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By Terrence M. Carroll, Chu E. Ho, Dimitrios Niarchos

"Construction of the new extension to Terminal 4 at John F Kennedy International Airport in Queens, New York involved the application of tapered piles for foundation support. Initial design based on past load testing experience had indicated that a pile depth of 65 feet was necessary to achieve a capacity of 394 tons. However, piles with a single length of 62 feet were ordered and installed, which led to marginal performance of the piles. This paper presents the technical considerations for mitigating the situation based on a systematic review of three preliminary pile load tests and dynamic capacity measurements on the shorter piles. Consideration was given to the long term gain in capacity of tapered piles due to set up in the Glacial Sand. The observational approach to the evaluation of piling performance adopted on this project resulted in salvaging many piles which failed to comply with the specified driving criteria. It was acknowledged that a more prudent course of action was for the Contractor to have ordered more appropriate pile lengths that allowed for potential variation in soil conditions across the site. The 4.6% saving in pile material did not warrant the effort that was required to mitigate the 39% of installed piles that did not meet the specified driving criterion.INTRODUCTIONAn expansion project at John F. Kennedy International Airport in Queens, New York involved the Phase 2 extension of Concourse B at Terminal 4. The site consists of 4 to 5 feet of pavement over about 10 feet of hydraulically placed sandy fill. Below this is a layer of marsh deposit, comprising of soft organic clay and peat, up to about 11 feet thick. Beneath the marsh deposits is a deep layer of glacial sand which extends to well over 100 feet below ground. Figure 1 shows the typical subsurface profile at the site. The new structures were supported on 223 steel tapered piles. The piles consisted of a straight steel pipe 18 inches in diameter and 0.375 inches thick, with a 25 feet long tapered bottom section (diameter varying from 18 inches down to 8 inches at the pile toe). The piles were first driven to the founding depth and subsequently in-filled with concrete. The concrete strength (fc) specified was 4,500 psi and the yield strength of the steel piles (fy) was 50 ksi. Initial pile design, based on earlier experience with static pile load testing for Phase 1 development at the same terminal, indicated that a pile length of 65 feet was necessary. However, piles with a single length of 62 feet were ordered and installed by the Contractor, leading to marginal performance of the piles. This paper presents the technical considerations for the adoption of alternative pile driving criteria, based on a systematic review of the preliminary static load test results for the present site and PDA measurements obtained during pile installation, in order to accommodate the capacity of the shorter piles."

Jan 1, 2017

By Alessandra Savazzini dos Reis

A crescente preocupação em relação às áreas de proteção ambiental e ao alto consumo de argila, matéria-prima da cerâmica vermelha, ocasiona a indisponibilização progressiva de reservas de argilas no Brasil. Com isso, vê-se a necessidade de incorporar resíduos na massa argilosa para confecção de produtos de cerâmica vermelha. A indústria de cerâmica vermelha brasileira consome cerca de 10 milhões de toneladas de argila ao mês para produção de telhas e blocos. Na própria olaria são gerados resíduos, tal como, o resíduo de massa cerâmica crua originado na etapa de conformação das peças. Este trabalho visa incorporar o resíduo de massa cerâmica crua na massa argilosa usada em cerâmica vermelha. O resíduo foi caracterizado por meio de ensaios de FRX, DRX, limites de Atterberg e distribuição de tamanho de partículas. Corpos de prova feitos com massa argilosa e resíduo em teores variando de 10% a 90% (massa) foram conformados, secos à 110ºC, queimados à 900ºC em forno industrial e submetidos a ensaios de absorção de água, porosidade aparente, massa específica aparente e resistência à compressão. Os resultados evidenciaram que as propriedades cerâmicas avaliadas nos corpos de prova da massa argilosa incorporada com o resíduo atendem aos valores das argilas-padrão brasileiras para cerâmica vermelha.

Aug 17, 2017

By BUREAU OF MINES

This report is submitted in accordance with the provisions of the Synthetic Liquid Fuels Act of April 5, 1944 (30 U.S C. 321-325, as amended), which require that: "The Secretary of the Interior shall render to Congress on or before the first day of January of each year a report on all operations under this Act." Owing to the broad scope of the content and the diversity of interests represented, the Annual Report for 1953 has been divided into two separate publications. Each has been published by the Bureau of Mines as a Report of Investigations, and the respective titles follow: R. I. 5043, Part I - 011 From Coal. R. I. 5044, Part II 011 From 011 Shale. - Identical in each report, the introduction summarizes research progress made in 1953 under the entire Synthetic Liquid Fuels program. A free copy of each of these publications may be obtained by a written request to the Bureau of Mines, Publications Distribution Section, 4800 Forbes Street, Pittsburgh 13, Pa. The R. I. number and title of the publication desired should be indicated.

Apr 1, 1954

By Victor Dolmage

Introduction Although gold production in British Columbia began in 1859, lode gold was not produced till 1893. Since 1900, the annual production of lode gold has fluctuated between $3,000,000 and $6,000,000. About twenty per cent of this production may be regarded as by-product gold from base metal mining. The remainder comes from a few isolated but important mines, such as the Rossland mines, Nickel Plate, Surf Inlet, Premier, Pioneer, Bralorne, Reno, and Cariboo Gold Quartz, and from several less important mines. All of the above, except Pioneer, Bralorne, Reno, and Cariboo, are approaching or have reached the point of exhaustion, but all are now receiving, under the stimulus of the. present gold-mining boom, drastic resuscitative treatment, with, in some cases, signs of resurrection. Notwithstanding this, however, the main interest at the present time is focussed on the Bridge River and Cariboo fields. Both these fields were discovered in the early 'sixties' and, apart from the Cariboo placer production, both have from time to time contributed small amounts of lode gold; but it is only during the last two years that the real possibilities of these areas were discovered. and that they began to assume the appearance of goldfields of major importance. The two fields are sorme three hundred miles distant from one another and contain deposits of distinctly different types, so that the only reason for including them in one article is the fact that they came into prominence more or less simultaneously and at a time coinciding with, but not otherwise related to, the present gold-mining boom.

Jan 1, 1934

By A. P. Chaves, D. Jose Neto, M. G. Bergerman, E. S. Mano

"More complex ore comminution and concentration operations have found increasing application in the mining industry due to lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. They allow removing a significant mass of material with little or no content of the relevant mineral before the ore is fed into the processing plant, with the consequent reduction in the mass to be processed in downstream operations. Significant benefits arise out of the use of pre-concentration, such as higher contained metal output without the need to increase the grinding or flotation capacity, and longer mine life. The grade of marginal ores could be enhanced to a level that would make their exploration economically feasible, which would result in increasing exploitable reserves. Nevertheless, few studies to date have assessed the resulting impacts on ore grinding energy consumption and wear after the gangue is removed through pre-concentration operations. This study evaluated the energy consumption and wear of grinding circuits in Brazilian mining operations in which the feed has gone through a pre-concentration stage. Such assessment was based on different samples of sulfide and oxide ores. Laboratory tests were carried out to investigate the power consumption and wear of grinding circuits with and without a pre-concentration stage. Laboratory test results were used to simulate industrial grinding circuits based on both alternatives and illustrate the environmental and economic benefits of each one.INTRODUCTION Increasingly complex ore concentration operations in several stages have found broadening application in recent years in view of lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. Different ore processing technologies can be used for that purpose, such as magnetic separation, density segregation, and separation methods based on high-tech sensors (ore sorting). Currently, the most common methods are gravimetric processes, in view of their low cost, particularly jigging and dense medium separation methods, such as the drum and cone separators manufactured by Western Machinery Company, Teska, Drewboy, Norwalt, Dynawhirlpool and Tri-flo, and dense medium cyclones (CAMPOS; LUZ; BRAGA, 2010). The use of dry ore sorters has also grown significantly in recent years (Jose Neto et al. 2017). The selection of the separator type depends essentially on the ore particle size, required flows, and operating density ranges. All these methods may even be used after preferential blasting in mining (Grigg & Delemontex, 2015)."

Jan 1, 2018

By W. Curlook, V. G. Papangelakis, M. Baghalha

A pressure acid leaching process has been developed for the extraction of metal values, nickel, copper, cobalt and zinc, from base metal smelter slags. The basic concept contemplates cooling the smelter slags through solidification sufficiently slowly to induce a good measure of crystallization; and subsequently, after fine grinding, to pressure leach such slags at around 250°C while applying oxygen overpressure, utilizing smelter byproduct sulphuric acid. High levels of extraction of the slags' metal values are thereby achieved. It has been shown that if the same slags are quenched thereby producing an amorphous structure, the resulting metal extractions are very low. The process is applicable to smelting furnace throwaway/discard/dump slags, as well as to in-process converter slags. By extracting the bulk of the residual base metal values in the throwaway/discard/dump slags, the resulting leached residues are rendered virtually benign vis-à-vis the external environment.

Jan 1, 2004

By R. E. Robinson

I shall present a concept for the development of the resources of this country and its neighbours that repre¬sents a fantastic challenge to our scientists and entre¬preneurs. This concept offers prospects of development that must make our previous achievements seem equivalent only to the first act in a drama enacted on the stage of Southern Africa. I hope to illustrate how, in Act Two, chemistry will play a dominant role, and chemists and chemical engineers will be among the principal actors.

Jan 1, 1980

By R. L. Cosgriff

A commercial, battery-powered mine vehicle has been equipped for remote operation in coal mines. This vehicle is controlled by an operator from the remote station. Command signals originating at the remote station as well as video and data signals originating on board the vehicle are relayed between the remote station and vehicle using a single coaxial line. This coaxial line is normally 2,000 feet in length and is reeled in and out from a drum mounted aboard the vehicle The vehicle has a maximum speed of 6 ft/sec and a minimum speed of 4 ft/sec using 36-volt excitation of the traction motor. If this traction motor is excited by two of the three batteries, 24-volt excitation, the vehicle will travel at approximately 2 ft/sec. The speed can be reduced by the operator to 1 ft/sec. This vehicular system has been tested in coal mines. Presently, the major limitation of this system is associated with fatigue failure of the splices in the coaxial line and lack of mobility caused by its 3-wheel design.

Jan 1, 1974

By John S. Stevenson

ZEBALLOS is a relatively new mining camp. It is on the west coast of Vancouver island, approximately 195 nautical miles northwestward from Victoria. Previous to 1934, a small amount of placer gold had been recovered from the Zeballos river and tributary creeks. However, it was not until the winter of 1934-35, when shipments of high-grade gold ore were made from the property of the White Star Gold Mines, Limited, that lode gold mining really began. Since then, several new mines and many promising prospects have been found. Milling in standard sized mills only commenced late in 1938, when the 75-ton mill of Privateer Mines, Limited, and the 50-ton mill of Spud Valley Gold Mines, limited, were first turned over. The most striking feature of the camp is the high-grade quality of the ore as usually mined. At one property, the ore along a drift 650 feet long has ranged from 5.8 ounces per ton to 17.5 ounces, over average vein-widths ranging from 8.3 inches to 14.5 inches in selected blocks along the drift. One . high-grade shipment of 196.6 pounds of ore from the same property contained 142.877 ounces of gold. The present paper deals only with that part of the area in which mining operations are most active, namely the main Zeballos River valley and its tributaries, Spud and Goldvalley creeks. During the summer of 1938, prospecting was carried on beyond this circumscribed area. The geology and early developments in the area have been described in the following reports: (1) CLOTHIER, G. A., Annual Report of the British Columbia Minister of Mines, 1929, p. 376; 1930, p. 441; 1932, p. 205; and 1933, pp. 252-254. (2) GuNNING, H. C., Geological Survey of Canada, Summary Report, 1932, Part A-II, pp. 29-50, Zebaltos River Area, Vancouver Island, B.C. (3) STEVENSON, John S., Annual Report of the British Columbia Min-ister of Mines, 1935, pp. F-38-40. ? ( 4) BANCROFT, M. F., Geological Survey of Canada, Memoir 204, 1937, Gold-Bearing Deposits on the West Coast of Vancouver Island Between Esperanza Inlet and Alberni Canal. (5) STEVENSON, John S., British Columbia Department of Mines, 1938, Lode-Gold Deposits of the Zeballos Area. (6) MAcDoNNELL, G. F., The Privateer Mine, Zeballos; The Miner, Van-couver, B.C., December, 1938.

Jan 1, 1939

By Jeffrey Y. Foley

In 1980, the Bureau of Mines investigated the northern Darby Mountains on the Seward Peninsula, AK, for radioactive mineral deposits. Uranium is concentrated in silicified shear zones in biotite quartz monzonite of the Darby pluton. The shear zones are best exposed in steep, narrow, avalanche gullies; they are characterized by radiometric anomalies and by uranium and thorium geochemical anomalies. Radiometric and geochemical anomalies are also found over altered biotite quartz monzonite where there are no visible shear zones. The radiometric and uranium anomalies are often spatially, but apparently not genetically, associated with alkaline mafic and felsic dikes. Similar geochemical and radiometric anomalies over discolored altered zones and geochemical anomalies in sediments downstream from the altered zones indicate that additional areas may also be favorable targets for uranium deposits. Analyses of panned, heavy mineral concentrates show no significant concentrations of uranium or thorium in resistant heavy minerals. This indicates that radioactive elements in the Darby pluton are concentrated in soluble, nonresistant minerals that may constitute a recoverable uranium resource.

Jan 1, 1986

By George E. Fish

This report describes investigations conducted by the Bureau of Mines from 1957 through 1959 in the Roseland anorthosite-titanium belt of Nelson and Amherst Counties, Va., for the purpose of studying the titanium resources of the area. Three titanium deposits containing much saprolite ore derived from the decomposition of anorthosite and diorite were selected for detailed study Following a reconnaissance of the reported titanium occurrences in the belt. These three deposits occur in or are associated with anorthosite. Most of the occurrences are situated on or near the contact between the anorthosite and the gneissic country rock. The saprolite deposits are as much as 1.5 miles long, 1,000 feet wide, and 100 teat deep and contain significant reserves of titanium-bearing material estimated in excess of 20 million tons. Where it was penetrated by drilling, the unweathered rock beneath the saprolite contains nearly the same titanium values as the saprolite.

Jan 1, 1962

By Joël P. T. Kapusta

Back in 1995, Air Liquide and Union Minière presented a joint paper at the Copper 95 – Cobre 95 Conference in Santiago, Chile, describing the first full scale plant trials of shrouded sonic injection in a Hoboken converter at the Hoboken smelter in Belgium. Almost a quarter of a century later, the technology known as ALSI, or Air Liquide Shrouded Injection, has been tested or commercially implemented in several copper and nickel smelters. Despite these successes, the copper industry did not adopt it widely in the same manner the steel industry adopted the Savard-Lee tuyere in the 1970s and beyond, not even in the way the lead industry adopted it with the Queneau-Schuhmann-Lurgi, or QSL, process. The development and implementation of bottom-blowing smelting and converting technologies in China in the last ten years, however, changed the industry’s perception that high- and ultra-high oxygen injection in copper smelting and converting was indeed possible under specific process conditions. In this paper, I retrace the key learnings of my journey with sonic injection over the twenty five years from my humble beginnings in my early years with Air Liquide, through plant trials and technology implementation in the late 1990s and into the first decade of the new millennium, and ultimately, to the most conclusive proof that the sonic injection design methodology I established is valid, and the calculation tools I developed are accurate. I conclude by sharing my thoughts about whether the deployment of the Savard and Lee legacy within the nonferrous industry was just a pipe dream or whether it will become a reality. INTRODUCTION In the context of lower quality ores and changing economic markets, copper smelters need to continuously innovate and improve to remain competitive and respect their corporate social responsibility engagements. One avenue towards this business, social, and environmental goal is to increase process intensity while lowering fossil fuel consumption to lower greenhouse gas emissions and reducing process off-gas volumes to better capture As and SO2–laden emissions. I believe high oxygen sonic injection for submerged tuyere copper bath smelting and converting is one technology that can help smelters achieve that goal of higher business, social, and environmental performance. Twenty five years ago, when I discovered that the Savard-Lee tuyere had revolutionized the steel industry (Savard & Lee, 1966; Knuppel, Brotzmann, Fassbieder, Savard, & Lee, 1972), I had a dream — or was it a vision? — that within the first decade of the new millennium, modern copper smelters operating submerged tuyere bath smelting and converting vessels will have implemented high oxygen sonic injection and will be reaping the financial and environmental benefits that the steel industry enjoyed in the 1970s. As we approach the end of the second decade of the new millennium, I have to admit that my dream has been all but shattered as the majority of copper bath smelting and converting vessels today continue to operate under bubbling regime conditions. This mode of operation is archaic, still requires tuyere punching and blows at inherently low enrichment levels, particularly in converting, producing large volumes of process off-gases. Under such operating conditions, regulations and emission quotas for As, SO2, and particulate matter oblige smelters to use not just primary or secondary hoods, but sometimes even tertiary hoods. I vividly recall being told, fifteen or twenty years ago when visiting smelters to promote the application of the Savard-Lee tuyere in nonferrous processes, that implementing sonic injection was not economically viable due to the high cost of compressing air and oxygen. Some of the smelters I visited back then have since mandated their engineering partners to design and build secondary or even tertiary hoods. I cannot fathom how secondary and particularly tertiary hoods, with all of their auxiliary equipment and added ducting, could be more economically viable than purchasing and installing a few compressors, expanding the pipeline network for compressed air and oxygen, and installing a new control valve train to feed sonic tuyeres. Besides, adding hoods does not address the problem of As and SO2-laden fugitive emissions at its source but merely provides a costly mitigation for it by capturing larger volumes of process off-gases rather than reducing these large volumes in the first place. Moreover, hooding does not reduce energy consumption nor does it increase process intensity, two aspects that I believe are critical for smelters to remain competitive and sustainable in a deeply changing market environment.

Jan 1, 2019

By J. M. WADSWORTH

The purpose of this bulletin is to describe the methods of constructing and operating representative types of plants in the United States used for removing the light hydrocarbons from petroleum by continuous distillation, such plants being commonly known in the trade as topping or skimming plants. In the discussion of each plant an endeavor has been made to arrange the text similarly in order to facilitate comparison and to emphasize the important features. The various experimental values for the specific and the latent heats of the oils apply approximately to the oil treated. Careful experiments with each oil and its commercial fractions were not justifiable in view of the purpose of this report. It is regretted that limitations for recording data at the different plants made impossible the determination of a heat balance for each, which would have provided an equitable method of comparing efficiencies. The writer has confined himself to a comparison of the relative efficiencies of the distilling apparatus alone by the following method: Effi . f till d tt" _ Heat theoretically required. ciency 0 SIS an se mgs - Heat content of fuel consumed. The plants described are all in California where the topping industry has had its growth accentuated by the character and the use of the oil handled. The scarcity of suitable coal made the adoption of other fuel necessary, and the heavy oil of California supplied the need. To raise the flash point and to dehydrate this oil, various plants have been developed. However, the topping industry is represented in other fields; the Roxana Petroleum Co. of Cushing, Okla., and the Warner-Quinlan Asphalt Co. of New Jersey, are operating Trumble plants, and Texas and Oklahoma operators have been experimenting with different pipe retorts for continuous running. In addition to the reasons for topping cited above, in California topping has other purposes which give the plants practically a universal field in the oil industry. These additional purposes are (1) to remove the lighter constituents of the oil prior to storage for a long period, thus reducing the losses from evaporation, (2) to dehydrate and clean the oil, and (3) in conjunction with a complete refinery, to remove the lighter fractions cheaply and quickly, leaving a residue to be rerun for lubricants, coke, and other products. The reader in studying a plant for possible adaption to his own use should note that local considerations enter into the design and size of a plant. Several questions present themselves, as follows: 1. What type is suitable for the oil? 2. How much money is available for construction? 3. Will the volume of residuum be large enough for heat exchange with the crude? 4. Can the heat content of the vapors be used to reduce the cooling-water requirements? 5. What method will best recover the heat from stack gases? 6. Are the various pieces of apparatus adequate in size and best adapted to their purpose? 7. Is every possible provision made for the recovery of waste heat? 8. What products will be made, and what volume of each? 9. Is there provision for the recovery of light vapors? 10. Will the saving of fuel justify the capital and maintenance charges on the regenerative apparatus contemplated? It is regretted that information concerning the operation of topping plants with eastern and Middle West oils is not available. The writer carefully canvassed the Middle West, but did not find a plant where operation had progressed beyond the early experimental stages and reliable figures could be furnished. The reader will find fuel economy and heat recovery emphasized throughout the descriptions. The conservation of the available petroleum supply is of the utmost importance, and the Bureau of Mines presents this paper to encourage the hearty cooperation of operators to that end. The Baume gravity scale used throughout the report is that of Tagliabue with a modulus of 141.5 for conversion to specific gravity.

Jan 1, 1919

By William P. Harris

The Lincoln Terminal System is described as a device with the capability to deliver technical information, monitor student performance, and assure learning in industrial training. An experimental unit, the LTS-3S, was constructed and delivered to the Bureau of Mines with appropriate lesson material for a test of feasibility and acceptability of this form of training in the mining environment. Operations were conducted at two mine maintenance schools. The overall results were that (1) there was a substantial improvement between tests before and after self-training on the LTS, (2) students found this an acceptable way to learn, and (3) reaction by training personnel and supervisors was favorable toward the feasibility and advantages of using the LTS in the mining environment. Transfer of the LTS to industry depends on availability of reliable units and adequate lesson material. The requirements for authors of training materials were established based on advice from mine training experts, formal analysis of lesson development procedures, and experience from efforts in lesson development at Lincoln Laboratory-It was concluded that experienced mine training instructors were best qualified to proceed effectively and economically to format instructional material for the LTS, if supported by well-designed facilities and services. Discussion with mining experts confirmed the desirability of generating training materials and delivering instruction at distributed locations to meet local training needs and in direct support of industrial operations.

Jan 1, 1975

By Mark K. Larson

Researchers at the U.S. Bureau of Mines have developed a FORTRAN computer program that can calculate stress states from overcoring measurements obtained from hollow inclusion cells, triaxial cells, strain gauges installed on the wall of a bored raise, doorstopper gauges, borehole deformation gauges, or a combination of any of these gauges. Such stress states are calculated with reference to global and principal coordinate systems. The background of the development of the program, its capabilities, and its special features, as well as the input required, are described in this report. Sample output is also shown in appendix C. Difficulties associated with numerical calculations of principal stresses and directions are pointed out. Threshold values for detecting these problems are reported; these values may be changed by the user as desired. Several test problems were set up to verify the computer program and were successfully solved.

Jan 1, 1992

This report describes the development, installation and performance of a lonpwall illumination system. The longwall illumination system was installed at the Greenwich Collieries 112, Cockport, Pa. It utilized flourescent luminaires, intrinsically safe power distribution and is the first longwall system installed in Pennsylvania.

Jan 1, 1976

By Willard P. Ward

SOME TIME in the year 1874 or 1875, I conceived the idea that spiegeleisen might be made -in a blast furnace from ores that were not carbonates, and which did not contain both manganese and iron in the same ore. Up to this time, such ores had formed the basis of all the spiegel that had been produced; and all the ferromanganese that was on the market before 1875 was made in crucibles, and cost about 00 per ton, for 80 per cent. Mn. I consulted the great steel metallurgist of the day, Alexander Holley, who listened attentively to what I had to say, and told me he did not think my plan was practical, so I abandoned it for the time being. But I was so stubborn that I could not get the notion out of my head. It seemed to me that a good metallurgist should be able to work the thing out in some way. I had already had some experience in smelting refractory lead ores in Utah, and was young and not lacking in self confidence, so after waiting a bit, I got Anton Eilers, the best all-around metallurgist I knew, and J. H. Bramwell, the best iron blast-furnace man I knew, both intimate friends of -mine, to come to my place in Bartow County, Georgia, and look over things. They remained for several days, and made all the examination they thought necessary; and they also advised me to give up the project, and either to keep the furnace running on car-wheel iron or to blow it out. After my talk with Holley, I improved my plant in several ways. I closed the top of the furnace, put in a hot-blast stove, a steam boiler and a Weimer blowing-engine which gave me blast enough, at a pressure high enough for all the requirements of, the furnace, and which I could bring up to a temperature of 600° to 700° F.

Jan 1, 1921

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining the potential for reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/ lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By B. J. Moore

This publication contains routine analyses and related source data for 528 natural gas samples from 21 States collected during calendar year 1965 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the' Bureau of Mines since 1917. The analysis published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4

Jan 1, 1966

By B. J. Moore

This publication contains routine analyses and related source data for 528 natural gas samples from 21 States collected during calendar year 1965 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the Bureau of Mines since 1917. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4

Jan 1, 1966