these solutions would be most viable.Paper written on project work carried out in partial fulfilment of B. Eng. (Mining Engineering)"

Jan 1, 2015

By D. Brün, T. W. Nattkemper, T. Kuhn, T. Schoening

Underwater exploration for marine resources using camera-equipped devices (OFOS, ROV, AUV) is receiving growing attention. This development is creating a continuously growing pile of digital underwater images leading to a serious bottleneck in the analysis. However, any harvesting strategy must be coupled to an efficient and effective assessment of the biodiversity in the area of interest and in nearby control areas. To integrate manual image and computational image interpretation on different levels (i.e. regarding geology and environmental sciences and taxonomy), sophisticated software support is required, which is not yet offered explicitly, neither by commercial software companies nor by academic or other publicly founded institutions. Here, we present the first version of a new digital asset management system that offers functionalities for easy data management, sharing, manual annotation and integration of computational modules for image enhancement/pre-processing and interpretation. The functionality is demonstrated with data from the CCZ provided by the BGR Hannover.

Sep 1, 2014

Unrelieved residual strains can influence the states of stress in rock masses. If cheap, stable structures are to be constructed in Tock in which large pressures are exterted by unrelieved residual strains, the pressures must be either utilized or neutralized. A photoelastic technique has been used to show that the release of residual strains in rocks is influenced by the mechanical properties of anisotropic rock fabrics. The relationships between directions of residual strain release and the attitudes of minor geological structures have been determined. For engineering design purposes it is possible to estimate the principal stress directions in rock containing unrelieved residual strains if the attitudes of such minor geological structures as foliation planes, lineations, and joints are known.INTRODUCTIONQuarry workers have long been aware that near-surface rocks may be highly stressed. In many cases the stresses are too large to be the result of gravitational loads. Dale (1923, pp. 34-35) gives many instances of deformation produced by the violent release of residual strains in quarry rocks. Coates (1963) has described powerful rock bursts and cases of rock deformation underground implying the existence of much larger stresses than are likely to result from present-day gravitational loads. The only explanation is that pressures of up to several thousands of pounds per square inch may be caused by unrelieved residual strains in rock.Instruments have been developed for measuring states of stress in rock masses. Most stress determinations in rock have been made on the assumption that rock behaves as a simple elastic material. It is now known that rock is a...

Jan 1, 1964

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in'progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America.The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

Remote sensing methods have been used to evaluate vegetative growth patterns for many applications, though relatively little work has focused on tracking mine reclamation progress. For coal mines in Central Appalachia, reclamation approaches that include production of biofuel feedstocks are increasingly attractive, as these may yield significant post-mining land values and contribute to carbon-neutral energy supplies. To optimize productivity, the influence of reclamation parameters must be well understood ? which necessitates tracking biomass production over long time periods. Satellite-based estimations may offer low-cost alternatives to conventional biomass appraisals, and also the potential to provide critical input for carbon accounting at varied spatial scales. In this paper, we use biomass production experimental plots on reclaimed mine sites established by the Powell River Project (PRP) for a comparative study between satellite measurements of Normalized Difference Vegetation Index and inventory estimates of biomass under a variety of conditions. The PRP is a unique public-private partnership in the coalfields of southwestern Virginia dedicated to enhancing beneficial use and environmental protection of mined lands.

Feb 27, 2013

By Ron J. Elliott, Dylan Wedgewood

A series of five signature holes were blasted at the Highvale Mine and the resultant seismic data was analyzed to make recommendations on how best to address neighbour complaints regarding blast vibrations. From an analysis of peak vibration levels measured at the closest neighbour for blasting during 2016, it was determined that the blast vibration intensity varied between 1.4 to 4.3 mm/sec (0.06-0.17 ins./sec.), well below the level of concern for the onset of minor damage to residential structures, however, the frequency of the blast vibrations was between 2.2 and 9.7 Hz, which is within the range of the natural resonant frequency for a single story home. This was determined to be the cause of the neighbour complaints, as the home would be responding to the blast vibrations.

Jan 1, 2018

By Douglas Henrique Milanez

A nanocelulose possui grande potencial de inovação e apelo sustentável, podendo ser obtida a partir de três vias principais: processo mecânico, hidrólise ácida e biossíntese bacteriana. Poucos estudos verificaram os avanços tecnológicos, bem como as principais organizações que dominam tecnologias envolvidas nas três vias principais de obtenção. Este estudo objetivou mapear as principais organizações e caracterizá-las conforme o processo de obtenção, mediante indicadores elaborados a partir de registros bibliográficos de documentos de patente indexados na base de dados mundial Derwent Innovations Index. Foi efetuada a mineração de dados para analisar a evolução do patenteamento, os principais titulares e os subdomínios tecnológicos no período de 2002 a 2011. Também foi realizada a mineração do texto contido nos títulos e resumos dos registros bibliográficos para mapear os processos de obtenção de nanocelulose e suas relações com os titulares. Os resultados indicaram o envolvimento de diversas instituições, sobretudo da China, dos EUA, do Japão e da Finlândia, além da característica emergente dos desenvolvimentos tecnológicos de cada processo. Não foram identificados titulares do Brasil, conforme os critérios e as fontes adotadas no estudo. A metodologia empregada mostrou-se útil para a obtenção dos resultados pretendidos e abre espaço para o seu aprimoramento mediante novas pesquisas.

Aug 8, 2018

Greater use should be made of lineations in investigations of the engineering properties of rock masses and in structural studies guiding prospecting programmes.A prominent alignment of elongate mineral grains and stretched pebbles usually marks the primary direction in which metamorphic rocks have been extended by flow. In local adjustment zones separating masses that have extended different amounts, this lineation has been a direction of slip. Kinks and crumples resulting from this slip lie in secondary lineation directions transverse to the primary mineral lineation.During deformation relatively mobile materials move into dilatant zones caused by irregularities in primary flow directions. This secondary movement transverse to lineated, primary-flow directions is the cause of crenulations and folds with axes parallel to flow lineations.INTRODUCTIONThe arrangement of inequidimensional particles in rocks is rarely statistically random. Platy minerals tend to be parallel to bedding and foliation planes. Elongate particles and linear structures lie most frequently in certain lineation directions. The types of elongate particles in lineated rocks include needle and blade shaped mineral grains, sheared out segregations, and stretched pebbles, amygdules, and aolites.Crenulations and kinks are the most common of the linear structures involved.Faint lineations are readily overlooked. Even strong lineations have been ignored. This is unfortunate as even weak lineations may be important.Use of lineation information Well-developed lineations influence the mechanical properties of rocks. Quarry workers have long known that the mechanical properties of rock masses vary directionally...

Jan 1, 1965

By N. Kumar Kittusamy

ALTHOUGH MANYSTUDIES HAVE SHOWN an association between operating heavy construction equipment and symptoms of musculoskeletal disorders (MSDs), little research has been performed that systematically characterizes the exposure of operating engineers to ergonomic hazards. This study evaluated: 1) vibration at the seat/operator interface;2) transmissibility of vibration in the Z-axis; 3) psychophysical ratings of vibration level and vibration discomfort; and 4) postural requirements of the job. Results indicate that the digging operation had higher levels of total weighted acceleration than high- or low-idling conditions. Transmissibility data showed that the seat amplified vibration, particularly in the lower frequencies. Seats demonstrated that they may not be sufficient in protecting operators from long-term effects of vibration exposure. High positive correlation was found among subjective ratings (vibration discomfort and vibration level), but moderate positive correlation was found between subjective ratings and quantitative vibration levels. Postural evaluations revealed that the operators were required to assume awkward postures of the neck, shoulder and trunk while performing their jobs. Work-related injuries and illnesses pose a continuing threat to the health and well-being of American workers. The construction industry has been historically recognized as having higher rates of fatality, injury and illness than other industries (McVittie285+; BLS). In 1994, an estimated 218,800 lost-work-day injuries were reported in the construction industry (BLS). Construction also had the second-highest incidence rate for sprains and strains. Although the industry has made progress since then, injuries and illnesses, including MSDs, continue to because for concern.