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By A. K. Bhattacharya

Cylindrical bridge piers are widely used and equations exist that can predict the maximum depth of local scour around such piers. Scour around piers is an undesirable phenomenon, as it requires the foundation to be placed to a greater depth resulting in increased cost, making it worthwhile to investigate scour-reducing measures. A number of scour-reducing measures have been tried out for cylindrical bridge piers including placing a concrete collar around the pier, having a delta-wing projecting upstream in front of the pier, placing riprap around the pier, using a group of piers instead of a single pier, having a slot in the pier aligned in the longitudinal direction. The objective of this study is to investigate the effect of upstream protective piles on reduction of maximum local scour depth around a cylindrical bridge pier. The upstream piles are placed at different radial distances in front of the pier and the scour depths are observed. The proposed equation of Dey (1997) for determining the maximum depth of scour around a cylindrical bridge pier is used. The reduction of local scour around the pier is compared with local scour around an unprotected pier.

Jan 1, 2009

By Takeyasu Ito, Mayumi Someno, Kazuhiro Goto

SINCE the pioneering work by Kiukkola and Wagner,1 many experiments have been reported on solid electrochemistry at elevated temperatures. However, the studies have been confined to experiments under isothermal conditions. One may conceive many situations under nonisothermal conditions. With two different temperatures T1, and T2 at the two electrodes, the electromotive force, E of a Galvanic cell will be expressed by the following equation under a steady state heat transfer in solid electrolytes of zirconia-lime and thoria-lime. E = ^ $ l&-dGO2+a(T2-Ti) [1] where tO2- is the transference number of oxygen ions in the electrolyte, Go, is the chemical potential of oxygen, and a is the coefficient of the thermoelec-tromotive force due to the temperature difference. The objective of the present study was to evaluate the coefficient of the thermoelectromotive force for zirconia-lime and thoria-lime under isobaric condition. The physical meaning of this coefficient is out of the scope of the present communication. The experimental cell assembly is schematically shown in Fig. 1. The zirconia-lime electrolyte tube and thoria-lime electrolyte tube were 8.0 mm OD and 5.0 ID, from commercial sources with chemical analyses of 94.8 wt pct ZrO2, 3.85 pct CaO, 0.83 pct SiO2, 0.25 pct TiO2, and 0.05 pct Fe2O3; and 95.0 pct ThO2, 4.0 pct CaO and rare earth metal oxides, respectively. The specific gravity was 5.5 g per cu cm for zirconia-lime and 9.8 g per cu cm for thoria-lime. Original powder size before shaping and sintering the tube was several microns for both electrolytes. The distance separating the two electrodes was 4.0 or 5.0 cm. Platinum wire of 0.5 mm diam was used for the electrodes. The temperature gradient was controlled by heating one electrode with a small heating coil of nichrome wire. The temperatures at the two electrodes were measured with two calibrated Pt-13 pct Rh:Pt thermocouples, directly contacting the two platinum electrodes. The atmosphere was either air or pure oxygen. The partial pressure of oxygen in air was considered equal at the vicinities of the two electrodes, with negligibly small thermal segregation in the gas phase. The difference of the chemical potential of oxygen was controlled only by the temperature difference at the two electrodes and not by the oxygen pressure difference. The temperature ranges were 600" to 1200°C for zirconia-lime and 850" to 1200°C for thoria-lime electrolytes. Fig. 2 shows the relation of the measured electromotive force and the difference of the oxygen chemical potential at the two electrodes for zirconia-lime and thoria-lime electrolytes. The electromotive forces in the figure were measured by a *0.05 mv potentiometer. The chemical potential difference was calculated by the following equations.'

Jan 1, 1970

By P. Schwarzkopf, J. H. Brophy, J. Wulff

A constitutional diagram has been proposed for the tantalum-rhenium alloy system. Rhenium dissolved in tantalum up to 48 wt pct, and the maximum solubility of tantalum in rhenium is 5 wt pct. Intermediate x and s phases were found. X-ray diffraction, metallography and melting points were employed. SEVERAL investigators have described the phases present in the tantalum-rhenium alloy system, but no detailed account of the phase diagram prior to the present investigation appears to be available. Greenfield and Beck' reported the solubility of 48 to 54 at. pct Re in tantalum, a s phase at 41 at. pct Ta, and x phase isomorphous with a Mn from 37 at. pct Ta to less than 25 at. pct. They employed as-arc melted specimens and heat treatments at 1200 °C lasting 72 hr.2 Duwez3 reported the existence of a a phase at the composition Re3Ta2. Niemiec and Trzebiatowski4 observed a lattice parameter a = 9.69A, for the x phase at a composition Ta7Re22, but no s phase. Savitiski and Tylkina5 have shown a hardness maximum at the composition 40 at, pct Ta and a somewhat lower plateau from 35 to 10 at. pct. Knapton6 indicated results similar to those of Greenfield and Beck.' The present investigation describes the phase relationships in the tantalum-rhenium alloy system determined by melting point measurements, X-ray diffraction and fluorescence, and metallography. EXPERIMENTAL PROCEDURE Commercial 99.7 pct Ta powder from Fansteel Metallurgical Corp. and 99.9 pct Re powder from Chase Brass and Copper Co. were used for alloy preparation. The powders were weighed to desired nominal compositions and then pressed without binder into compacts weighing 5 or 10 g. The compacts were arc-melted six times on alternate sides on a water-cooled copper hearth using a nonconsumable tungsten electrode in an atmosphere of titanium gettered helium, at a pressure of 500 mm Hg. In most cases this procedure yielded alloy buttons of satisfactory homogeneity. A series of alloy specimens were analyzed wet chemically for use as standards for X-ray fluorescence. All specimens were analyzed by fluorescence and the results showed that the compositions differed by less than 3 pct Re from the original as-weighed nominal composition.* On the basis of self-

Jan 1, 1961

By R. F. Abernethy

A small-scale method was developed for determining the free-swelling index of coal samples of limited quantity, especially the macerals. Results of a series of tests using a 0.3-gram sample correlated well with those by the standard method using a 1-gram sample. The standard and small-scale methods are modified to give unrestricted swelling for those coals having swelling index numbers above 7.

Jan 1, 1971

By Vernon K. Garrett, Gerhard Sauer

INTRODUCTION Generations of tunneling engineers had to fight not only against bursting rock and squeezing ground but also against the destroying power of water. Intrusion of groundwater into the tunnel opening affects the stability of the tunnel support system, reduces the safety of the traffic inside the tunnel, induces corrosion of installed equipment, and provides for creeping currents at electric facilities. Aware of these problems, engineers of the Washington Metropolitan Area Transit Authority and their consultants opened the way for a new approach in sealing a tunnel. It was made possible by accepting a new method of tunnel construction scarcely applied in the U.S. before. This new technique, the New Austrian Tunneling Method (NATM), provided the basis for the successful installation of a PVC-membrane between two separated shells of tunnel lining, and the carefully directed drainage of groundwater. Beside of the economic benefits already attained by applying the NATM for tunnel construction, the Authority now saves millions of dollars otherwise necessary to maintain the tunnel during its lifetime (Garrett, 1986; Setzer, 1986). But there is a large number of leaking tunnels built according to conventional methods, some of them facing severe problems jeopardizing the safe utilization of these structures. Recently developed methods indicate that even those tunnels can be rehabilitated without extensive costs by draining and sealing them afterwards. A road tunnel in the Austrian Alps provides the scene for a major attempt to convert one of those leaking tunnels into a dry structure.

Jan 1, 1987

By Juan J. Monsalve, Nino Ripepi, Richard Bishop, Jon Baggett

"Terrestrial laser scanning (TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel, with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network (DFN) for each discontinuity set. I-Site Studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.INTRODUCTIONAccording to the Mine Health and Safety Administration (MSHA), between 2006 and 2016, the underground stone mining industry had the highest fatality rate in 4 out of 10 years, compared to any other kind of mining (MSHA, 2016). Additionally, during that same time, 40% of the fatalities were due to ground control issues, such as roof and rib collapses and pillar bursts. The National Institute for Occupational Safety and Health (NIOSH) developed guidelines for designing underground stone mines (Esterhuizen, Dolinar, Ellenberger, and Prosser, 2011). However, these guidelines do not apply to all underground stone mines.Monsalve, Baggett, Bishop, and Ripepi (2018) present a case study of an underground limestone mine experiencing a structurally controlled mode of failure. The authors analyze different methods to study that type of instability. They conclude that the integration of terrestrial laser scanning (TLS) with discrete element modelling (DEM) can be used to prevent rock falls in underground excavations to enhance worker safety. However, an adequate rock mass characterization and structural mapping must be performed in order to generate reliable models that allow the engineer to have a better understanding of the rock mass behavior."

Jan 1, 2018

By R. Allington, G. Walton

The approach has been applied with success to the restoration of chalk workings in southern England, and research and trials relating to restoration blasting and the replication of limestone dale landforms have been undertaken. An essential prerequisite for application of the technique is rigorous geomorphological analysis of the locality to ensure that final quarry landforms are consistent with the local geomorphological and landscape setting. It is always important to ensure compatibility of the final landform with the intended after-use, and to achieve this it is also essential that such restoration schemes have a sound geotechnical basis. A disadvantage of the approach is that final slopes tend to be flatter, especially in weaker strata where natural slopes are not steep; the implications for reserves may be unacceptable, particularly in quarry extensions

Aug 1, 1994

By Alan Quiroga

Nestled between Meridian Park and Howard University in the heart of Washington, D.C., the historic block between 14th, V and W streets North- west featured several original struc- tures, many of them dating to the 1800s. During its rich history, this square block has been home to a variety of different organizations including automobile showrooms and repair businesses, a parking garage, various industrial warehouses, and, in recent years, the headquarters of the renowned D.C. nonprofit Martha's Table. The revitalization of the buildings in this block also known as the Collection 14 project involved the transformation of aging and historical structures into a new multi-use development. The redevelopment project was distinguished by the retention of period street-facing building facades (to the extent possible) to preserve the character and culture of the historic neighborhood while revitalizing the block with some modern construction elements. The complexity of the project and difficult subsurface conditions required specialized and extensive sheeting, shoring and underpinning work to be performed. This project had many parties involved, including: • • • • Owner: Madison Investments Owner's representative: Compass Design & Development General contractor: McCullough Construction Civil engineer: Vika Capitol Structural engineer: Ehlert Bryan Architect: Perkins Eastman DC Geotechnical engineer: GEI Consultants Sheeting and shoring contractor: Steele Foundation

Aug 1, 2023

By A Woodley, A N. Danoucaras

In 2012 the Bureau of Meteorology, under the banner of the Water Accounting Standards Board, released the Australian Water Accounting Standard 1 (AWAS 1). This standard has been in development since 2007 with key milestones being the release of the Preliminary Australian Water Accounting Standard in 2009 and the exposure draft of the Australian Water Accounting Standard in 2010. Throughout this period, the Minerals Council of AustraliaÆs Water Accounting Framework has developed concurrently with the Australian standards and the standards have informed elements of the framework. However, the framework is not identical to the standard as the objectives between the two are different. The objective of the Water Accounting Framework is to create consistency in water reporting of the minerals industry and to assist companies reporting to corporate sustainability initiatives. The objective of AWAS 1 is to provide information to water management bodies to facilitate decisions about the allocation of water resources. Companies are to report on an annual basis - not only physical flows of water but contractual requirements to supply and obtain water - regardless of whether the transaction has been fulfilled in the reporting period. In contrast, the Water Accounting Framework only reports on flows that have physically happened. The paper will provide summary information on aspects of AWAS 1 that are most relevant to the minerals industry, show the alignment and differences between AWAS 1 and the Water Accounting Framework and explain how to obtain the information for the AWAS 1 reporting statements.CITATION:Danoucaras, A N and Woodley, A, 2013. Alignment and differences between the Australian Water Accounting Standard and the Water Accounting Framework for the minerals industry, in Proceedings Water in Mining 2013 , pp 85-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By R. T. Saxon

Prior to November 1975 there were several failures of front -wheel spindles on large haulage truck s in B.C., attributed to fatigue cracks. Since that time, a non-destructive test program has succeeded in detecting the cracks before catastrophic failure, However, the author regards the failures as just one example of a. general unreliability in large high-strength steel castings and urges the industry to look to forgings for sensitive components of heavy equipment.

Jan 1, 1977

By Michael Gauna, Christopher Mark

"Coal bursts involve the sudden, violent ejection of coal or rock into the mine workings. They are almost always accompanied by a loud noise, like an explosion, and ground vibration. Bursts are a particular hazard for miners because they typically occur without warning. Despite decades of research, the sources and mechanics of these events are not well understood, and therefore they are difficult to predict and control. Experience has shown, however, that certain geologic and mining factors are associated with an increased likelihood of a coal burst. A coal burst risk assessment consists of evaluating the degree to which these risk factors are present, and then identifying appropriate control measures to mitigate the hazard. This paper summarizes the U.S. and international experience with coal bursts, and describes the known risk factors in detail. It includes a framework that can be used to guide the risk assessment process.BACKGROUNDCoal bursts involve the sudden, violent ejection of coal or rock into the mine workings. They are almost always accompanied by a loud noise, like an explosion, and ground vibration. Bursts are a particular hazard for miners because they typically occur without warning. During the years 2012-2014, serious coal bursts occurred at three different U.S. room and pillar mines. These events resulted in three fatalities and two permanently disabling injuries (MSHA, 2014; MSHA, 2013). In all three instances, the events occurred during pillar recovery at depths exceeding 1,000 feet (300 m). None of these three mines had previously reported a burst to MSHA. Coal bursts also occurred at three longwall mines during this same time period.Despite decades of research, the sources and mechanics of bursts are not well understood, and therefore these events are difficult to predict and control. Experience has shown, however, that certain risk factors are associated with an increased likelihood of a coal burst. A coal burst risk assessment consists of evaluating the degree to which these risk factors are present. In addition, some control techniques are effective in reducing the likelihood of an event or protecting miners from their effects."

Jan 1, 2015

By Anthony J. Konya

"This paper was written during part of the author’s student co-op with Cargill Salt at its Avery Islandunderground salt mine in Louisiana. Blasting salt is a unique type of blasting that is different than blasting other rock types. The plastic nature of salt, along with its large swell factor make salt a challenge to blast. The Cargill salt mines use and have tested a variety of different methods for breaking salt in an efficient manner, however these blasting methods are rarely used in other operations nor talked about today."

Jan 1, 2016

By A L. Zawadski, B G. Putland

"This paper discusses a method to build a calibrated comminution circuit model, using historic operating data and blend information that is useful for forecasting and optimising plant performance, as well as evaluating expansion opportunities. A preferred method for building a calibrated power-based comminution model is discussed and justified based on two case studies, offering low-cost and effective strategies to utilise existing information for the maximum possible benefit.The first example is the Lefa Gold Mine located in Guinea, West Africa operating a semi-autogenous grinding (SAG) and ball milling circuit with recycle crushing (SABC). Daily blend information and operating data was utilised to build and calibrate a power-based model of the comminution circuit. The least squares regression method was used to solve the SAG mill specific energy requirement and the operating work index (Wio) for each individual ore type. The calibrated model was used to evaluate expansion strategies to sustain throughput at higher proportions of fresh ore based on the proposed life-of-mine schedule.The second example is the Ok Tedi Copper-Gold Mine in Papua New Guinea operating a SAG and ball milling circuit (SAB). The circuit limitation would often shift between the SAG mill and the ball mill due to variable ore characteristics and feed blend. Typical SAG mill relief strategies, such as recycle crushing or secondary crushing, required significant capital expenditure and the potential throughput benefit would vary depending on ore type, making economic justification difficult. Daily blend information and operating data was used to build and calibrate a power-based model of the comminution circuit to identify ore types that might benefit from higher blast intensities to increase fines content, thus relieving the SAG mill limitation and increasing overall throughput without a major capital investment.Citation:Zawadski, A L and Putland, B G, 2016. Calibrating Comminution Models Using Operating Data to Forecast and Optimise Plant Performance, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 17–26 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By M. Nambiar

Due to the remote locations of mining projects and the need for long transmission lines to provide electrical power, mining sites often operate with poor network power quality and low short-circuit capacity. To cope with this situation, more and more mining operators are considering the installation of appropriately designed synchronous condensers together with power factor correction and harmonic filter systems (PFC & HFS). The installation of such power quality equipment is viewed as a technological advancement in the mining application. An adequate level of short-circuit power is essential and has to be ensured for the safe and reliable operation of especially large cycloconverter-driven gearless mill drive systems (GMDs) used for grinding. This paper explores the impact, technical advantage and reasoning for the selection of this advanced hybrid technology to cope with the power system challenges of future mining projects. It also delves into the potential problems and how to address them.

By E. M. Wilde

Through the USGS's National Coal Availability program, coal resource appraisals have been completed for three 7.5-minute quadrangles (Willow Crossing, Colstrip East, Colstrip SW) in the Powder River Basin area of southeastern Montana. Available coal reserves (original reserves minus tonnages affected by current restrictions) vary from 44 to 70 percent of the original reserves. Major restrictions impacting each area also vary. In each area, one or two beds contain most of the reserves, but up to eleven beds contain available coal. The main beds in completed studies are the Knobloch, Rosebud, Sawyer and Flowers-Goodale. Three additional areas (six 7.5-minute quadrangles) are in preparation.

Jan 1, 2001

By John H. Fowler

"Most of the aggregate used in Nova Scotia is produced from numerous glaciofluvial and ice-contact deposits scattered throughout the province. Production from bedrock sources is increasing, with most of the coarse aggregate used in the Halifax-Dartmouth area coming from quarries operating within the metro area.A recently completed provincial sand and gravel inventory mapping program has identified some ""resource-poor"" areas where comprehensive aggregate evaluation programs are underway. Although some areas of the province are experiencing aggregate supply problems, large volumes are exported to markets as far away as Bermuda.IntroductionThe Nova Scotia Department of Mines and Energy has been involved with aggregate resource studies for several years, although sand, gravel and crushed stone are not designated as minerals under the Mineral Resources Act of Nova Scotia. Our role has been to provide the aggregate industry with resource data as well as provide similar information to governmental agencies involved with municipal planning, water resource studies and environmental protection regulations. Several private consulting firms use the information in many of their site development studies.We became involved with aggregates in a rather roundabout way. Several years ago, an outcry from inhabitants of a small coastal community over the removal of sand and gravel from a local beach moved the provincial Department of Lands and Forests to take action to protect provincial beaches. We were asked by the Department to provide information and to suggest alternative sources here operators extracting sand and gravel from beaches could relocate. This request initiated an aggregate inventory survey in southeastern Cape Breton, which was later extended to cover the entire province. The initial provincial sand z and gravel inventory survey provided a series of 1:50,000 maps showing the distribution of sand and gravel deposits in the province."

Jan 1, 1982

By Jeffrey D. Thatcher, Debra W. Struhsacker

With the burgeoning development of precious metals heap leach mining projects throughout the country regulatory agencies are beginning to take a closer look at the short-and long-term environmental consequences of heap leach mining. This increase in regulatory review is occurring on federal, state and local levels, and is affecting both large- and small-scale mining developments. Small-scale mining developments are receiving especially critical regulatory scrutiny because in the eyes of some regulatory agencies, small developers lack the credibility automatically accorded to major mining companies. This is due in part to a bad image of small miners based upon past environmental problems and permit violations caused by a few, small operators. The proponent of a small mining development thus faces special problems during the project permitting process, and must convince the regulatory authorities of his company's ability and commitment to plan, develop, and decommission a mining operation in compliance with environmental regulations. Not only must the small developer have a thorough understanding of the regulatory requirements affecting his project, he must also devote considerable effort to careful internal planning in order to produce a well organized approach to project permitting. The importance of proper planning cannot be overstated. Project planning is key to convincing the regulatory agencies that the small miner is capable of developing a viable project. More- over, the economics of a small mining project demand permit acquisition at modest cost and in a timely fashion. A well planned permitting effort will thus ensure that permits are received within budget and on schedule. This paper will review the federal, state, and local permitting requirements for heap leach projects, and the variability of these requirements from state to state. The environmental assessment process for projects developed on public lands, and the acquisition of zero- discharge water quality permits, air quality permits, and local special use permits as they apply to small mining developments will be discussed. The paper will conclude with a review of project decommissioning and cyanide neutralization requirements and their implications for small-scale heap leach projects.

Jan 1, 1987

By I Minniakhmetov, J Ashford

Orebodies constitute naturally occurring, commonly highly variable concentrations of minerals in the earth’s crust formed through varying and highly unpredictable processes. Orebody knowledge is a core foundation of a mining company’s asset base underpinning all decisions about Mineral Resource and Ore Reserves, future production, development and ultimately the profitability and competitiveness of a mining enterprise. The decision to invest in a mineral project is usually based upon a techno-economic evaluation of the project and having clear approval pathways to gain local community support and address social and environmental impacts. The main objective of the techno-economic evaluation is to determine the optimum development sequence for the particular orebody in question and to estimate the economic viability of the project and the future return on investment to its stakeholders, balancing the inherent value of the mineral in the ground against the costs of development and market pricing. With the exception of market-driven commodity prices, virtually all revenue and cost estimates fundamentally stem from the understanding and subsequent modelling of the orebody. A reliable estimate of the ore deposit grade and other geological value-drivers is the foundation upon which the business case for future mine development and operation is intricately dependent. Orebody knowledge is, therefore, the fundamental driver of the mineral project cycle, influencing the progression of studies and consequently, the resource company’s ability to declare Exploration Results, Mineral Resources or Ore Reserves which govern the source and cost of funding available to the project. Drilling provides a ‘vector’ to the true nature of the orebody and effectively buys time to manage the technical risk associated with the orebody. Despite its perceived high cost, in both time and money terms, drilling is the only available technology for acquiring the necessary orebody knowledge to support technical and economic studies and to minimise orebody-driven cash flow uncertainty and volatility. However, like all costs, pressure to minimise drilling budgets is ubiquitous across the minerals industry. Paired with inappropriate key performance indicators, drilling is often regarded as a cost to be minimised, rather than an investment to be optimised. Furthermore, as future deposits get deeper and more complex, the collection of orebody knowledge is increasingly on the critical path for project development. The increasing cost of data collection pertaining to these deposits increases the temptation to minimise orebody knowledge gathering at the cost of long-term value as the reduction or postponement of drilling results in greater orebody knowledge risk at all stages of the value chain. Indeed the true cost of the decision to drill less is rarely known until the mine is in operation, well after the mine project evaluation team has moved on. This paper aims to promote orebody knowledge as the fundamental source of endogenous project financial risk and, consequently, its critical importance in project financial evaluation. Furthermore, the report documents experimental research into the development of an econometric model for valuing orebody knowledge. Using the density of drilling data as a proxy measure of orebody knowledge, the proposed approach integrates well-established stochastic grade modelling techniques with the mathematical mechanics of Decoupled Net Present Value (DNPV) which, combined with stochastic grade modelling (conditional simulation), lends itself to the financial International Mining Geology Conference 2022 | Brisbane, Australia and Online | 22–23 March 2022 3 assessment of orebody knowledge risk. Based on this approach, a metric is formulated, representing the minimum value of the orebody knowledge added by additional drilling

Mar 22, 2022

Several industrial-scale HydroFloat separators have recently been installed at Mosaic?s South Fort Meade beneficiation plant for the purpose of improving phosphate recovery and throughput capacity. This technology was implemented after numerous laboratory, bench-scale and on-site, pilot-scale test campaigns. The results from this detailed test work provided sufficient justification for the complete retrofit of the existing coarse and ultra-coarse flotation cells. Data indicate that the metallurgical results obtained with the full-scale separators are consistent with that obtained during both the bench- and pilot-scale evaluations. The benefits, theory of operation and commissioning of the equipment are also discussed.

Jan 1, 2007

By Edward J. Jr Walter, Edward J. Walter

The vibration problem is approximately fifty years old. The original investigation of the U.S. Bureau of Mines was begun in 1930. Significant investigation into the problem was done by Crandell, Langefors, et al, Edwards and Northwood, and again by the Bureau of Mines. This resulted in an effective Safe Limit standard expressed in particle velocity as 2.0 inches per second.

Jan 1, 1979