Search Documents

By Jacob T. Wainwright

The object of this paper is to describe some efforts and observations by the writer relating to this subject. Althongh the usual type of' blast-furnace is a most efficient device for smelting and melting purposes, it is not suitable for utilizing the cheaper grades of fuel, such as coal-slack and certain gaseous fuels. This problem not only involves the consideration of the furnace as a suitable apparatus, but also embraces the consideration of the chemical and calorific properties of the proposed fuel. In the hearth of the ordinary blast-furnace an extremely high temperature is maintained. This extreme temperature is due to the complete combustion of the fuel in the hearth, and before the gases reach the zone of fusion their temperature is reduced, by the absorption of carbon, 2300 degrees Fat). In a smelting-furnace, the maintenance of this extreme temperature at the hearth becomes useless when it can be reduced without

Jan 1, 1889

By F. M. Stewart

A paper by Hurst and van Ever-dingen in 1949 led to the practical solution of many nonsteady-state flow problems.' Subsequently, applications of this material have been discussed by several authors. The purpose of this note is to outline a simplified direct procedure for water-influx pressure predictions for pressures above the bubble point. The prcposed procedure is unique in that after the "time-conversion factor" and the "influx constant" are obtained, predictions are made without trial and error. The elimination of trial and error is made possible by expressing certain PVT characteristics as explicit functions of pressure. The procedure is applicable to fields producing at pressures above the bubble point and under radial water drive from an infinite aquifer. In the usual applications it is required to predict (1) withdrawals given future pressure history or (2) reservoir pressure, given future withdrawals or production. The theory, assumptions and conditions under which the nonsteady-state solutions hold are covered in the references and are not repeated. The simplified direct procedure outlined here has been developed from published solutions for the so-called "pressure case". A similar direct procedure for the same special conditions has been developed for the "rate case"; however, in this instance the procedure is lengthy and offers no advantage over the trial-and-error solution. Consequently, this paper covers only the procedure based on the pressure case. DISCUSSION Under the pressure case prediction of withdrawals from a water-drive field, given the future pressure history, involves the use of a nonsteady-state water-influx term together with the material balance equation. The solution of a particular problem requires the following steps: (1) division of past pressure and production data into equal time intervals; (2) computation of cumulative water influx vs pressure drop for each time interval of past history using the material balance equation; (3) determination of the best values for the "time-conversion factor" and the "influx constant" by equating the nonsteady-state influx term with the influx computed in Step 2 (this requires a trial-and-error procedure); (4) prediction of influx for a given pressure drop using the influx term and the computed factors from Step 3; and (5) calculation of fluids produced using the predicted influx in the material balance equation. A forecast of the water-oil ratio or water production rate is required to complete the calculation. It is assumed that a reliable estimate of original oil in place is available, as well as the production and pressure history, and data on reservoir fluid characteristics. If the original oil in place is unknown, it may be computed simultaneously with the tinie-conversion influx factors2,3. However, the oil in place so computed may be considerably in error3; consequently, it is usually preferable to use oil in place estimated from pore-volume data unless there is considerable doubt as to its accuracy. The Material Balance Equation Above the Bubble Point Above the bubble point the simpli-

By A. R. Kiani-Rashid

Controlled graphitization has become known as a practical method for improvement of wear resistance and machining properties in steels. In this paper, the effect of heat treatment on microstructure of CK45 steel has been investigated. Austenitising was carried out at 920°C for 5 hours. Besides, isothermal transformation was conducted at 750°C in the time range of 1-20 hours. The microstructure of the steel considerably changes by this heat treatment process which exhibits the effects of temperature, appropriate austenitising duration and isothermal transformation. Conducted experiments show a suitable distribution of semi-spherical graphite particles especially on the surface of the steel. Also, analyses demonstrate that the amount of formed graphite in the austenitising temperature 920°C is more than graphite in single heat treatment temperature of 750°C.

Jan 1, 2010

By Rodolfo Baca Chávez

Las operaciones de perforación y voladura de los depósitos de fierro en Marcona, requieren de cálculos que permitan generar diseños de perforación y voladura respectiva de un determinado banco. En este sentido, el presente texto señala a través de diversos ejemplos, el cálculo para determinar las mallas y las tablas respectivas que luego son utilizadas para un proyecto determinado y de acuerdo a esto, conocer la malla, tipo de material, explosivo a usarse, etc. Asimismo se presenta un programa de computación aplicable a dichos cálculos aplicados en la elaboración de tablas y perforación en los depósitos de dicha minería. Esta forma de elaboración es adaptable a cualquier variación, especialmente de costos.

Nov 20, 1978

By Yang Tsang Woo

The method of making coke that has been adopted at the Kaiping and other collieries in northern China resembles, to some extent, the familiar bee-hive oven process of the United States, except that a kiln with permanent sides is used instead of a closed oven, and the products of combustion are drawn off at the bottom. In building coke-kilns in China, two circular holes, 8 ft. 6 in. in diameter at the bottom and 13 ft. in diameter at the top, are excavated in the ground, and connected at the bottom by a flue, as shown in Figs. 1 and 2. The sides and bottom of the kiln are lined with fire-bricks, and covered with a lager of fireclay, and a rectangular opening, 6 in. by 8 in., connects the bottom of each kiln with the main flue. Around the edge of the hole, and overlapping the lining, is a wall of fire-brick extending 2 ft. 6 in. above the level of the ground. An open space 5 ft. wide is left in this wall, through which the coal is carried into the kiln and the resultant coke removed. This space, of course, is bricked up during the time that the coking-operation is being carried on. The wall is pierced with nine flue-openings uniformly placed around the circumference, each interverliilg space in the wall being strengthened with a brick buttress, as is shown in Figs. 2 and 4. The floor of the kiln, as well as the main flue, is lined with fire-brick. Before charging the coal, it is first placed in shallow bamboo sieves, 2 ft. in diameter, and immersed in a trough 10 ft. long, and 3 ft. wide, fed with pit-water, in which it is washed by hand. Fig. 3 shows the manner in which the washing is done. From 25 tons of good "dust" coal, 22.5 tons of washed coal are obtained. When ready to charge the coal into the kiln, a temporary cone-shaped flue of fire-wood and lump coal is first built to a

Jan 1, 1906

By D. H. Davis

HAND picking was the earliest form of coal preparation, first practiced to improve the outward appearance of the coal being loaded and to remove any pieces that might appear objectionable to the buyer. It is still extensively practiced on the plus 1-in. sizes and particularly on the plus 4-in. and larger sizes. The percentage of ash reduction that can be obtained by hand picking depends entirely upon the amount of free impurity occurring in the coal. In a particularly dirty seam, where a considerable quantity of rock occurs with the coal as mined, hand picking produces sizable reductions in ash. If the coal is prepared clean at the working face hand picking is a final check; in some cases, on the smaller sizes, it is practiced only to show that an effort is being made to prepare a clean product. Because of the variety and different methods of handling coal, the early plants were not always adapted for e5cient hand picking. At most mines an attempt is made to - remove the visual impurities at one or more of the following places in the surface plant: (1) in the tipple during screening; (2) on picking band, belt, or shaking conveyors; (3) during the loading of the coal as it goes into the railroad car. Whatever the physical arrangements of the plant may be, the usual practice is to run the coal over the screen, picking table or boom at such a rate that each piece of impurity is exposed to the view of the picker. Coal should be uniformly sized and spread out on the table so as not to exceed one particle in depth. The flow should be even in tonnage and the speed of travel should be from 30 to 60 ft. per minute and not exceed 80 ft. per minute. The dirtier the coal, the slower the speed required for a fixed number of pickers. Actually, picking capacity depends on the number of particles per minute that can be picked out and rejected. The percentage of impurity removed is determined by this and the average weight of piece rejected. Handling a mixture of sizes from nut to the largest lump over the same picking table or conveyor is not conducive to efficient separation by hand picking because the lump hides the smaller impurities. Picking tables should not exceed 5 ft. in width, so that a picker on either side will be able to remove impurities from the center of the table. Guards usually are placed at the side of the screen, boom or table, to allow the pickers to stand close enough to remove the impurities without too long a reach.

Jan 1, 1950

By K. F. Clark

Some 30 years ago Stevenson (1940) underscored the fact that most of the world's molybdenite production came from the Cordillera that comprise the western part of North America, and that the northern extension of the Cordillera into British Columbia is not essentially dissimilar to the United States section. Therefore, in view of the successful development of molybdenite resources in the United States, he concluded that prospecting in the Canadian section f the Cordillera should be encouraged. However, as recently as seven years ago Schneider (1963) remarks that no large economic deposits have been brought into production in British Columbia, although one important property was being evaluated. World production f molybdenum ore was sporadic until 1900. Among the very early producing areas in North America were Arizona and New Mexico in the United States. World War I provided the stimulus that brought the Climax deposit into production, and in 1920 Questa, New Mexico followed, although the ore came from fissure vein deposits at that time. In the early part f this century high grade deposits in various parts f the world containing 5-20 percent MoS2 were exploited. In Canada most production during World War I came from Quebec and Ontario. With the build-up of world tension and the inception f hostilities in 1939, British demand was satisfied by United States producers (Schneider, 1963).

Jan 1, 1970

By M E. Taulis, S Hayton, D A. Manhire, J G. Pope

Successful development of coal seam gas (CSG) resources in low-rank coalfields such as the Powder River Basin has raised interest in CSG from low rank coal in New Zealand. Kenham Holdings Limited holds 12 Petroleum Exploration Permits (PEP) covering some of New ZealandÆs low-rank coal and lignite resources and has engaged CRL Energy Limited to assist in the systematic evaluation of the CSG potential of the permits. To date, exploration results from seven New Zealand coalfields reflect differences in coal type, rank, depositional environment and depth of burial between coalfields. Several of the explored coalfields are considered prospective for CSG. One of the most advanced Kenham exploration programmes is in the Hawkdun Coalfield, Central Otago.   The Hawkdun Coalfield contains a single, thick lignite seam with properties that are similar to the Powder River Basin. Preliminary results indicate the Hawkdun Coalfield is prospective for CSG with the potential to contain between 25 and 60 PJ of gas; enough to supply a 30MW power station for ten to 25 years. Further drilling is planned to investigate the economic viability of the Hawkdun Coalfield. The in situ permeability of the lignite, the amount and availability of free gas, gas saturation at depth and market opportunities will determine its economic viability. If initial pumping and production results in the planned exploration programme are promising, the Hawkdun Coalfield will be further developed with additional production drillholes to form a trial production pod.

Jan 1, 2004

By W. J. Douglas

The mine manager in today's environment is faced with a wide variety of problems and challenges which must be addressed if efficient and profitable operations are to be achieved. Expansion of operations has, in many instances, resulted in inexperienced work crews, face supervisors, and superintendents. The complexities of a mining system preclude rapid movement through the learning curve for moat personnel. The management of production suffers both from this inexperience and the lack of standard procedures and methods for planning, schedul ing and analyzing production systems. The lack of visibility of information, as well as of the operations themselves, due to their remoteness, adds to the problem of production management.

Jan 1, 1980

By A. G. Merma

In this work, the electrocoagulation technique was studied in order to treat chemically stabilized concentrated oil-water emulsions. This study was mainly focused on the effects of operating parameters such as initial pH, current density, reaction time, electrode distance and inlet concentration on the separation of oil as measured by the chemical oxygen demand -1(COD) method. The synthetic emulsion was prepared from Shell - Talpa 30 oil (3g.L-1) and sodium dodecyl sulfate (1.0 g.L), having a Zeta potential around -70 mv at pH 8.7. The process was carried out in an electrocoagulation cell with a set of four parallel monopolar electrodes. This set consisted of two aluminum plate anodes and two 316L stainless steel plate cathodes. Kinetic curves showed that the electrocoagulation process exhibits three phases: (1) an initial phase, where the COD did not decrease because the solution had not reached the minimum amount of dissolved aluminum required to cause the break-up of the emulsion, (2) a reactive phase during which COD decreased due to possible agglomeration of the precipitates and (3) a steady-state phase where the COD did not change. The results showed that the period to reach the reactive phase decreased as the current density increased and the pH values decreased.

Jan 1, 2009

By F. L. Burchard, Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Coolie, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay Counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. DevELopments during 1941 Nearly 1600 wells were drilled in the district during 1941 as compared with more than 1700 in 1940. However, the ratio of successful drilling operations was higher and some 1200 oil wells were completed. Production held about even with the previous year, as did the number of producing oil wells. Known oil reserves increased slightly throughout exploration, which generally was carried on at greater depths than in former years. The average depth of discovery wells was 300 ft. deeper than in 1940. Although discoveries were evenly divided numerically between horizons above the base of the Strawn series and those below the Strawn, the deeper horizons, including the Bend series of the Pennsylvanian, the Mississippian limestone, and the Simpson and Ellenburger of the Ordovician, furnished most of the increase in oil reserves. The largest single addition to the reserves was in the Ellenburger formation in the K.M.A. field. During the year 112 wells were completed in this horizon, bringing the total developed acreage to some 4600 acres. The Straan series in K.M.A. also received considerable development in 1941, with 114 completions. K.M.A. Pressure Maintenance Satisfactory progress was made by the K.M.A. Pressure Maintenance Association in 1941. At the end of the year, 99 wells were being used for input and total monthly volume of gas returned to the reservoir reached a high of 340,548 M cu. ft. in December from a low of 208,853 M cu. ft. in February. Total volume of gas returned during 1941 was 3,306,052 M cu. ft. To the end of the year, 150 cu. ft. of gas had been returned for every barrel of oil produced from the reservoir while the input ratio for December was 397 cu. ft. Per

Jan 1, 1942

By Wang QP, Quan YH

Mechanical models are established in accordance with the degree of mining on both sides of the coal pillar, and formulae were derived which calculated the superposition stress distribution and the width of the plastic region. The stability of the coal pillar was analysed and a reasonable size of coal pillar determined, in accordance with the elastic region rate. Further practical examples for the stability of the coal pillar are calculated and simulated.

Jan 1, 1992

By C. B. Daellenbach

The influence of reduction roasting and thermal shock on the grindability of a refractory low-grade Michigan iron ore was examined in bench scale tests. The quantitative effects of the various treatments were evaluated at three sieve levels: 48, 100, and 400 mesh, using ball mill grindability and work index parameters as response indicators. Data from the testing program were analyzed statistically as a means of isolating the effects of cooling rate, roasting temperature, and ore chemical condition. All three variables were found to have an important influence on the grindability of the treated ore; ore chemical condition and roasting temperature had the most pronounced effects.

Jan 1, 1970

By J. L. Chakravatti

INTRODUCTION Mining of uranium does not differ, in many respects, from the mining of other metals; the ore must be drilled, blasted and transported in an underground or surface mine. Underground mining proceeds by the continuous development and advancement of a network of passages and rooms or stopes from which ore is excavated. As in most mines, rock conditions and ore grades in uranium deposits vary from area to area and between different mines. For mineral benefications of this ore in the mills, use is made of various chemicals, often with toxic or hazardous properties.1 As well as the need to control the more conventional hazards associated with any mining and milling operation, special care needs to be exercised in the mining and milling of uranium because of the radioactive nature of the ore. This requires that we examine closely the radiation hazard areas encountered in the mining and milling of uranium, with the broad overview of some of the basic facts in the radiation hazard control programme. To place the hazard in its proper perspective, we require recognition, evaluation and control of those factors arising in and from the workplace which may cause sickness, impaired health and affect the well being among workers or citizens of the community. The radiation environment in uranium mine is complex and variable. Although uranium ore is only mildly radioactive, it naturally contains a complex mixture of radioactive isotopes. Workers are exposed to external gamma radiation, to some beta radiation and to airborne radon, radon daughters and ore dust. All of these types of exposures warrant considerations in formulating control procedures but, in general, radon daughters are known to present the dominant risk. The basis of dose limitation in radiological protection is risk limitation. Long-term epidemiologic studies of United States uranium miners and that of miners in Czechoslovakia indicate that the incidence of lung cancer can be accounted for by a linear relationship with exposure to radon decay products.2 On the basis of this proportional exposure-risk relationship, a risk coefficient for lung cancer in the range of 1-5.10-4 WLM-1 during the total lifetime, has been estimated by UNSCEAR3 and other researchers. It should be noted that this risk coefficient includes the excess lung cancer risk from external gamma radiation in mines and from other carcinogenic chemical effects, if any, to which the miners are normally exposed during their underground work. It also takes into regard the possible synergistic influences. This paper reviews the occurrence of radiation and its control factors and the development of engineering design features for the environmental control at Denison Mine. NATURAL URANIUM SERIES Uranium is the most common element in the Earth's crust. It is widely distributed in nature in all rocks and is readily measurable in the sea. Hence, radon gas is universally produced in every part of the globe. Mining is patently confined to ores containing more than half a kilogram, or so, per tonne of uranium unless it is combined with other marketable metals. Uranium-238 is the first element in the uranium series. In all, there are 13 radioactive decay products of 238U (Fig. 1), ending up as a stable isotope of Lead-206. The whole basis of the radiological hazards associated with the mining and milling of uranium is dependent on the behaviour of these isotopes during each phase of the process.

Jan 1, 1981

By John Hall

THE recently announced run of three years, nine months and eleven days made by a. crucible steel melting furnace of the Columbia Tool Steel Co., which is claimed as a. world's record, brings forcibly to our attention the great improvements that have been made in the design, construction and operation of the Siemen's regenerative crucible- melting furnace since its introduction in this country. Credit for this advance should be given to the furnace designer, the manufacturer of refractories, and the operators of the furnaces, whose persistent efforts and intelligent co-operation in attacking the problem have resulted so satisfactorily. There are three factors that determine the life of a crucible furnace, or any other furnace for that matter : Design, nature of refractories and conditions of operation; (including the nature of steel melted) and to some extent these factors are interdependent. Thus, for instance, if a crucible furnace is to lie operated single turn and allowed to cool off considerably at night, in order to save fuel, the use of clay-brick melting holes may be advisable, since silica brick is not well adapted to endure rep eated heating and cooling. But the total life of a clay-brick melting hole is necessarily short. Again, if local conditions such as danger of flood make necessary the building of the furnace largely above ground, so that the radiation of beat is promoted, the cooling down of the furnace over the week ends, when no steel is melted, will be considerable-and the contraction of the furnace that results tends to wrack it to pieces. The character of the metal being melted affects the life of the furnace to a great extent. Low-carbon steels and steels made from iron and charcoal require higher temperatures and much longer melting tune than high-carbon steel or steel made largely from scrap; the life of the furnace will be shorter, and the number of heats melted will be much less, when such materials are melted.

Jan 9, 1913

By J. H. Gray

"IntroductionIn 1980, Fording Coal Limited started conceptual planning studies which led to major changes in the long-range mining plan at their Fording River Operations. These new plans have been completed and are now in operation.To assist personnel in a timely completion of this major revision to the long-range plan, existing in-house drill hole data base and scheduling systems were used and a computerized Mine Modelling and Planning System was purchased. With these tools, plan s were developed which led to completion of initial access to the peak of Eagle Mountain and the start of mining operations in March 1983. As mining area s open up and new geo logical data is obtained, detailed plan s are being extended and revised.With the geology and mine plan s on line, this work can now be done with less effort and plans ca n be adapted to provide flexibility in mining operations. Changes in market conditions can be accommodated by moving mining operations into different seams for different coal types. The computer systems are used to revise pit designs and schedules accordingly."

Jan 1, 1986

By R. R. Sayers

Ventilation may be defined as the process by which vitiated air of an enclosed or partly enclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level Per Cent. Oxygen.................................................. 20.94 Nitrogen................................................. 78.09 Carbon dioxide........................................... 0.03 Argon................................................... 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxide, ammonia, ozone........................................ traces Carbon Dioxide Limit For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent, carbon dioxide. Nevertheless, in mines it sometimes occurs in sufficient quantities to cause symptoms in men or even unconsciousness and death. One-half of 1 per cent. of carbon dioxide in normal air causes a slight and unnotice-able increase in the ventilation of the lungs, that is, a man exposed to one-ha,lf of 1 per cent. of carbon dioxide will breathe a little deeper and a little faster than when in pure air. If 2 per cent. of carbon dioxide is in the air, the lung ventilation will be increased about 50 per cent.; if there

Jan 1, 1927

By George H. Ashley

The Legislature of the Commonwealth of Pennsylvania at its last session passed a new act dealing with barrier pillars, which may have a wide interest in other states. In the past the laws of Pennsylvania have required that the superintendent of a mine "shall not permit the mining of coal within 50 ft. of any abandoned mine containing a dangerous accumulation of water, until said danger has been removed by driving a passageway to tap and drain off said water, as provided for in this act: Provided, That the thickness of the barrier pillars shall be greater aid shall be in proportion of one foot of pillar thickness to each one and one-quarter feet of water head, if in the judgment of the engineer of the property and that of the district inspector it is necessary for the safety of the persons working in the mine." Thus it has happened that a thickness of several hundred feet has necessarily been left in pillars in mining. It has seemed to many in the mining industry that this left an unnecessary amount of coal in pillars, and did not provide that the pillar be left equally on the two sides of the mine. As a result the General Assembly of 1927 by Joint Resolution authorized the Governor to appoint a Commission of "seven prominent citizens, of whom four shall be recognized mining engineers, one shall be a hydraulic engineer, one a geologist of recognized standing in his profession, and one a State mine inspector from the bituminous coal mining district, to investigate and report upon barrier pillars in the bituminous coal region." The Governor appointed the following Commission: Morris Coulter, Clearfield Bituminous Coal Corp., Indiana, Pa.; A. E. Roberts, Monroe Coal Mining Co., Revloc, Pa.; George T. Lewis, Westmoreland Coal Co., Irwin, Pa.; Morris Knowles, hydraulic engineer, Pittsburgh, Pa.; Thomas A. Mather, State Inspector of Mines, Tyrone, Pa.; A. B. Jessup, Anthracite Coal Operators Association, Jeddo, Pa.; George H. Ashley, State Geologist, Harrisburg, Pa. Mr. Coulter was elected Chairman and Mr. Ashley, Secretary. This Commission held meetings in Harrisburg, Johnstown and Pittsburgh. It obtained and considered the laws and experiences of other states and European countries. Some of its members conferred at length with the directors and other members of the U. S. Bureau

Jan 1, 1930

By George Young

DURING the spring of 1910 I visited a number of open-pit brown-coal mines and underground workings in the vicinity of Halle, Halberstadt, Leipsic, Cologne and Bonn. The notes which I took and the observations which I made at the time have been condensed and make up the principal part of this paper. Certain supplementary information has been taken from several sources which are given in the paper. The mining of brown coal is one of the important industries of Germany. The coal varies in color from dark brown to almost black and is soft like loam. Pieces of wood and strips of bark and, even parts of tree trunks are frequently encountered in the excavation although the coal for the most part consists of a pulverulent, more or less matted mass of small particles of vegetal matter. It is a product between peat and lignitic coal. An analysis, taken from Coal Resources of the World shows the approximate composition of the material: Moisture, 53.73 per cent.; ash, 4.98; fixed carbon, 18.08; volatile carbon, 23.31 per cent. The principal characteristic is the amount of moisture. This seldom runs less than 48 per cent. The ash is usually low and ranges from 5 to 10 per cent. The sulphur content is usually less than 0.5 per cent. The heating effect of the fuel ranges from 2,000 to 2,500 calories.

Jan 2, 1916

By Ian Campbell

THE year 1952 was marked by several new alltime highs in industrial mineral production; by an easing of the critical situation with respect such minerals as fluorspar and sulphur; by important production of asbestos, lithium, and rare earths; by the perfecting of new products which will place new demands upon industrial mineral supplies, such as "Fiberfrax", and the finding of new uses for old minerals, such as wollastonite; by continuation of basic and applied research; and publication of a notable study of the national mineral economy, viz., the "Paley Report".

Jan 2, 1953