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By Gregory M. Molinda

Coalbed discontinuities historically have been hazardous to mining as well as obstructions to efficient production. An effective means of mapping these features is needed in order to plan safe and efficient mine development. This Bureau of Mines report discusses the use of surface seismic techniques for this purpose. At a southwestern Pennsylvania mine, a system of coalbed discontinu-ities (paleochannels) was accurately mapped by the Bureau of Mines using borehole log methods and underground observation. This site was chosen to test the value of a high-resolution surface seismic reflection on technique for coalbed mapping. A statistical study performed at this mine indicated that the probability of accurately delineating this paleochannel system with conventional borehole methods was remote. A total of 1.47 miles of high-resolution seismic survey, comprised of four seismic profiles, was conducted in known and suspected coalbed discontinuity areas. Several test holes were drilled on the seismic lines in order to evaluate the interpretations. It was found, based on these and other existing boreholes, that it is possible to predict these dis-continuities. Paleochannel washouts were correctly predicted in several instances but in other instances were either incorrectly predicted or not predicted in areas of known discontinuities.

Jan 1, 1988

By Naiyi Li, Henry Hu, Alfred Yu

"In the past few years, various squeeze cast aluminum components have been developed and successfully implemented in various vehicles by the automotive industry because of their superior engineering performance. However, fundamental understanding of the formation of air gap during squeeze casting processes is still very limited despite of its significant influence on the extent of heat transfer between the casting and mould. In this paper, a mathematical model has been developed to simulate phenomena of air gap between the casting and mold' during squeeze casting of aluminum alloys. The model considers the effect of process parameters such as applied pressures and mold temperatures on the events of air gap formation. The predication indicates that the occurrence of highly enhanced heat transfer in squeeze casting of aluminum alloys primarily results from the presence of excess applied pressures.IntroductionA number of squeeze cast Al components has been developed and used in mass-produced vehicles in the past few years, such as steering knuckles, Road wheel, Engine Block etc. This is attributed to their superior engineering performance. In squeeze casting, the cooling rate can be increased by applying high pressure during solidification which results in the noted refinement in the micro structure scale leading to better casting properties. However, the excessive pressure increased interfacial heat transfer coefficient is affected during the solidification by air gap formation and die surface condition etc., which is believed to increase thermal resistance at the casting/die interface [l - 4]."

Jan 1, 2004

R. W. Raymond, New York, N. Y,:—Since the presentation of my note on this subject at the New York Meeting, Professor Louis has pointed out an error in my statement of his conception of " pitch "—namely, he understands the pitch, in the restricted sense which he proposes, to be the angle of inclination of the axis of an ore-body, measured on the vertical plane drawn through the body; whereas, I represented him as proposing to define " pitch " as the angle of inclination of an oblique body, measured on the plane of the dip, in the direction of the strike. The difference will appear upon consideration of the accompanying isometric projection, Fig. 1, in which ABCD represents the plane of the inclosing ore-deposit (vein or bed), and AC the axis of the oblique ore-shoot. ABE is the angle of the dip, as universally understood; and ACE

Jan 1, 1909

By P. S. Lewis

Shortage of natural gas is reviving interest in low-Btu fuel gas made by gasifying coal in fixed-bed producers. The Bureau of Mines gasified strongly caking Pittsburgh bed coal over test periods lasting four days in an experimental gas producer located at Morgantown, W. Va, Mechanical stirring throughout the fuel bed was effective for keeping the fuel moving and this stirring made the operation successful; hence, the gas producer was named the stirred-bed producer. Nuclear density gages were applied as control instruments to indicate coal flow and fuel level, and to record the frequency and location of void spaces in the bed, The gas, of nominal 140 to 165 Btu/scf calorific value, could be burned in a boiler for generating steam.

Jan 1, 1972

By Fred P. Gerbracht

Jul 20, 1955

By Rhelman Rossano Urzêdo Queiroz

Amostras de um aço Dual Phase, não deformadas e deformadas à temperatura ambiente e em condições de envelhecimento dinâmico foram examinadas por microscopia eletrônica de transmissão, visando analisar modificações na subestrutura de deslocações na faixa de temperaturas em que ocorre o fenômeno. Observaram-se mudanças significativas no padrão de distribuição das deslocações que evoluiu de uma distribuição uniforme, no material deformado à temperatura ambiente, para uma distribuição em forma de linhas alongadas a 200°C e 300°C, culminando em uma subestrutura complexa com elevada densidade de deslocações a 350°C. A 400°C, a distribuição uniforme foi novamente verificada. As imagens obtidas não indicaram a ocorrência de formação de carbonetos de transição ou precipitação na martensita durante a deformação nas temperaturas em que foram observados os efeitos de envelhecimento dinâmico.

Aug 7, 2018

By E. E. Donath, L. L. Hirst, L. C. Skinner

Two processes are available for the production of synthetic fuels from coal high-pressure hydrogenation and the carbon monoxide-hydrogen synthe- sis. This paper presents some ideas and new developments in coal hydrogen- ation that have been incorporated in an estimate for the production of 30,000 barrels per day of liquid fuels, mainly gasoline. A few comparisons of the processes will be helpful before discussion of the details of pro- posed improvements in the hydrogenation process. The principle of the high-pressure hydrogenation process ie the addi- tion of hydrogen at pressurea in the range of 3,000 to 10,000 p.s.i. to coal at elevated temperature and with the help of catalysts. On the other hand, the principle in the Fischer-Tropsch synthesis is the complete break-down of coal into a mixture of carbon monoxide and hydrogen, followed by the catalytic combination of these two gasse into hydrocarbons or suitable catalysts. For the synthesis, moderately elevated pressures of about 350 p.8.1. will bo used in the immediate future, although it can be carried on at atmosphoric pressure with certain catalysts. The products of these two processes using coal as raw material are almost as differont as hydrocarbons can be. The products of the high-pres- sure hydrogenation of coal reflect the original constitution of the coal. They are, therefore, rich in ring compounds, both aromatic and naphthenic, but, due to the action of highly comprcesed hydrogen and catalyst, are satu- rated and very stable. These constituents give the gasoline a high octane number and excellent rich-mixture performance, combined with good gum and storage stability. Therefore, this gasoline is suitable for aviation gaso- line or base stock. The Diesel fuel can be hydrogenated to a centane number of 45 or higher, which is entirely satisfactory for operating normal Diesel

Dec 1, 1948

By W. A. Toohey

Introduction From the earliest times it has been an inherent trait of man to build or create something for his own use or convenience. The need of some form of shelter other than that of the caves led him to bind together stones and other materials to form walls for his abode. Moistened clay which hardened upon drying was no doubt first employed. The Assyrians and Babylonians appear to have employed it or the bitumen found in their country. The early Egyptians and Greeks used some form of lime in their construction work. In addition to these shelters, other structures received attention, and, long before the Roman Empire was established, the Carthaginians made use of a natural cement as binding material. Portions of an aqueduct, seventy miles long, in Northern Africa, built in those early days, are still in use. The Etruscans were the first people in Italy to employ a mortar in their buildings. The Romans, learning the art from the Etruscans, improved the mortar by using a mixture of lime and volcanic ash, called 'puzzolan', and built not only roads but those famous structures, the ruins of many of which exist to this day. The Pantheon at Rome, built by Hadrian about 120 A.D., is perhaps the finest example of the early use of cement in building construction. With the decline of the Roman Empire, the art of making cement seems to have been lost, and for centuries the builders of Europe used only lime mortar. Pure limestones were selected for making the lime and great care was taken in the preparation of the mortar, the supply for one year being made the previous season and left to thoroughly slake or 'ripen' in pits covered with earth. The mortar thus produced gave excellent service above ground or where it was exposed to the hardening action of the air, but would not harden under water.

Jan 1, 1927

By Elmer A. Jones

Development work in mines of St. Joseph Lead Co., Southeast Missouri, using trackless loading equipment shows definite advantages: Speed of cleaning, ability to work on steep grades and sharp crosscuts, good later tracking conditions, and possibility of wasting rock in old abandoned stopes.

Jan 1, 1950

By Joseph D. Davis, G. S. Scott, Palmer B. Place

In the course of investigations made by the Bureau of Mines in cooperation with the Trent Process Corporation, into the properties of mixtures of oil and coal, a comparative study was ma.de of the 'behavior of these mixtures and their cons ti tuents on destructive distillation. Mixtures of a petroleum oil and bitminous coal were first distilled under carefully controlled conditions, and then charges of the eame oil and coal were distilled separately under similar conditions. The quantity and quality of the distillation products were determined, and. resul. ts were compared. This comparison furnished a basis tor judging whether grea, ... er values in products can be obtained by distillation of oil and coal in mixtures than· b:, their separate distillation. In making the mixtures, the method used in t~e Trent process for cleaning coal was followed. The paste or plastic emulsion of oil and coal obtained is called "amalgam".••• When finely pulverized wet coal is mixed with approximately one-third its weight of. oil and agitated with a large excass of waj;er, the coal and oil agglomer-. ate to form a paste or amalgam. A large portion of the extraneous ash original.17 in the coal remains suspended in the water, with which it can be decanted from the amalgam. Ir the latter is now thoroughly drained and kneaded after the manner ot working butter, most of the excess water enclosed can be removed. This, .in brief, constitutes the Trent process for cleaning coal, The effectiveness of the process for cleaning coal has been studied••••. by the Bureau, and the results of the study show, in general, a high ash reduction an:l good recovery of combus ti bl e f'rom coals of medi ,mi and hi~ rg,nk. With coals of tht lowest rank, such as li@!Rlites, the process is only moderately auccessf'ul, owing to the difficulty attending the preparation of coherent amalgams, Oil losses to wate~ and refuse are small, and apparently it would be practical to rotate the same oil in the cleaning process if some efficient method were devised for recovering it from the amalgam, so a distillation process naturally suggested itself.

Dec 1, 1921

By T J. M Harvey

This paper gives an overview of the ASHRAE LibHuAirProp, CoolProp and REFPROP software packages. These packages were predominantly developed for heating, refrigerating and air conditioning engineers and the refrigeration and steam power industries, although CoolProp and REFPROP also cover combustible gases. The main aim of this paper is to highlight the existence capabilities and status of the different packages and where they can be used. The paper gives typical examples of the use of these software packages, specifically as Excel add-ins, and provides a comparison of results of typical mine psychometric and gas drainage calculations using the packages and more traditional ventilation and gas drainage calculation methods. The paper also introduces a hybrid method that improves accuracy compared to traditional methods. In typical mine situations, the use of software packages is probably not required; however, with the increasing accuracy of instruments, potential greenhouse emission costs and the sale of mine gas, more accurate measurements and calculations can potentially save (or make) significant sums of money.CITATION:Harvey, T J M, 2015. The use of psychometric, thermodynamic and transport property software in mine ventilation and gas drainage calculations, in Proceedings The Australian Mine Ventilation Conference, pp 201–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By E. Sun

Tailings disposal is a significant consideration for the mining industry, with the majority of the ore processed in most mining operations ending up as tailings. Several tailings dam failure accidents have occurred during the past few years and mine tailings dam failures are occurring at relatively high rates. Tailings dam failure is disastrous with the serious damage and the loss of lives. To increase the tailings dam safety, a tailings dam monitoring and pre-alarm system (TDMPAS) based on the internet of things and cloud computing platform has been accomplished with the abilities of real-time monitoring of the saturated line, impounded water level, rain fall and the dam deformations etc. The TDMPAS has been applied in several mines in China and helped the mine engineers monitor the tailings dam safety and get warning information automatically and remotely in any kind of weather conditions. This work has been demonstrated the tailings dam monitoring and pre-alarm system (TDMPAS) is meaningful to monitor the tailings dam physical safety condition. The TDMPAS could be applied to monitor all the national tailings dams online in the future.

Jan 1, 2012

By Michael A. Knott

Large lateral forces on bridge foundations due to extreme events such as vessel collisions, earthquakes, and wave forces on storm surges during hurricane events are often the controlling design condition for bridge foundations. A review of the American Association of State Highway and Transportation Officials (AASHTO) vessel collision analysis and design codes used in the United States for highway bridges will be presented. The paper includes the background and development of the AASHTO Guide Specification and Commentary for Vessel Collision Design of Highway Bridges (1991) and vessel collision provisions of the AASHTO LRFD Bridge Design Specifications (3rd Edition 2004 and the approved 2005 Interims). Experience in using the AASHTO codes will be discussed and observations on the adequacy and gaps, comparison with the European Standard Code, and recommendations for immediate and long term needs will be presented.

Jan 1, 2013

By D. Yu. Paleev, O. Yu. Lukashov, A. Yu. Krainov, E. R. Shrager, I. M. Vasenin

The gas-dynamic method is presented of calculation of explosion-proof distances during an explosion of the methane-air mixture in mine working. On the basis of this method is modelled of shock waves interaction with explosion protective parachute partitions, obstructions and water barriers. Calculations have been carried out of attenuation factors of shock waves during their interaction with explosion protective structures, arranged near conjugation zones of mine workings. Possibilities have been analysed of suppression of intensity of shock waves and of propagation of shock waves control in mine working network of coal mines by installation of explosion protective structures.

Jan 1, 2003

THERE have been two important accomplishments of the Truman administration; the Hoover Commission report on inefficiency and waste in government and the report of the Paley Commission on the natural resources of the United States. Both reports are in the interest of the American people and should transcend the boundaries of political parties. Both reports are starting points for the formulation of policies which must be continuously revised to meet changing conditions. Regardless of the outcome of the election the principles embodied in these two great documents must be kept alive. The Paley report is right in our own bailiwick of mineral raw materials and it behooves us to study it carefully as our responsibility to posterity. To those in the mining industry who have limited their field of observation to moving rock or to metal prices it may come as a surprise that our production of such staples as copper, lead, and zinc has fallen behind increased requirements to the point that substantial tonnages must be imported. Iron ore is next on the list and everybody knows that such metals as tin, tungsten, chromium, manganese, nickel, and cobalt are imported almost exclusively. The crisis in raw materials pointed up by the Paley report has been reported annually by Elmer Pehrson and others to small gatherings at the Mineral Economics Division sessions at the Annual Meeting for as long as we can remember. In September 1949, the United Nations Economic and Social Council held an international resource conference at Lake Success which disclosed these same grave conclusions: - Consumption of raw materials is multiplying at an alarming rate, faster than discoveries or replacements are being made. - Production has been wasteful and utilization lavishly beyond enginee¬ing and practical requirements. - Industrialized nations are depleted and many raw materials consumed by industry are not found in the industrialized countries. - Nations formerly exporters of raw materials are increasingly building their own consuming industries. - Political forces in the world are limiting access to raw materials. The Paley Commission selecting the quarter century, 1950 to 1975, to project raw material requirements for the United States, pointed out obstacles to meeting these requirements, and made recommendations for procurement. It is not important that we disagree that cobalt consumption will reach 344 pct of present, or fluorspar 187 pct when iron and ferroalloys are only expected to increase 75 pct. What is important it that the fabulous appetite of the United States for mineral raw materials has consumed more since World War I than was consumed by the entire world in all recorded history prior to 1914. And, unless the people of the United States are satisfied to remain at their present standard of living (which is unthinkable) this consumption is correctly plotted by the Paley Commission as continuing to expand. If the U. S. is to continue on a course of progress, it must procure raw materials wherever it can at the lowest possible cost. Natural resources are clearly an area in which the broadest cooperation between industry and government must exist to achieve efficient exploitation, economic consumption, and expansion of sources of supply. The message of the Paley report requires action comparable to that of the North Atlantic Pact. Its implication is as significant as military preparedness. It is a world problem. It is a mining engineering problem. Don't let it die!

Jan 1, 1952

By George Markon

The importance of United States coal exports as a component of the national economy, the potential for growth of these exports, and the inter-national character of this sector of the coal industry are described in this report. The report summarizes some of the many background elements in the rise of United States coals to preeminence in highly competitive world markets. It presents some insight into this important sector of United States industry and the positive contribution of this sector to the Nation's balance of payments. It contains pertinent basic statistics on production, trade, and consumption of coal in most major markets for 1960-66. The report examines the movement of United States coals from mines to export markets, tracing and describing origins, exit ports, prices, and trends as well as inland and ocean freight rates and other data vital to an under-standing of some of the practices and complexities of the United States coal markets abroad. A brief sketch of coal production and consumption in principal importing countries is also presented with a short review of some of the more current practices and problems of these countries. Coal produced in inland areas of the. United States can be moved to and distributed economically within coal-producing countries overseas and in Canada. Quality coals from the United States can successfully compete with foreign coals in nearly any area of the world on a truly economic basis because of their high grade and their low cost which derives from the high productivity of the miner and from reasonable ocean freight rates. Because of tariffs, trade embargoes, quotas, and other restrictions, how-I ever, foreign coal markets are relatively limited. Further limitations are imposed in some countries by economic conditions which restrict all imports as a matter of financial and economic necessity. Despite these obstacles, United States coals have brought lower cost quality coals to a large segment of the foreign energy market.

Jan 1, 1968

By Jean-Paul Drolet

"This paper charts, briefly, the :salient facts of international trade in minerals and their products and Canada's place in it. It also reviews inter-national agreements, economic groupings and national measures to channel and regulate production and trade in minerals. Canada's mineral industry now produces raw materials worth $3.7 billion per year, making this country a giant among mineral producers. Two-thirds of this production is exported, chiefly to the United States, accounting for about 30 per cent of Canada's merchandise exports and topping all other classes.However, several other nations are also pressing the development of their mineral resources and markets. The Soviet Bloc, China and principally Australia and Africa are becoming important suppliers of basic raw materials to some traditional markets of Canada in Europe and Japan.The outlook for Canadian mineral exports to the countries of the Common Market, Great Britain and Japan is good, although some tariff barriers remain troublesome.Concerning the United States, our most important market, Canada is seeking to have that country lift import quotas on lead and zinc, and re-cent statements by U.S. authorities give hope that this may be achieved soon. Moreover, Canada wishes to obtain easier access to the American market for several of its metals and minerals.Canada is now participating in the Kennedy Round of tariff talks under the auspices of the General Agreement on Tariffs and Trade (GATT), and is seeking to open wider doors for its exports of products.In summary, Canada has done reasonably well in some mineral commodities on world markets, but has lost ground in others. Any slackening of Canada's efforts in the development and marketing of mineral resources would soon lead to the decline of its role in the world miueral economy."

Jan 1, 1966

By J. P. D. Strydom

The transmission of excessive vibration to the human body can cause physical stress that may result in crippling pain or permanent disability. Rock drills are known to transmit high levels of vibration that are difficult to attenuate through conventional approaches to vibration isolation. However, it can be shown that once the ISO frequency weighting has been applied, most of the vibratory effect of the rock drill?s motion is concentrated at the drill?s operating frequency. This observation opens the way for utilizing a concept known as vibration absorption, aimed at attenuating the rock drill?s vibration. In essence this entails using the inertia of a secondary vibratory system to counteract the motion of the handle. This article documents an investigation into the use of such an absorber for attenuating rock drill vibration and demonstrates the feasibility of such an approach. A mathematical model of such an absorbing handle was developed and used for design studies. Based on these investigations an experimental prototype model was manufactured and tested. A significant reduction in vibration levels could be achieved.

Jan 1, 2002

By B. MohammadSadeghi, S. Bakhshivash, M. Haghshenas, F. Rahimi

"Constrained groove pressing (CGP), as a severe plastic deformation (SPD) technique, is one of the applicable methods for sheet metal forming capable of producing ultra-fine grained materials (UFGMs). In CGP, processing and die design parameters can significantly affect the deformation response of sheet metal specimen. Having said this, in the present research the effects of die design variables and processing parameters (i.e. shear angle and friction) on the deformation behaviour of an Al-Mg-Si Alloy are studied thoroughly. Finite element analysis (FEA), was used to evaluate the effectiveness of mentioned parameters on the deformation homogeneity, strain distribution and pressing load variations. Also, mechanical properties of the deformed sample in term of micro-hardness was analyzed. It is observed that with increasing the shear angle, effective stress, strain and pressing load are enhanced. Moreover, by increasing the coefficient of friction, pressing load enhances. The color coded micro-hardness measurement showed a good agreement with the strain distribution obtained from FEA (higher hardness for the zones associated with higher shear plastic strain values).INTRODUCTIONWork hardening results in enhanced mechanical properties upon cycles of deformation (Hosford & Caddell, 2007). However, the formability of the processed products are affected by work hardening reducing the possibility of processing in subsequent deformation cycles. Therefore, many industrial processes cannot be performed on sheet metals to produce products with desired mechanical and physical properties (Valiev, Islamgaliev, & Alexandrov, 2000). Severe plastic deformation (SPD) is an effective grain refining technique which can impose large plastic strains through cold working on a metallic specimen (Bisadi, Rastgou, Payganeh, Zeynali, & Ghahremani, 2010). SPD techniques are mainly categorized into three types; sheet, bulk and tube forming. Among SPD sheet forming methods, Constrained Groove Pressing (CGP) (Shin, Park, Kim, & Park, 2002), Accumulative Roll Bonding (ARB) (Saito, Tsuji, Utsunomiya, Sakai, & Hong, 1998) and Repetitive Corrugation and Straightening (RCS) (Zhu, Lowe, Jiang, & Huang, 2001) possess potential applications in manufacturing industries."

Jan 1, 2016

By Howard J. Haselhuhn

"The effectiveness of reagent adsorption onto hematite ore particle surfaces is critical during beneficiation to promote effective selective flocculation and dispersion and increase iron oxide recovery. The relationship between aqueous calcium in the process water and the effectiveness of common iron ore dispersants has never before been studied. The nature of common dispersants was studied in the presence and absence of calcium in the process water. The settling behavior of hematite-rich iron ore at pH 11 was assessed in the presence of calcium and inorganic dispersants: sodium silicate, sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP) and organic dispersant ethylenediamenetetraacetic acid (EDTA). It was found that inorganic dispersants are ineffective at a pH of 11 without activating the surface sites of the ore particles with calcium. Organic dispersants, however, were found to be effective with and without surface site activation.IntroductionThe United States produced 54 million metric tons of concentrated iron ore in 2011 (Jorgenson, 2013). Over 8 Mt were produced using a process known as selective flocculation and dispersion (CCI, 2011). The grade of this ore is slowly depleting, making it imperative that processing efficiency improves. To increase processing efficiency, a complete understanding of the effects of chemical reagents in the process must be acquired. This process relies heavily on dispersants to disperse iron oxides from gangue minerals in settling processes. The mechanism that these dispersants use to disperse the ore and its relationship to calcium in the process water has never been studied. The following extended abstract summarizes the relationship between aqueous calcium in process water and the effectiveness of common iron ore dispersants at dispersing hydrated hematite ore. These tests were carried out at a pH of 11, as this is a typical pH used to ensure dispersion in selective flocculation and dispersion processes."

Jan 1, 2015