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By J. C. Bayles

Jan 1, 1886

By Oliver Bowles

GLASS razor blades, glass chairs, and marble window panes attest that creative genius was still active in 1935. Many less striking, though doubtless more important, developments are to be recorded for the nonmetallic mineral industries, and not the least of them is the establishment of an Industrial Minerals Division in the A.I.M.E. under the able leadership of Samuel H. Dolbear, Chairman. Thus the nonmetallics are rightly granted equal dignity with metals and fuels in the category of mineral industries. The brief review of progress that follows merely touches the fringe of important developments in this broad field.

Jan 1, 1936

By Davis M. Lapham

Ore bodies at Cornwall, Pennsylvania, have been mined since 1742 principally for iron from magnetite, but also for copper (in chalcopyrite), silver (in chalcopyrite), gold (in chalcopyrite), cobalt (in pyrite), sulfur, and crushed limestone aggregate. Metallization occurs as a limestone replacement above the essentially conformable, south dipping portion of a discordant saucershaped diabase sheet. Pre-Triassic and Triassic faulting have emplaced host Cambrian limestone and two Ordovician(?) hornfels units, now for the most part resting above diabase. Thermal metamorphism of carbonate-bearing country rocks largely to calc-silicates, is ubiquitous. Metasomatism, particularly of potassium, is unique to ore zones. Associated magnetite- actinolite mineralization replaces, in a preferential sequence, all earlier metamorphic and metasomatic minerals and rarely diabase chilled margin. Mineralogical (diopside, actinolite, mica, sulfides, oxides) and chemical (Fe, Cu, S, Co) zoning of the eastern ore body is focused down dip, near its western edge, along a major vertical fault through diabase. This zoning is spatially related to magnetite veins in diabase, to an ore body within diabase, and to a shear zone that probably extends through the sheet.

Jan 1, 1968

By Thomas L. Garrard, James A. Sprague, Rex B. McLellan, Samuel J. Horowitz

A simple rnodel for interstitial solid solutions has been devised in which each solute atom interacts with the solzlent lattice in such a way as to exclude an integral number of nearest-neighbor sites from being occupied by solute atoms. The vemaining interstitial sites ave not affected. In calculating the entropy of such a solution the increase in the number of interstitial sites available to solute atoms due to the ozlerlap of blocked sites is taken into account. The ther-modynamic functions and the solute activity fov the solution rnodel are calculated. It is shown that considevation of the overlap sues vise to a correction term of the order 8' ( where 0 is the ratio of solute to solvent atoms) in the thevmodynamic functions of the solution and the solute activity. The theo,uetical equation for the solute activity was used to analyze the available data for the activity of carbon in austenite at three different temperatures. The use of a computer enabled many comparisons to be made between the experimental activity data and those predicted by both the complex blocking model and the simple, widely used blocking model in which the ozierlapping of blocked sites is not taken into consideration. Even though at the highest concentvations oj carbon the value of 0 is small it is shown that the best fit to the experimental data is found with the complex blocking model. RECENTLY it has been shown by analysis of gas-solid equilibriums that many interstitial solid solutions can be described by the quasi-regular solution model in which the partial energy of solution E, is independent of composition and, apart from a composition-independent term due to nonconfigurational factors, the partial entropy is that of an ideal solution. Dilute solutions of nitrogen in both bcc and fcc iron,' dilute solutions of oxygen and silver,' carbon in a Fe,' and dilute solutions of carbon in ? Fe2 are all quasi-regular. In addition many hydrogen-metal solutions, both dilute and concentrated (with the notable exceptions of the H-Ni and H-Pd systems), can be described by this model.3 However, it has been shown that, at various temperatures, solutions of carbon in ? Fe begin to depart strongly from quasi-regular behavior at low concentrations. A plot of the activity of carbon in ? Fe relative to pure graphite vs atom fraction of carbon (Cc) calculated from Smith's data4 begins to depart from the (nonlinear) plot for a quasi-regular solution at about Cc = 0.02. Several statistical models have been proposed to account for the thermodynamic behavior of carbon in y Fe. Darken and smith4 set up a model in which a carbon atom in its octahedral site in the fcc lattice has either one or no neighboring carbon atoms in the twelve nearest-neighbor octahedral sites. It is assumed that the number of carbon atoms having more than one nearest neighbor is negligibly small and that a solute atom does not interact with another solute atom located at a greater distance than the first shell of interstitial sites. Thus this model contains two characteristic interaction energies. Darken and Smith showed that this model gives reasonable agreement with the measured variation of carbon activity ac with composition. It is noteworthy that Darken and Smith concluded from their analysis of the activity data using this model that there was a repulsive force between carbon atoms in austenite which reduces the concentration of C-C pairs below that corresponding to random mixing. Recently Aaronson, Domian, and pound5 have considered in detail the statistical model developed by Lachere and by Fowler and Guggenheim7 and have shown that it is compatible with the activity data for carbon in austenite. In Darken's model the energy of solution of carbon in austenite is dependent on temperature and concentration; the departure from Henry's law arises from the concentration dependence of the energy of solution. In Aaronson, Domian, and Pound's discussion of the Lacher, Fowler, Guggenheim model the interaction energy wy between adjacent carbon atoms in austenite is strongly temperature-dependent. Aaronson et al . suggested that this temperature dependence of wy and hence the energy of solution of carbon could be explained either by the formation of clusters of carbon atoms (despite the repulsive nature of wy) or by the dual occupancy of the octahedral and tetrahedral sites by the carbon atoms. However, a temperature-dependent heat of solution

Jan 1, 1968

By Arthur A. Center

AT the beginning of 1944 it was expected that the production of metallic zinc in the United States from domestic and foreign concentrates would exceed the 1943 figure though domestic production of concentrates was expected to drop below the 1943 rate, mostly in the Tri-State area. Imports of concentrates were estimated to more than take care of such deficiency. North American concentrate production, available for import to the United States or elsewhere during the year, was estimated at over 200,000 tons recoverable zinc content; South American at about 65,000 tons; Australian at about 50,000 tons. Production of both concentrates and metal in the United States, however, did drop, attributable in considerable part to man-power shortage in the industry. However production exceeded consumption, which fell off, and stocks of metal increased. These stocks have increased since the middle of 1942 but production and consumption are coming nearer to a balance. The A, B, and C premiums, which have played an important part in keeping up domestic production of concentrates, extend only to the middle of 1945 by present legislation. Congress is being asked for their continuance during the war and

Jan 1, 1945

By H. H. Richardson, E. H. Dix

Of all the alloying elements used in commercial aluminum alloys, copper stands out as by far the most important, and it is perhaps for this reason that the constitution of the aluminum-copper system has received the attention of a number of experimenters covering a period of approximately 20 years. It would be expected that during this time the equilibrium relations would have been thoroughly and exactly worked out. In a general way this is true, but there is a surprising lack of agreement in the details of the high aluminum end of the diagram, particularly in regard to the solid solubility of copper in aluminum, which has been given variously as 2 per cent. to 5 per cent. at the eutectic temperature. The importance of this is much greater than might at first appear to one unfamiliar with modern commercial aluminum alloys. This is true because, with one exception, the susceptibility of the strong alloys to heat treatment depends, in part at least, upon the solid solubility relations of copper in aluminum. In 1919, Merica, Waltenberg, and Freeman1 published the first detailed information on these solubility relations. They found that the solubility of copper decreases with falling temperature from about 4 per cent. at 525" C. to about 1 per cent. at 300" C. and is apparently still diminishing at lower temperatures. In 1921 there was published a brief account of the results obtained in the National Physical Laboratory, Teddington, England.2 This laboratory, however, reported that 5 per cent. of copper is soluble in aluminum at 540" C., and that this amount decreases to about 3 per cent. at 20" C. In the same year Ohtani and Hemmi3 reported a solubility of 4.8 per cent. copper at 520" C., 2.6 per cent. at 460" C. and 1.5 per cent. at 420" C.

Jan 1, 1926

By Linn Bradley

Introduction MARKED differences of opinion have been expressed by engineers interested in cleaning iron blast-furnace gases for use in hot-blast stoves and under boilers, in reference to the advantages of a hot-dry method over a cold-wet method. One point at issue involves the sensible heat energy in the moisture contained in the gas. Some advocates of the cold-wet methods claim that the condensation and resultant removal of the greater portion of this contained moisture by wet scrubbing, spraying or similar methods, results in a saving of some of this sensible heat energy, by reason of the fact that water vapor has a high capacity for sensible heat energy and may carry from the exit of a hot-blast stove, for example, more heat units than are sacrificed or lost when the gas is cleaned by this cold-wet method. Other advantages claimed for the latter method are: That gas burns more readily when it is free from moisture in any form; that because gas is made denser by cooling and removing the moisture it has a higher calorific value than hot gas carrying moisture; and that higher flame temperatures are obtained when the gas is cleaned by the cold-wet method. A search through the available literature fails to disclose any extensive calculations or records of conditions obtained in practice, bearing upon these phases of gas cleaning. This paper deals with these problems from the standpoint of the economy of using a gas of higher flame temperatures, of improved stove design, and of economy in the gas-cleaning department. Calculations have been made which show that by cleaning the gases by a cold-wet method the sensible heat energy of the blast-furnace gases is greatly reduced; and, in general, this loss of heat energy is far greater than that lost from the stoves or boilers due to the sensible heat capacity of the water vapor if carried away by the exit gases. By making use of the

Jan 2, 1917

By DR. RICHARD RATHBUN

ON behalf of the Regents and the Secretary of the Smithsonian Institution, it gives me great pleasure to welcome you to the National Museum; but it is to your own museum, since it belongs to you in common with all the people of the country. Still young in a life which has been beset with many difficulties, it has gathered strength and attained a growth quite unprecedented. In fact, it is this very growth which has been the chief cause of trouble, always leading far and away beyond the capacity for storage ; and to-day there is nearly as much material contained in outside buildings as is displayed in this one. You will, accordingly, find the collections crowded, the cases so close together that their contents are often difficult to view, and the arrangement generally lacking symmetry. You may, therefore, be inclined to regard us as poor custodians of the collections of a great nation, but I beg you to withhold your judgment for a while. From the beginning there has been abundant zeal and activity and a proper direction of affairs, but space and money have been lacking. There is now a prospect of better times. All about you here is a beautiful park, but without. a covering it is not adapted to museum purposes. Upon it, however, a new large building is going up, so extensive in its dimensions that technology can soon be given a fitting home, thus realizing one of the earliest aspirations of the Regents. Some sixty-five years ago the extensive returns of specimens from the famous Wilkes Exploring Expedition around the world began to reach Washington, where they were deposited in the Patent Office Building, and formed practically the first of the National Collections. Six years later the Smithsonian Institution, based upon the bequest of James Smithson, was

Jul 1, 1905

By M. Felsenthal

Engineers are frequently faced with the problem of having to predict oil recovery from a solution gas drive reservoir in the early life of a field. This is often the time when actual laboratory or field-derived gas-oil permeability (kg/k0) data are not yet available. Although excellent collections of k0/k0 data for various types of rocks may be found in the literature,1,2,3 a need exists for a more detailed correlation of k0/k0 data with core properties such as porosity, permeability, clay content or pore-size distribution. It is the purpose of this article to present this type of correlation for sandstone material. The correlation is based on laboratory tests performed on over 300 core samples from 19 reservoirs in the United States and Canada. EXPERIMENTAL Cores were analyzed by routine procedures, using samples of conventional size (7/8-in. diameter, 7/8-in long) cut parallel to the bedding planes. Air permeability was measured at 1.67 atm mean pressure in a Hassler-type apparatus. Porosity was determined with the aid of a Ruska bulk volume meter and a Boyle's Law rock volume meter, An evaporation method' was used to evaluate irreducible water saturations. Core samples were saturated with 25,000 ppm NaCl brine. The brine was reduced to the irreducible saturation, and the remainder of the pore space was filled with kerosene. This was followed by multiphase flow tests using the so-called "dispersed feed" technique.5 n this technique, gas and oil (kerosene and kerosene-saturated air) were dispersed with the aid of a porous Alun-durn feed head, the face of which contained a waffle-shaped system of Lucite-lined grooves. Oil entered the back side of the feed head and emerged at the raised areas of the front face. Gas was introduced directly into the system of grooves at the front face. The gas-oil mixture then entered the test core which was kept in capillary contact with the feed head. Permeabilities were determined from rate and pressure measurements and saturations from weights. All determinations were performed at equilibrium or steady-state conditions. Pore-size distributions were determined on selected samples by a mercury injection technique.6 GENERAL CORRELATIVE TRENDS When examining data from a given reservoir, it was noted that k0/k0 vs saturation curves became generally less steep as specific air permeability increased, a development that has a favorable effect on oil displacement efficiency by solution gas drive. This trend has also been reported by others in the literature.' An effect of porosity on k0/k0 data was also noted. This effect was not generally discernible in a study of relative permeability data for a given reservoir but became apparent when data for sandstone reservoirs of similar lithology but differing average porosity were compared. For instance, in a comparison of argillaceous and/or calcareous sandstones from 11 reservoirs ranging in average porosities from 14 to 28 per cent, a definite trend was noted, indicating that for a given permeability k0/k0 curves became less favorable (i.e., steeper) as porosity increased. A similar trend was observed for a group of comparatively clean sandstones from five reservoirs ranging in average porosities from 15 to 21 per cent. For a given permeability and porosity, comparatively clean sandstones gave more favorable k0/k0 curves than argillaceous and/or calcareous sandstone or chert reservoirs. The laboratory studies also showed that least favorable k0/k0 curves were exhibited by shaly sandstone, conglomerate, and sandstone containing carbon inclusions. Table 1 lists the various source reservoirs classified by lithology types. To facilitate a correlation of k0/k0 data with core characteristcis, it was found expedient to work with

By John V. Beall

Never having done it before, it took us all day and until 11 at night to select and pack for a four-day back- pack trip up Lake Chelan last month. When we were through, we couldn't lift our own pack and Sylvia's, OUT spouse's, we barely managed to budge. Nevertheless, the next morning we were at the dock to board the Laldy of the Lake for the 3 ½ -hr boat trip to Lucerne. Our dress and accouterments creating the appearance of a veritable expedition into the wilderness made a sharp contrast with our fellow passengers, a senior citizens tour group from Spokane. We had come out to Seattle for the SME Fall Meeting and were taking advantage of the occasion for a vacation trip back to Lucerne and Holden where we had lived briefly 25-years ago, and a backpack trip up Railroad Creek from Holden to the Glacier Peak country, weather permitting. No matter what you say, weather is important, and this is one of the ingredients that went into making the SME Fall Meeting and Exhibit in Seattle, September 22-24, a thoroughly delightful experience for the 700 plus persons who attended. Seattle is a beautiful city, but with late September sunshine, which we experienced, it is the best. The second ingredient, is a swinging host committee. Under the leadership of Don Anderson and Tom Van Zandt, co-chairmen, and Mrs. Cecilia Reed, Ladies Program, superb hospitality and fine arrangements were blended. Earl Beistline, from Fairbanks, organized a two-day short course on arctic operations which preceded the meeting and drew an attendance of 44. Dick Robbins, in charge of arrangements, provided Masters-at- arms for technical sessions and a presentation of the colors by the U.S. Coast Guard at the Welcoming Luncheon. Eric Cheney's field trips ranged far and wide with events both before and after the meeting. David (Jeff) Kroft, capably managed audio-visual operations with a group of students from the University of Washington. Charles Hochmuth worked long, hard and effectively before and during the meet- ing on finances. Hank Reed, managed an authentic three-ring circus as Entertainment Chairman. His activities covered two cocktail receptions for all registrants and a dinner-dance. Dolph Campbell and Joe Hackbarth provided publicity by press and TV (see p. 37-40). SME's meetings have certain characteristics and possibly not all of these are known to everyone. The first of these is the deliberate involvement of the AIME Section in the area of the meeting. Most trade shows and conventions are run 100% by a professional staff and although SME staff could also do this, it has been our experience that a more friendly and better meeting results when the local members apply their talents. Actually SME only considers a site for a meeting after it has received an invitation from a Section. The knowledge of local conditions which Section committeemen bring to a meeting is of great value.

Jan 1, 1971

By Donald A. Brobst

The minerals barite (BaSO4-barium sulfate) and witherite (BaCO3-barium carbonate) are the chief commercial sources of the element barium and its compounds whose many uses are nearly hidden among the technical complexities of modern industrial processes and products. Barite, the major ore mineral, is extremely vital to the petroleum industry which in 1980 consumed at least 90% of the world's production of 8.8 million tons as a major ingredient of the heavy fluid, called mud, that is circulated in rotary drilling of oil and gas wells. The remaining 10% of the barite production was consumed chiefly in the manufacture of barium chemicals and glass and as a pigment, filler, and extender. Barite occurs throughout much of the world and is available from three major geologic types of deposits-vein and cavity filling, residual, and bedded-in sufficient quantity at competitive prices to meet current demands. The world's demand for barite is expected to increase, and geologic circumstances are favorable for the discovery of new deposits of commercial value. Witherite is much less common and abundant than barite, although it is more desirable in many ways as a raw material for the production of barium chemicals. The United States has not produced witherite since about 1950; England is currently the chief producer of witherite. End Uses Most of the world's barite production since 1926 has been used as a weighting agent for the muds circulated in rotary drilling of oil and gas wells. The muds fundamentally are mixtures of water, clay, and barite in different proportions that vary according to local reservoir conditions. Muds with a specific gravity as great as 2.5 are used. The mud is pumped down the hollow drill stem, passes through the bit at the bottom of the hole, and rises to the surface in the space between the drill stem and the wall of the hole. In the course of this circulation the drill bit is cooled, cuttings are removed, the drill stem is lubricated, the walls of the hole are sealed, and the hydrostatic head of the column of weighted fluid helps to confine high oil and gas pressures. The latter feature aids in prevention of gushers, thus reducing both environmental pollution and waste of oil and gas resources as well as conserving the natural reservoir pressure for greater production and rate of recovery of the products contained in the rocks. Barite is particularly well suited for drilling mud because it is clean, easy to handle, soft (nonabrasive), heavy, virtually inert chemically, and relatively inexpensive compared to many other available heavy materials. Barite is used in the manufacture of glass in continuous tanks. The addition of barite homogenizes the melt and gives greater brilliance and clarity to the finished glass. Ground barite, both unbleached and bleached by sulfuric acid, is a common industrial filler, extender, and weighting agent. The rubber industry is a major consumer of barite as a filler. Barite also is added to bristolboard, heavy printing paper, playing cards, rope finishes, brake linings, clutch facings, plastics, and linoleum, to name but a few uses. Bleached barite has long been an extender in white lead paint because of its weight. The low index of refraction of barite, however, makes its ability to cover marks poorer than some other substances, but its low capacity for absorption of oil is a good feature. Off-color or unbleached barite can be used as a filler in colored paints. In the construction industry, some lump barite is used in concrete aggregate to weigh down pipelines buried in marshy areas and to shield nuclear reactors. Because barite absorbs gamma radiation well, its use reduces the amount of expensive lead shielding otherwise

Jan 1, 1983

By Elmer R. Kaiser

G. A. Vissac (Consulting Engineer, Vancouver, B. C.) —Some of the data presented in this paper, in connection with cost studies of washed coals, should be clarified and qualified. Washing a raw coal down to a low ash content may mean higher losses in refuse, but the cost of the operation may be more than compensated by the increased value of the resultant product. However, careful engineering and accurate machinery are required to insure maximum profits. Washing at a low gravity separation demands a very accurate automatic process, chiefly when the small sizes of coal are being handled. Coal consumers today are buying mostly on a Btu basis, cognizant of the fact that low ash contents result in lower installation costs and in savings in handling and transportation charges. The attached Table X gives the actual balance sheets of the various cleaning operations corresponding to various ash contents for the two coals presented in the paper, using the old technique of a two-products separation. or the new technique, now commonly used in Europe, of a three-way separation made possible by new methods and new equipment. Savings in capital costs, handling, and transportation have been calculated on the basis of a delivered cost f.O.b. plant of $10.00 per ton of coal at 16.5 pct ash (actual 1953 average price reported by Consolidated Edison, N. Y.), and of $3.50 at the mine also for 16.5 pct ash coal. In both cases this corresponds to values of 126 and 4.26 per 1 pct of combustible and per ton, respectively, on delivered and on at the mine prices. As an example, the middle western coal at 16.5 pct ash, raw, washed down to 4 pct ash in a two-way process will give 53.75 pct of clean coal at 4 pct ash and 46.25 pct of refuse at 31 pct ash. The value of the losses will be 0.4625x(100—31)x0.042 = $1.34. Add the cost of washing, capital, and operation, which is $0.35. The total cost will then be $1.69. But with a three-ways separation we will have 53.75 pct of first-grade coal at 4 pct ash, 37.25 pct second-

Jan 1, 1955

By A. J. Boynton

THIS paper is not the result of recent research with regard to any particular feature of iron metallurgy, blast-furnace practice or mechanical engineering. It is rather a series of notes with regard to contemporaneous progress in blast-furnace construction and operation, together with some suggestions as to changes and improvements that seem to be desirable. On April 1, 1930, a committee of the Chicago District Blast Furnace and Coke Association presented to that association a rather ambitious study of blast-furnace equipment, together with recommendations for the design of construction of a complete blast-furnace unit for the production of 1000 tons of pig iron per day. This report represented the result of months of study by members of the committee, all of whom were actively engaged in operation or design of blast-furnace plants. It is natural, therefore, that comments on the present state of the art should take this 1000-tons furnace, as recommended by the Association, as a basis for comparison with corresponding features of construction or design. See Table 1. In looking through this report at the present time, the significant difference is in the nature of the gas-washing equipment that today would be specified. In other respects, the installation would remain generally very much as it was outlined in 1930. The change in furnace dimensions would be very slight and of no especial significance, except with respect to changes in stock-line diameter, of which more will be said hereafter. The high-efficiency stove as developed by various designers is thoroughly described within this report, and few changes have taken place since. Blowing equipment shows refinement and reflects the improvement in steam engineering. Hoisting and charging equipment and ladles for the conveyance of iron and slag remain, in general, as they were in 1930. In accordance with a general tendency

Jan 1, 1935

By O. P. Arora, M. Metzger

Single-phase aluminum containing 1 to 600ppm copper was studied in 7 to 26 pct HCl. The corrosion rate in the autocatalytic stage was resolved into a constant intrinsic component and an acdelerating autocatalytic component, and attention was focused on the part of this stage where the corrosion rate could be described by a simple empirical relation. Autocatalytic corrosion in this period was localized and its rate increased rapidly with copper content and with the strength and chlaride content of the acid. The effects of adding cupric ion to 16 pct HCI were functionally and quantitatively inconsistent with the autocatalytic rates observed. A theory of these rates was given based on the deposition in nzetallic contact with the aluminum of part of the copper introduced by corrosion. It has long been known in a general way that aluminum containing sufficient copper suffers in hydrochloric acid an autocatalytic acceleration of corrosion resulting from the introduction into the acid of copper ions and their reduction on the specimen as elemental copper, which provides cathodes of low hydrogen overvoltage.'-3 In a previous paper, this phenomenon was identified in single-phase high-purity material at copper levels as low as 20 ppm and an empirical equation describing autocatalytic corrosion rates in 16 and 20 pct HC1 was presented. In the present work the range of acid strength and chemistry studied was extended, a more accurate empirical equation for the autocatalytic rate was determined, and a theory of this rate was formulated. A major source of interest in this system is the intergranular corrosion, which is also strongly influenced by copper content,= and an objective of the present work on general corrosion was to provide a basis for studying the role of copper content in intergranular corrosion, which is experimentally much less accessible.

Jan 1, 1963

By Peter N. Blakey, Thiann R. Yu, Douglas O. Tansey

A flexible, efficient, and relatively low-cost drilling and blasting operation has evolved at Texasgulf Canada, Ltd.'s Kidd Creek underground mine. Located 32 km (20 miles) north of historic Timmins, Ontario, the underground operation utilizes a sublevel open stoping method developed with large-diameter blastholes. Over the years, Kidd Creek engineers have experimented with various drill-and-blast techniques, leading to the present-day practice. Continuing work is being conducted to further mechanize the blasting operation.

Jan 6, 1976

By Jerry Tien

Mine regulators are normally used for proper air distribution in underground mines. They are deliberately introduced resistance in the regulated airway, and by altering sizes, they can distribute specific air quantities to regulated splits and free splits (4, 5). The enactment of the Federal Coal Mine Health and Safety Act of 1969, the Federal Mine Safety and Health Amendments Act of 1977, and the regulations adopted by the Mining Enforcement and Safety Administration (now called the Mining Safety and Health ministration) prompted greater discussions of optimal mine regulator locations because of the Act's stringent ventilation requirements (2, 3). For example, by requiring the separation of the air used in the belt haulage entries from the intake and return airways, the regulations required the creation of a third type of airway---the neutral airway, as opposed to the intake and return airways, adding to the complexity of a mine's ventilation network. It is the intent of this report to show that panel regulators should be located in intake airways at the neck of a panel for a blowing fan system and in return airways at the neck of a panel for an exhausting fan system in order to achieve optimal air control. A computer simulation model is used to determine optimal mine regulator location.

Jan 1, 1983

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935