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By Joseph Grumer

Theory pertaining to the exchangeability of fuel gases on appliances has been extended to exchanges of propane or butane with mixtures of these. In particular, new considerations were developed bearing on the hazard of an occasional emission of carbon monoxide and flashback and blowoff possibilities. The new considerations involve using current requirements for approval of liquefied petroleum gas appliances. These requirements were used to predict allowable tolerances in chemical composition of liquefied petroleum gases for existing appliances. In addition, changes in gasline pressure were computed which may be substituted in place of fuel exchanges during testing of appliances,

Jan 1, 1962

China has made great progress in thick coal seam mining, commonly characterized by longwall top-coal caving mining and single-pass longwall mining with a large cutting height. At present, the maximum mining thickness of longwall top-coal caving reaches 20 m while that of single-pass longwall mining approaches 8.8 m. The top-coal caving–related technologies have significantly improved the mining efficiency of thick coal seams and have also made a great contribution to the centralized underground mining of coal. Thus, the number of underground coal mines is greatly reduced in China. However, due to the increase of the mining height and the changes in mining operations, the overburden movement caused by the mining of thick coal seams is more intense, and the influence scope is larger, which brings a series of new problems on ground control of longwall faces. In order to enhance ground control and improve the mining efficiency of thick coal seams

Jul 28, 2020

By H. H. Dreissen, F. J. Fontein

The operating principle of the classifying cyclone has been described often but some special aspects of the cyclone receive further clarification here. In addition, several uses of the classifiers are summarized and made clear by means of practical examples. In coal and ore washeries, the washing cyclone is widely used for the separation by specific gravity of sizes up to about 12 mm. This application has lately been extended to the separation by specific gravity of particles up to about 50 mm. This use makes special demands on the construction and wear resistance of the cyclone. The sieve bend, a development of the Dutch State Mines which is less well known than the hydrocy-clone, is dealt with at some length. The sieve bend is an apparatus designed for wet screening. Attention is given to the variables influencing the performance of the sieve bend. Hydrocyclones are now so widely applied that it would be difficult to find an industry not, directly or indirectly, using them or knowing how to use them since publications on this subject abound.1-3,5,9-11,13-15 However, because of the large number of variables influencing the operation of classifying cyclones, it is not entirely possible to calculate the results of this type of cyclone. Therefore, a number of lesser known variables will be discussed here along with some special applications of the classifying cyclone. FACTORS INFLUENCING CYCLONE CLASSIFICATION Shape of Particles: The shape of particles may cause a much coarser classification than the one expected, considering the sieve analysis and the cyclone dimensions chosen. This was clearly shown by feeding a mixture of spheres and disks in water into a cyclone. The spheres were 0.36 mm diam and the disks, 3 mm diam and 0.03 mm thick. These dimensions were chosen in order that the disks and spheres might have the same rates of fall under gravity. Both spheres and disks had a specific gravity of 1.05. The results obtained with these particles in a cyclone are summarized in Table I. Test No. 2 shows that the catch of spheres was

Jan 1, 1963

By S. C. Carniglia

Bayer-process alumina hydrate becomes in turn the source of a host of special products in addition to the calcines that feed aluminum reduction cells. Though relatively smaller in tonnage, specialty aluminas serve important industrial markets in an exciting and growing variety. Production methods and applications are discussed for: (1) trihydrate as flame retardant in organic materials; (2) high-surface-area transition aluminas as desiccants and scavengers, catalysts and substrates; (3) calcines for industrial ceramics, refractories, and abrasives; and (4) tabular alumina for refractories, bed supports and other uses.

Jan 1, 1977

By Faruk Oksuz

The owners of large infrastructure projects are challenged on how to implement sound engineering and construction contracting strategies that address their prime expectations: a quality job, on time and within budget. With the increasing number of large engineering and construction projects worldwide, owners continue to search for alternative contracting strategies to address their risk, quality, sustainability (operability and performance), schedule, and budget concerns. Coupled with the shortage of resources, delays, political pressures, and other obstacles in procurement and negotiation processes, engineers and contractors are also looking for creative ways to optimize contract packaging strategies for efficient and successful project delivery. This paper compiles an array of decision making criteria and suggests a balanced evaluation, ranking and selection strategy in procurement of both engineering and construction services for large tunneling and other infrastructure projects. A number of owners? general preferences and viewpoints are discussed on large tunnel programs encompassing water and wastewater conveyance systems, pump stations and treatment facility upgrades. Contract packaging strategies and project phasing and segmenting alternatives for preliminary engineering, final design, construction management, and actual construction of facilities are featured for several large water and wastewater infrastructure projects. While the selection (and the relevant selection process and criteria) and performance of service providers, whether for engineering or construction, have profound effects on the outcome of any given project, this paper only examines strategies for con-tract packaging. More specifically, the authors evaluated case studies and developed a range of recommendations for packaging of large water and wastewater infrastructure projects with multiple components.

Jan 1, 2008

By A P. Brown

Access arrangements required with landowners and occupiers; relaxation on size of permits; lack of confidentiality for information provided; one-stop shop under RMA, removal of standing; plethora of controls; post-closure; funding for long-term security.

Jan 1, 1997

By K. J. Fair, H. W. Smith, D. R. Francis, J. M. Toguri

"Bench-scale batch milling and screening tests were carried out on secondary aluminum dross 10 produce an aluminum concentrate. To complement these tests, an analysis of a commercial plant was also performed by sampling dross at various stages in the plant's milling and screening circuit. These studies have indicated that benefits of increased capacity, grade and recovery of aluminum metal can be realized by addition of screens before the ball mill, longer grinding period and by grinding the smaller size fractions more efficiently.To test the predictions, a plant test was performed on the milling of100tons of secondary dross. The recycling of the large size fraction (+1/8 in.) of aluminum dross through the impact mill rather than through the rate limiting ball mill resulted in a comparable aluminum grade. The ball milling of the _1/ 8 in. + 10 mesh size gave a dross grade of71% AI. A lower feed rate to the ball mill resulted in a higher final grade. With minor modifications, secondary dross can be processed in 22% of the time it takes with the present circuit without a sacrifice in grade.IntroductionSecondary aluminum dross is a mixture of metallic aluminum, aluminum oxides and salts (alkali halides). Any comminution process deforms or slowly grind s the malleable metal phase and reduces the size of the friable, brittle, oxide-salt phase relatively fasterr(1).The milling of aluminum dross is performed to upgrade the metallic aluminum fraction. Figure I shows a flowsheet for the milling of secondary dross as presently practised at Metals and Alloys Co. Ltd., Toronto, Ontario. At point A, large acceptable grade material is hand picked for refurnacing, the unacceptable off-grade material is sent to the sweat furnace and the remaining, + 2 in. fraction is recycled through the 3.9 ft by 4.1 ft impact mill. For simplification, three ball mills are shown. However, in reality there is only one, a 5 ft by 10 ft ball mill used in a semi-batch mode. The 2 in. + 3/8in. and 3/8 in. + 10 mesh products are remilled in the ball mill. The -10 mesh material is discarded as waste."

Jan 1, 1987

By T. T. Read

TWO papers on health and safety were given Thursday afternoon when a joint session of the Health and Safety Committee and the Mining Methods Committee was held. T. T. Read presided and the first paper, on ventilation at Climax, was presented by the author, L. H. Glanville. In the subsequent discussion by Cloyd M. Smith, P. B. Bucky, B. F. Tillson, D. F. Haley, J. L. G. Weysser, and others a number of interesting points not covered by the paper, which appears in full in the January Mining Technology, were brought out. Ventilation troubles in mines so often hinge on the air being too hot and damp that it was interesting to hear of one where it is frequently too cold and too dry.

Jan 1, 1943

ADDRESS BY THE PRESIDENT OF THE INSTITUTE (MR. J. G. SYMONS) IN PRESENTING THE AWARD TO ELLIOTT SYLVESTER TIMOTHY O'DRISCOLLTim O'Driscoll comes from a mixture of Irish and Scottish stock. His family on the paternal side settled on land in Western Australia in the middle of the last century. His family on the maternal side were part of the W.A. goldfields scenc, including places such as Kanowna, and the Great Fingal mine, near Cue, where his grandfather lies buried.The combination of land and mining environments may perhaps have contributed to an innate interest in geology shared by Tim and his two brothers, all of whom became geologists.Tim showed an early liking for mathematical and geometric subjects, and in his B.Sc. studies at the University of Western Australia he took a major in mathematics along with geology in 1940.His first job was on the Kalgoorlie Golden Mile, and then at Norseman. After serving as a flying boat navigator in the north and south Pacific theatres in World War II he returned to Kalgoorlie and thence to Broken Hill.

Jan 1, 1977

By J. B. Czirr

MESA Corporation has completed a four-year program for the Bureau of Mines to develop a technique for measuring roof competence in underground coal mines. The preferred technique employs a tracer gas that is injected into a roof borehole drilled near the working face. The tracer gas performs the dual purpose of determining the pressure loss rate from the borehole and of marking the diffusion pattern of the the escaping gas. The primary detection technique relies upon observation of the rate of pressure drop in a hole drilled in the roof strata under test. If this measurement indicates a significant probability of roof collapse, the gas diffusion pattern is outlined with the Leak-gun tracer-gas detector. These two techniques provide a comprehensive method for predicting the relative probability of roof collapse in operating coal mines.

Jan 1, 1985

By Robert B. Parsons

"Exploration and development of mineral resources in developing countries by Canadian-based multinational mining companies is becoming increasingly common. One problem being encountered is that the objectives of the governments of developing countries can differ from those of developed countries. These objectives are not always consistent with maximizing returns from the projects, which can create conflicts between the mining company's responsibility to its shareholders and the desire to be a good corporate citizen. This article discusses how a mining tax regime can be designed to make the social goals of a government consistent with the economic goals of the company.IntroductionAt the recent International Seminar on Mining Taxation organized by CIM and the United Nations there was considerable discussion about the role of international mining companies operating in developing countries. Not surprisingly, given the diversity of backgrounds of individuals attending the Seminar, there were different opinions about what this role should be.Government PositionRepresentatives of governments pointed out the strong desires of their countries for technology, high-level technical training of their workforce, increased employment, and development of social infrastructure. They pointed out that, to a large extent, these objectives could be more efficiently met by mining companies operating in the country than by the governments themselves. For example, a multinational mining company (""MMC"") would have extensive knowledge of the various technologies available, and would have performed a detailed evaluation of the mineral resources before choosing the most cost-efficient technology for that project. They would, therefore be in an ideal position to assist the country in importing and developing such technology. Similarly, the company could provide opportunities for hands-on training, both at the technical and managerial levels, which would otherwise be unavailable to the government."

Jan 1, 1991

By W. E. Curran

For years the geographical isolation of the Southern iron-ore district from the great producing centers in the North and East enabled it to meet its conditions and solve its own problems without regard to the practices and policies of other districts, but during the past few years distances have been shortened, practices and wages are being standardized, and these changing conditions have brought new problems to the South. Development of Pig Iron in the South The development of the pig-iron business in the South was very slow during its early years, gained speed rapidly in the latter part of the nineteenth century, reached its peak in 1918 and was on the decline before the depression that began in the latter part of 1929. The first blast furnace in Alabama was built at Cedar Creek in 1818, the year before the state was admitted to the union. In 1830, Daniel Hillman was sent from Tuscaloosa to found an iron works in Roupes Valley, where rich pockets of brown ore were numerous. He built a forge on the site of what later became Tannehill furnace and called it the Roupes Valley Iron Works. There pots, pans, plows, and horseshoes were made of metal from his Catalon forge; shaped by a large hammer operated by water power. Daniel Hillman died in 1832 and the ironworks lay idle until 1836, when Col. Ninion Tannehill bought the property, rebuilt the forge and, using slave labor from his plantation, operated and enlarged the works. By 1845 he had built two crude furnaces and did a flourishing business in ovens, skillets and kettles, which found a good market all over the South. In 1855, the plant was sold by Colonel Tannehill to Moses Stroup, an experienced ironmaster from Pennsylvania. He tore down the old furnaces and built a new plant, the ruins of which stand today (Fig. l). This furnace plant operated continuously until it was destroyed by Northern troops in 1865. It was never rebuilt, so that the shell in the picture is the same furnace that made many tons of guns and shells for the Confederacy during the war period.

Jan 1, 1938

By W. E. Curran

For years the geographical isolation of the Southern iron-ore district from the great producing centers in the North and East enabled it to meet its conditions and solve its own problems without regard to the practices and policies of other districts, but during the past few years distances have been shortened, practices and wages are being standardized, and these changing conditions have brought new problems to the South. Development of Pig Iron in the South The development of the pig-iron business in the South was very slow during its early years, gained speed rapidly in the latter part of the nineteenth century, reached its peak in 1918 and was on the decline before the depression that began in the latter part of 1929. The first blast furnace in Alabama was built at Cedar Creek in 1818, the year before the state was admitted to the union. In 1830, Daniel Hillman was sent from Tuscaloosa to found an iron works in Roupes Valley, where rich pockets of brown ore were numerous. He built a forge on the site of what later became Tannehill furnace and called it the Roupes Valley Iron Works. There pots, pans, plows, and horseshoes were made of metal from his Catalon forge; shaped by a large hammer operated by water power. Daniel Hillman died in 1832 and the ironworks lay idle until 1836, when Col. Ninion Tannehill bought the property, rebuilt the forge and, using slave labor from his plantation, operated and enlarged the works. By 1845 he had built two crude furnaces and did a flourishing business in ovens, skillets and kettles, which found a good market all over the South. In 1855, the plant was sold by Colonel Tannehill to Moses Stroup, an experienced ironmaster from Pennsylvania. He tore down the old furnaces and built a new plant, the ruins of which stand today (Fig. l). This furnace plant operated continuously until it was destroyed by Northern troops in 1865. It was never rebuilt, so that the shell in the picture is the same furnace that made many tons of guns and shells for the Confederacy during the war period.

Jan 1, 1938

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

By E. W. Krampert

Oil development continued active in Wyoming during 1937, with much of the interest centered on prospecting for new pools, following a rather intensive seismograph play in 1936. The new fields of Lance Creek, Medicine Bow and Quealy were the centers of intense development in proved areas, but routine drilling occurred in most old fields. A new and deeper producing horizon (the Leo sand) was opened up in the Lance Creek field, which materially extends the producing area and will probably account for continued active development during 1938. The discovery in 1936 of oil in the Eocene Wasatch formation at Powder Wash, northwestern Colorado, tended for a time to stimulate prospecting in the deep Tertiary basins, but this interest as rapidly declined after drilling several failures on similar structures and the discovery that the productive area at Powder Wash itself was very small. A most interesting test of an Eocene structure was drilled by The Superior Oil Company of California on the South Baggs structure, in Carbon County, Wyoming. South Baggs is one of the best developed structures in the Red Desert Washakie Basin, which also includes the Hiawatha gas field and the Powder Wash gas and oil field. The Superior Oil Co. started the well according to contract but apparently had lost interest in the prospects, for it abandoned the well at 2138 ft. without testing the oil-bearing and gas-bearing horizons of the Wasatch. The Sinclair Wyoming Oil Co. drilled a deep test in the Muskrat gas field to the Madison. This well discovered oil in the Embar formation, which was considered noncommercial because of depth. After the Embar was abandoned the hole was plugged back and the various sands tested by shooting through the casing with the Lane-Wells gun. The Lakota sand was found to contain high-pressure gas and the well was completed as a 24-million-foot gasser at 2175 lb. rock pressure. This is a new sand in an old field. The Italo Petroleum Co. drilled a flank well on the Hamilton dome structure and found oil in the lower Embar formation. Thk merely extends the limits of production, as one old well on the structure had

Jan 1, 1938

By W. Smith

The U.S. Bureau of Mines (USBM) is using laboratory and computer-based techniques to investigate the post- failure behavior of yielding pillars and pillar reinforcement techniques to control entry deformation. Poorly dimensioned yield pillars, can cause adverse ground conditions. Laboratory studies to evaluate various reinforcement techniques for controlling yield pillar deformation were conducted. A cracking and crushing model is used to evaluate potential tensile and compressive failure planes within pillars of various widths to assess the degree of yielding and stress redistribution. The use of an elasto-plastic model to evaluate the effect of various reinforcement on yield pillars is also discussed. These procedures effectively account for the residual pillar strength, important in yield pillar design.

Jan 1, 1995

Seventy-three of the 90 naturally occurring elements that are found in the earth's crust are metals or metalloids. The quantities of metals used annually in the United States range from about 100 million metric tons (steel) to a few kilograms (osmium). The recovery of metals from discarded products or industrial process wastes, especially those metals that are used in large quantity, are very expensive, or are unusually toxic, is important to the national economy and to the natural environment. From its inception in 1910, the U.S. Bureau of Mines (USBM) has been the Government's prime source of information on metals recycling, as well as a major innovator in recycling technology. Statistical data on scrap generation and processing have been summarized annually for many years in the USBM's Minerals Yearbook. Most of the data for individual metals discussed in this report were extracted from that publication.

Jan 1, 1993

By L. O. Bacon

This Bureau of Mines report summarizes the results of laboratory work in the design of instrumentation for obtaining the dynamic tensile strength of rock at minimum loading. Minimum loading is defined as the lowest tensile loading by pulse reflection to cause fracturing. The instrumentation for obtaining dynamic tensile strengths of rock cores evolved into the use of a compressed-air pellet gun to impact one end of a rock core, suspended by wires, at increasing increments of air pressure. Maximum strain was measured on most or all of the impacts, and the strain at fracture of the core was obtained by extrapolating the pellet velocity-strain curve to the pellet velocity at fracture. Stress at tensile fracture was obtained from the maximum s train, and the dynamic Young's modulus was calculated from the rod velocity by using simple rod theory.

Jan 1, 1962

By William H. Lewis

Energy Research Corp., under contract to the Bureau of Mines, has developed a new miners' caplamp battery. The new battery is based on nickel-cadmium technology and offers significant improvements in performance with reduced size and weight when compared to the conventional lead-acid battery presently in use. This report describes the design and fabrication of the nickel-cadmium battery, which utilizes a roll-bonded electrode structure. The final battery design has a 15-A-h capacity in a 2-112-lb package, which is over 2 lb lighter than the present lead-acid caplamp battery.

Jan 1, 1983