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By Kung-Lee Wang

SUSTAINED growth characterized the U.S. economy in 1964. Many new peaks were achieved in production, sales, employment, employee earnings, and business profits. At the end of 1964, the economy had experienced 4 years of uninterrupted expansion, and the greatest net gains in output for all postwar cyclical advances had been registered. There were no indications of the various weaknesses which have previously characterized advanced stages of business expansion. Both gross national product (GNP) and national income were 6.7 percent higher than in 1963. In 1964 GNP totaled $628.7 billion, a gain of $39.2 billion over the 1963 figure. On an overall basis, prices rose 1.75 percent in 1964. The real volume of output of goods and services (GNP in constant dollars) increased by 5.0 percent ill 1964; this was more than the 3.8-percent gain in 1963 but less than the 6.6 percent gain in 1962. The 1964 output gain also exceeded the average 3.7 percent annual increase for the postwar period. Congress authorized a two-stage tax reduction designed to further stimulate economic growth and employment. The tax cut favorably affected the 1964 economy in the following ways: By helping to boost personal income, corporate profits, and industrial production; by accelerating the pace of consumer spending and business capital expansion; and by increasing employment, thereby reducing unemployment to 5 percent. Three major problems remained unsolved. These were unemployment of 3.7 million persons, poverty conditions among more

Jan 1, 1965

By J. B. Clark

In multiphase ternary diffusion studies, plots of the variation bf the composition on the isotherm constitutes one of the most effective methods of presenting experimental results, especially if such plots are made in a manner which relates the composition path on the isotherm with the diffusion layer structure in the couple. Unfortunately, if different conventions for plotting are used serious misinterpretations occur readily, causing apparent disagreement between investigators who actually share the same viewpoint. A common convention for mapping these diffusion paths is needed at this time because with the increasing use of the electron-probe X-ray microanalyzer, a much greater number of ternary diffusion studies can be expected in the near future. In an effort to prevent unnecessary confusion in the future litera- ture, a convention for these plots is proposed, as outlined below. A hypothetical example of the use of these conventions is given in Fig. 1 where the path of composition through the diffusion structure of the 100 pct A/50 pct B, 50 pct C couple is plotted on the appropriate isotherm of the ABC system. The lower case letters relate the region in the diffusion layer structure to the appropriate composition on the ternary isotherm. 1) The diffusion path is plotted on the isothermal section corresponding to the diffusion temperature of the couple. 2) The terminal compositions of the plotted diffusion path are the initial compositions of the couple halves—provided infinite boundary conditions are maintained. If, in either couple half, infinite conditions are not maintained, then the path terminates at the composition of the exterior surface of the couple. If, at this surface, the composition varies with time or if the plotted path is time dependent, then the diffusion time should be noted beside the plotted path. 3) A solid line crossing a single phase field (e.g., line a-b in Fig. 1) denotes an existing layer of that phase in the diffused couple. 4) A dashed line crossing a two-phase field parallel to the tie lines (e.g., line g-h) represents an interface between the two phases with interfacial compositions designated by the ends of the tie-line. The line represents no spatial extent. 5) A solid line crossing a two-phase field so as to cut tie lines (e.g., line b-c or line j-k) represents a locally equilibrated columnar two-phase layer. The solid line should cut those tie lines which correspond to the lateral interfacial equilibria along the columnar

Jan 1, 1963

By Q. Cheng

This paper introduces the multi fractal interpolation method (MIM)developed for handling singularities in data analysis and for data interpolation. The MIM is a new moving average model for spatial mapping and interpolation. The model decomposes the raw data into two components: singular and nonsingular components. The former can be characterized by a localized singularity index that quantifies the scaling invariance property of measures from a multifractal point of view. The latter is a smooth component that can be estimated using ordinary kriging or other moving average models. The local singularity index characterizes the concave/convex properties of the neighbourhood values. The paper utilizes a binomial multiplicative cascade model todemonstrate the generation of one- and two-dimensional data with multi-scale singularities which can be modelled by asymmetrical multifractal distribution. It then introduces a generalized moving average mathematical model for analysing and interpolating data with singularities. Finally, it is demonstrated by a one-dimensional case study of de Wijs’ data from a profile in a zinc mine, that incorporation of spatial association and singularity can improve the interpolation result, especially for observed values with significant singularities.

Jan 1, 2015

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

The Phoenix mine on the Mararoa Reef at Norseman, Western Australia, provides an outstanding: AUstralian instance of the recurrence of payable ore beneath the bottom of an abandoned mine, and an interesting and instructive example of the development ofideas with regard to ore recurrence in a particular district. The Mararoa Reef is the most productive of several hypothermal goldquartz vains in pre-Cambrian basic volc81olics which strike northsouth and dip on the average, 45 degrees east. The Phoenix minewas abandoned at 500 ft. vertical depth after producing 342,000 tons of 9.9 dwt. recovery grade (equivalent to nearly half of the total production of the Norseman field) from a 2,500 ft.. long, horizontally disposed oreshoot, which is reported to have had an ore outcrop only 30 ft. in length.Interest in the field was revived in 1933, and by 1941 new ore mined and developed on the Mararoa Reef by Central Norseman Gold Corporation N.L. amounted to approximately 700,000 tons of 6.7 dwt. recovery grade. In the same period another oreshoot of similar size and grade was developed by Norseman Gold Mines N.L., south of the old Mararoa company's site. As shown by the plans, the ore occurs in discontinuous shoots. The intervening area of shear is poor in quartz as well as in gold. Geological work on behalf of Western Mining Corporation Ltd., and Central Norseman Gold Corporation N.L. has been in progress in the mine and in the field more or less continuously from 1913 to 1941 and again since 1946. This paper describes the successive advances in the understanding of the exploratory problem up to late 1941, to which several investigators have contributed. It is published by permission of the Board of Directors of Central Norseman Gold Corporation N.L., owners and operators of the Phoenix and other mines.Development of the Prospect.In 1933 Western Mining Corporation acquired an option over the Phoenix property and adjacent leases. H. E. McKinstryl visited the mine and recognised that the ore occurred primarily on the flatly dipping sections of the vein, as distinct from the steeply dippingsections, in a wide shear zone with reverse movement. Many of the flatly dipping fractures were seen to exhibit tension phenomena and to link one shear plane to the next below on the footwall side. The flat links carried much more quartz than the steeper shears.Later, H. J. C. Conolly, assisted by J. D. Campbell, examined the prospect and by contouring the vein with reference to an inclined...

Jan 1, 1950

The contract objective was to evaluate sources of airborne quartz and research control methods that would assist underground mine operators in complying with respirable dust standards which have been reduced because of quartz in the dust exceeding five percent. The work involved: Phase I -evaluate sources of quartz dust at the roof bolter work location; Phase II -evaluate the relationship between the quartz content of the coal and adjoining rock strata and quartz exposure at the roof bolter and continuous miner locations Phase III -conduct laboratory tests to determine performance parameters for roof bolter dust collector systems. The underground surveys for Phases I and II determined: (1) the continuous miner typically is the greatest source of quartz exposure for the miner and roof bolter operators when single-split ventilation is utilized, (2) a statistically significant relationship be­tween quartz content in face material and operator exposure was not determined and data suggested mining equipment and procedures may be more critical. The Phase III lab tests indicated the use of dust hog-type bits, filter cartridges, maximized collector airflow, and reduced bit rpm should be utilized to minimize dust liberation at the roof bolter.

Jan 1, 1985

By Oswaldo Ortiz Sánchez

El presente trabajo describe la alternativa de uso del mortero de resina en la fijación de pernos de anclaje de las excavaciones mineras, consolidación y disipación de vibraciones en los cimientos de plataformas para la instalación de molinos, winches, tolvas, etc. Esta opción surge en respuesta al problema de reforzamiento con pernos de anclaje en ambientes con aguas corrosivas o en proceso de deformación acelerada en las excavaciones mineras, así como ante obstáculos de subsidencia de cimentación en plataformas, donde se encuentran instalados equipos de gran tonelaje, y que producen fuertes vibraciones durante su funcionamiento.

Jul 31, 2003

By J. E. Misiewicz, A Rozendaal

Paper presented at Geofluids '93, held in Torquay, UK, 4-7 May 1993. The tin field consists of a fragment of Lower Proterozoic volcanosedimentary rocks surrounded by granitoids. Almost all the significant deposits are hosted by arkoses and are classified as replacement and space-filling types, with particular styles of mineralisation dominating at different mines. Petrological and geochemical investigation of borehole cores from four centres indicated the presence of a stratified zone 500-600 m thick and continuous over at least 20 km along strike, consisting of pervasively altered clastic arenitic sediments. The alteration is zoned into a grey-green sodic albitised footwall, an 80 m thick sericitised-tourmalinised sulphidic tin zone and a red haematitic potassic hanging-wall. The zoning and the localisation of three cassiterite phases are consistent with the tectonic history and with multiple pulses of stanniferous hydrothermal fluids derived from late differentiates of the granites over a prolonged period. Areas of high fracture density acted as conduits for the fluids, whose initially rapid ascent was retarded by decreasing pressure contrast, limited development of fracturing and/or impermeable shaly arkose to cause lateral spreading and pervasive alteration over a broad, stratified front. Lateral overlapping of local fronts at the various centres suggests a continuous zone, while the many petrological and geochemical similarities point to a shared fluid composition

Aug 1, 1995

By Robert Hivick, Frank Sames

The control of environmental effects, especially blast vibration and airblast, has become a dominating planning criterion for most surface blasting operations. Compliance with existing regulations is generally achieved through constraints in the blast design, or monitoring programs. Commonly, blast vibration and airblast signals are rated and compared by their maximum amplitude and the associated principal frequency. However, this data reduction limits the interpretation of the influence of varying blast design parameters on the vibration and airblast.

Jan 1, 1999

By S. Maurhofer

The Uetliberg Tunnel in Switzerland is the longest tunnel in Zurich?s new Western Bypass Expressway, connecting the Birmensdorf bypass in the west with the existing Zurich-Chur national motorway in the east. Thus the tunnel links the Zurich-West motorway interchange with the Zurich-South interchange (shown in Figure 1). The Uetliberg Tunnel project comprises two parallel tubes, each about 4.4 km long. The two tunnel tubes are connected every 300 m by a transverse walkway and every 900 m by a transverse roadway (Figure 2). The SOS niches are spaced 150 m apart. Portal stations with machinery rooms are located at the west and east portals. The tunnel falls with a gradient of 1.6% from the west portal at Wannenboden to the east portal at Gänziloo. The Project costs are about CHF 1.12 billion. The carcass construction started in March 2001. The Opening of the Uetliberg Tunnel is planed in spring 2009.

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 Moorrees C, Everson P

A detailed examination of carbonic acid leaching of crude iron-containing magnesia derived from Savage River magnesite shows that the rate and extent of magnesium and iron dissolution are affected by the slake time, leaching temperature, carbon dioxide pressure, pulp density and rate of agitation. In order to produce high-purity magnesia from the leachate by precipitation and calcination, the optimum leaching conditions, which are those that yield maximum magnesium and minimum iron dissolution, have to be a compromise in terms of the above parameters. For example, iron dissolution can be limited by leaching at an elevated temperature (-45°C), but because the maximum concentration of magnesium biearbonate decreases rapidly with an increase in temperature, it is necessary to use a low pulp density (-2 per cent solids) in order to achieve an acceptable degree of magnesium dissolution.Evidence is obtained that iron dissolution involves the formation of a soluble ferric bicarbonate complex that decomposes at elevated temperatures. The extent of iron dissolution is much higher than might be expected and it is probably because the original magnesite contains siderite in solid solution with the magnesite; on calcination, the hematite whieh is formed is in a very finely divided condition and hence more reactive.

Jan 1, 1983

By H. H. Bleakney

The merit of reduction-in-area as a criterion of quality in metals is shown to lie in its influence on breaking stress, but the virtue of elongation is not easy to find. In order to assess the value of elongation, either as a measure of quality or as a guide to design, it will be necessary to separate the overall de-formation occurring in tension tests from the localized deformation associated with localized reduction in area. The obstacles to a successful solution of this problem have been shown to be more formidable than is generally appreciated, and a new solution to the problem has been suggested. This solution involves a de-vice by which an electric circuit is broken when the particular value of strain is reached that is to be taken as the point of separation between general and localized deformation. The report presents results from a number of tests on both low-carbon and alloy steels. These results indicate that the selected criterion of separation is accurately identified by the proposed method; that it

Jan 1, 1962

By A. M. Krzanowski, T. S. Golosinski

"This paper presents results of a study undertaken to determinethe feasibility of mining plains overburdens with bucket wheel excavators. Based on extensive geotechnical testing of overburdens under study, the relations between material geotechnical properties and its cuttability were defined. The properties with the highest correlations to the cuttability werethen used to develop the material diggability classification. This classification may be used for identification of overburdens and coals mineable by bucket wheel excavators.IntroductionLow cost of mining and high productivity can be achieved when mining unconsolidated soils and soft rocks with bucket wheel excavators. As a result this mining equipment will likely be introduced into plains coal mines. At present there are plans to use a bucketwheel excavator (BWE) in at least one mine by the end of this decade. Unfortunately, the performance of a BWE deteriorates rapidly with the increasing strength of mined material. To avoid costly misapplication, material diggability must be defined in advance of an application (i.e. the force required at the cutting edges of BWE buckets must be quantified). Correct definition of material diggability permits reliable selection of a BWE, or may indicate unsuitability of this equipment for a particular application.The reported studyu i was undertaken to investigate the diggability of typical prairie overburdens and thus provide a guidance for likely future applications of bucketwheel equipment. Investigations concentrated on the parts of overburden most likely to create problems for a BWE mining. These are defined in Table 1. At present, thin layers of the two investigated materials (samples K and L) are mined by a BWE in an oil sand mine, after being loosened by blasting."

Jan 1, 1987

By Atta Ur Rehman, Kwame Awuah-Offei

"Information diffusion potential of a social media user affects how quickly information about a mineral project can diffuse through that user. If management can use social media and network analysis in community engagement programs to understand how fast and how far information will diffuse to communities and followers of particular social media users, it can selectively focus on the most influential users. This article proposes a method to examine the information diffusion potential of social media accounts. The work uses Gephi, an open source software, to extract and analyze data from different Twitter handles to predict their information diffusion potential. The work uses case studies of real Twitter users (e.g. mining news organizations and bloggers) associated with mining to illustrate the approach. The case study results show that there are significant disparities in information diffusion potential that will demand selective attention. This research will help mines develop effective social media engagement strategies.The mineral industry provides raw material for industrial activity to support society (Martens and Rattmann, 2001). Mines have changed from conventional mining practices to sustainable ones because of the negative impacts of mining in the past and increased public awareness (Wang et al., 2016). The concept of sustainable mining is getting mature, as stakeholders (e.g., governments, investors and host communities) are getting more involved in mining projects (World Economic Forum, 2014). The failure of mining companies to address the demands of these stakeholders might result in the failure to acquire a social license to operate (SLO) (Thomson and Boutilier, 2011). The SLO, if granted, is mutually beneficial to all stakeholders. Mines prefer being granted SLO and keeping it to avoid any kind of social unrest due to their operation (Prno, 2013; Moffat and Zhang, 2014). Mining communities can grant different levels of SLO ranging from withholding SLO to psychologically identifying with the project (Joyce and Thomson, 2000; Thomson and Boutilier, 2011).Most of the previous work to understand community perceptions and SLO in mining is generally qualitative (ICMM, 2012a; Thomson and Boutilier, 2011; Prno, 2013; Moffat and Zhang, 2014; IFC, 2014). In particular, there is limited work on how community perceptions change over time due to information diffusion (Boateng and Awuah-Offei, 2017). However, SLO changes with respect to time (Yates and Horvath, 2013), which can result in risks that are not easy to predict. Mine managers and engineers have a desire to understand these changes so as to mitigate these risks (Que and Awuah-Offei, 2014; Que et al., 2015)."

Jan 4, 2018

The structural design of a mine haul road involves the determination of cover thickness requirements above the in-situ or sub-grade material. The specification of these layerworks is a critical component in the overall road design process. Poor design often leads to premature failure of the road, safety is often compromised and productivity and equipment service-life will certainly decrease. Historically, the California Bearing Ratio (CBR) cover-curve design method has been widely applied to the structural design of mine haul roads. More recently, established mechanistic design principles have superceded the CBR approach to haul road design, using a multi-layer model to represent the various road structural layers. The structural design and associated layer thickness requirements are then determined following a maximum strain criterion. This paper develops a case-study evaluation of the CBR cover-curve and mechanistic design methodologies and through a comparative analysis of layerworks and materials, highlights how improved structural design can be achieved mechanistically.

Jan 1, 2011

By Lon A. Williams

This appendix contains drawing lists and drawings of components and assemblies designed for the prototype portable and machine mounted lighting systems per Tasks II & IV of Contract No. H0220065.

Jan 1, 1976

By S. C. Brown

A number of studies have suggested that microscale asperities enhance bubble-particle attachment efficiency; however, in practice the roughening of particulate surfaces can also lead to a decrease in flotation. In the present investigation, it is proposed that nanoscale asperities may be partially responsible for this phenomenon. It is suggested that as inter-asperity separation distances are reduced capillary effects are enhanced leading to the formation of stable liquid domains, which adversely impact bubble-particle adhesion. In addition, obstruction of surfactant self-assembly may occur, further limiting flotation.

Jan 1, 2003

By William A. Hustrulid

A technical and economic evaluation of the potential for improving mining productivity through the use of underreamers in blastholes, specifically in relation to Minnesota taconite, Arizona surface copper and in situ mining operations is presented. Included are (1) a review of the drilling and blasting practices presently being used, (2) a discussion of current underreamer technology. (3) the presentation of a general economic cost model for underreaming, (4) the application of the model to surface taconite, surface copper and in situ mining, and (5) a summary discussion including required performance specifications, potential overall benefits, and recommendations for further development.

Jan 1, 1977

By Chris Bennett, Drupad Desai, Kirit Mevawala

INTRODUCTION The design/build (D/B) philosophy of contract delivery is neither new nor unusual when it comes to at-grade, elevated or high-rise structures. But when it comes to constructing underground facilities, there were no examples to be followed in early 90sin the continental United States or its territories. When DMJM+HARRIS was selected as general architectural and engineering consultant for the Tren Urbano (TU) project in Puerto Rico, one of the requirements of the Federal Transit Administration (FTA) for funding commitment was to use TU as a demonstration project utilizing design/build contract delivery method. Now fifteen years later, New York City Transit (NYCT) has instituted a similar requirement for their first Tunnel Boring Machine (TBM) contract for the Second Avenue Subway. As with most construction mega-projects, lots of things have happened and there were several lessons learned from the TU experience that are now being applied to Second Avenue. Both of these projects require building tunnels and underground transit facilities in heavily traveled corridors of an urban city, in the vicinity of active business and commercial enterprises. To enhance the challenge, there are noise and vibration sensitive and historic urban receptors either over or along both the transit corridors. Column free Tren Urbano station caverns over18 m (60 ft.) wide were built in soft ground conditions within 3.6 m (12 ft.) of the surface under an aging heavy utility corridor, while NYCT tunnels with station structures stretching the limits of rock caverns to 34.8 m (100 ft.), were planned in rocky geology with the presence of shear and fault zones and some mixed face conditions. BACKGROUND During the early period of design/build experimentation, the speed with which the contract procurement packages could be put together enabled the owners to take advantage of the major efforts underway to rebuild the infrastructure that was suffering from post-World War II neglect. Use of design/build for new starts was unheard of and most of the projects were smaller in nature in order to allow the methodology to be tested. Development of functional design packages with the understanding that the D/B

Jan 1, 2005