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By A. E. Nehrenberg

IN an earlier publication' it was shown that the.. shape assumed by a volume of growing austenite is inherited from the prior structure. The matrix grains of pearlitic microstructures are equiaxed, and austenite grows in an equiaxed manner in these prior structures. Martensite and bainite, on the other hand, have an acicular grain structure, and the austenite produced in such structures grows in an acicular manner. In the discussion of this paper' it was pointed out that in cold-rolled tempered martensite, austenite grows in an equiaxed, rather than an acicular manner. The results of an experiment carried out to arrive at an understanding of this behavior are illustrated by the micrographs. Fig. 1 shows the acicular microstructure produced by heating tempered martensite to a temperature within the Ac1-Ac3 range, 1350°F. When tempered martensite is cold rolled, then heated to the same temperature, the equiaxed structure shown in Fig. 2 is produced. A sample of cold-rolled tempered martensite heated at 1350°F just long enough for the formation of a small amount of austenite is shown by Fig. 3 to have an equiaxed (recrystallized) ferrite grain structure. The small particles of. austenite which formed at 1350°F in the equiaxed ferrite matrix are likewise equiaxed. Thus, the equiaxed growth of austenite in cold-worked tempered martensite is not a contradiction of the principles described in the previous paper, for the growth pattern reflects the matrix grain structure existing at the time of austenite formation. References A. E. Nehrenberg: The Growth of Austenite as Related to Prior structure. Trans. AIME (1950) 188, pp. 162-174; Journal of Metals (January 1950). 2 J. R. Vilella and R. A. Grange: Discussion of ref. 1. Trans. AIME (1950) 188, pp. 1378-1381; Journal of Metals (November 1950).

Jan 1, 1953

By G. H. Cady, L. C. McCabe, D. R. Mitchell

While running certain float-and-sink tests, unit coal calorific values were determined for gravity fractions of a series of Illinois coals from several districts in the southern part of the state. When these values were plotted against specific gravity what appear to be characteristic curves of somewhat different shape were obtained for each district represented. This in itself seems noteworthy. The shape of the curves seems to indicate that the lightest fraction of the coal, which inspection shows to be largely vitrain, suffers the least deterioration in storage. It was also observed that on dilution curves established with dry ash and B.t.u. values the fractions of 1.35, 1.40 and 1.50 sp. gr., which constitute the greater weight per cent of a given coal sample, fall more frequently on a straight dilution line than do the lighter or heavier fractions of the same sample. In most instances there is a marked steepening between the 1.35 and the fraction of lighter gravity. In general the curve increases in steepness between the fractions of 1.50 and 1.70 specific gravity. The variations in the unit coal-specific gravity curves as well as those observed in dilution curves which appear to be pertinent to this problem are: (I) variation in coal substance with change in specific gravity, (2) variation in kind and quantity of mineral matter with the specific gravity of the fraction, (3) factors of analytical procedure which tend to introduce error in analysis, particularly in high-ash and high-sulfur fractions. DISCUSSION (A. C. Callen presiding) E. Stansfield, ? Edmonton, A1ta.-—The necessity of avoiding oxidation in grinding and in drying should be emphasized. My assumptions as to pure coal coincide with t,he author's but most of my curves are nearly straight lines. The low sulfur content

Jan 1, 1934

"The effect of operational conditions, such as air flow rate, impeller speed and solid concentration, as well as the effect of solids concentration and frother dosage, on the bubble size distribution produced in a lab scale flotation cell, were investigated. The cell was operated under batch conditions. The measurement of bubble size was accomplished using an automated photographic technique. The technique enabled fine and coarse bubble distributions to be measured in two-phase (liquid-gas) and three-phase systems (solid-liquid-gas). In each experiment, around ten thousand bubbles were characterized.This paper discusses the main results obtained using the new photographic technique and compares these with previous findings available in the literature. The results indicate that photographic techniques combined with digital imaging processing might become a standard technique for measuring bubble size distribution in flotation machines.HUT BUBBLE SIZE ANALYSERThe importance of having precise and reliable equipment for measuring bubble size distribution in industrial flotation machines has been widely recognized. The measurement of bubble size, particularly in three-phase systems, is rather complex due to the opaque nature of the pulp. However photographic techniques combined with ingenious sampling techniques are utilized for overcoming this difficulty. The technique named HUT, combines previously developed visualization methods with digital image processing procedures. In this technique bubbles and aggregates are exposed to a monochrome progressive scan camera. The acquired images are directly stored in a computer connected to the camera for post-processing. The sampling apparatus consists essentially of a vertical tube for collecting bubbles, a viewing chamber and a collection chamber, where particles carried by the bubbles are released. The function of the collection chamber is to maintain the viewing chamber clear for imaging purposes. Each image is automatically processed off-line, using digital image tools. In this paper the advantages and limitations of this new technique are described."

Jan 1, 2003

By J. Jolly, R. V. Wheeler

This short note on the probable character of the organic sulfur compounds in coal can do no more than indicate lines of research. We have no new experimental work to describe, nothing comparable in value with the careful studies of American coals by Powell and Parrl and Yancey and Frazer. A study of the manner in which sulfur compounds exist in British coals (and their behavior on heat treatment) is rendered increasingly necessary by the fact that the British reserves of good coking coals of reasonably low sulfur content are fast being depleted. We believe that it is essentially by a study of the modes of formation, occurrence, and decomposition of the various types of inorganic and organic sulfur compounds in coal that it will be possible, with hope of success, to attack the problem of purifying coals, otherwise eminently suitable for coking, from these objectionable ingredients. Sulfur, so far as is at present known, does not normally occur in the free state in the coal conglomerate, but is chiefly distributed, irregularly, in three forms : 1. As primary constituents of the coal conglomerate, organic in nature and probably associated with those molecular complexes that have resulted from the degradation of the proteins of the plant tissues responsible for the formation of the coal mass. These constituents can be classed as "organic sulfur." 2. As metallic sulfides, e.g., iron pyrites. 3. As metallic sulfates, e.g., calcium sulfate and ferrous sulfate. (The occurrence of these compounds varies with the occurrence and degree of degradation of class 2.) It is usually found that sulfur compounds of class 3, the metallic sulfates, are present in coal in small proportions only, amounting to about 1 or 1.5 per cent. of the total sulfur. The compounds in classes 1 and 2 are therefore of more importance. Class 1 alone will receive considera-

Jan 1, 1925

By H. Sherman

The general curtailment of activities, so marked in 1931, was continued and intensified in 1932 and although production was maintained at approximately the level of the previous year, 1932 was chiefly characterized by the virtual cessation of drilling in many of the proven fields, a further decline in wildcatting activities, particularly in the Maracaibo Basin, and the relinquishment of large blocks of unfavorably located acreage. A total of only 60 wells was completed during the year of which six were wildcats, while at the same time concessions aggregating approximately. 3,222,000 acres were renounced and reverted to the National Government. The maintenance of production at the previously established level was made possible through the large potential built up by drilling in previous years and by a gradual increase in pumping and gas-lift installations. Towards the end of the year there was a slight but perceptible tendency towards increased drilling in certain of the proven fields. Total production for the year came to 118,076,000 as compared to 118,418,000 bbl. for 1931, while exports amounted to 114,758,000 as against 116,683,000 bbl. in 1931. Table 1 shows production and exports and the average rate per day for the first half of 1932 as compared to the second half. Table 1.—Petroleum Production and Exports in 1932, Venezuela (Barrels of 42 Gallons) Production Rate per Day Export Rate per Day I January-June............ 61,943,000 1 390, 347 July-December.......... 56,133,000 305,071 50,788,000 276,022 Total.........,....... 118,076,000 322,612 114,758,000 313,546 During 1932 the number of active vessels comprising the Lake Maracaibo fleet of shallow-draft tankers was still further reduced, some being temporarily laid up and some transferred to service in other coun-

Jan 1, 1933

By Paul Worsey, Richard P. Ayres, Mark F. C. Schmidt

A new alternative technique designed to reduce rock scatter and flyrock during boulder blasting is being developed at UMR. The method uses small explosive charges and is designed for shooting in close proximity, while utilizing common blasting products found on the operators’ site. This ongoing work is being conducted internally as graduate and undergraduate level research. A paper describing the general technique was published in last year’s proceedings. This particular portion of the work was performed as an undergraduate research project as part of the requirements for the explosives emphasis degree option at UMR. Previous model work was performed using cubes of concrete. However, in real life boulders are often flat and irregular rather than perfect cubes. The purpose of this work was to determine how to deal with flatter boulders. The work comprised using different geometry blocks (simulated boulders) of the same volume (1 cubic ft.). Square concrete boulders using an 8.5bag concrete mix were cast using different width to height ratios (varying from 1: 1 to 3.7:1). Single 5/8 inch holes were drilled to 2/3 the depth of the blocks, charges placed approximately l/2 way in to the holes and the holes filled with water. The explosive charges comprised ICI Masterdets containing a OSg High Explosive base charge and incremental added weights of C4 explosive. In the experiments, the block height was progressively reduced and to compensate the charge weight was increased until acceptable fragmentation was achieved. It was found that a significant increase in charge wt is required to achieve the same fragmentation as the width to height ratio increases (the boulder becomes flatter). Furthermore, the increase in charge weight required is proportional to the width to height ratio. Basically, you have to use a higher powder factor for flatter boulders.

Jan 1, 2000

By William R. Beloff, Franklin M. Grynkewicz, Puza

Construction of the MBTA Red Line Extension through Somerville, MA, called for driving twin tube tunnels through a zone of approximately 83m (273 ft) with mixed face conditions. While the majority of the tunnels were driven through competent hard rock using drill and blast techniques, the mixed face zone was advanced using floating crown bars for primary support. The overburden consisted of medium clay, underlain by water bearing glacial till, over a sloping bedrock surface. Due to the unusual nature of the construction techniques, a program was undertaken by the Contractor to monitor ground movement and stresses in the temporary steel supports. This paper presents a description of the instrumentation employed, as well as the measured ground movements and support stresses. Additionally, the tunneling techniques are briefly presented and commented upon. PROJECT DESCRIPTION The Davis Square to Porter Square Tunnel Contract is part of the Massachusetts Bay Transportation Authorities (MBTA) Red Line Extension from Harvard Square in Cambridge to the Alewife Brook Parkway via Somerville. The 5.1km (17,000 ft) Red Line Extension consists of four major new stations, three of which will be interlinked via tunnel construction, and the remaining station will be the last link of an open cut portion, and a terminal point for this phase of the extension. This 866m (2,790 ft) portion began at Porter Square in Cambridge and rose at a 4% slope through Somerville, terminating at the new Davis Square Station. Twin tube tunnels were constructed through 763m (2,517 ft) of rock and 83m (273 ft) of mixed face conditions at the Davis Square end. Figure 1 presents a plan view of the entire contract.

Jan 1, 1981

By W. N. Key, L. C. Acton

Freeport Minerals Co.'s Ertsberg East underground operation typifies the cliche that all the "easy" ore deposits have already been found. Despite its location, in a remote Indonesian rain forest, and the effort and expense required to develop the ore body, the mine was developed on schedule, under budget, and with minimal disruption of the adjacent open-pit mining operation. Development of the Ertsberg East copper, gold, and silver ore body took less than two years after exploration drilling and feasibility studies were completed. In addition, the project came in well under its targeted budget of $101.5 million. Initial block caving and underground ore production took place last year. About 3 kt/d of Ertsberg's total 8.6 kt/d ore production is currently mined underground. This will increase to 5.4 kt/d by year's end. Underground operations will eventually account for all of Ertsberg's production, as the open-pit ore body is depleted. Freeport Minerals is currently studying the possibility of increasing total Ertsberg East production tonnage to 10.5 kt/d by 1983. The equipment, work practices, and development methods at Ertsberg East (Gunung Bijih Timur or "GBT"), while typical of other block caving mines, were modified for rapid mine development and maximum ore recovery. Located in the Irian Jaya province, "Gunung Bijih" is the Indonesian expression for the Dutch "Ertsberg" that in English means "ore mountain." "Timur" means "east" and relates to the fact that the new underground ore body lies about 1 km east of the open pit. The area surrounding GBT is mountainous, with peaks from 4.2-5 km. The underground mine adit and surface plant are located at a 3.6-km elevation. The mine, 4° south of the equator, gets 5.1 m/a of rain, but has an average daily temperature of only 13°C because of the mine's elevation.

Jan 7, 1981

By Rush N. Hosler

This paper was prepared for the purpose of answering some of the many questions as to why, in the construction of Pennsylvania's Coal Mine Schedule Rating Plan, various factors were, or were not, taken into consideration. Much has been written about merit and schedule rating of industrial risks from an actuarial viewpoint, therefore this phase of the question is taken up only so far as may be necessary in presenting the practical application of the plan now in use. Companies writing fire insurance, about 30 years ago, were the first branch of insurance to use schedule rating; the values assigned their items were largely a matter of judgment. In 1913, the Industrial Commission of Wisconsin evolved the first schedule rating plan to be applied to industrial risks under compensation insurance. Pennsylvania, in 1916, with the inception of its Compensation Act, was the first state to apply the principles of schedule rating to coal mines. A definition of the term "schedule rating" submitted by the writer in a brief to the Safety Committee of the United States Coal Commission is as follows: Schedule rating, as applied to compensation insurance, is an instrument to measure the hazard of known causes of accidents to which employees are exposed in industry and thereby determine an insurance rate commensurate with said hazard. It was first applied to Coal Mining in 1916 in Pennsylvania.' In other words, for a mine operator to insure his employees for injury under the Workmen's Compensation Act, it is necessary that he pay a certain premium based on his payroll. If all mines were assessed the same premium, it would be unfair for the mine with low natural hazard, good safety conditions, and good accident experience to pay the same premium as a mine with bad conditions and experience, therefore schedule rating was introduced.2

Jan 1, 1925

By H. D. Pearsall

It is well that the usual system for supplying water at high pressure purposes of hydraulic mining possesses serious disadvantageense, delay and large annual repairs. Where plough work possible, the first expense of the ditch is moderate; but it is verynree years before the work is solid and the ditch water-tight, lxPenditure for repairs being needed during this time and greaf water occurring. Moreover, in the course of a long ditch, it happens that part of it has to traverse a diffi cult country fluming, masonry, or other expensive construc tion is necessich makes even the first cost high. The life of flumes is also) The ad visa if pumping water instead of supplying by gravity has therefore been suggested, when sufficient water-power for the purpose oping happens to be available. But the expense of the requiuchinery and its complication, which involves skilled attend expensive wear and tear, has hitherto pre vented. The author ever, having been called upon to make plans and estimates for Lulic works for an extensive placer-mine in Colo rado, has such in devising pumping arrangements which are free from these sections, and are in fact estimated to cost less than half what a din the usual plan would cost. Several incidental advantages in plan also accrue, which will be referred to more particularly be The works placer-mine have not yet been carried out, on account of final arrangements, but in the meanwhile an hy draulic 'engineilar to that designed for the mine, has been con structed and so work for other purposes in England; and in order to explane plan which I have recommended for working the placer-mine will' describe this, which is actually at work, in preference to cibing the one which is not yet constructed. The engine machine acts on the principle of the hydraulic ram

Jan 1, 1888

By N. B. Pilling, R. E. Bedworth

The corrosion of metals is one problem on which time and thought have been expended for many years. In the effort to avert the destructive action of a hostile environment, attention has been directed almost entirely to the conditions under which most metallic structures are called upon to perform, and the extensive and complicated phenomena attending the corrosive action of atmospheric agencies, acting at the ordinary atmospheric temperatures, have been studied, but there is unanimity of opinion regarding many fundamental facts. One neglected phase is the corrosive action of various gases upon metals exposed to temperatures considerably higher than the atmospheric range, and more especially the attack of atmospheric oxygen upon exposed metallic surfaces. That the problem is difficult is connoted by the practical dominance of industrial electric heating by alloys of one type (nickel-chromium). Proprietary interest may account, in part, for the paucity of information available upon even the most general factors determining the behavior of metals and alloys when exposed to such exacting conditions. The present paper gives some conclusions reached as the result of experimental work, extending over several years, on the mechanism and contributory factors of the high-temperature oxidation of a number of simple unalloyed metals; it is free from experimental detail and proof. High-temperature metallic oxidation may be considered as a phase of metallic corrosion. The scheme outlined below, in which corrosive agent and environment are the principal criteria, is one way of analyzing the several groups of corrosion phenomena. Erosion.—Disintegrating or destructive action by physical causes. Corrosion.—Disintegrating or destructive action by chemical causes. Low-temperature Corrosion.—Solid participating phases essentially immobile: (a) Gaseous agent; (b) liquid agent: action electrolytic and action non-electrolytic. High-temperature Corrosion.—Solid participating phases possess diffusive mobility: (a) Liquid agent; (b) gaseous agent: reducing gases, oxidizing gases. (1) Water; (2) miscellaneous elemental and combined oxygen.

Jan 1, 1923

By James Norman, Oliver C. Ralston

DIATOMACEOUS earth occurs in deposits widely distributed throughout the nation. The chief producing areas are in the Western States, where many high-grade deposits are known. Eastern deposits of diatomite are unsatisfactory for many purposes either because of impurity or because of the extremely fine particle size. Eastern users of diatomite, on the whole, must pay for transportation of the material from the west coast. The freight rate is necessarily high because of the great bulk of the diatomite. A satisfactory process of purifying the diatomaceous earths of Maryland and Virginia, which are unsuited for wide use only because of impurities, should be of value to eastern users. In the past, benefication of diatomite by wet processes has been limited to classification or sedimentation for the removal of sand from diatoms. Calcination with salt is used to produce a white diatomite when iron is present in the impurities, and small amounts of clay are rendered inactive in the process. No treatment has been developed whereby a large proportion of clay can be removed from a low-grade diatomaceous earth to give a diatomite of very high purity. In August 1937 the Federal Bureau of Mines, in cooperation with Dr. R. C. Williams, of Baltimore, undertook the problem of purifying low-grade Maryland diatomite by Froth flotation. Work was done at the Eastern Experiment Station, College Park. Unless otherwise stated, the crude diatomite used was from the Patuxent River deposits near Dunkirk. This material, consisting of roughly one-third each or clay, quartz sand and diatoms, was representative of the usual low-grade marine diatomite found in the Coastal Plain Miocene beds of Maryland and Virginia and sporadically in other Atlantic coast states. As received, it contained 50 to 60 per cent moisture and probably had been wet since its formation.

Jan 1, 1942

By Henry R. Tiedemann, Eugene H. Skinner, George E. Wickham

The need for ground support research in underground excavation has been well identified in recent years by many studies in the subject area (1, 2, 3, 4, 5). A typical conclusion from these reports (1, 2) is that the drill-and-blast (D & B) mining or the mechanical tunnel boring machine (TBM) methods are expected to be continued in use for the needs of tunneling in the immediate future. The Organization for Economic Co-operation and Development (OECD) sponsored in June, 1970 advisory conferences on Hardrock and Soft Ground Tunneling (3,4). These two reports were based on the combined response received from approximately six hundred inquiries from 17 nations in the summer of 1969 and which concerned all aspects of present-day inadequacies of, and the needed improvements in the technology of tunneling. Some specific problem areas in ground support and tunnel linings were: 1) the ability to successfully predict rock loads that must be carried by the support system; and 2) inadequate methods for determining the load-carrying capacity of the various support systems. Therefore, the problem area is clearly defined by these two objectives: 1) To find means of predicting rock loads; and 2) To develop methodology for determining safe, efficient, and economical ground support design practices. Noting these research needs from a great number of sources, the United States Bureau of Mines, Spokane Mining Research Center (SMRC), acting as agent for the Advanced Research Projects Agency (ARPA), undertook contract research effort in these problem areas. Work by Jacobs Associates has studied a methodology for specification of temporary artificial support based on the dependent sequence of mining operations and prediction of various rock conditions in the pre-excavation stage. The major thesis is that rock behavior is the

Jan 1, 1997

By William Fink

Two of the aluminum-alloy systems previously studied-the alumi-num-titanium and the aluminum-chromium-exhibit a peritectic reaction at the extreme aluminum end of the diagram. Preliminary work indi-cated that the aluminum-zirconium and certain other aluminum systems were similar in this respect. The present paper, the twentieth of a series from the Aluminum Research Laboratories, reports the results of a recent investigation of equilibrium relations in aluminum-zirconium alloys of high purity, which confirm the preliminary observations. PREVIOUS INVESTIGATIONS There has been only one investigation of the aluminum end of the aluminum-zirconium system. Sykes1 prepared and studied alloys containing 0 to 70 per cent Zr. The lowering of the freezing point of aluminum by the addition of zirconium was found to be very little, if any (less than 2°C.). He placed the solid solubility of zirconium in aluminum at room temperature between 0.57 and 0.97 per cent. A few other investigators have attempted to determine the com-position of the intermetallic compounds occurring in this system. Hönigschmid2 obtained the compound ZrAl3 as a by-product during the preparation of ZrSi2. He made no attempt to prepare other aluminum-zir-conium compounds. Weiss and Newmann3 prepared an alloy by heating aluminum with a double fluoride of potassium and zirconium. When this alloy was treated consecutively with caustic soda and hydrochloric acid, there was a residue, which contained approximately 72 per cent Zr and 28 per cent Al (Zr3Al4). Marden and Rich4 prepared an alloy in the same way, treated it with caustic soda, and obtained a residue of silver-white crystals, which contained 70 per cent Zr and 30 per cent Al (Zr3Al4).

Jan 1, 1939

By Angela Binder, Oliver Langefeld

"The future of mining will be characterized not only by the application of modern technology, but also by the harmonization of economic, environmental and social issues. These areas set major future challenges which are complex and demand extensive knowledge. As an example, mining of highly complex orebodies for the supply of often critical raw materials, needs to consider technically demanding and cost-intensive extraction issues. The amount of tailings, which need to be stored, increases with the amount of ore mined. Therefore, the negative impact on environment and society increases. Hence mining becomes expensive with regard to all three aspects: economy, environment and society. In view of a sustainable mining practice this challenge should be used as an opportunity. The positive impact should be maximized for present and future generations. The objective is to create and use the mining openings in an optimum way related to sustainability. The approach of Blue Mining, which focuses on energy and ergonomics in the field of Sustainable Development, enhances the closure planning by recommending subsequent usage of such openings for energy storage. The approach fosters among others the implementation of the 7th Goal for Sustainable Development defined by the United Nations with the assurance of access to affordable, reliable, sustainable and modern energy for all. The usage of underground storage increases the stability of solar and water power usage, which are otherwise unreliable. Blue Mining embeds these issues in the main planning effort long before groundbreaking. This approach involves experience from past and current projects. This paper introduces the concept of Blue Mining with respect to post-mining utilization of a mine for energy storage. Methods and perspectives are presented with examples covering best-practices and lessons-learned."

Jan 1, 2017

By Arthur Redfield

IN ESTIMATING the unmined petroleum reserves of Central America, it is not feasible to employ the methods that have been worked out in the oil fields of the United States. No producing wells have been brought in and no drilling sections have been made public. It is accordingly necessary to fall back on a crude "barrels per square mile" estimate. The method chosen is a comparison of the structure of the foreign field of unknown reserves with that of some supposedly analogous North American field of which the reserves have been estimated. This method makes no pretense at scientific accuracy; bit furnishes a working basis for an estimate. The areal geology of Central America is illustrated in the map prepared by Sapper and more recently in the geologic map of North America accompanying U. S. Geological Survey Professional Paper No. 71, "Index to the stratigraphy of North America." Disregarding for the present the Arrow Quaternary coastal plains and alluvial deposits of the river valleys, three chief zones may be distinguished. These are: A zone of late eruptive and effusive rocks; a zone of highly folded pre-Cambrian(?) or early Paleozoic crystalline schists and slates, considerably intruded by pre-Tertiary plutonic rocks; and a zone of more or less folded sediments, chiefly of Cretaceous or Tertiary age. The zone of late eruptive and effusive rocks of Central America begins in southeastern Chiapas, Mexico,. and extends, with increasing breadth, across southern Guatemala, across practically the whole of El Salvador, and across southern Honduras to the valley of Rio Goascorán, where the igneous zone attains a width of about 100 mi. (160 km:) East of the Goascorán Valley late eruptives and effusives play a subordinate part, being confined largely to the Departments of Valle and Choluteca. Dikes and sills of igneous rocks intrude the sedimentary formations of central and northern Honduras.

Jan 7, 1922

By Bauer. Larry G.

The vast coal reserves in the Wyoming, Montana, North and South Dakota region are sufficient to supply the total energy needs of the United States for several hundred years. Not only is there an abundance of this sub-bituminous and lignite coal available, but it is easily obtainable by strip-mining . The overburden varies from several feet to several hundred feet. This western coal has yet another asset, namely, a low sulfur content. Whereas eastern and midwestern coal has a sulfur content of 2.5%, the upper Great Plains coal contains sulfur in the 0.5% range. The importance of the sulfur content of the coal is a direct result of federal government emission standards for sulfur dioxide (SO2). Hand (1) points out that "sub-bituminous coals and lignites have a propensity for retaining this sulfur in the ash under certain conditions which is not evident in higher rank coals." This would tend to reduce further the SO2 concentration in the combustion gases of boilers. Western coal is no panacea, however, in that it is far removed from most population and industrial centers. Furthermore, the moisture content of the coal varies from 20 to 40%. This moisture is almost exclusively inherent, that is, it is chemically and physically bound to the organic matter of the coal. It is believed that the water forms a part of the coal structure perhaps as water of hydration of organic salts or organic acids, perhaps by hydrogen bonding, or perhaps by simple adsorption (2). The primary market for this coal is the electric power industry. Lesser markets will be as coke for the steel industry and possible as a raw material for coal gasification and coal liquefaction plants.

Jan 1, 1983

By W. W. Adams

"Fatal accidents at coal mines throughout the United States killed 234 employees during January 1924, according to reports from State mine inspectors to the Bureau of Mines of the Department of the Interior, Included in the number of fatalities are 68 deaths caused by two explosions during the month, one explosion occurring in a mine at Johnson City, Ill., and causing 32 deaths, and the other in a mine at Shanktown, Pa., and causing 36 deaths. The fatality rate for the month was 3.94 per million tons, based on a production of 59,435,000 tons of coals In January 1923 the fatality rate was 3.52, based on 206 deaths and an output of 58,458,000 tons.Bituminous mines in all States reported 202 fatal accidents, the production being 51,170,000 tons., and the fatality rate being 3.92, as compared with 3.28 for January last year, For the anthracite mines in Pennsylvania, the reports covered 32 fatalities, which, on the month's output of 7,955,000 tons, indicated a fatality rate of 4.02 per million tons, as against 4.89 for January 1923.As compared with January 1923, the reports for January of the present year indicated lower fatality rates per million tons for all of the main causes of accidents except explosions. For falls of roof and coal, the fatality rate per million tons declined from 1.85 in January 1923 to 1,68 in January 1924; for haulage accidents the rate declined from 0.62 to 0.42; for explosives, from 0.19 to 0.12; for electricity, from 0.12 to 0.07. The rate for explosions increased from 0.21 to 1,31 per million tons. -- Reports of Investigations, Department of the Interior, Bureau of Mines."

Feb 1, 1924

By Dever Ashmead

ENGINEERS, operators, miners, and others di-rectly interested in mining will readily agree that more of well-directed illumination in mines will result in a reduction of accidents and general im-provement in the working conditions, comfort, and effi-ciency of those employed underground. Progress has been made in the amount of illumination from individual lamps carried by miners. The candle, which a great many of us can remember as the general method of lighting, was replaced by the oil lamp or torch, later by a specially prepared oil known as "Sunshine," and eventually by the carbide cap lamp. The metal mines still present a field for progress from the standpoint of general illumination, particular-ly those mines having high stopes. Attention is being more and more focussed upon the advantages of im-proved lighting in mines, in order that the underground employee may benefit as the factory workers have al-ready done. The management is vitally interested in the morale of its employees, the reduction of costly accidents and increased production, all of which, judging by results in other industries, will be sub-stantially benefitted through the means of improved general illumination. From data available to the writer, 40 to 50 per cent of the accidents in the metal mines occur at the face; they may be due to roof falls, movement of loose ore, loading of cans, handling of tools, etc. Very probably a large proportion of these accidents may be attributed to lack of light. If sufficient illumination had been present the employee could have seen what was happen-ing and taken the proper precautions. The introduc-tion of better illumination means better visibility, de-crease in accidents, and increase in efficiency.

Jan 6, 1928

By Eric Jette

THE unusual physical, electrical and magnetic properties of the iron-nickel alloys has given rise to a voluminous literature. This work will be reviewed critically in "The Alloys of Iron and Nickel," a monograph of the Alloys of Iron Research Series, soon to be published. In what follows we shall therefore confine ourselves to those of the earlier investi-gations that involved the use of X-ray crystal-structure methods. The earliest X-ray work on the iron-nickel system was by Miss Andrews1. Using the powder method of X-ray analysis purely as a means of identifying the phases present, she located a region between 20 and 30 weight per cent nickel in which body-centered and face-centered phases coexisted. No lattice constants nor details of heat-treat-ment were reported. Bain2 also reported some qualitative observations. McKeehan3 made a systematic investigation over the whole of the system, giving many of his alloys four and some five different heat-treatments. In alloys furnace-cooled from 900° to 950° C. he found two coexisting phases between 0.15 and 30 per cent nickel. The precision of the lattice-constant measurements was low in comparison with what can be obtained today.. Even for alloys of the same heat-treatment, differences in the constants were often between two and ten parts per thousand. In regions where no change of lattice constant with heat-treatment should occur, differences of the same order of magnitude were found. Since the maximum change in the lattice constant of nickel with change of composition is only about 2 per cent of the constant for pure nickel, these variations in the constants for a given alloy cause the points

Jan 1, 1936