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By Bryan Buchholz, N. Kumar Kittusamy

Previous studies indicate that operators of heavy construction equipment are afflicted by musculoskeletal injuries of the arms, shoulders, neck, and lower back. These injuries appear to be due to excessive periods of sitting (static posture), work intensity, whole-body vibration, high resistance levers, repetitive motions, and awkward postures. (2-5) Although numerous studies have shown an association between operation of heavy construction equipment and symptoms of musculoskeletal disorders, very little research has been performed that systematically characterizes operating engineers' exposure to ergonomic hazards. The objective of this study was to systematically characterize the ergonomic hazards associated with excavating operations. As such, the following were performed: (1) vibrations were measured at the operator/seat interface (X, Y, and Z axes), and at the floor of the cab (Z axis); (2) psychophysical ratings of whole-body vibration (WBV) level and overall seat design were obtained; and (3) postural assessments of the job were made. Methodology This study evaluated an inexperienced female operator performing excavation, utilizing two different pieces of equipment. The operator was 37 years old, 162 cm tall, and weighed 80 kg. She had approximately 15 hours of operation time (experience) on the equipment evaluated. The two pieces of equipment used were: a Case Super 580E (1986) backhoe/loader, and an Insley H-2000 excavator (1975) (see Figures 1 and 2). More evaluations were performed on the backhoe/loader than on the excavator. The following evaluations were performed on the Case equipment: 1) vibration levels at the seat and floor; 2) psychophysical ratings of the overall seat design and vibration levels (for the task duration, and for an 8 hour duration); and 3) postural assessments. For the Insley equipment, all of the evaluations were performed except vibration measurements. When the evaluations were conducted, the following environmental conditions were noted: the temperature was 31°F, and soil and terrain conditions were rough and frozen.

By A. George Stern

[In the examination of bentonitic clay suspensions used for oil-well drilling fluids3/ (and for other purposes, such as a core binder for foundry sand) it is important to have comparative tests for evaluating them. A satisfactory clay for these and other purposes should have the property of forming what is commonly called a "gel," but the measurement of this property has been a real problem. To date the solution has not been satisfactory, and some of the difficulties are considered in, this, paper, which describes a simple form of instrument (identified as an eykometer) for measuring the yield point under hydrostatic conditions of non-Newtonian clay suspensions, including those muds that are thixotropic. An oil-well drilling mud serves several functions, many of which depend on the "gel" characteristics of the mud. Among the more important functions are: (a) To plaster the sides of the hole to prevent caving of the walls; (b) to prevent the loss of the circulating fluid out of the hole by seepage; (c) to carry sand and cuttings out of the hole to the surface as they are formed by the rotary drill; and (d) when circulation of the fluid stops for shut-down or other unavoidable cause, to hold the cuttings in suspension by the setting up of the gel, thereby avoiding the difficulties that result when these cuttings are allowed to fall through the fluid and pack at the bottom of the hole.]

Jan 1, 1940

By Carrie Pourvahidi

The California High Speed Rail Authority (Authority) was created by the State of California through legislation in 1996. The purpose of the Authority is to plan, construct, finance and operate a statewide intercity high speed passenger rail system. In 2004 the Authority prepared a programmatic level environmental document in compliance with the California Environmental Quality and National Environmental Protection Acts (CEQA and NEPA).The Authority and Federal Railroad Administration (FRA) were the lead agencies overseeing the development of the environmental documentation. The resulting document includes two volumes and 64 supplemental technical reports analyzing the transportation needs for California and the selection of an approach to meeting the project transportation needs. The Programmatic Environmental Impact Report and Environmental Impact Statement (EIR/EIS) identified High Speed Rail as the most environ-mentally protective, sustainable and economical approach to meeting the state?s projected transportation needs.

Jan 1, 2008

By T. A. Sullivan

Refining in a molten salt electrolyte was investigated as a means of recovering nickel containing less than 1 percent and preferably less than 0.2 percent cobalt from nickel products containing up to 5 percent cobalt. Electrolytic separation of nick and cobalt was accomplished in a molten KCl-LiCl-NiCl2 electrolyte. Nickel containing less than 0.10 percent cobalt was routinely prepared. Factors that influenced the transfer of cobalt to the refined product were the nickel concentration of the electrolyte, the cobalt concentration of the electrolyte, the ratio of nickel to cobalt in the electrolyte, and cathode current densities. A method of recovering the cobalt from the electrolyte was developed. The possibility of preparing high-purity nickel by this process was shown, as well as the preparation of various cobalt-nickel-tungsten alloys.

Jan 1, 1968

By Jesús Astuvilca

Con el objeto de mejorar las condiciones de seguridad y continuar el incremento de la producción a corto plazo, la empresa minera Yauliyacu implementa el uso intensivo del software minero DATAMINE. En ese sentido, el presente texto describe la implementación de este programa, donde la data de estas vetas y cuerpos polimetálicos son trabajados con el objetivo de automatizar los trabajos de geología, ingeniería y topografía. Los resultados obtenidos permitirán avanzar en aplicaciones diversas como: estimaciones locales y globales, control de leyes, proyecciones de costo de minado, evaluación de estrategias de dilución, diseño y planeamiento de minado.

Jul 17, 2000

With the change in legislation under the Resource Management Act 1991 (RMA), the responsibility for administering the effects of blasting on the environment, has transferred from an essentially central government system to local bodies. This naturally will allow for a variety of compliance levels and control procedures which will depend on the particular local body and rather ad hoc arrangements. It is anticipated that the existing NZ Standard on blast vibration levels will soon be replaced by the Australian Standard. These changes raise the question as to what should be used as suitable compliance levels to prevent damage to structures. The paper will address the measurement, control levels and the appropriateness of current standards in relation to the overall legal framework of the RMA.

Jan 1, 1996

Arsenic (As) removal behavior from Changgoon mine tailings was investigated using Acidithiobacillus ferrooxidans (A. ferrooxidans) in well-controlled batch reactors by varying pulp density (0.5?4%, pH=1.8, temp=30oC), reaction initial pH (1.8?2.2, pulp density=0.5%, temp=30oC), and temperature (25?35oC, pulp density=0.5%, pH=1.8). The initial concentration of As in the mine tailings used for bioleaching tests was about 30000 ppm, and the size range of tailings used in this study was 63?74 µm. The reaction speed and initial cell concentration were fixed to 150 rpm and 107 cells/mL, respectively. To complement leaching experiments, pH, oxidation/reduction potential (ORP), and amount of ferrous/ferric ions in leachate were analyzed. Scanning electron microscopy and x-ray diffraction analyses were also conducted for the samples before and after leaching to see if any morphological and compositional changes in tailings took place during leaching process. The As leaching efficiency increased with decreasing pulp density, decreasing pH, and increasing temperature in the presence of A. ferrooxidans. Specifically, no significant change in As removal rate was observed when pulp density d 2% while the removal rate dramatically decreased at pulp density of 4%. Regarding pH effect, As removal rate was much more enhanced at lower pHs (i.e., 1.8 and 2.0) compared to pH 2.2. Increasing temperature was observed to tend to enhance As removal rate, showing about 20% enhanced leaching rate under 35oC compared to 25oC and 30oC at the elapsed time of 5 days. The results for As removal behavior at different conditions (i.e., pH, temperature, pulp density) were consistent with the change in pH, ORP, and ferric ion concentration in leachate, showing greater removal rate at the condition with lower pH, and higher ORP and ferric ion concentration in leachate. Furthermore, decreasing removal efficiency was likely in part due to the extent of the formation of by-product (i.e., jarosite) of ferric ions.

Feb 27, 2013

By David L. Bickel

The following instructions and descriptions are presented in two parts to assist an individual to make the borehole deformation gage transducer, and to assemble and test the three-component borehole deformation gage. This Bureau 8 of Mines three-component borehole deformation gage (4, 8, 11)2 fits in a 1-1/2-in-diameter borehole that is drilled in rock and then overcored to determine rock stress.

Jan 1, 1978

By W. T. Wertman

A research program to aid development of better and more efficient methods for producing petroleum and increasing its ultimate recovery from underground formations is an integral part of the work of the Bureau of Mines on conservation of the Nation's natural resources. Economic, efficient production of recoverable oil and gas from a reservoir depends to a great extent upon the best and most accurate information that can be obtained from a study of the reservoir rock and its fluid contents. Information on oil and water saturation is pertinent and essential in wildcat, extension, and pool wells for good reservoir operations and prediction of performance. This report presents results of an investigation by the Bureau of Mines of core recovery and degree of drilling-fluid contamination occurring during cable-tool coring operations using oil-base mud. Representative core samples were obtained from 6 major oil-producing sands in 8 fields of West Virginia, Pennsylvania, and New York. Field-mixed, oil-base drilling mud was used for the first coring test, and lightweight, premixed oil-base mud, with an organic chloride tracer added, was used in coring eight other wells. Tracer analyses were made to determine contamination of core by drilling-fluid filtrate. Core analyses, including oil and water content and minimum interstitial water-saturation tests, were made on selected core samples to compare and evaluate water saturations determined by the two methods.

Jan 1, 1958

By Fritz J. Klingler

From site demolition, to design, to construction, Detroit's new Tiger Stadium project is required to be completed within a short 2 ½ years from award of the design-build contract. Such extreme schedule requirements together with somewhat difficult ground conditions at the site, resulted in several challenges in the design and construction of the deep foundation system for the stadium. During the geotechnical investigation, an intermittent water bearing sand layer was encountered overlying the hardpan at the site. As a result, some concern developed regarding the potential for collapse of caisson bells within this layer, as well as the potential for flooding of the caissons during drilling. Although sand and/or ground water was encountered within about half of the caissons, standard drilling and belling methods were used, and adverse conditions were controlled in almost all cases through expeditious drilling, inspection and concreting of the caissons. This paper will present a summary of the ground conditions, design and specification requirements, and construction methods used to successfully install the caissons for this project.

Jan 1, 1999

By Suk han Jang

This paper describes the tower foundation design and construction experience for the 345kV Youngheung marine transmission line, which has been in commercial operation in Korea since July, 2004. This transmission line was designed and constructed to meet the rapidly increasing power demands of metropolitan areas and supply stable, bulk electric power from the Yonghung thermal power plant into metropolitan areas. This transmission line passes over the west sea, Lake Sihwa and over land. In order to successfully complete this project, and to safely support the tower during severe maritime conditions, several types of tower foundation such as Pad and Chimney foundation, Pier (Cylindrical) foundation, R.C.D foundation, Jacket pile foundation and Steel pipe pile + concrete mat foundation were developed and used. As the world?s first and longest marine transmission line, the 345kV Yonghung marine transmission line operates successfully, thanks to several high-tech civil engineering technologies and KEPCO?s accumulated experience.

Jan 1, 2007

By David S. Bowling

The ER-300 Series White Recorders were developed to provide on economical, yet invaluable instrument for those who desire permanent recordings of such data OS displacement, vibration, concussion (air borne effect) and velocity information. The precise monitoring of earth displacements and air blast magnitudes aids quarrymen and construction contractors in estimating safe blasting limits when operating in populated areas. A refraction model is available for recording velocities which permit the determination of weathered zone depths as well as the .depths to other subsurface formations. The dual purpose (Refroction- Displacement) systems ore utilized for velocity studies and displacement - oir blast measurements.

Jan 1, 1990

By Corale L. Brierley

Beneficiation of phosphate in the southeastern United States generates a slurry of finely divided clay. These clay-wastes are impounded to allow the particulates to settle. The aggregation of phosphatic clay-slime wastes and slimes produced from potash beneficiation by microbial processes was studied using several bacterial species known to produce polymeric substances. Experiments included flocculation capacity of clay-slimes by whole cells, the determination of respiratory activity of whole culls in the presence of phosphatic clays, observation of clay flocculation rates by polymers derived from these organisms, and clarity of polymer-flocculated clay suspensions. The polymer-producing organisms exhibited little capacity for flocculating phosphate and potash clay-slimes. Fungal spores of Cladosporium cladosporioides (isolated from a phosphate clay-waste impoundment), when agitated with clay-slime for several days, caused the clay to form pellets. Separation of the clay/fungal pellets (density 1.1 g ml-1) from the process water might he possible using a screening technique. Studies with C. cladosporioides included the determination of suitable energy substrates and supplements for growth, absorption studies of a pigment produced by the organism, determination of the time required for bioflocculant production by the organism, and an elucidation of the conditions required for the pelletization of clay-slimes by the fungus.

Jan 1, 1982

By Healy T. W, Dixon D. R

The present study 'of pure ZnS and NiS and ZnS (marmatite) by detailed electrokinetic methods has shown that by careful control of experimental parameters much new' information on sulphide-water interfaces can be obtained. Time-dependent processes of alteration of sulphide surfaces are foHowed by electrokinetic methods and indicate that the isoelectric point of the surface depends on elemental sulphur coverage, oxidation product coverage, and the conditions which promote or minimize such reaotions in the presence and absence of activator.

Jan 1, 1977

By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By R. S. Dean

In general, the Division conducts investigations relating to the treatment of ores and metallurgical products from the condition to which they are mined to the refined metal. At the object of conserving natural resources and eliminating waste by furnishing information on current methods of metallurgical practice making fig fundamental studies of metallurgical processes and developing new processes and alloys to the point of demonstrating their or value. Office of the Chief Engineer The functions of the technical units of the Office of the Chief Engineer are indicates

Jan 1, 1941

[Module 10. Internally Cued Operating Contingencies Prerequisite: Modules 1-7 - Estimated Instructional Time: 2.42 hrs. Module Abstract Trainees, using programmed instruction, describe the cues, consequences, operational sequences, and possible causes resulting from loss of air pressure from power fluctuations, and from a failure of the automatic lubrication system. Although some of the contingencies may be initially signaled by an alarm or from the oiler, each trainee will demonstrate proficiency in the appropriate operating techniques and procedures. This module also includes a review component for those trainees identified in the assessment exam as requiring less detailed instruction.]

Jan 1, 1976

By T F. McConachy, B I. A McInnes, R A. Binns

Within the last decade, major research discoveries have been made in the submarine realm of magmatic and hydrothermal activity of arc-backarc systems in the southwestern Pacific. These include identification of numerous particulate-poor, gas-rich (CO2-CH4) hydrothermal plumes emanating from arc front volcanoes, actively forming porphyry-copper-gold style mineralisation, and new backarc spreading systems erupting alkali basalt-trachyandesite magmas. Major goals of these studies have been identification of modern analogs to ancient volcanogenic massive sulfide ore bodies, and quantification of the volatile fluxes though supra-subduction zone systems.

Jan 1, 2002

By Madgwick J. C

The monosaccharides glucose, galactose and arabinose, and the polyols glycerol and mannitol (0.1 Ufo WIV) supported pure and mixed culture heterotrophic bacterial manganese leaching of solid pyrolusite (MnO2, 2% W/V) to yield 14-38 mg/litre manganous ion in 3 days from a simple mineral salts media at 30°C. Supplementation of pure bacterial isolates growing on glucose with soluble intracellular photosynthate from freshwater algae (0.07 g/l carbohydrate) and marine algae (0.11 g/l) led to an improvement in Mn++ yields of 24 and 100 per cent respectively. Extracellular products of the freshwater algae (0.3 g/l carbohydrate) boosted recoveries by 57 per cent.

Jan 1, 1982

By Jean-Claude LeRoy, Herman Keller

"INTRODUCTIONEROCON's work is the reclamation of mine wastelands. It has had considerable experience in particular in the reclamation of gold mine tailings in the Canadian Shield since the latter part of the sixties when most gold mines were closing down.A typical example is the famous Hollinger Mine in Timmins which produced $566 million worth of metal from 1910 to 1968 and had left behind some 56 million tons of tailings covering about 1,000 acres which were reclaimed on very short order and are now lush meadows of agricultural quality.To date, practically all gold mine tailings have been reclaimed once and for all by establishing a permanent, self-sustaining and maintenance free vegetation cover.RECLAMATION & THE MINING TOWNSThe first appreciation of people in a mining community where the tailings have been revegetated will be noticing one day the elimination of dusty conditions that used to arise formerly on every dry and windy day. In that respect, EROCON encourages not only vegetating the tailings but also the immediate surroundings of the mills and plants themselves at active mines. The elimination of windborne dust will result in an appreciable decrease in maintenance costs of plant and machinery and more pleasant working conditions for all."

Jan 1, 1975