Search Documents

By Yi Luo

In dealing with various subsidence cases, accurate predictions of mining induced subsidence are the basis for correct assessment of subsidence influences and subsequent mitigation efforts. There is a good demand for a reliable tool to perform the subsidence predictions and related tasks. A comprehensive and integrated subsidence prediction model, CISPM, developed by the senior authors in the later 1980?s and early 1990?s (Peng and Luo, 1992) is one of such tools. Built on solid mathematical models and calibrated by a large number of collected subsidence cases, CISPM provides a rich set of features needed in subsidence engineering and research works. Its reliability and usefulness have been proven by numerous field applications. This upgrade of CISPM will not only preserve its original features and reliability but also provide some new needed features and a more user-friendly working environment.

Jan 1, 2008

By Patrick Cloutier

Presentation objectives ? Introduce discrete-event 3D computer simulation as a tool to design, improve and optimize construction projects: ? Describe a real typical construction project planning issue. ? Present an applied use of simulation to solve this issue. ? Detail benefits of using simulation versus traditional planning methods.

Aug 1, 2013

By Kameron Ray, Ruilin Yang

This paper compares the modeling results obtained by using a single seed waveform (SS) versus multiple seed waveforms (MS) as inputs to the Multiple Seed Waveform (MSW) blast vibration model. The field data for the comparison was collected at a coal mine. The results of the comparison showed that the MSW model yields more accurate predictions and significantly higher correlation to field measurement when using MS as input. When using a single seed waveform as input, different seed waves result in different predictions of PPV. In contrast, using the multiple seed waveforms as an input, more consistent results are obtained.

Jan 1, 2013

By Michelle Stokes, Alexandra Miller, Campbell McKenzie

"The ancestral Ringarooma River in northeast Tasmania has transported alluvial tin and other heavy minerals from their onshore source of stanniferous Devonian granites downstream into what is now Ringarooma Bay. Previous exploration work has demonstrated the presence of potentially economic tin mineralisation within the palaeochannels and terraces associated with the submerged river.The offshore tin resource lies directly on the seabed or with less than 2 m of overburden, and within 5 - 50 m water depths in the wider bay area. The main river channel continues offshore for at least 13 km, with high tin grades found within the palaeochannel but also dispersed across the sea floor as a sheet wash, a result of Quaternary sea level change reworking the placer deposits. This drowned portion of the coastal plain contains a continuation of rich tin leads as low gradient anastomosing channels, and has been delineated by marine seismic and drilling activity since the 1960s. Tin grades in the Tertiary and Quaternary alluvial profiles vary from 50 - 300 g/m3, with the highest concentrations in the coarser basal horizons. A previous offshore explorer estimated a resource of 194 Mm3 at 150 - 250 g/m3.Kenex Ltd created 3D models of the paleochannels and the mineralisation with the aim of better constraining the resource estimate and identifying additional depositional areas. The modelling was undertaken with the input of geophysical data, bathymetry and geochemical sampling of the seabed surface and from historic offshore drill holes. A prospectivity model covering Ringarooma Bay was produced to target tin-bearing gravels. Predictive maps were created to represent various features of the offshore mineral system, including assessing gradient changes in palaeochannels and their sinuosity. The model identifies areas with higher potential for alluvial tin mineralisation and will be used to focus the exploration programme over tenements currently held by Kenex Ltd."

Sep 1, 2014

By Peter Faust, Jeremy Zorne, Timothy Siegel, Diane Fiorelli

Professional sport venue construction follows a very simple rule. Once the decision has been made to move the team to a new place, construction shall begin immediately, so that not more than one or two seasons pass by stuck in the old home. Such tight construction schedules require a different approach than traditional design-bid-build contracts. Design is mostly done on the fly, the construction schedule becomes a main risk factor and an early contractor involvement is desired. As specialty contractors become more and more sophisticated, owners, their construction managers or the general contractor have realized the value of ideas and modern technology they can bring to the table for a successful and fast project completion. Local knowledge and experience in a variety of solutions play a key role in the specialty contractor’s ability to provide added value to the project. This is also true for the specialty foundation contractor, who needs to understand the complexity of such modern structures from its integrate foundation, over the delicate concrete structure to a potentially fancy movable stadium roof. Not to mention all the modern high tech equipment which shall make such a place a great customer experience. His expertise shall enable him to propose the most suitable foundation element for the given ground condition and application. Rather to build what others have designed, his strength is to propose alternate concepts which will be faster and (hopefully) more cost effective. This paper highlights different value engineering (VE) input a specialty foundation contractor had on 3 major sports arena projects in California. Together with the entire team from owner to GC, including the Geotechnical (GEOR) and the Structural Engineer of Record (SEOR), the most efficient and best performing foundation solution can be found every time. But such an approach also requires the open mind of the owner to entertain last minute changes when the permit drawing set has already been submitted for approval.

Jan 1, 2018

By Hal W. Hunt

Heavier loading and more efficient equipment is helping to keep driven piles competitive in America. Better Knowledge and testing of soils and support materials make it practical to use higher stresses; this is being strongly promoted by those directly concerned with timber, steel and concrete piles. Readily available point protection is increasingly used to assure penetration of piles without damage to full load bearing capability. Fabric drains are being installed with pile equipment to speed consolidation of soils. Sheet pile configuration has changed; production has been reduced largely because of imports. Dynamic checking of representative piles for load carrying capability is replacing conventional load testing of just a pile or two ? at much lower cost.

Jan 1, 1987

By John S. McCartney, Ismaail Ghaaowd

This study presents the results from centrifuge modeling experiments performed to understand the effects of temperature changes on the pullout capacity of scale-model energy piles embedded in normally- consolidated clay layers. The energy pile under investigation is an aluminum cylinder instrumented with internal strain gages and thermocouples, and its temperature is controlled using an internal electrical resistance heater. The energy pile was first heated until the temperature, pore water pressure, and volume change of the surrounding clay layer stabilized, after which the energy pile was cooled. Pullout tests were then performed on the energy piles heated to different temperatures to understand the effects of the preceding heating-cooling cycle on the pullout capacity. In addition, the clay undrained shear strength profiles were measured using push-pull T-bar penetration tests before and after heating. INTRODUCTION When a heat source such as an energy pile is embedded in a saturated clay layer, temperature changes will result in changes in pore water pressure as the rate of heating is typically faster than the rate of pore water drainage (Campanella & Mitchell 1968, Abuel-Naga et al. 2007, and Ghaaowd et al. 2016). Although all soils will initially expand during undrained heating, normally consolidated soils typically exhibit permanent contraction while overconsolidated soils exhibit expansion after sustained heating when drainage is allowed (Vega & McCartney 2015). Subsequent drained cooling typically leads to elastic contraction. Thermally- induced changes in pore water pressure and volume during transient heating and cooling may affect the soil- structure interaction of energy piles, as well as the ultimate capacity of the energy pile. This study is relevant as relatively few studies have been performed on the behavior of energy piles in soft clay (e.g., Ng et al. 2014), with most focused on the behavior of drilled shaft energy piles in stiff rock or overconsolidated clays (e.g., Laloui et al. 2006; Murphy et al. 2015; Wang et al. 2015; McCartney and Murphy 2017).

Jan 1, 2018

By Elaine T. Cullen

Human beings are natural storytellers and story listeners. We learn very early that stories entertain us, but also give us the ?rules? about what is expected of us and how to make meaning of our experiences. Stories are integral to our lives, and have great power to change or influence how we think or how we react. They are an innate part of how we learn, and have obvious benefits to trainers or educators who are trying to impact what and how we learn. This paper and presentation discuss the social and cultural power of stories, and how they have been used to develop training for skilled blue-collar workers. Included will be examples as well as suggestions for trainers on where to find stories, what type of stories to pay attention to, and how to use them to improve occupational safety training.

Jan 1, 2008

By Robert E. Hershey

1. This investigation shows that the most important beds in Claiborne County, from the standpoint of present production and reserves, are the Coal Creek and Jellico. Together, they contain 69 percent of the known recoverable reserves in the county. Reserves in five other beds are tabulated in this report; in order of quantity of reserves, they are: Blue Gem, Lower Pioneer, Pewee, Big Mary, and Rex. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 60 million tons, as of January 1, 1953. Of this total, 55 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to permit making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

By Michael S. Wieland

This report focuses on the U.S. Bureau of Mines research regarding desensitization and malfunction of delay detonators and cap-sensitive explosives. Delay blasting in underground coal generates tremendous shock waves and rifting forces that fracture and heave coal. The shock waves from charge explosions radiate outward in all directions through the coal, impacting neighboring charges with later delays. The impact phenomena have debilitating effects, causing degrees of reduced charge performance ranging from misfires or weak detonations to out-of-sequence detonations. Impaired charges react poorly, fracture less coal, and produce fumes with higher toxicity. Coal-mine, underwater, and simulator tests were conducted to more thoroughly understand the shock damage mechanism. Recently the U.S. Bureau of Mines partially resolved the malfunction problem by demonstrating the feasibility of formulating a rugged explosive. This rugged cap-sensitive candidate passed the requisite tests for certifying an underground coal-mine explosive. With natural aging the formulation rapidly lost initiation sensitivity. The charge formulation had to be rebatched to finish the testing and therefore could not be certified.

Jan 1, 1992

By Alexander Filotti, Stanley Merjan

"Abstract. The paper shows the benefits and accomplishments of this relatively new but established product on the pile foundations market in the United States. The first part of the paper describes general aspects of the design, construction, and geotechnical capacity (designed and in situ) of Tapertube piles. The qualities resulting from the design and manufacturing of the Tapertube pile will be presented first.The second part of the paper describes the installation of Tapertube piles for an addition to Terminal One at JFK International Airport and The Edge development. A carbon print analysis for both projects is developed using the EFFC-DFI carbon print calculator. For the JFK project the benefits of using BIM in redesigning the project for Tapertube piles are explored.General description.The tapertube pile consists of a tapered tubular bottom section attached to a conventional pipe extension. The 50 ksi steel for the taper is mechanically folded into a polygonal cross-section (usually 12-sided) with a longitudinal welded seam. The tapers are fabricated in many sizes with bottom diameters varying from 8 to 14 inches, top diameters from 12 to 20 inches, lengths from 10 to 35 feet, and steel thicknesses from 3/16 to 1/2 inch. A conical steel shoe or a flat plate is welded to the bottom of the taper and the top of the taper is circularized to match the outside diameter of the pipe extension. The inclination of the tapers is generally between 1.5% and 2.5%.The pipe extension is fully butt welded to the taper and has the necessary length for the pile to develop the requisite capacity. Concrete fill for the piles is generally 4,000 p.s.i. or more. Typically the piles are shopassembled and shipped to jobsites in lengths to 80 feet."

Jan 1, 2014

By F. P. Haver

The Federal Bureau of Mines developed a 10,000-ampere cell to determine the economic feasibility of producing high-purity electrolytic titanium from mill scrap or offgrade sponge. Operating variables were investigated, matetial handling procedures were established, and the cost of electrorefining titanium was determined. The prototype cell produced premium-grade metal (<100 Brinell hardness number (B.h.n.)) from very impure Kroll sponge at a processing cost of less than $0.60 per pound. Refined metal was deposited at the cathode in the form of coarse (85 percent plus 34-mesh), hexagonal crystals of a titanium when the cell was operated an 850° C. A cathode current density of 1,000 amperes per square foot and a molten sodium chloride electrolyte containing approximately 5 percent by weight of soluble titanium were used. In continuous operation, at the optimum number of ampere-hours, (40,000), the current efficiency averaged slightly less than 60 percent. It was possible to supply large enough amounts of electric current for electrolysis to maintain the temperature of the bath, thus reducing overall power consumption to less than 5 kilowatt-hours per pound of metal refined.

Jan 1, 1961

By R. L. Merek

There were 63 fatalities in the California petroleum industry in 1929, the largest number in any year since 1923 and an increase of 34.0 per cent over 1928, when 47 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. It will be observed from the accompanying chart that after following a consistent decline for 4 years, the fatality curve turned upward in 1923 and advanced sharply in 1929. Although this increase in fatalities coincided with a period of intensive development it tends to indicate some laxness in the industry during a period of increased hazards. Intensive drilling campaigns are usually started hurriedly and conducted with a great demand for speed, and the result is that accident-prevention work is too often relegated to a position of minor importance.

Jan 1, 1930

By R. L. Marek

There were 63 fatalities in the California petroleum industry in 1929, the largest number in any year since 1923 and an increase of 34.0 per cent over 1928, when 47 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. It will be observed from the accompanying chart that after following a consistent decline for 4 years, the fatality curve turned upward in 1923 and advanced sharply in 1929. Although this increase in fatalitics coincided with a period of intensive development it tends to indicate some laxness in the industry during a period of increased hazards. Intensive drilling campaigns are usually started hurriedly and conducted with a great demand for speed, and the result is that accident-prevention work is too often relegated to a position of minor importance. [ ]

Jan 1, 1930

By Peter (Yunqing) Zhang

Longwall recovery under weak roof conditions could have considerable delay if the immediate roof is weak and deteriorates during screening. A pre-driven longwall recovery room is a feasible solution to minimize the impact of longwall move on production. In this longwall recovery project, a 16-ft recovery room was pre-driven to cover screening, and the shearer cut another 16 ft outby to reach the final recovery line. The pre-driven recovery room was carefully monitored as the face was approaching it. The longwall face operated very well as it cut into the recovery room. The recovery process took about 13 days, and considerable time was saved compared with the previous panel. The support in pre-driven recovery room was designed to handle both front abutment pressure and weak immediate roof conditions. Pumpable standing support was used to support the cantilevered roof as the fender pillar narrowed and collapsed when the face cut into the recovery room. To ensure the stability of the recovery room, 3-D computer modeling was used to evaluate the support system. Abutment pressure, critical fender pillar width, bolting system, pumpable cribs and shield support were considered in the model. The recovery room was carefully monitored during longwall recovery. Roof-to-floor convergence and crib convergence were recorded every shift as the longwall face was approaching the recovery room. Roof, floor and pillar activities and crib performance were also observed as the face cut into the recovery room. This paper presents the support design for the recovery room, evaluation of the support system through computer modeling, and details of the monitoring results.

Jan 1, 2006

By D. Christofferson

This final report documents the cooperative efforts of the Engineered Systems Division and the Mining Equipment Division of FMC Corporation during performance of Bureau of Mines Contract H0252091. Improved operator compartments incorporating overhead canopies, logical arrangements of controls, and design features offering greater operator comfort were developed and retrofitted to the FMC 320A roof bolter and 6L shuttle care The vehicles were evaluated in underground operations at separate mine sites. The successful evaluation has resulted in incorporation of the designs as standard features of the 320A roof bolter, and the 5L, 6L, and 10L shuttle cars.

Jan 1, 1978

By Scott Turner

The present rapid growth of coal stripping in the United States is a curious reversal of the tendency of mining to proceed from outcrop to depth. A combination of technical and economic factors bas stimulated the use of stripping methods until today many million tons of coal We being recovered by open cuts from sites that an earlier generation of engineers would have passed by as not commercially mineable or, if workable at all, only by underground methods. The total quantity of bituminous coal and lignite mined in the United States by stripping in 1928, the latest year for which detailed figures are available, was 19,789,000 short tons. Of this, 71,000 tons came from small workings not equipped with power shovels and 587,000 tons from properties in which stripping and underground work were carried on at the same mine; but as neither of these types is representative of modern stripping practice, they will be omitted in the discussion that follows. The total from strip pits proper in 1928 was 19,131,000 tons, produced by 176 pits employing 385 steam or electric shovels.3 Figures by States are given in Table 1. Detailed statistics will be found in Economics of Strip Coal Mining; a study by O. E. Kiessling, to be published by the United States Bureau of Mines.

Jan 1, 1930

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 J. D. Findlay

The demands on development in London in recent years has led to the increasing use of top down construction methods in which there is a requirement to place steel columns to high tolerances into large diameter bored piles with deep cut-offs. A number of different proposals for the sequence of construction are being suggested. The tolerances requires for the steel columns are becoming increasingly stringent. This review examines a number of basic construction proposals and comments on the problems and solutions used by foundation contractors to provide the required foundations.

Jan 1, 1989

By W G. Szymczak, Leslie C. Taylor

The University of Maryland (UMD) has conducted a series of small-scale tests using explosive charges buried in saturated sand. Twelve different combinations of depth of burial of the charge and height of the target plate above the soil were tested. The target plates did not deform plastically. High-speed video was used to track the motion of the plate. The video data are analyzed to determine the position and velocity of the plate as a function of time. The results of this analysis are compared with computations performed at NRL using the BUB2D computer code. This code treats the saturated sand as an incompressible visco-plastic fluid which yields according to a Drucker-Prager (frictional-cohesive) yield surface. Comparisons of simulations with experiments are presented. In the cases examined so far, the velocity grows very quickly to a peak and then slows, first with a deceleration greater than one “g,” which then transitions to an approximately one “g” deceleration. An analysis of air drag on the plates has shown that its effect is negligible in the time span of interest. In all cases in which the BUB2D code can be applied, the computations compare favorably with the results of the data analysis. This suggests that the code and model used in the computation are properly capturing the physics of the interaction between the soil and a non-deforming plate.

Jan 1, 2007