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By Alexander Field

The hot-rolling properties of a series of high-sulfur steels are described. From a consideration of the sulfur, manganese, and zirconium contents of these steels, it is shown that zirconium reacts with the sulfur content of molten steel in accordance with the equation Zr + 2S = ZrS2. Zirconium disulfide appears in the finished state as gray-colored inclusions, similar to manganese sulfide in plastic behavior and general appearance. Zirconium completes its act of deoxidation before proceeding to combine with sulfur and indirectly increases the effective sulfur-combining power of any manganese which may be present. IN A previous paper,1 the experimental methods used and some of the results obtained in an extensive investigation of steels containing zirconium were described. The present paper considers in greater detail one of the most interesting of these effects, namely, the elimination of "red shortness" and the occurrence in steel of a compound of zirconium and sulfur. A consideration of the actual percentages of zirconium, manganese, and sulfur in numerous steels in the light of behavior during rolling has led to new conclusions of the most practical import regarding the reciprocal relationships of these elements. The microscopic examination of high-sulfur steels containing zirconium has also been productive of interesting results. Before discussing the experimental data in question, it may be stated, briefly, that the reaction between zirconium and sulfur in molten steel may he represented by the simple equation, Zr + 2S = ZrS2, and that the zirconium sulfide thus formed occurs in the finished steel in the form of gray-colored inclusions, closely resembling manganese sulfide and, like the latter, exhibiting plasticity at rolling temperatures. Molten steel containing zirconium retains such a negligibly small amount of oxygen in solution that the foregoing reaction goes to completion.

Jan 2, 1924

By K. L. Morton

This technical note reviews the status quo of mud rushes and flooding, which have claimed them lives of many people in underground mines in South Africa and globally. Given that the causes are well known and can be managed, the note calls for the development of a national and global standard on flood and mud rush prevention in order to save lives.

Mar 30, 2026

By A. Dogan Paktunc

Abstract - The Mechanic Settlement pluton is a small body of mafic and ultramafic rocks of tholeiitic affinity, occurring in the Late Neoproterozoic volcanosedimentary rocks of the Avalon terrane of the Appalachian Orogen. The lenticular-shaped intrusion is layered and consists of ultramafic and mafic lithologies in at least six cyclic units that are relatively thin or short-lived. The lowermost exposed portion of the intrusion is characterized by the cumulate sequences of olivine and olivineclinopyroxene and display relatively flat rare earth element profiles. In the overlying lithologies, plagioclase is the dominant cumulus phase following olivine in the crystallization sequence. Olivine ranges in composition from Fo73 to Fo85 and plagioclase from An62 to An89. Variations in the compositions of orthopyroxene and clinopyroxene are within Wo0-4En52-87Fs11-45 and Wo39-50En23-50Fs3-19. These mineral compositional variations in part reflect cryptic patterns and correspond to normal fractionation trends in cyclic units. Elevated Pt and Pd concentrations of up to 2.6 ppm occur in ten zones within the central cyclic series in association with both the peridotitic and gabbronoritic rock types. The mineralized zones are about several meters thick and appear to have lateral continuities over several hundred meters, suggesting that they are stratiform. Platinum-group elements (PGE) occur as discrete platinum-group minerals (PGM) including vysotskite, merenskyite, michenerite, sperrylite, stillwaterite, and hollingworthite that are associated with magmatic sulfides composed of pentlandite, pyrrhotite, and chalcopyrite. PGM grains range in size from a few micrometers to well above 20 µm. Sulfur isotope ratios and the Se/S ratios of the mineralized rocks are typically higher than the mantle values. Sulfide saturation probably occurred as a result of assimilation of crustal rocks and magma mixing during emplacement of subsequent pulses of magma. Repetition of the PGE mineralization in rather thin cyclic units suggests that the replenishing magma probably had high PGE levels and was saturated with respect to sulfide during emplacement. Ingression of the replenishing magma into the chamber in a turbulent plume and its mixing with the resident magma was probably responsible for the formation of the PGE mineralizations in the Mechanic Settlement pluton.

Jan 1, 2000

By A M. Suchowerska, J P. Carter, J P. Hambleton

"In order to effectively predict the roof collapse of underground openings using continuum models, it is imperative that a realistic failure criterion is used to represent the rock mass. However, for coal mining operations, there is still uncertainty as to the appropriate failure criterion that should be used for the coal measure strata. This study compares stability numbers and collapse mechanisms for a rectangular underground opening predicted based on three commonly used failure criteria: the standard Mohr-Coulomb, Mohr-Coulomb with a tension cut-off and Hoek-Brown. Three methods of analysis are considered: an analytical upper bound method an upper and lower bound finite element formulation the displacement finite element method.The theoretical results are also compared with field measurements of subsidence above longwall coal mining. For the standard Mohr-Coulomb failure criterion, the friction angle governs the shape of the collapse mechanism, and the so-called critical width (the cavity width above which failures extend to the ground surface) ascertained from field observations in the New South Wales coalfields corresponds to a friction angle of approximately 30°. On the other hand, predictions obtained based on the Hoek-Brown failure criterion consistently overestimate the critical width. The results also show that tensile failure governs the stability of the cavity and shape of the collapse mechanism when a tension cut-off is introduced for the Mohr-Coulomb yield criterion.CITATION:Suchowerska, A M, Hambleton, J P and Carter, J P, 2014. Prediction of roof collapse for rectangular underground openings, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 367–374 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By W. W. Mein

IN March 1949 the Calaveras Cement Co. was sued by five landowners whose properties are located in the vicinity of the plant. These landowners—all of them cattle ranchers—sued for dust damages of $120,338 and for an injunction preventing the company from casting dust upon their properties in injurious quantities. The issue was split, the jury deciding the amount of damages and the court handling the injunction features. The action came to trial before a jury in April of that year and resulted in damages being awarded in the amount of $7,508. A month later the court issued its injunction requiring recovery of stack dust to an 87 pct minimum. The Calaveras plant, shown in Fig. 1, is located three miles from San Andreas in the heart of the Mother Lode country, about 45 miles east of Stockton, Calif. Since it is in a small town, the company's responsibilities to its employees and to the community are different from those of plants located in large centers of population. Construction of the plant was begun in 1925, and production was started the following year. Standard gray Portland cement as well as several specialty cements are produced. Production facilities have been continually enlarged so that the present capacity is more than double what it was 25 years, ago. The most important item in the company's expansion program was the purchase in 1945 of an 11 ft 3 in. x 360 ft Allis-Chalmers kiln which had been declared surplus by the Defense Plant Corp. The company is now able to produce about 2,500,000 bbl of cement a year, and employment at the plant is approximately 300. The production of cement has always involved a dust problem, solution of which has been attempted in a number of different ways. By far the most efficient method of catching dust discharge is electric precipitation. Soon after the company went into production in the 1920's, the landowners near the plant began complaining about dust discharge. The company settled the matter by paying them a total of $27,000 for dust damages incurred during the period from 1929 to 1938. In the latter year the two-unit Cot-trell Electric Precipitator shown in Fig. 2 was installed and collected over 85 pct of the dust resulting from operation of the two 11 ft 3 in. x 10 ft x 240 in. kilns. From 1938 until 1946 the landowners registered no objection and were apparently satisfied with that dust recovery. In 1946, however, the substantially higher production resulting from operation of the new kiln immediately overtaxed the facilities of the existing two-unit precipitator. In a short time claims for dust damages were again received from the landowners. The company informed them that because of postwar shortages it would take several years to install a new precipitator. The company stated that it intended to purchase an additional precipitator and offered in the meanwhile to pay the landowners a fair amount to cover their damages. This offer was rejected and the landowners filed suit in the Superior Court of Calaveras County asking for total damages of $120,-338 and for the injunction outlined above. Case for the Ranchers The attorneys for the plaintiffs produced three different types of witnesses: first, the landowners themselves and members of their families; second, other cattle raisers who were sympathetic to the plaintiffs; and third, several types of technical experts: veterinarians, soil chemists, and an aerial photographer. The testimony of these witnesses was designed to establish that the flue dust from the plant had not only damaged the land and the forage, but had also caused fluorine poisoning to their animals. By a combination of these causes, the plaintiffs attempted to prove substantial loss of profits.

Jan 1, 1952

By Richard J. Mainiero, James H. Rowland

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true. While there have been some disastrous world-wide accidents involving the transport of industrial explosives, this is not the case in the U.S. Over the past 10 years, accidents related to the transport of explosives used in mining and construction have resulted in 5 major injuries, 11 minor injuries, and no fatalities. Explosives and ammonium nitrate (AN) transport outside the U.S. has not had such a good record; there have been 4 major explosives or AN transport accidents resulting in a total of more than 300 deaths. Most of these fatalities could have been prevented if the accident site had been evacuated once the explosive or AN cargo began burning. The safe history of explosives and AN transport in the U.S. is due to diligent efforts by government, labor, and industry. However, accidents will become more common and disastrous if we become complacent.

By R. Lincoln

A surplus of vanadium has resulted from the tremendous output of uranium, of which vanadium is a byproduct. More knowledge of the properties and characteristics of vanadium as a pure metal has been needed so that industry can take advantage of its availability and use it according to the best principles of conservation. Besides the problem of utilization, there is the ever present need of finding new materials which will satisfy specific and demanding requirements of science and engineering; vanadium or one of its alloys may possess the latent potential for filling some of these needs. Thus this? research project was undertaken by the Bureau of Mines to determine and examine some of the physical and mechanical properties of pure vanadium. A corallary investigation was the determination of the effect of the interstitial contaminants, oxygen, nitrogen, and carbon, on unalloyed vanadium. The vanadium used for these determinations was principally the product of experimental production of the Bureau. The evaluation of this material, as small quantities became available, provided most of the data that have been obtained.

Jan 1, 1962

By E. G. Beinlich

The continuing search for faster, safer, and more economical methods of excavating underground openings has led the staff of the Mather mine of the Negaunee Mine Co. directly to mechanical boring of raises and drifts. The mine is located within the city limits of Negaunee and Ishperning in the eastern portion of the Marquette Iron Range in the Upper Peninsula of Michigan. It is owned jointly by McLouth Steel Corp., Bethlehem Steel Corp., Republic Steel Corp., and The Cleveland-Cliffs Iron Co., who also serves as the operating agent. A total of 2,400,000 tons of iron ore averaging over 60% Fe is mined annually by the block-caving method. This provides feed for the Pioneer pellet plant at Eagle Mills where 1,450,000 tons of pellets are produced yearly with the remaining tonnage being sold as coarse ore. Technical staff of Cleveland-Cliffs have long realized that improved methods of advancing raises and drifts were a necessity if underground mining of iron ore was to survive the transition period in the steel industry's requirements from direct-shipping ore to pelletized ores. For this reason, the Mather mine embarked upon an experimental raise-boring program with a prototype machine in 1961. Improvements since that time in equipment and practice have resulted in the acceptance of mechanical boring of raises as a standard development tool and a vital link in the fulfillment of an orderly development schedule. Advancement of large-diameter openings such as main-level drift headings by mechanical methods in the harder, more competent types of rock has developed more slowly in the mining industry due to the need for more compact and portable machinery and improved bit technology. Many of the obstacles have been overcome by the manufacturers, and in March 1967 it was decided to proceed with a program to bore approximately 4000 ft of 13-ft-diam drift in the Mather graywacke footwall rock.

Jan 1, 1970

Fault detection and identification are major challenges in process engineering and manufacturing and the key component of abnormal event management systems. Timely detection, diagnosis and rectification of abnormal or faulty process conditions can lead to savings of billions of dollars in equipment damage and lost productivity, not to mention the prevention of injury and loss of human life associated with industrial accidents. A major contributing factor to current losses in industry is the reliance on human operators to interpret high-frequency samples from hundreds or thousands of variables simultaneously. As a result, the automation of fault detection and diagnosis is seen as crucial to the successful implementation of abnormal event management, the need for which is becoming all the more urgent given the increased complexity associated with modem industrial plants. In this paper, a methodology for process monitoring that uses support vector methods to extract nonlinear features from data is discussed and applied in the diagnostic monitoring of an industrial liquid-liquid extraction column.

Jan 1, 2005

By Werner Klein

The Production Management solution (Level 3) covers TYASA’s existing steel making plant, billet caster and new Castrip based coil production line in Ixtaczoquitlan, Mexico. It steers the order based production utilizing product routing information and corresponding process instructions for the individual processing units. A seamless material tracking along the entire production route from heat creation in the electric arc furnace down to the final coil product provides TYASA with the genealogy information customers require for flat products. At each important process step the Level 3 compares actual quality related production results with order requirements. In case of deviations from ordered quality the plant staff is guided by rule based dispositions. The highly configurable solution supports customer to operate its production plant as a smart factory in the sense of industry 4.0.

Oct 30, 2017

By Marcio B. Fonseca

Nickel-cobalt laterite deposits have become the focus of attention for hydrometallurgical processing. Following the lessons of the second generation high pressure acid leach (HPAL) projects in Western Australia other Ni-Co laterite projects are now evaluating potential HPAL projects with a rigorous integrated approach that begins with geological modeling, resource estimation and metallurgical studies. The Vermelho nickel-cobalt laterite deposit has been under exploration and study for several years with investigations of various metallurgical processes. Recent HPAL studies have indicated that the nickel and cobalt laterite at this deposit is amenable to upgrading by silica rejection followed by pressure leaching. These studies have required a detailed geological investigation to generate a new resource model. The recent development of a sophisticated geological model integrated with a multi-element resource estimation for this complex tropical nickel laterite deposit in northern Brazil provides an example of the contribution of geology at the critical project stage where process technology decisions are made on relatively small samples of the total resource.\ Keywords: Ni Laterite, Geological Modeling, Resource Estimation

Jan 1, 2004

By Thomas M. Barczak

This report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) self advancing roof supports, (3) high capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of: longwall utilization, production capability, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By R. L., Fullman

During the past year there have been a number of significant investigations that have furnished evidence on the driving forces governing grain growth and on the role played by boundary impurities. Thus Burke has shown that in high purity alpha brass the rate of grain growth in the earliest stages is approximately inversely proportional to the existing grain size. This relation agrees with one derived by Zener assuming that surface energy was the driving force in grain growth. Also in confirmation of the surface energy hypothesis, Burke found that growth virtually stopped when the grain boundaries or even only the grain corners were melted.

Jan 1, 1949

By Michael Amick

Over the last few years as the coal industry has seen an increase in the price of coal, a renewed interest in the additional mining of pre-law highwall sites has occurred. Much premium coal and property remains behind these pre-law highwalls but access to mining is limited because prior mining used auger machines to remove coal from under the highwall. Older augers seldom reached more than 200 feet and often no more than 100 feet but this zone of auger holes destabilizes the highwall to where additional mining is often unsafe. If the reserve is large enough, the highwall can be stabilized with common flyash and cement grouts to form a face-up for an underground mine but this expensive method is usually not practical for continuous use with a highwall mining machine. It is estimated there are hundreds of miles of highwall riddled with auger holes where the coal reserve available is ill-suited for deep mining for a variety of reasons. However, these same properties are ideal for additional mining with state-of-the-art highwall mining machines that have a reach up to 1200 feet, except to the relatively thin auger mined de-stabilized zone. The renewed interest in highwall mining these properties has driven research into finding an economical way to stabilize the highwall so the highwall mining machine can recover additional coal. This research discovered and fine-tuned a process that is economical and is successfully supporting the highwall at a highwall mining operation. This paper discusses the research involved in determining the strengths need, the methodology used to place any grouts, the effect on mining plans and the increased recoveries. ARMPS-HWM is used extensively in this research. The failure of the highwall, when not grouting, and the success, when grouting using the new materials and equipment utilized, confirmed the ARMPS-HWM method.

Jan 1, 2007

By Travis Rhoden

Merriam Webster?s Collegiate Dictio­nary (1996) defines team as ?a number of persons associated together in work or activity? and teamwork as ?work done by several associates with each doing a part, but all subordinating personal prominence to the efficiency of the whole? (page 1209). According to Dr. Geller, author of Building Successful Safety Teams: Together Everyone Achieves More (1998), a team of people working together for industrial safety consists of as few as two people or as many as fifteen who have complementary skills, assignments, or abilities for completing a particular task. Effective teams have members who share a common mission and relevant goals, and they share specific methods to reach their goals and accomplish their mission. They also have an evaluation system in place for holding themselves mutually accountable for goal-directed responsibilities.

Nov 1, 1998

By R. Loj

Katowice Coal Holding (KHW) is one of the largest coal companies in Europe. The company owns five coal mines with a daily output of around 60 000 tons of coal. In the Katowice city area, very good quality steam coal is extracted. The depth of mining varies between 400 and 1100 m and some of the mines rank amongst those most afflicted by methane in the Upper Silesian Coal Basin, with the methane hazard having a significant impact on production and safety. ?Myslowice-Wesola? mine, being a part of the Katowice Coal Holding is characterized by high methane and rockburst hazards. The mine is equipped with a modern surface drainage pumping station. At the mentioned mine, longwall 514 was selected for analysis of its methane emission. The longwall was extracting the thick seam 501 (over 4 m), at a depth of over 900 m, which was subject to high stress and high gas concentration conditions. At a distance of about 50 m above, seam 501 is covered by thin seam 416. The strata between these two seams are sandstone and mudstone layers. In the floor of seam 501, with a thin shale interlayer, is located seam 510, which is the thickest (over 10m) and richest coal seam in the Upper Silesian Coal Basin. In longwall 514 and it?s vicinity, methane was the dominant risk. For this longwall three methods of classical gas drainage were carried out. At first, drainage was undertaken using long boreholes from a cross-cut at level 665 m, located far from the production panel. Later, it was performed using typical boreholes drilled from the ventilation gallery (tail gate road). Finally, it was undertaken using a degassing drift executed in the upper coal seam 416. All of these headings, ie. cross-cut level 665 m, the ventilation road and conveyor road in seam 501 and the degassing drift in seam 416, were equipped with media for drilling and proper drainage pipelines. Due to the high rockburst hazard and some problems with caving, several kinds of de-stressing and torpedo blasts were carried out in both coal seams and roof rocks. The subsequent analysis and experiments allowed the establishment of some general rules for carrying out degassing operations effectively. The effectiveness of a degassing drift was demonstrated. In some instances, the system allowed more than 70% of the total methane released to be captured and fed into pipelines. The aforementioned blasts had a marginal impact on methane emissions and the efficiency of degassing methods. Cyclic drilling and regular switching of boreholes in phase with the mining progress and working face advance were shown to be essential.

Aug 1, 2013

By B. P. Simser, R. K. Brummer, A. Mortazavi, P. P. Andrieux

"A large-scale panel destress blast was fired at Brunswick mine in the fall of 1999 in order to reduce the ground stresses in a critically important neighbouring mining region. This work, sponsored by the Mining Division of CAMIRO and Brunswick mine, consisted in heavily choke-blasting — and subsequently leaving in place — a massive waste sulphide pillar in the southwest end of the 1000 m level. This paper describes the approach and design methodology used to try to maximize breakage in the rock mass in the area to destress, while minimizing damage to critical infrastructures in the vicinity. The loading operations, as well as the results of the blast — in terms of its field performances, as recorded by near-field blast vibration monitoring equipment, visual postblast assessments and measured impact on the regional stress field — are discussed as well. A brief comparison between the measured stress changes and inelastic numerical modelling of the test site is also presented.Un tir à grande échelle de relâchement des contraintes dans un pilier a été effectué à la mine Brunswick à la fin de l’automne 1999 dans le but de diminuer les contraintes de terrain dans une très importante zone de production adjascente. Ces travaux, financés par la division minière de CAMIRO et la mine Brunswick, consistaient à tirer violemment sans aucune face libre, et à laisser en place, un pilier de sulphures massifs au sud-ouest du niveau 1000 m. Cet article décrit l’approche et la démarche conceptuelle utilisées pour tenter de maximiser les fractures dans le pilier visé, tout en minimisant les dommages collatéraux à des infrastructures critiques se trouvant dans les environs immédiats. Les opérations de chargement des explosifs et les résultats du tir — en termes de ses performances, telles qu’évaluées par de l’équipement de monitoring rapproché des vibrations de tir, d’observations visuelles, et de son impact sur les contraintes de terrain locales — sont également discutés."

Jan 1, 2003

By F. J. Perzak

The Bureau of Mines conducted a flammability study of plastic ventilation ducts. Six rigid 16-in-diam fiberglass-reinforced plastic ducts from five manufacturers were examined using laboratory-scale, large-scale, and full-scale fire tests. The laboratory-scale tests included the American Society for Testing and Materials E162 radiant panel test, the E2863 oxygen index test, and the standardized small-scale flammability test (S3FT) developed by the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, and replicated by the Bureau of Mines. Ten-foot lengths of the same ducts were also subjected to a large-scale vertical fire test, and 20-to 30-ft lengths were tested in a full-scale in-mine fire test at the Bureau's Lake Lynn Laboratory mine. The data from the laboratory-scale radiant panel test and oxygen index test indicated that the ducts were fire-resistant, However, five of the six ducts failed the S3FT and vertical fire tests, and four of the ducts failed the full-scale in-mine tests with flame propagation rates that ranged from 3 to 10 ft/min. The results indicate the need for improved fire-resistant plastic ducts. The good agreement between the S3FT re-sults and the vertical and full-scale tests show that the S3FT provides a good indication of the flammability of fiberglass-reinforced plastic ducting under realistic fire conditions.

Jan 1, 1987

By Shiro Ban-ya, John Chipman

Equilibrium in the reaction was investigated at temperatures of 1500°, 1550°, and 1600°C for sulfur concentrations up to 7.2 wt pct. Multisample crucibles contained the liquid alloys in a resistance-heated furnace using a technique especially designed for the study of more complex alloys to be reported separately. Modern free-energy data are used to correct the H2S:H2 ratio for dissociation of H2S and calculalion of the partial pressure of S2. Published data on the equilibrium are similarly corrected. Thermodynanzic treatment of the data employs the composition variable zs = nS/(nFe — nS) and the activity coefficient Gs = as/zs The data at 1500" and 1550°C are fitted by the equation log s = —2.30zs. Within the limits of experimental error the same coefficient is applicable to the data at higher temperatures. Equations are given for the free-energy change in Reaction [I] as well as for the solution of S, gas in the metal. The heat of solution of 1/2 s2 is -32.28 i2.5 kcal. Uncertainty in the free energy is very much smaller. For dilute solutions of interest in steelmaking, the activity coefficient of sulfur is unchanged from that listed in Basic Open Hearth Steel-making. DETERMINATIONS of the thermodynamic properties of sulfur in liquid iron by Morris and williams1 and by Sherman, Elvander, and chipman' provided a basis for control of sulfur in steelmaking processes. From the standpoint of understanding the chemistry of metal plus nonmetal in liquid solution they left several questions unanswered. The activity of sulfur in dilute solution at about 1600°C was well-established but temperature coefficients were uncertain, due at least in part to the use of the optical pyrometer and uncertainty regarding the effect of sulfur on emissivity. It appeared that deviation from Henry's law increased with increasing temperature, a most unusual behavior requiring either confirmation or disproof. These studies were based on experimental determination of equilibrium in the reaction: At high temperatures H2S is partially dissociated so that the gas mixture contains HS, S2, and S in addition to HS. At the time of the earlier studies the free energies of these constituents were unknown and it was therefore impossible to make adequate correction for dissociation. Observations on the effects of alloying elements by Morris and coworkers1, 3 and by Sherman and Chip-man4 enable us to assess the effects of alloying elements on the activity and to make corrections for incidental impurities in the binary liquid. These studies as well as a number of more recent investigations will be reviewed in detail after out own experimental results have been presented. It was our purpose in planning this study to avoid uncertainties regarding the emissivity of alloys and the errors of thermal diffusion which plagued some of the early attempts,5 by using a resistance furnace and thermocouple in preference to induction heating and optical pyrometer. Modern data on free energies of the gaseous species are to be applied to our data and to those of other investigators to obtain corrected values of K1 and of the activity coefficient and ultimately to relate the sulfur content of the bath to the equilibrium partial pressure of S,. Extension of the study to include ternary and complex solutions will be described in a later section. EXPERIMENTAL METHOD a) Preparation and Calibration of H2-H2s Gas Mixture. The source of hydrogen sulfide was a preparer mixture of 43 pct H2S, balance hydrogen, contained in a large aluminum cylinder. This was passed through anhydrone and through a microflowmeter. Hydrogen was passed through platinized asbestos, ascar-ite, and anhydrone, and through a capillary flowmeter. Argon was passed through copper wool at 500°C, then through ascarite, anhydrone, and a flowmeter. The flow rate of hydrogen was kept constant at 200 ml per min, to which an arbitrary amount of the hydrogen-hydrogen sulfide mixture was constantly added and then the prepared gas mixture was introduced into the reaction tube through a gas mixer. In certain experiments 200 ml per min of argon was added to the hydrogen-hydrogen sulfide gas mixture to increase the total flow rate of gas. The ratio of hydrogen-hydrogen sulfide in the inlet gas was checked for each run by chemical analysis. A sample of the gas taken from a bypass was bubbled through zinc and cadmium acetate solution (4 pct zinc acetate, 1 pct cadmium acetate, and 1 pct acetic acid) to remove hydrogen sulfide from the gas mixture, and the flow rate of the remaining hydrogen was measured by a soap bubble method to determine the volume of hydrogen. The amount of hydrogen sulfide absorbed in solution was determined by titration with iodine against sodium thiosulfate, with starch used as the indicator. The ratio of hydrogen sulfide to hydrogen in the inlet gas could be kept within ±2 pct in the range from 10-2 to 5 x 10"4 which corresponds to from 0.2 to 7.0 wt pct sulfur in liquid iron. b) Furnace Arrangement. Fig. 1 shows the furnace arrangement and the shape of the alumina crucible used in this experiment. A vertical-tube silicon carbide electric resistance furnace contained the reaction tube which consisted of two parts, the gas-tight

Jan 1, 1969

By R. M. Young

In. East Kootenay, two Companies are operating, the Crow's Nest Pass Coal Company of Fernie, with mines at Coal Creek and Michel, and the Corbin Coal and Coke Company, of Corbin and Spokane. Wash., with mines at Corbin. The Crow's Nest Pass Coal Company has also coke-ovens of the bee-hive type at Fernie and Michel. The mines have a productive capacity, with present development and plant, of approximately 1,500,000 tons of coal, and of 300,000 tons of coke annually. The total production in 1923 was 828, 990 tons of coal and 65.990 tons of coke. In the early years of operation, the mines furnished a very large percentage of their output to the railways and smelters. These were, in fact, the primary markets for which the mines were opened and the ovens constructed. The Great Northern Railway had built into Femie, and later extending its line to Michel, became a heavy consumer of both of these mines. The Spokane International, connecting the Crow's Nest branch of the C.P .R. with Spokane, furnished tonnage to Corbin. The Canadian Pacific Railway bought for Crow's Nest consumption. The smelters at Grand Forks and Trail in the Boundary country were large and steady consumers of coke, while in-termittently Northport, Butte, Helena, and Great Falls shared in the product of the ovens.

Jan 1, 1924