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CHARLES KIRCHHOFF, Chairman. ALBERT SAUVEUR, Vice-Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Harvard Sq., Cambridge, Mass. John Birkinbine, J. E. Johnson, Jr., J. S. Unger, William H. Blauvelt, William Kelly, Felix A. Vogel, James Gayley, Richard Moldenke, Leonard Waldo, Henry D. Hibbard, Joseph W. Richards, William R. Walker, Henry M. Howe, C. F. W. Rys, William R. Webster, Robert W. Hunt, E. Gybbon Spilsbury, Frederick W. Wood. A. A. Stevenson, J. S. Unger and C. F. W. Rys have accepted membership on the Iron and Steel Committee. The Program Committee has held two meetings- in New York and has perfected the preliminary plans for the October meeting. The Committee will meet again in September. The following provisional program has been laid out by the Program Committee, but is subject to later additions and changes :

Jan 9, 1913

By E. M. Hillary, D. F. Sangster

"Abstract - As a contribution to the World Minerals Geoscience Database Project, an index-level database comprising information on 142 SEDEX Pb-Zn deposits and occurrences was constructed in Microsoft Access 95 format. Although consisting of only basic information, the compilation, with full referencing of all data, is possibly the largest non-corporate SEDEX Pb-Zn database in the world. It thus provides an opportunity to make geoscience queries of SEDEX Pb-Zn deposits on a scale not previously available. This report provides a summary of the results of a few such queries both as a contribution to a better understanding of SEDEX lead-zinc deposits and as a demonstration of what even such a simple database can offer.During the compilation process, it became apparent that SEDEX Pb-Zn deposits could be assigned to one of the following three sub-types: Type 1 (53.5% of total) in which sulfide minerals are the only exhalative components; Type 2 (33.1%) in which the exhalative components are sulfides plus chert, siderite/ankerite, and/or barite; Type 3 (13.4%) which contains any components of Types 1 and 2 plus abundant iron-oxide minerals (commonly magnetite) and/or is associated with iron oxide-rich sedimentary rocks.Highlights of systematic queries of the database reveal that:1. a majority (84%) of the world’s SEDEX Pb-Zn deposits are not underlain by a discordant footwall feeder zone or vent complex;2. 63.6% of deposits occur in Proterozoic strata followed by a second peak in the Devonian (16.8%). Of those in the Proterozoic, 83% of Type 3 deposits occur in the Gondwanaland supercontinent, whereas only 42% of Type 2 and 39% of Type 1 are located in this large paleo-landmass;3. median (Pb+Zn) grades in Types 1 and 2 fall between 9% and 10% with a majority clustering within this range. Type 3 grades, however, range from ~1% to ~20% (Pb+Zn) with a median of 5%; 4. median size of Type 3 deposits is ~33 Mt, whereas Type 1 and 2 median sizes are ~7 Mt and ~8 Mt, respectively.The report concludes with a brief discussion of how an index-level database such as this can be used in conjunction with other, similar databases to reveal interesting and instructive relationships for guiding both research and exploration."

Jan 1, 1998

By José Sancho, Julia Ayala, Purificación García, Begoña Fernández

"Electrofilter dust, a residue generated in the last stage of the Bayer process in the hydroxide aluminum calcination, was characterized to evaluate the alumina that was potentially extractable with sulfuric acid. The process studied aims to produce aluminum sulfate for water coagulant uses, taking advantage of the residues that accumulate in large quantities in the proximity of plants with difficult recycling for storage. Acid leaching is carried out at different concentrations of sulfuric acid, at different temperatures, pulp densities, and times, to dissolve gibbsite and transition aluminas. The result is an aluminum sulfate solution without iron and with commercial specifications.IntroductionElectrofilter dust is a residue generated in the last stage of the Bayer Process [1] in the hydroxide aluminium calcination. The residue is a mixture of alumina and hydrates which have not completed their calcination process.Electrofilter dust, composed by alpha alumina, gibbsite and transition aluminas [2] can be leached in an acid medium by putting most of the aluminium in solution; the remaining residue should be mainly andisolved alpha alumina. In many hydrometallurgical processes, sulphuric acid has been selected as the cheapest and the most effective leachant [3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]The aim of this study is to determine the effect of temperature, acid concentration and pulp density on the sulphuric acid leaching of electrofilter fines for aluminium dissolution, in order to produce aluminium sulphate for water coagulant uses. This will provide a commercial product and at the same time eliminate the environmental problem created as a result of the storage of large quantities of electrofilter fines in the vicinity of the Bayer plant."

Jan 1, 2008

By G. Glinski, K. A. Pericleous

"Recent advances in new computational modelling techniques such as Lattice-Boltzmann and Dissipative Particle methods offer the prospect of simulating complex fluids such as colloidal and dense suspensions in industrial processes. They are referred to as mesoscopic methods since they lie between molecular dynamics at a microscopic atomistic scale «lO-9m) and traditional macroscopic CFD methods (> 1O-2m). The models behave like a 'coarse-grained' gas consisting of fictitious interacting particles, which are much larger than the real molecules of the actual fluid they represent. Inter-particle forces are set so that the collisions collectively mimic the phenomenological transport properties and flow of the underlying fluid at a macroscopic scale.Much of the developmental work to date has focused on laying theoretical foundations based on thermodynamic and kinetic theory. Successful applications include predictions of macroscopic transport properties of complex fluids and flows in porous media and filters. With the constant increase in computational power, these mesoscopic methods are now sufficiently developed to determine their suitability to simulate complex fluid flows in real industrial processes. This work describes the application of meso scopic methods to the stencil printing of solder pastes in the assembly of electronic components. The aim of this work is to assess the ability of these methods to study the transport mechanisms of individual solder particles suspended in the flux solvent as they enter and fill the micro-apertures of a stencil. This paper demonstrates the coupling of such mesoscopic methods to continuum CFD methods to predict the flow of dense suspensions (i.e. solder paste) in industrial processes."

Jan 1, 2001

By Edwin Dudley Martin

DURING the past twelve years the iron and steel industry has made a major advance through the development of the continuous wide strip rolling mill. So far-reaching have been the results that not only has a better product been sold at a lower price but this improvement in quality has permitted manufacturers of products using steel to make important savings in the cost of fabrication. The net result has been a better product at lower cost to the consumer without reduction in either employment or of wages paid within the industry. That is why the iron and steel industry is proud of its attainment. Being a basic industry of strategic importance, such an advance in technology has had its effects on our internal economy, our standard of living, and our industrial power as a nation in both peace and wartime.

Jan 1, 1939

By J. W. Freeman, E. E. Reynolds, A. E. White

Fram a study of 63 systematic alloy modifications it was found that molybdenum, tungsten, and columbium, added individually or simultaneously, and increases in chromium cause major improvements in 1200°F rupture strengths of Cr-Ni-Co-Fe base alloys. Rupture strengths were a function of the effect of composition modifications on both the inherent creep resistance and the amount of deformation the alloy would tolerate before fracture. THIS paper describes the results of an investigation of a series of alloys with systematic variations of the chemical composition of the following basic alloy: C, 0.15: Mn, 1.7; Si, 0.5; Cr, 20.0; NI, 20.0: Co, 20.0: Mo, 3.0; W, 2.0; Cb, 1.0; N, 0.12; Fe, 32.0 pct. The 62 modifications of this alloy were produced under conditions which minimized all factors influencing properties at high temperatures except composition. Melting, fabrication, and heat treatment were carefully maintained constant. Stress-rupture properties at 1200°F were used as the primary criteria of evaluation of the alloy. The objective of the study was to obtain data for determining the fundamental role of the influence of alloying elements on properties of heat-resistant alloys at high temperatures. In addition the results should be useful in determining optimum chemical compositions, the sensitivity of properties to variations in composition, and the degree to which alloy content could be reduced while retaining worthwhile properties. It is difficult or impossible to develop correlations between properties at high temperatures and systematic variations in chemical composition from published data for wrought heat-resistant alloys developed for gas turbines.' ' The main reason for this is the extreme dependence of the properties on conditions of treatment of the alloys." In most cases variation in final treatments between alloys so influences the properties that the influence of chemical composition is obscured. In addition it is recognized Table I. Basic Alloy and Some Modifications Used Basic AllOy, Variations in Element Pct Composition, Pct C 0.15 0.08. 0.40. 0.60 Mn 1.1 0.03,0.25.0.50,1.0,2.5 S1 0.50 1.2, 1.6 Cr 20.0 10, 30 Ni 20.0 0, 10,30 Co 20.0 0. 10, 30 MO 3.0 0. 1.2.3, 5, 7 W 2.0 0, 1, 5, 1 Cb 1.0 0.2,4,6 N 0.12 0.004, 0.08, 0.18 Fe 32.0 that variations exist between heats of the same alloy which are related to melting practice and that there is a strong possibility that conditions of hot working influence response to final treatments. The development of heat-resistant alloys has been based on the gradual accumulation of data roughly related to composition from extensive testing programs. There is every reason to believe that in most cases the optimum compositions have been achieved by this procedure in the alloys commercially available. There are, however, very little data showing the influence of systematic variations of composition free from the influence of other factors, particularly for alloys of the type investigated. Several investigators of cast alloys have demonstrated compositional effects, notably Grant,1-6 Epremian,t Guy,8 and Harder and Gow.9 Sykes10 eviewed the work on the wrought alloy Rex 78 and the systematic variations of carbon, copper, molybdenum, and cobalt leading to the development of the stronger Rex 337A alloy. From the papers by Wilson11 and Henry12 it is possible to deduce the beneficial effect of substituting cobalt for iron in 0.45 pct C-20 pct Cr-20 pct Ni-4 pct Mo-4 pct W- 4 pct Cb alloys. Wilson mentioned but did not present the extensive compositional studies involved in developing these alloys. Binder" showed optimum properties for 3, 2, and I pct, respectively, for molybdenum, tungsten, and columbium in 20 pct Cr-20 pct Ni-20 pct Co-30 pct Fe alloys for limited systematic variations of these

Jan 1, 1953

By Q. Wu

Neural network methodology is used to predict mean particle size resulting from rock blast fragmentation. A blast data base developed in a previous study is used in the current study. A part of this blast data was used to train a single-hidden layer back propagation neural network model for each of the similarity groups obtained in the same previous study. Levenberg-Marquardt algorithm provided the most stable and efficient training out of the four algorithms evaluated. An extensive analysis was performed using a part of the blast data to estimate the optimum number of units for the hidden layer for each similarity group. The remaining blast data are used to validate the trained neural network models. Capability of the developed neural network models is determined by comparing predictions with measured values and predictions based on one of the most applied fragmentation prediction models appearing in the blasting literature. Prediction capability of the neural network models was found to be strong and better than the existing most applied model. Diversity of the blasts data used is one of the most important aspects of the developed models. The developed neural network models are suitable for practical use at mines.

Jan 1, 2011

By Michael Rieber

A new mode of coal transportation based on the principles of pneumatic conveying has been recently, proposed by Soo, et al. [5]. Pneumatic transport is not a novel concept and commercial experience with pneumatic pipelines for short haul distances is plentiful. The list of applications is long and includes transporting ores, chemicals and pharmaceutical products, agricultural products, and domestic and industrial wastes. The study by Soo, et al. [5] updated an earlier one [l0] and presented the most recent economic evaluation of pneumatic transportation of coal. Their preliminary study concluded that there are immediate advantages for short-distance transport (less than 100 miles) and that it is both technologically and economically feasible. That study also concludes that pneumatic transport has a higher potential and more promising profitability in long-distance applications than rail if new track and roadbed must be built. Some of the advantages of long and short distance pneumatic pipeline transport of coal compared to rail and slurry transport are: 1) Replacement of diesel fuel consumed by unit trains, as the pipeline can be powered by coal-generated electricity; 2) Reduction of the skilled-labor costs required for upgrading and maintaining railroads; 3) Elimination of signaling, rerouting and overpass costs due to increased rail traffic on' mainline trackage;

Jan 1, 1977

By M. Zaki El-Sabban

Tables of chemical thermodynamic properties for the ideal gas state from 0° to 1,000° K are reported for eight alkanethiols, three cycloalkanethiols and arylthiols, six thiaalkanes, two dithiaalkanes, three thiacycloalkanes, and three thiophenes. They are based on current physical and thermochemical constants and definitions, reliable vibrational assignments, and the latest insights into molecular structure and energetics.

Jan 1, 1970

By Muhlis Nezihi Saridede, Burak Birol

"Plastic wastes become a huge problem day after day due to the growth of plastic industry. Hence, plastic wastes are used as a raw material for other industries to eliminate this problem. Polyethylene Terephthalate (PET), which is a commonly used for plastic bottles, may be used as a reductant for iron production because of its C and H content. In this study, composite pellets containing iron ore concentrate, flux and reductant were prepared. Crystallized PET bottles and coke were used as reductant after ground. The prepared pellets were reduced at 1400°C for 30 min. and iron nuggets were produced successfully. Usage of waste PET purely as reductant in composite pellets gives a higher metallization degree and proper carbon content than coke or PET and coke mixture.IntroductionPlastics can be seen everywhere, especially at packaging industry in our common life. The increase of plastic usage ends up with an important problem, the increase of plastic wastes. Many studies have been carried out about usage of plastics as reductant in blast furnace such as Ogaki et al.[1], Heo and Baek [2], Saridede [3], Minoru et al.[4], etc. Besides, Kato et al. [5], Nomura and Kato [ 6] and Rongfang et al. [7] have pointed out the use of plastics in coke ovens regarding to its calorific content. In EAF steelmaking, a mixture of coal/coke and plastics can be used as an energy resource instead of only coal or coke. [8] Also, the usage of PET and PC in self-reducing composite pellets increased the reduction rate. [12]PET (Polyethylene terephthalate ), which is commonly used for soft drink plastic bottles, is an important municipal waste due to its C and H content. Its molecular formula is (C10H8O 4)n. Demir and Dincer showed that PET can be crystallized at 250°C to have the ability to be ground to a size of -100 µm. [11]"

Jan 1, 2011

By J. R. Thoenen

In June 1929 the Bureau of Mines issued a 13-page information circular entitled "Mineral Wool," which was one of the first publications to present to the public Rome technical aspects of the mineral-wool industry. Since then several articles on the subject have appeared in the technical press as well as in publications of State organizations. Inquiries for information on mineral wool have continued to be received by the Bureau of Mines in large number, and in 1935 it was decided to make a field survey of the plants then producing and to collect therefrom technical data to be compiled in a paper for nubile distribution. With the cooperation of the industry, this survey was made, and Information Circular 6984, Mineral Wool, was published in January 1930. The issue was exhausted after a few months, and requests for copies continued to come to the Bureau. As opportunity arose, further field studies were made in American as well as Canadian plants. The present circular contains the essential information in Information Circular 6994 together with date from later field studies.

Jan 1, 1939

By Edgar Marburg, William R. Webster

The desirability of bringing about greater uniformity in specifications governing iron and steel is generally recognized, and has found expression within recent years, in the efforts of numerous technical societies in that direction. When the International Association for Testing Materials was organized at Zurich in 1895, a committee was appointed, charged as follows: " On the basis of existing specifications, to seek methods and means for the introduction of international specifications for testing and inspecting iron and steel of all kinds." The American representation on this international committee consisted originally of five, and now of eight members. In view of the magnitude and importance of the subject, the Executive Committee of the American Section of the International Association for Testing Materials, since incorporated as the American Society for Testing Materials, appointed a committee of 34 members, including the American members of the above-named international committee, to frame standard American specifications for iron and steel. This committee reported on specifications for (1) Structural Steel for ridges and Ships; (2) Structural Steel for Buildings; (3) Open-Hearth Boiler-Plate and Rivet-Steel; (4) Steel Rails; (5) Steel Splice-Bars; (6) Steel Axles; (7) Steel Tires; (8) Steel Forgings; (9) Steel Castings ; (10) Wrought-Iron. These specifications were designed to be fairly representa-tive of the best current American practice, and were adopted by letter-ballot of the Society in August, 1901. The leading engineering societies have participated at various times in the discussion of these specifications and have lent valuable assistance through the appointment of special committees on like, or closely related, subjects. The American Society of Civil Engineers discussed the spec-

Jan 1, 1905

By S. Fletcher, C. Calle, K. Constanti-Carey, R. Ruzbacky, M. D. Horne

Laboratory test-work has established that two classes of redox catalysts based on anthraquinone and bipyridinium derivatives are effective in accelerating the rate of removal of metallic iron from reduced ilmenite (RI) in the aeration step of the Becher process. Two water-soluble anthraquinone derivatives are efficient: 9,10-anthraquinone-2,6-disulfonicacid, disodium salt (catalyst AQ-2,6) and 9,10-anthraquinone-2-sulfonic acid, monosodium salt(catalyst AQ-2). When 0.2 per cent w/v of either was added during aeration the rate of metalliciron removal was accelerated by two to three times. Furthermore, the addition of either compound resulted in magnetite (Fe3O4), the iron oxide phase preferred in commercial practice, being formed. However, both AQ-2,6 and AQ-2 were rapidly lost from solution during aeration although their catalytic activities persisted even when their concentrations in solution were low(<0.05 per cent w/v). The negatively charged anthraquinones were lost from solution most probably by adsorption onto the magnetite that has a net positive charge at the pH values encountered during aeration. To address this problem, the catalytic activities of positively charged bipryridinium derivatives were tested. Two water-soluble bipyridinium compounds, paraquat (1,1’-dimethyl-4,4’-bipyridinium dichloride) and diquat (6,7 dihydrodipyrido [1,2-a:2’,1’-c] pyrazinediiumdibromide), were found to significantly accelerate the rate of removal of metallic iron from reduced ilmenite, and both gave magnetite as the oxide product in the laboratory tests. Moreover, recycle tests showed they were not lost from solution as quickly as were the anthraquinone derivatives. Results in larger scale plant laboratory reactors also showed a significant increase in aerationrates when diquat was added and magnetite was again the oxide formed. However, the oxygensupply to the reactors was insufficient to achieve the maximum effect of the catalysts on theaeration rates. The limited supply of oxygen in a full scale aerator may prevent the application ofthe catalysts in a commercial Becher operation. Keywords: Becher process, aeration, anthraquinone, bipyridinium, redox catalyst, reduced ilmenite

Jan 1, 2003

By D. Berberick

On January 5, 2012, the Mine Safety and Health Administration ordered the closure of the Silver Shaft, the primary underground access to Hecla?s Lucky Friday Mine, for removal of built up backfill material that accumulated over time on the shaft walls and furnishings. Lucky Friday and Cementation USA personnel worked quickly to identify the most effective means to get the mine back into production. The team developed a fast-track procurement and refurbishment plan utilizing shaft sinking winches, headframe modifications, a partial shaft sinking Galloway, and modified cages to not only complete clean-off of buildup, but also replace pipe brackets, shaft steel, and power and communications cables as needed in the 1,860 m (6,100 ft) deep shaft within 14 months.

Feb 23, 2014

||Abad, Leopoldo F, College of Min, Univ of California Berkeley, Cal &apos;23 ||Abarquez, Ramon F, Met, Bureau of Science Manila, P I &apos;24 ||Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, Ohio &apos;21 Abbott, A N , Mines Supt , Mazapel Copper Co , Ltd Concepcion del Oro, Zacatecas, Mexico &apos;23 Abbott, Clarence E, Gen&apos;l Supt, Iron Mines Div, Tenn Coal, Iron & R R Co, 1405 Minnesota Ave, Bessemer, Ala &apos;04 Abbott, Louis Benjamin, Chief Engr, Consolidation Coal Co, Elkhorn Div &apos;Jenkins, Ky &apos;15 Abbott, Robert R , Met Engr, Peerless Motor Car Co Cleveland, Ohio &apos;12 ||Abbott, Wells Osborn, Ray Consolidated Copper Co Hayden, Ariz &apos;23 Abeel, George H, Jr, Cons Min Engr 4612 W 17th St, Los Angeles, Cal &apos;18 Abel, Albert E, Asst to Pres, Valley Mould & Iron Corpn Sharpsville, Pa &apos;19 ?Abeloff, Miran S Address Wanted &apos;21 Abernathy, G E, Kansas State Teachers College Pittsburgh, Kans &apos;20 Abey, Hiroshi, Min & Met Engr, Takata & Co, 2 Yeirakucho, Nechome, Kojimachi-ku,

Jan 1, 1923

A compilation of papers presented at the Third WVU Conference on Coal Mine Electrotechnology in Morgantown, West Virginia, on August 4-6, 1976. Papers cover areas of electric power, electronic communications, detection and location of trapped miners, and electronic sensors and monitoring systems.

Jan 1, 1976

By Metehan Erdogan, Ishak Karakaya, Fuat Erden, Emre Ergül

"The FFC Cambridge process was suggested as a promising Si production technique for the expanding solar energy industry. Direct electrochemical reduction of bulk SiO2 plates and porous SiO2 pellets in molten CaCl2-NaCl salt mixture were investigated at 750°C by applying 2.8 V potential difference. The produced Si powder was brown and found to be contaminated by the Ni and stainless steel plates used as the cathode contacting materials. The reduction rates of the bulk SiO2 plates and porous SiO2 pellets were compared from variations of current and accumulative electrical charge that passed through the cell during the electrochemical reduction. The amorphous bulk SiO2 plates were reduced slightly faster than porous pellets of crystalline SiO2. The overall reduction potential of SiO2 pellets against the graphite anode at 750°C in molten CaCl2-NaCl salt mixture was determined as 2.3 V by cyclic voltammetry. This potential was supported by calculations.IntroductionMetallurgical grade Si cannot be directly used in electronic industry and some intermediate steps are required to produce industrial solar grade silicon (SOG-Si). A promising alternative solar grade silicon production technique is the FFC Cambridge Process [1]. Production of Si by electrochemical reduction of SiO2 at 850oC in molten CaCl2 electrolyte was first studied by Nohira et.al. [2]. In their study; Si formation was observed on bulk SiO2 cathodes after 1 hour of electrolysis. Complete electrochemical reduction of porous SiO2 pellets was first reported by Jin and his coworkers [3]. The mechanism of electrochemical reduction of SiO2 to Si in molten CaCl2 was explained in another study [4]. Reduction rates of bulk SiO2 and porous SiO2 pellets were also compared previously and it was found that reduction rates for bulk plates were higher [5]. Furthermore, it was reported that mixing Si into porous SiO2 pellet increased the reduction rate [5]. Mo [2, 4-7], Ni [3, 8, 9] or Si [6] were used as cathode contacting materials in various studies. Yasuda et. al. [6] produced Si with 99.80 % purity using Si plates as cathode contacting material to reduce metal contamination."

Jan 1, 2012

By Guiming Yang, Xiaoxian Huang, Zhiyun Ji, Min Gan, Lishun Yuan, Xiaohui Fan, Zhiyuan Yu

"The roasting characteristics of hematite pellets containing MgO were studied where magnesia powder, serpentine and magnesite were used as magnesium-additives respectively. The mechanical strength of both preheated and roasted pellets decreased when MgO content increased, which implied the addition of MgO had an adverse effect on pellet consolidation. By adding flux containing CaO, the mechanical strength of both preheated and roasted pellets were improved. The addition of calcium flux facilitated the formation of calcium ferrite and provided a certain amount of liquid phase, resulting in faster diffusion ofMg2+ and Fe3+. The result showed that diffusing speed of Mg2+ was enhanced by 1.48 times, and rate constant of Fe203 crystalline growth was enhanced by 62% when basicity was around 0.4. Improvement of mineralization degree and recrystallization of Fe203 assisted in consolidation of hematite pellets containing MgO.IntroductionOxidized pellets are ideal iron-bearing burdens in blast furnace. At present, magnetite is the main raw material for oxidized pellet production in China. However, as the rapid development of iron and steel industry, resources of magnetite have been depleted and cannot satisfy the requirement of pellet production. Using hematite concentrates to produce oxidized pellets has become a trend [1, 2]. Many pellet enterprises abroad nowadays have adopted high proportions of hematite concentrates when producing oxidized pellets, e.g. the percentage is 100% in a lot of Brazilian factories [3, 4]. But high proportion of hematite concentrates will lead to low mechanical strength and high reduction swelling index of pellets. Some studies show that Mg-bearing pellets have excellent metallurgical properties, and the reduction swelling phenomenon can be solved by adding fluxes containing MgO [5, 7]. However, there are problems such as low pellet strength and bad roasting characteristics for MgO-bearing pellets, which remains an obstacle in pellet industry. Hence, it's vital to undertake the study on strengthening measures for indurations of Mg-bearing hematite pellets."

Jan 1, 2013

By James A. Barr

[CONTENTS PAGE Foreword. By JAMES A. BARRI A New Core Barrel for Prospecting for Phosphate in Florida. By I. M. LEBARON 2 Prospecting for Phosphate in Tennessee. By W. F. GUENTHER 6 Machine Prospecting in Tennessee Brown Phosphate. By H. O. PICKARD, JR8 Diamond Drilling through Flint Horizons in Tennessee. By HENDON R. JOHNSTON9] Foreword PROSPECTING methods used in Tennessee have gradually improved with the years, as required by depletion of the easily accessible and shallow deposits and the universal trend toward mechanization, and as necessitated by exploring deeper beds, often occurring under limestone and flinty overburden. In the early days it was a very simple matter to dig pits by hand, using a plentiful supply of local farm labor to expose relatively shallow deposits of "brown rock" under shallow clayey overburden that would stand up without timbering. Visual inspection of the exposed phosphate and expert judgment of the"grade" analysis, aided by a "biting" test to reveal presence of unwanted silica, furnished most of the information required. All this might be helped by a few samples sent to the local chemist[t] who supplemented his income by judicious trading or tanning a few bear skins. The extra curricula activities did not affect the accuracy of the analysis which hold up even under present day standards. Some shot and core drilling was done in Hickman County, mostly for the limestone-like blue Phosphate deposits. The next step was the use of a 4-in. posthole auger, hand operated as described by Guenther, followed by- a completely mechanized rig, as described by Pickard. Both these methods are practically adapted to the prospecting of the relatively soft brown rock deposits at moderate depths of clay overburden. For prospecting in areas of deeper overburden, such as are often found in Hickman County, up to 150 or even 200-ft depths, a modified core-drilling method is described by Guenther. Johnston describes a special diamond-drilling technique, developed by TVA, to penetrate flint horizons, which was adopted by the International Minerals and Chemical Corporation to prospect in Hickman County where deposits had previously been prospected at considerable expense and with difficulty, by Small, temporary, hand-dug shafts.

Jan 1, 1947

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a &apos;heat value&apos; basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957