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By P. M. Solozhenkin, V. P. Nebera, V. D. Skorohodov

"Aqueous dispersions of air specifically prepared on the basis of flotation reagent solution acquire active properties in relation to the solid surface and may be imply as a medium for flotation ores. Such aerated solutions were defined as Activated Aqueous Dispersions of Air (AADA) with 5-6:1 ratio and the procedure of mineral separation was defined as a flotation process under non-equilibrium conditions. These procedures differ from conventional flotation mainly in reagent interaction with minerals through their adsorption films on gas bubbles simultaneously forming flotation complexes. Gas-liquid mixture is kept till an adsorption layer of reagents close to the limit value is formed on the surface of bubbles. The theoretical basis of AADA is considered.The results of two-phase gas- liquid mixture (AADA) were studied. Two versions of AADA were considered. Electrical surface potential of the air bubbles with the surfactant film, untreated minerals particles in Coulomb attraction and flotation complex formation were analyzed. Special flotation machines were constructed for separation of mineral suspension in air dispersion, whose effectiveness was confirmed in flotation of apatite waste of Kovdor ore. FK-9 machine introduced on Kovdor iron ore combine for the recovery of apatite from current departures of factory. The froth product contained 7.2 % P2O5, with recovery of 44 % apatite, which was processed for getting melted phosphoric-magnesium fertilizers."

Jan 1, 2003

By Manuel Vicente Vásquez

El presente texto describe dos posibles alternativas para el diseño de ventilación de la mina Mallay, ubicada en la provincia de Oyón, Lima. La infraestructura de la mina tiene 6 niveles, donde se ha previsto contar con 3 chimeneas principales de ventilación, cuyo requerimiento de aire mediano y largo es de 70,707 y 154,652 cfm, respectivamente. En ese sentido, se plantean dos alternativas de solución para este sistema de ventilación: La primera alternativa consiste en la construcción de dos chimeneas a superficie para la extracción del aire viciado y en el que cada chimenea contará con un ventilador principal como extractor en superficie. Mientras que la segunda alternativa, utilizará el nivel 4470 para la extracción a superficie del aire viciado mediante un ventilador principal instalado en la bocamina. Para ello, se realizará una ampliación a una sección de 10’x10’ en los primeros 70 m de la bocamina y se construirá un by pass para permitir el acceso al nivel. De las dos alternativas planteadas, ambas satisfacen el requerimiento de aire a mediano y largo plazo de la mina, con la diferencia que la segunda alternativa cuenta con la ventaja que el Nv. 4470 ya existe y sólo requiere ampliar la sección; mientras que en la primera alternativa las chimeneas tienen que ser construidas.

Sep 12, 2011

By G. D. Cody, D. S. Beers, B. Abeles

The thermal diffusivity (thermal conductivity divided by specific heat) of Armco iron has been measured over the temperature range 30º to 1025ºC. The results are in good agreement with the thermal diffusivity computed from published values of thermal conductivity and specific heat, except near the Curie point and at the a to y phase transition, where the measured diffusivity undergoes rabid variations. The differences observed are ascribed to a rapid variation in the electronic thermal conductivity near the Curie point, and a decrease in the lattice thermal conductivity, at the a to ? phase transition. A major difficulty in measuring the thermal conductivity of materials at high temperatures is the determination and elimination of radiation losses. It has been shown, however, that in measuring thermal diffusivity D (thermal conductivity/specific heat) radiation losses can be taken into account exactly.' In order to test the performance of a newly designed apparatus for measuring thermal diffusivity of solids,' we measured Armco iron to an accuracy of 2 pct in the temperature range 30" to 1025°C. This material was selected since both the thermal conductivity,3'4 k, and specific heat,5 C, are known accurately in this temperature range and thus the measured values of D could be compared with D computed from the pub-

Jan 1, 1962

By Fernando Guevara

Many smelting and slag-cleaning furnaces operate with cooling systems designed to freeze a slag layer over the refractory to protect it. The fluid flow and heat transfer conditions associated with the freeze layer and mushy zones are poorly understood. These phenomena were simulated with a small-scale room temperature, 2-dimensional model, using an aqueous solution of calcium chloride to simulate the slag. Reasonable similarity with conditions encountered with copper and nickel smelting systems was achieved (Pr 50 and Ra 108, in the laminar-turbulent transition). Measurements of the freeze layer development and velocities were made with the Particle Image Velocimetry (PIV) technique. Direct Numerical Simulations (DNS) were also made of the unsteady fluid flow and heat transfer problem. It was found that the solidification process is well described using an improved model for high molecular viscosity in the mushy zone. Solid front growth, isothermal profiles, velocity profiles and heat transfer through the walls showed good agreement between the PIV and DNS results. Experimental and numerical velocity profiles close to the freeze layer show a parabolic behaviour in the vertical velocity profile which is completely different from the calculation of heat transfer using a sharp interface model. The reason for this is attributed to the effects of the mushy zone with a high viscosity and high shear stresses acting on that area.

Jan 1, 2006

By C. F. Nagel

This paper is written primarily for those who are familiar with the processes mentioned but who desire a further insight into some of the fundamental principles. It does not give a complete description of the various practices employed in the working of aluminum and its alloys, but presents a few illustrations of the essential respects in which aluminum differs from other common metals, and emphasizes the controlling factors of the processes under consideration. Heat Treating Certain aluminum alloys are capable of having their mechanical properties greatly altered by a heat-treatment process. The degree of this irnprovement may be illustrated by some typical properties of dura-lurnin (Table 1). It is essential that the material be in the wrought condition in order to obtain rnaximum heat-treatment effects. In the case of duralumin, the process consists of heating the metal to a prescribed temperature and then quenching it. Immediately after quenching, the material is relatively soft though not as soft as in the annealed state. If allowed to stand at room temperature, the material changes, increasing in hardness and strength without loss of elongation, but at the expense of the plasticity. This action is very rapid at first, gradually diminishing in intensity and to all practical purposes being completed in about four days. This process of hardening is termed

By C. F. Nagel

THIS paper is written primarily for those who are familiar with the processes mentioned but who desire a further insight into some of the fundamental principles. It does not give a complete description of the various practices employed in the working of aluminum and its alloys, but presents a few illustrations of the essential respects in which aluminum differs from other common metals, and emphasizes the controlling factors of the processes under consideration. HEAT TREATING Certain aluminum alloys are capable of having their mechanical properties greatly altered by a heat-treatment process. The degree of this improvement may be illustrated by some typical properties of duralumin (Table 1). It is essential that the material be in the wrought condition in order to obtain maximum heat-treatment effects. [ ] In the case of duralumin, the process consists of heating the metal to a prescribed temperature and then quenching it. Immediately after quenching, the material is relatively soft though not as soft as in the annealed state. If allowed to stand at room temperature, the material changes, increasing in hardness and strength without loss of elongation, but at the expense of the plasticity. This action is very rapid at first, gradually diminishing in intensity and to all practical purposes being completed in about four days. This process of hardening is termed

Jan 1, 1928

By W. Hitchcock

To enable the analysis of stability for a mine feasibility study a variety of geotechnical engineering parameters need to be obtained. At the early stage of a project it is usual for those responsible for the study to require a wide spatial distribution of RC holes in order to define a resource at the lowest possible cost. By the time a geotechnical study has commenced drilling priorities have usually switched to improving the definition of a resource, by drilling with diamond coring methods in the central area of the main orebody. The usual timing for geotechnical data collection is therefore after a wide distribution of holes have been drilled but which contain little geotechnical information. Conventional methods employed usually involve estimation methods, including book values and examination of disturbed core, or expensive additional drilling. With downhole geophysical methods we can economically take advantage of existing holes to obtain continuous values for density, defect orientation and ranking, elastic modulus values, unconfined compressive strength estimates and fracture frequency. This paper presents the results of a geophysical study and discusses the advantages and potential pitfalls of the method as compared to conventional methods of data collection.

Jan 1, 1999

By Dinesh Agrawal

Microwave energy has been in use for variety of applications for over 50 years. These applications include communication, food processing, wood drying, rubber vulcanization, medical therapy, polymers, etc. In the last two decades microwave heating has been also applied very effectively and efficiently to heat and sinter ceramic materials. Microwave heating is recognized for its various advantages, such as: time and energy saving, very rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved mechanical properties, better product performance, etc. The most recent application of microwaves has been in the field of metallic materials for sintering, brazing/joining and melting. Several common steel compositions, pure metals and refractory metals have been sintered in microwaves to nearly full density with improved mechanical properties. Many commercial powder-metal components of various alloy compositions including iron and steel, copper, aluminum, nickel, Mo, Co, Ti, W, Sn, etc., and their alloys have also been sintered in microwaves producing better properties than their conventional counterparts by using a 2.45 GHz multimode microwave system. This work has been further extended to join and braze bulk metal pieces, especially super alloy based turbine blades. Further, in a specially designed microwave cavity, even the bulk metals can be made to couple with the microwave field and melted. The implications of these findings are obvious in the field of powder metal technology.

Jan 1, 2006

Since the introduction of water cooled test rings the operation of cupelling retort bullion has not alone been sImplified, but has also been the means of concentrating the bullion for the fining test in a much shorter time.The first water cooled test ring which I used was rectangular in shape, inside dimensions 5 ft. 3 in. x 2 ft. IQ in., and made of i in. mild steel plates, with a water space of 9i in. x 3t in. However, it was found that as soon as the filling commenced to wear and the litharge came in contact with the jacket, the plate was gradually affected on the lines of the wash, caused by the blast. After a while the inside steel plate went beyond the factor of safety, and was then substituted on the sides and the front of the test ring by a tin copper plate, which has stood now for the last five years without showing the least signs of wear or leakage.The test remains in use as long as the bottom is regarded as safe, and toward the end of the life of the test the litharge is allowed to work against the copper plate.

Jan 1, 1901

By Ernest J. Conway

Seventy-four human factors research and development projects were identified for possible Bureau funding. The projects were based on (1) literature surveys, (2) reviews of accident statistics and reports, (3) interviews with equipment manufacturers, MSHA, and Bureau personnel, and (4) site visits to 26 mines. The projects are divided into the following categories: those related to (1) mobile equipment, (2) maintenance shops and areas, (3) plants and mills, (4) organizational factors, (5) safety programs/data, and (6) training. The projects were rated by industry and MSHA people in terms of benefit to the industry. Projects were placed into three categories of priority. The highest priority contained 25 projects with 26 in Category 2, and 23 projects in the lowest category.

Jan 1, 1982

By C. F. de Mendonca, T. Kater, R. P. de Souza

The authors are to be commended for finding a material for pellets binding that we were unable to uncover during the investigations that led to US Patent No. 3,748,116, “Method for producing metallic iron powder from iron ore concentrate, ” July 24, 1973, by G.G. Reed, Jr., J.M. Karpinski, and S.V. Fox. This patent concerns a method of processing “super’ ‘-concentrates prepared from magnetite or “blue dust” into molding-grade metallic iron powder for use as a bulk commodity, in contrast to current methods which produce small batches that are custom-blended with additives and/or alloye to customer specifications. The one thing we had not found at that time was an organic binder (mineral-matter-free ) that would allow induration to produce hardened pellets that would survive SL/RN Direct Reduction. Peridur appears to provide this missing link needed for large scale (200 t/a, or 220,460 stpy) single line plant capacity consistent with a low market price to ensure greatly broadened use of metallic iron powder. I hope that industry will adopt this combination so that metallic iron powder usage can fulfill its potential

Jan 9, 1985

By E. H. McCleary

The Alamo Mine The Alamo mine is located about seventeen miles northwest of Walsenburg, Colorado, on the Loma Branch of the Denver and Rio Grande Western railroad, in the foothills of the Black Mountains of Huerfano County. Prospecting Mr. W. B. Lewis of New York City, president of the Oakdale Coal Company and also president of the Alamo Coal Company first became interested in this property in 1920. After all natural features of the surface had been carefully examined by Mr. Lewis, he was convinced that the property was underlaid with coal seams. Plans for prospect drilling were made at once and this drilling was started late in 1921. In all, eight drill holes were put down to the Trinidad sandstone which underlies the coal measures in this field. These drill holes in general, showed very satisfactory results. Two workable coal seams were penetrated by most of these drill holes, the upper seam being six and one half feet thick and the lower seam having a thickness of ten and one-half feet. The two seams are separated by forty feet of sandstone and shale. Analyses of the seams proved each to be of a very high grade bituminous coal possessing hardness much above other bituminous coals, and having very bright lustrous appearance. Tests of more than a year's duration proved the coal to store excellently in closed bins and also in open bins where coal is exposed to elements. The drill hole data further showed the coal seams to pitch more than fifty per cent or about twenty-six and one-half degrees. The pitch direction being approximately South 65 degrees East. The drill holes further proved the coal seams did not outcrop at any point on the property, and no evidence of coal outcrop has been found in near vicinity. A splitting and pinching out of seams was found to occur some two hundred to three hundred feet of theoretical outcrop at very Western boundary of property. The most Easterly or No. 6 drill hole has a depth of eight hundred fifty feet to floor of lower coal seam. The Trinidad sandstone was found to be immediately under the lower coal seam, and the Pierre shales lying under this sandstone. Plans for Development and Sinking Having obtained sufficient data, plans for development of the property were carefully made sometime in advance of the actual opening of the mine. Every condition was carefully studied and the maximum production of clean and well prepared coal at as low a cost as possible during the entire life of mine was kept uppermost in the minds of all. The life of mine is estimated at approximately fifty years. It was decided to open up the lower and thicker seam first, and due to the pitch and other conditions a slope opening was decided upon for its extraction. The pitch of the coal having been found to be from fifty to sixty per cent or twenty-six to thirty degrees, the plan of driving the slope directly down the pitch of seam was eliminated and a plan that would give a more economical grade was decided upon. To obtain a lesser grade, a point several hundred feet west of-and at a less elevation than the theoretical outcrop of coal seam was selected for the slope opening. (Fig. 18.) To have driven directly down the pitch of coal seam would also have given the slope an uneven grade as the pitch of coal seam varied as it approached the crop. From this point of opening, the slope was to be driven on a thirty-one per cent, or' about seventeen degree pitch to intersect coal seam in No. 6 drill hole, a distance through the Pierre shales and Trinidad sandstone of two thousand five hundred fifty feet, the slope to be driven practically due East

Jan 1, 1925

By Kerry J. Stanaway, Thomas E. Garnar

Titanium was discovered in 1791 and, four years later, was named after the Titans of Greek mythology. Titanium metal was first made in 1910, but was not used commercially until the 1950s when it was nick-named The Wonder Metal of the Age. The first titanium dioxide (TiO2) white pigments were produced commercially in 1915; more than 90% of the titanium minerals produced in the world today are used in the manufacture of white pigments. The remaining 10% are used to manufacture titanium metal and other uses such as welding rod fluxes. Titanium mineral mining began in the United States between 1880 and 1900 in Chester County, Pennyslvania. Rutile from a deposit near Roseland, VA, was mined in 1901. The use for the rutile was limited to production of a few titanium chemicals and for coloring ceramics. Larger scale mining for ilmenite, rutile, and zircon began in Florida to provide chemical materials for use in World War I in 1918. This mining ended in 1928. Large scale mining of titanium minerals in Australia began when Benick, Anderson, and Porter (later called Tamco) started mining the beach sands at Yamba in New South Wales in 1935. Ilmenite production from beach sands in the State of Kerala in southwestern India also began in the 1930s. The 1940s saw many changes in titanium mineral mining. Extensive deposits of ilmenite and ilmenite-bearing iron ores were discovered in eastern Quebec. The Pigments Department of E.I. Du Pont de Nemours & Co. lost their high grade Indian ilmenite supply after World War II began, and they were forced to use lower grade ilmenite from National Lead's (now NL Industries) Sanford Lake Deposit, near Tahawus, NY, in the Adirondack Mountains. At the end of the war, Du Pont undertook an intense search for a domestic ilmenite source. With the cooperation of the US Bureau of Mines, Du Pont geologists found a very large deposit east of Starke, FL, in 1946. In 1948 Du Pont entered into a contract with Humphreys Gold Corp., who operated a heavy minerals mine near Jacksonville, FL, to construct a plant and operate it for a period of ten years. The plant started up in 1949 and operated under Humphreys' management until the contract expired in 1958. Du Pont has operated the plant since that time. In 1956, a second plant was designed and built by Du Pont a few kilometers northeast of the town of Lawtey. The 1960s saw titanium mineral production expand in the southeastern US with Humphreys' contract mining Du Pont's ore body at Folkston, GA. In the early 1970s. American Cyanamid and Union Camp Paper Co. formed a joint venture company, Titanium Enterprises (TE), to mine and separate titanium minerals from Union Camp's ore deposit southwest of Green Cove Springs, FL. In 1975 the TE plant was shutdown and later sold to Associated Minerals (USA), Inc. (AMC), a subsidiary of Renison Goldfields Consolidated Ltd., an Australian company. It now operates under the name RGC (USA). Mineral production grew in the 1970s with the development of extensive heavy mineral deposits at Eneabba in Western Australia and Richards Bay in the Republic of South Africa. The 1980s saw the construction of a very large ilmenite mine and synthetic rutile processing plant in the state of Orissa southwest of Calcutta, India. At the same time, concern for titanium mineral shortages expected by the end of this century, gave rise to a flurry of exploration activity during the mid 1980s. As a result, large deposits were found in Virginia and North Carolina. New deposits were also discovered in Australia. Fig. 1 shows the distribution of world titanium deposits and mines. The world TiO, production capacities are given in Table 1.

Jan 1, 1994

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Jan 1, 2009

By Mohsen Amir-Rahmat

The ore of Sarcheshmeh copper deposit that has been located in the south ?east of Iran, contains four type of rock that they have their specific hardness and strength according to their alteration type and mineralization. Blasting of these various types of mine rocks prepares various types of size for the product of mine as the feed of concentration. Along the crushing of this feed a few factors effect on the efficiency of the crushing unit. The aim of this project has been the consideration of the effect of ore size on the efficiency of crushing unit. For this investigation along the year 2000 A.D., six sample from feed and six sample from product of crushing unit have been prepared. The results of the screen analyze of these samples has shown that the size of feed has been lesser than the primary plan and the size rate of the product has been bigger than the primary plan. Also in this research the effect of feed size on the quality of product size has been considered.

May 1, 2003

By W. R. Deeths

The Great Plains Coal Gasification Project is the first commercial scale grass roots synthetic fuels (SNG) plant to be built in the United States. The plant will be constructed in two phases, with each phase producing 125 million cubic feet per day of pipeline quality (970 BTU per cubic foot) substitute natural gas from lignite coal. The plant is located north of Beulah in Mercer County, North Dakota. The first phase complex, when completed, will cost about 1.2 billion dollars and will include all necessary process units, oxygen production, steam generation, coal handling and preparation, utilities and infrastructure. The plant will be owned and operated by, the Great Plains Coal Gasification Associates, a partnership consisting of the following companies: ANG Coal Gasification Company, Mid Con Corporation, Tenneco, Inc., Transco Energy Company and Pacific Lighting Co. The Project began in late 1973 with a Phase I feasibility study and site selection study. The feasibility study was completed in 1975, at which time Kaiser Engineers and C. E. Lummus, the two engineering contractors, proceeded with a Phase II conceptual engineering design for the project. The culmination of the Phase II work was the publication of a detailed scope definition and control estimate, which was to become the cost guideline for procurement and plant construction. Following an engineering slowdown period in 1979, due to continuing delays in regulatory procedures, detailed engineering effort was reinstituted in early 1980 and by mid-1981 was approximately 35 percent complete. The total home office engineering effort amounts to approximately 3.5 million man hours of work split between Kaiser Engineers and Lummus. These totals exclude the engineering effort expended by Lurgi of Germany in the process design. The gasification plant shares the site and certain other facilities with the Basin Electric Power Station. Among these facilities are the plant access railroad, peripheral drainage ditch and raw water supply system. In addition, the gasification plant will draw its power directly from the Basin main substation, and Basin will receive coal from the gasification plant, consisting of the coal fines which cannot be gasified in the Lurgi units. The overall construction program covers a period of approximately 44 months with mechanical completion and initial gas production slated for late 1984. Craft labor requirements amount to approximately 11.5 million man hours and the work force peaked in excess of 4,500 people. In anticipation of an early resolution of both Federal Energy Regulatory Commission ruling and Department of Energy loan guarantee commitments, certain work on the site was commenced during 1980. This work consisted of site rough grading, driving of piles, and erection of three of the plant auxilliary buildings. Orders and subcontracts were placed for compressors, pumps, electrical equipment, material handling equipment, piping, structural steel, boilers, oxygen plant and cooling towers. Over 40 major Federal, State and local permits were required. Among these were such diverse permits as: ? Soil conservation ?Railroad and pipeline rights of way ? Certificates of site compatibility ? Permits for structures in areas controlled by the ? U.S. Army Corps of Engineers ? Environmental permits required by the North ? Dakota Department of Public Health. The preparation of an Environmental Impact Report began in September of 1973. FPC (now FERC) guidelines and North Dakota special requirements were followed except that, at the time, the highly structured form of environmental impact statements we know today was not in use. We were required to develop a number of new sampling and evaluation techniques and reporting procedures at a time when the requirements were vague and often contradictory. In March 1975, field studies were completed and submitted to the Bureau of Recla¬mation, which then began to prepare its own EIS. Two years later, in May 1977, public hearings began on the Project. The hearings and public review of the report drew over 400 comments or questions. Responses o the comments were in¬corporated in a Final Environmental Impact Statement issued in January 1978. In March 1975, the original filing was made for an FPC Certificate of Public Convenience and Necessity which included: ? A technical feasibility study ? An Environmental Impact Assessment ? An Economic and financial feasibility assessment. An amended filing was submitted in 1976 to build the plant in two phases because studies then indicated that the cost of the plant had increased substantially. A second amended filing was submitted in 1977 to reflect the involvement of Peoples Gas (now Mid-Con Corporation) in the Project. At the time, it was believed that an FPC Certificate could be issued by December 1977. However, approval would be contingent on the U.S. Bureau of Reclamation having a complete Final Environmental Impact Statement for the Project. In 1977, with the formation of the Department of Energy, the FPC

Jan 1, 1984

By W. E. Bonini, E. A. Hickok

IN the course of an investigation directed toward expanding ground-water facilities in Essex and Morris counties, New Jersey, the Board of Water Commissioners of the city of East Orange authorized a seismic-refraction survey' for the purpose of de-lineating bedrock topography below unconsolidated overburden. Results of the survey were highly satisfactory and led to the preparation of a comparatively detailed bedrock contour map. Knowledge of the bedrock depth and configuration was an important aid in selection of sites for test drilling. The portion of the East Orange Water Reserve under consideration is in the flood plain of the Pas-saic River about 10 miles west of Newark, N. J. The flood plain is about 175 ft above mean sea level and is bordered by low hills rising to elevations of approximately 250 ft. The bedrock underlying the Water Reserve consists of sandstone and shale of the Triassic Brunswick formation and is covered everywhere by deposits of unconsolidated glacial outwash sand and gravel, lacustrine clay, and recent river silt as much as 150 ft thick. Yield of wells in the sandstone and shale averages 100 to 200 gpm. Since production wells constructed in the sand and gravel aquifer in the buried river valley shown on the contour map (Fig. 1) yield 300 to 1400 gpm, it was proposed to locate additional production wells in this buried valley, where the yields per well would be maximum. In 1939 and 1946 the East Orange Water Dept. had electrical-resistivity surveys made to determine depths to bedrock. From the resistivity data the exploration company prepared a bedrock contour map. A well field expansion program begun in 1955 utilized this information to locate sites for test wells along a predicted northward extension of the buried valley in which existing production wells are located. After several test wells (wells 201-205) had been drilled, it became apparent that the resistivity information was unreliable." For example, test well 201 recorded bedrock at a depth of 72 ft, whereas the resistivity depth determination was 130 ft. As a consequence, the test drilling program was temporarily suspended and a seismic survey was under- taken to determine the topography and extent of the buried valley known from well records to underlie the existing well field. In the first phase of this study, several seismic shot point locations were placed at sites where well logs had been obtained previously. This procedure is necessary in a new area to determine whether the seismic method is applicable and what degree of accuracy is to be expected. At the East Orange Water Reserve, depths obtained from the shot points near test wells 202, 203, and 204 were within 8 to 11 pct of the depths logged (Table I). With this assurance that accurate results could be obtained, additional seismic spreads were located on the Water Reserve. Using a portable refraction seismograph, in the fall of 1955 a crew of four men shot a total of 29 reversed seismic spreads in a period equivalent to six field days. Charges as heavy as 3 1b of 40 pct dynamite were necessary at a few places to overcome ground vibrations caused by traffic on nearby highways. At most other sites, a 1-1b charge was sufficient. Travel-time plots were made for all spreads, and depths and true velocities were calculated according to formulas for multiple sloping layers by Ewing, Woollard, and Vine.' The plot of spread 7 (Fig. 2) is typical of the short spreads in which bedrock was shallow—about 50 ft in this case. Where there were not enough arrivals through the bedrock to define the high velocity bedrock line, the spreads were lengthened. This was done by placing shots on line several hundred feet away from each end of the line of geophones. It was then possible to construct complete reverse plots for both short and extended shot points (see spread 27, Fig. 3). Four individual depths were calculated from each extended spread. Three and in some cases four seismic layers were observed. The surficial layer had a velocity range of 900 to 1200 fps, the lowest velocity recorded. This seismic layer is above the water table and is interpreted as recent river silt. The bedrock had the highest velocities, which ranged from 10,600 to 16,400 fps. Intermediate velocities ranged from 4500 to 6800 fps. In every case the intermediate layer was within

Jan 1, 1959

By Milton Fies

ALTHOUGH pig iron from iron ore and red cedar charcoal preceded the mining of coal by many years, for tradition says that Alabama iron was used to shoe the horses of Andrew Jackson's soldiers, coal was not produced until 1830. In that year, coal was mined in Tuscaloosa County, in the vicinity of what is now the University of Alabama, and shipped on flat boats (obviously during the wet season, for there were many shoals) down the Warrior River to Mobile. About that time, the first railroad, the Decatur & Tecumseh, was being constructed in northern Alabama to overcome the obstructions to freight traffic caused by the now well-known Muscle Shoals in the Tennessee River. This railroad was patterned after a railroad at Mauch Chunk, Pa., which was used for hauling anthracite from the Panther Creek valley. The Alabama railroad, which required about four years to complete, was 46 miles long and was used solely for the transportation of cotton. Although it was a failure, it demonstrated the practicability of the undertaking, and the succeeding railroads, which were begun in 1834, 1848, 1852, and 1853, added immeasurably to the development of the coal resources of the state. Between the years 1830 and 1860, practically all the coal mined in the state was dug from the outcrop near the river or from the river beds, and shipped by boat to Mobile. Transporting coal down the Warrior River was one of great risk, required much skill, and frequently had heavy losses. It is recorded that this coal was sold to the gas company in Mobile in 1844; it was most likely mined from the Black Creek Seam. In 1914, on the completion of Lock 17, the Warrior River became a navigable stream from 9 miles above Cordova, Ala., to Mobile and offers a great opportunity for the future development of the coal resources of the state.

Jan 9, 1924

By Shane Baker

Cementation Foundations Skanska Ltd encountered many significant challenges in designing and constructing the foundations for the LNG (Liquefied Natural Gas) tanks and associated structures at the Isle of Grain, Kent, UK. With LNG cargo ship levels fixed by the adjacent English Channel, the platform could not exceed critical thickness in order to achieve final grade level, so a safe and efficient working platform for construction equipment on extremely poor alluvial soils was designed and installed. The detailed pile design also required particular analysis of the pile group behaviour and considered seismic load cases not usually associated with UK pile design. Continuous flight auger (CFA) piles were the chosen foundation solution and design was verified through preliminary and working pile tests both axially and horizontally. Contaminated land and existing foundations from a previous oil terminal meant that removal of spoil was extremely costly so specific measures were taken to minimise the off-site disposal. The management of a package of general Civil Engineering in addition to the piling scope, coupled with an unrelenting production program has forced a raising of the bar for this foundation technique.

Jan 1, 2006

Metana Minerals commenced life in 1970 and graduated to a mining company in 1981 with the opening of a small alluvial tin-tantalite mine at Wodgina (W.A.) The present board of directors assumed control of the company in 1978 and established the exploration and development philosophies that have guided the company's expansion to its present status as an emerging diversified miner. An ability and willingness to raise equity capital when required has been a feature of the company. Company activities include exploration for gold, diamonds, heavy mineral sands, polymetallic (base and precious metals) deposits, strategic minerals, rare earths, oil and gas in a geographical distribution covering the entire Australian mainland Metana owns and/or operates four gold mines (Reedy, Mt Magnet, Youanmi and Howley) and at the time of writing is developing a fifth gold mine - its first underground mine - at Rothsay. In contrast to many similar or larger sized companies, Metana undertakes most activities itself rather than through the use of consultants or contractors. In-house services include: analytical and metallurgical laboratories, plant engineering design and construction, drilling and mining (earthmoving) Metana Minerals has established an enviable reputation for technical excellence and this expertise has placed the company in a sound position to continue its growth pattern into the future. This growth will be achieved through a combination of low cost and successful exploration and acquisition of suitable mines either directly or through corporate activity.

Jan 1, 1989