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The National Labor Board, on June 25, ended its activities preparatory to final, dissolution by the President. No new cases will be heard nor new applications received. Controversies, jointly submitted, that could not be concluded prior to June 30, were assigned to the joint chairmen or a section of the board for disposition. The conclusion of the board's activities marks the passing of. one of the governmental agencies created during the war to further production of war materials. The board was organized under a Presidential proclamation with former President Taft and Frank P. Walsh of Kansas City as joint Chairmen, and with five members representing labor, five employers' representatives, and two members acting for the public. Mr. Walsh resigned soon after the signing of the armistice and was succeeded by Basil M. Manly of Washington. During the year that ended May 31, the hoard received 1245 cases, made awards in 462 cases, dismissed 391 for various cases, referred 315 to specified agencies, and suspended one case. Fifty-three cases remained on the docket because the hoard could not agree, and 23 cases were pending.

Jan 8, 1919

By George F. Weaton, Eugene P. Pfleider

13.4-1. History. During the past ten years the mining and production of iron ores has been through a revolution. From 1939 through 1948, which included World War II, 561,000,000 tons of iron ore was mined and shipped from Minnesota's Mesabi Range to the blast furnaces of the United States for the production of iron and steel products (20, 28, 29). The iron mining industry, anticipating the exhaustion of this highly productive source of raw material, instigated a worldwide search for new sources of iron ores. This search was highly successful, both as to quantity and quality. Venezuela (38), Canada (17, 28, 42), Peru (19, 23, 50, 52, 54, 56) Chile, (1, 66, 75), Brazil, and Liberia were among the countries where enormous deposits of high quality iron ores were discovered. The exploitation of these deposits took away the monopoly held by the Lake Superior region for so many years and created a highly competitive market for high quality natural iron ores. 13.4-2. Exploration and Development Practices. SPECIFIC TO IRON MIN- ING. American industries are motivated to continue exploration because new ore discoveries often lead to an improved competitive position with respect to raw material supply. Exploration techniques have advanced rapidly in recent years, to a degree that potentially important iron ore reserves, stratigically located, may now be detectable by application of a combination of refined and diversified geophysical exploration methods. Since the days of the dip needle, iron ore people have placed greatest reliance on the magnetometer. Its successive stages of development progressed from the balance and the torsion type to the fluxgate, and then to the "sophisticated" magnetometers-conceived and developed in th field of atomic physics. By far the greatest advancement in magnetometer prospecting was made when the self-orienting fluxgate magnetometer took to the air. This was not a new development, but it was a breakthrough in reconnaissance investi-

Jan 1, 1968

By R. Stefanko, Y. J. Wang, H. R. Hardy, R. Y. Kim

Since 1964, the Dept. of Mining at The Pennsylvania State University has been carrying out extensive studies associated with the phenomena of microseismic activity and inelastic behavior in geologic materials. Briefly, the program to date has involved the following stages 1) Study of the microseismic noise and energy rates for selected geologic materials under incremental, uniaxial tension.1,2 2) Investigation of the frequency spectra of microseismic activity of selected geologic materials under incremental, uniaxial tension.3,4 3) Investigation of the time-dependent inelastic deformation of geologic materials and the analysis of such deformation in terms of mechanical models.5, 6 4) Simultaneous study of microseismic activity and time-dependent inelastic deformation in geologic materials under incremental, uniaxial compression.7,8 Details of the research involved in stage 4 of the program constitute the subject of this chapter. It should be noted that the majority of the experimental data quoted in this chapter forms part of a thesis to be presented by one of the authors (Kim) in partial fulfillment of the requirements for the Ph.D. degree in mining engineering at The Pennsylvania State University. During the last two or three years, a number of important papers have been published which deal primarily with the fundamental structure and mechanical behavior of geologic materials. Recent papers 9,10 have provided research workers in the rock mechanics field with a meaningful overall picture of rock as a structural material. The concept that many

Jan 1, 1970

By V. Steve Reed, Ed L. Reed

The in situ leach mining process generates a waste stream that is high in sulfates, total dissolved solids, and radium 226. During the mining phase, the volume of the waste stream is relatively low and consists primarily of the bleed stream. During the restoration phase, larger volumes of waste water are generated. These waste streams require environrnentally sound disposal. The low net evaporation rate in the Coastal Bend area precludes pond evaporation as a feasible disposal alternative. Reverse osmosis is a practical method of reducing the volume of the waste water handled, but the concentrated waste stream from the reverse osmosis unit must be disposed properly. Deep well injection into highly saline reservoirs is considered a sound method of disposing of the liquid waste generated by in situ mining in the Gulf Coast uranium district. Thirteen injection wells have been permitted to serve the disposal needs of the leach mining industry in Texas. Of these 13, 11 have actually been drilled. Seven applications are pending. The injection zones for the permitted wells range from depths of 3050 to 6200 feet. Pressure limitations imposed on these wells range from 500 psi to 1350 psi. The following criteria are used to determine the desirability of a disposal well site: 1. A minimal number of nearby, improperly plugged borings which penetrate the disposal zone; 2. Minimal crustal disturbance; 3. Sufficient salinity of the water contained in the disposal zone; 4. Protection of oil and gas producing zones; and 5. Sand of sufficient permeability and areal extent to handle the desired volume without fracturing the reservoir. 1. Improperly plugged borings: During the early part of the century, oil wells, gas wells and test holes were drilled using cable tool equipment, often with a minimum amount of surface casing. Production casing, when it was set, was often partly removed when the holes were abandoned. Thus, wells drilled prior to 1940 frequently have less than 100 feet of surface casing and either no production casing or the upper part of the production casing removed. Additionally, these holes are often plugged only with mud. The close proximity of these holes to an injection well location are a concern in that they can provide an avenue for injection-depth fluids to migrate up the bore hole and jeopardize shallower fresh water reservoirs. Usually, where there are more than 6 or 8 poorly plugged borings in a 2 1/2 mile radius of the well site, it is preferable to examine deeper zones for disposal well potential. The deeper zones are especially attractive where the borings are not in a cluster, which renders monitoring more difficult. Often, even the deeper disposal zones are penetrated by a few improperly plugged borings. When this condition arises, the potential for leakage through the borings can be addressed in the following ways. a. Demonstration that the static head in the boring is higher than the anticipated increase in bottom hole pressure generated at the boring by the disposal well. A 100 psi differential between these two pressures is recommended. The calculated increased pressure at a boring caused by injection should be refined using annual bottom hole pressure measurements in the disposal well. Figure 1 illustrates an injection pressure map which can be overlain on the oil well map to determine the anticipated increase in pressure expected at each oil, gas or abandoned hole. b. Shallow ground water monitoring. A shallow monitor well is drilled next to the boring and both pressure and quality measurements are made periodically in the shallow well. c. Disposal zone monitoring. Recently there has been a tendency for regulators to require disposal depth monitor wells instead of shallow well monitoring. We consider disposal depth monitoring to be a less effective method of monitoring because it provides only indirect evidence of potential problems. Assumptions have to be made for the unplugged borings, such as mud weight, that are not addressed by the disposal zone monitoring program. There is little improvement with this system to that discussed in "a" above. A shallow zone monitoring program, however, yields direct evidence of a developing problem with an unplugged boring. Leakage by the boring will be detected quickly by an abnormal increase in pressure in the shallow well. Quality monitoring will detect upward migration of poor quality fluids. The pressure data provide an early warning of impending leakage; the quality monitoring will detect actual fluid migration.

Jan 1, 1980

By W. W. Mason

The US began exporting coal in the late 1800s, at first in very small quantities to Canada and, beginning in 1897 and 1898, to the east coast of South America. Shipments to European countries began on a very limited basis in 1902 and these shipments increased gradually until World War I when shipments overseas increased from 7.3 Mt/a to 20 Mt/a. After the war exports dropped as fast as they had increased and, with the exception of exports to Canada, remained at very low levels until just after World War II when the US again emerged as a major coal exporter. World War II left the coal industries of Europe in ruin. As the US was the only country able to supply large quantities of coal at reasonable prices needed for reconstruction of the European economy, the US coal exports overseas expanded rapidly to 38.6 Mt in 1947. Additionally, we shipped 23.8 Mt of coal to Canada in that year for a total export of 62.3 Mt. Unfortunately, that level was not reached again until 1957 when exports reached an all-time high of 69.3 Mt - a high that has not been reached since. Over the years the level of US coal exports has fluctuated fairly widely. Approximately 80-90% of all US coal exports are high quality metallurgical grade coal so our exports level depends directly on world-wide economic conditions and world steel production levels.

Jan 1, 1982

The engineering personnel shortage, present and impending, so well brought out in the article in Mining Engineering in the August, 1951 number, both in the editorial lead and the article by William B. Plank and Henry J. Petrie, has left untapped and has ignored a potential source of supply that would fill the need ably and with complete satisfaction. This source is comprised of the women engineers- and geologists, both presently, trained and able to handle work at all levels, and the many who would make splendid engineers and geologists if they could hope for even a modest taste of the square deal that should be theirs, but, as we all know, is not. I write from experience. It is not pleasant or sensible to have to urge borderline cases among men students to consider engineering and geology as careers to fill the need, when I have far more able, interested and suited young women students whom I must divert into other channels. It does not make sense to scrape the bottom and sides of the barrel to induce potentially second or third rate male engineers and geologists to enter the profession when we have superior material among the women, eager to do good work in these fields. It does not make sense for these men to become second or third rate in these fields when they might be first rate salesmen, musicians, advertising copywriters or policemen. Nor does it make any more sense to force potentially first rate female geologists and engineers to become second or third rate and very frustrated typists, kindergarten teachers, dress sales-women or clerks. At this point I am willing to admit that where superstitious -miners object to women in underground workings, men are available for the jobs. Moreover, it is not necessary for women to be sent into the most difficult country, if there is reluctance on either side of the contract. There may be fewer of them eager for the roughest assignments, in proportion to the men, but women are so accustomed to discrimination far more complete than that against any racial or religious group, that a reasonably tough assignment would seem like a heaven-descended joy. In my own experience, I have found that my girl students majoring in geology, could keep up with me in the field in the roughest terrain, but. the men, all but the best students and the most physically fit young men, complained that they could not keep up with me and that I always "walked their-legs off. The women, a few men and I always returned with bags heavy with well chosen specimens and proper notes. Most of the men carried no specimens and-but poor scraps of notes on loose bits of paper. Yet the men were urged to prepare for a career in engineering or geology if their examination marks were reasonably good. When we find that we still have a shortage of engineers and geologists, after putting all the qualified women to work, then we may begin to worry. Until then, we are simply fooling ourselves as we wander in, a forest of outmoded tradition and emotional habit reactions. MARY W. GARRETSON ASSOC. MEMBER, AIME SCARSDALE, N. Y.

Jan 1, 1952

By F. W. Bloecher

D ETERMINATION of the surface area of finely divided minerals is of interest to mineral engineers engaged in flotation, comminution, and dewatering studies. In the industrial minerals field, many materials are classified as to fineness according to their specific surface (surface area per unit weight). A method of surface area determination has been tested and used in the Richards Mineral Engineering Laboratories at M.I.T. It involves low temperature krypton adsorption measurements using the technique described by Beebe.1

Jan 3, 1951

By Henry A. Ley

Oklahoma produced about 40,000,000 bbl. less crude oil in 1930 than it did in 1929, but developed the largest initial production from current well completions ever recorded in its history. The output of this year would have exceeded all previous years had it not been for state-wide production curtailment. The record initial production of 5,911,982 bbl. from new oil wells completed during the year is accounted for entirely by the rapid development of the Oklahoma City field. Completions declined to the lowest levels since 1909, as a result of a marked reduction in number of dry holes incident to reduced wildcat exploration. Leasing was most active in western and northern counties of the state west of Oklahoma City, but on a much smaller scale than in the preceding year. Geological and geophysical surveys were likewise most active in this western territory. The urge to deeper objectives resulted in the discovery of oil on the Cement fold. Changing economic conditions have created a distress situation among the marginal operators in northeastern localities of the state. Elsewhere in the state production records and successful exploitation of new supplies have been eclipsed by a new social concept of the industry in accord with natural economic developments. Many of the producers of crude oil have organized for a voluntary stabilization of the industry by regulating the output of wells. To enforce their measures these operators have sought for and secured the support of the state. Consequently, the current position of the crude-oil producer is not unlike that of the natural-gas producer—withdrawal of supplies in accordance with market needs. And while the industry as a whole is artificially stabilized by these measures individual operators and some of the integrated concerns suffer hardships. Oil Developments and Production The early operations in Oklahoma were confined to northeastern and eastern localities, beginning in 1885. The first commercial oil wells were completed in 1894, near Chelsea in Craig County, from Cherokee sands in the lower portion of the Pennsylvanian section. Scattered

Jan 1, 1931

By W. L. Zeigler

THE year 1930 in the Ceur d? Alene district was one of curtailment in production. Many of the small properties were closed entirely and only three large. producers, the Bunker Hill & Sullivan, Hecla, and the Morning mines were left producing at capacity. No innovations in milling were evident, but progress was made in reducing costs as is always necessary in times of low metal prices. One new concentrator was constructed, a 500-ton daily capacity selective flotation plant for, the Jack Waite Mining Co. This mill uses coarse crushing, followed by hand sorting, for both a high-grade ship- ping ore and waste. The remainder of the ore leaving the sorting belt is crushed in a new type Traylor reduction crusher to %-in. size and stored in large capacity mill ore-bins. The grinding is done with ball mills, in closed circuit with a Dorr classifier to 75 per cent - 200 mesh. Minerals Separation 24-in. flotation machines are used both for a lead and a zinc concentrate, with double cleaning in each case. The concentrates are dewatered in Dorr thickeners and filtered on Oliver late-type filters.

Jan 1, 1931

By Linda P. Bono

Some mining engineers are pursuing their destinies in places far removed from what they might have envisioned back in the classroom. The path they follow to work each day may wind down Wall St., Park Avenue, LaSalle, or Market; their offices are in modern skyscrapers which offer all the amenities-air conditioning, thick carpets, attractive decor, and executive lunchrooms, to name just a few. The papers on their desks are a combination of financial figures and feasibility studies. But even in these surroundings there are indications of what these men do and where their professional interests lie-minerals are everywhere, from vast collections to one symbolic paperweight. . . there are sometimes specks of dirt under fingernails from a recent on-site inspection, belying the traditional banker's garb. . . and there are the wistful comments about finding it necessary to get out in the field.

Jan 9, 1978

By W. D. Ludemann, J. E. Dor, L. A. Shepard

Recovery of the creep resistance of 99.99 pct pure Al was studied at temperatures 540°, 573°, 600°, and 611°K. Poly-crystalline specimens crept under a stress of 950 psi to a strain of 5.5 pct were allowed to recover for periods of from 1 min to 16 days under a residual stress of 4.4 psi. Increased creep rates upon reapplication of the 950 psi stress evidenced softening of the material. The activation energy for the recovery process was found to be 64,000 cal-per mol. THREE major observations have clearly revealed that the creep of polycrystalline aluminum above about 510°K is controlled by the rate of climb of jogged edge components of dislocations past the barriers impeding their motion: 1) Extensive polygonization, characteristic of climb, takes place during creep.'9' 2) The activation energy for creep equals the estimated activation for self-diffusion. 3) The stress law for creep coincides with theoretical predictions based on the climb mechanism.4,5 The decreasing rate during the primary stage of creep must be ascribed to the introduction of additional barriers to the glide of dislocations. During secondary creep the density of barriers must remain constant, the rate at which new barriers are formed being equal to the rate at which they recover. For this reason the nature of the barriers, and their rates of formation and recovery, are significant to a complete understanding of creep. It is proposed here to study the kinetics of the recovery of barriers to creep of high-purity polycrystalline aluminum in the climb range. The technique will consist of creeping a series of tensile specimens under a prescribed stress to given state following which the specimens will be recovered for various times and temperatures under approximately zero stress. The amount of recovery will be determined by comparing creep curves following the recovery. EXPERIMENTAL PROCEDURE The material used for this investigation was a 99.99 pct pure Al supplied by the Aluminum Co. of America in sheets of 0.001-in. thickness having an H-18 temper. The spectroscopic analysis of impurities gave Cu-0.004 wt pct, Fe-0.002 pct, Si-0.001 pct, others-0.000 pct. Creep specimens were machined with their tensile axes in the rolling direction of the sheets. Annealing in a molten potassium nitrate-potassium nitrite bath for 1 hr at 686K, followed by air-cooling, resulted in a grain diameter of from 0.22 to 0.27 mm. Creep machines were equipped with constant stress lever arms of the type suggested by Fullman, Carreker, and Fishher,' which maintained the applied stress to within 0.04 pct of the reported value of 950 psi. Creep strains were calculated from extensions over a 6-in. gage section to the nearest 3 X 10"5. The temperatures of testing, 540°, 573", 600°, and 611°K, were obtained by immersing the specimen and extensometer assembly in a molten KNO2-KNO3 bath. Temperatures during the periods of creeping could be maintained constant to within better than ± 1°K. Correlation of creep data at different temperatures of testing demanded the use of an appropriate temperature-compensated time 8. Previous investigations have shown that the creep of pure metals at temperatures above about 0.55 of their melting temperatures can be correlated by the functional relationship3" e=f(0), s= const. [1] where e = total plastic strain during creep f = a function that depends on stress a = stress 6 = te-Q/RT = a temperature-compensated time t = time under test Q = 35,500 cal per mol = activation energy for creep R = gas constant, and T = absolute temperature In the present series of tests all of the creep was conducted under the same stress of 950 psi. To provide identical initial conditions for the recovery all specimens were first crept to a temperature-compensated time of = 47 X 10-14 min which resulted in a creep strain of 0.055 + 0.005 regardless of the creep temperature. During recovery, a small stress (4.4 psi) was permitted to remain upon the specimens to maintain tautness in the pulling assembly and to prevent mechanical damage to the soft specimen. After each recovery period, the full stress was reapplied and

Jan 1, 1961

By Bernard Greifer, Walter Rose

The purpose of this note is to call attention to a source of difficulty which can be responsible for inaccurate estimates of wetting liquid pressure gradients in mixture flow experiments of the Hassler1 type. It has been our experience occasionally to observe what were indicated to be negative pressure gradients, and these were regarded as anomalous in the sense that physically they seemed to contradict the requirement that the flux be in the direction of the potential field. At first it was thought that our scheme of assembling barriers and core sample led to such asymmetry in the distribution of isobars that the manometric leads at each end of the core were responding to internal pressures (within the core sample) which could be either positive or negative with respect to each other, and which in fact might tend to reflect on different effective core lengths in an unpredictable fashion as the wetting liquid saturation was changed. However, no compelling evidence of this possibility has been established. In addition, we were cognizant of the requirements to be satisfied in selecting manometric instrumentation to minimize the delay in response of the manometer to the differential pressures being measured, and were thus assured that our observations of anomalous pressure gradients could not be explained by faulty instrumentation. What we suggest is that if a leak sink occurs in the fluid lines connecting the core to either side of the differential manometer, errors exceeding 100 per cent may result in the estimation of wetting liquid pressure gradient, even though the leak is of such small magnitude that its existence would tend to be obscured by evaporation effects. This is because in a system with leaks at the specified places, the manometer rec- ords at steady state the pressure drop across the manometer barrier elements in addition to the pressure drop across the core sample. This possibility will be illustrated below analytically and by numerical example for the special case where the leak occurs on the high presure side of the core, since we are especially desirous to explain the significance of our observations of the so-called negative pressure gradients. It will be indicated, however, that leak sinks on the low pressure side of the core can account for observations of anomalously high values of pressure gradient, and that multiple leaks on both sides of the core can provide for some compensation so that the errors in pressure estimation are reduced. However, the major point to be emphasized is the fact that the impractical-ity of detecting the small leak sinks which give rise to the difficulties makes it a complicated task for the experimenter in a particular case to know with certainty that his estimation of pressure gradient lies within the limits of error which can be tolerated. Fig. 1 shows the electrical analog of the flow system we have employed in our studies. The inflow and outflow barriers. Rbl and Rb2, the manometer barriers, Rm1, and Rm2, and the core sample, Rc— for a particular fluid saturation and distribution— are all designated as resistance elements; the flowmeter is designated by an ammeter, A; the pressure source is designated by E; and the manometric device is designated by the voltmeter, V. Included in the circuit are the variable resistances, Rx and Ry, which may be regarded as the leak sinks, and which, in general, can vary in magnitude from zero (i.e., a large hole or shunt in the system) to infinity (i.e., no

Jan 1, 1950

By V. H. Wilhelm

Drilling activity in California during 1939 decreased approximately 15 per cent from that of the previous year. New reserve discoveries were the lowest in many years, but extensions, development of deeper sands, and reappraisals, indicated enough new potential to more than equal 1939 withdrawals of about 223,644,000 barrels. On June 1 a new uniform method of allocation was adopted, which had the immediate effect of reducing production, so that approximately 6,000,000 bbl. of crude were withdrawn from storage during the year. Market demand averaged 628,845 bbl. per day as compared with a daily production of 612,945 barrels. The rate of drilling was slow during the first five months because of the unfavorable storage situation. Subsequent to the adoption of the new uniform method of allocation on June 1, drilling was speeded up and continued at a rapid rate throughout the remainder of the year. As a result of prospecting, four new fields were discovered and seven fields were measurably extended. All of the new discoveries were made in the San Joaquin Valley. Statistics of production and development arc given in Fig. 1 and Tables 1 to 3. New Discoveries Coalinga-Northeast.—The Amerada Petroleum Corporation discovered a second Eocene shore-line field north of the Coalinga Nose when it brought in well S.P.L. 7-17 in sec. 17-19-16, flowing 4230 bbl. of 32.4" gravity oil and 14,200,000 cu. ft. of gas at a depth of 8237 ft., from the "Gatchell" sand of Eocene age. This field, 2 miles north of the Coalinga Nose field, is considered to be a separate structure because it has a gas cap and a lower water table. The structure is a broad, gentle anticlinal nose probably separated from the southerly Coalinga Nose field by a shallow syncline. Production is sealed updip by the pinching out of oil sands. The average sand thickness is approximately 200 ft., the top 75 ft. containing mainly gas. The sand has an average permeability of 1000 millidarcys and an average porosity of 25 per cent. The productivc area of the field is estimated to be between 1200 and 1500 acres.

Jan 1, 1940

By V. H. Wilhelm

Drilling activity in California during 1939 decreased approximately 15 per cent from that of the previous year. New reserve discoveries were the lowest in many years, but extensions, development of deeper sands, and reappraisals, indicated enough new potential to more than equal 1939 withdrawals of about 223,644,000 barrels. On June 1 a new uniform method of allocation was adopted, which had the immediate effect of reducing production, so that approximately 6,000,000 bbl. of crude were withdrawn from storage during the year. Market demand averaged 628,845 bbl. per day as compared with a daily production of 612,945 barrels. The rate of drilling was slow during the first five months because of the unfavorable storage situation. Subsequent to the adoption of the new uniform method of allocation on June 1, drilling was speeded up and continued at a rapid rate throughout the remainder of the year. As a result of prospecting, four new fields were discovered and seven fields were measurably extended. All of the new discoveries were made in the San Joaquin Valley. Statistics of production and development arc given in Fig. 1 and Tables 1 to 3. New Discoveries Coalinga-Northeast.—The Amerada Petroleum Corporation discovered a second Eocene shore-line field north of the Coalinga Nose when it brought in well S.P.L. 7-17 in sec. 17-19-16, flowing 4230 bbl. of 32.4" gravity oil and 14,200,000 cu. ft. of gas at a depth of 8237 ft., from the "Gatchell" sand of Eocene age. This field, 2 miles north of the Coalinga Nose field, is considered to be a separate structure because it has a gas cap and a lower water table. The structure is a broad, gentle anticlinal nose probably separated from the southerly Coalinga Nose field by a shallow syncline. Production is sealed updip by the pinching out of oil sands. The average sand thickness is approximately 200 ft., the top 75 ft. containing mainly gas. The sand has an average permeability of 1000 millidarcys and an average porosity of 25 per cent. The productivc area of the field is estimated to be between 1200 and 1500 acres.

Jan 1, 1940

By R. Clare Coffin

The production of oil in the Rocky Mountain district, including southeastern New Mexico, increased from 33,048,630 bbl. in 1930 to 34,325,163 bbl. in 1931. This increase was due to production in New Mexico, which exceeded the 1930 figure by approximately 5,000,000 barrels. Total production by fields is given in Table 1. Exploration during 1931 resulted in the discovery of a new oil-producing horizon in the Big Muddy field in Natrona County, Wyoming, and ' the discovery of a new gas pool in the Powder Wash structure, Moffat County, northwestern Colorado. Gas was discovered also in the Frontier sands of the Bunker Hill dome, Carbon County, Wyoming, but no test has yet been made by which to determine the significance of this discovery. All other exploration which resulted in increasing the known reserves of oil and gas in the district was confined to drilling in partly outlined fields where known limits of production were extended. During the year two major gas pipe lines were completed in western Montana, and one in southwestern New Mexico was extended into Arizona. One new project involving the marketing of natural gas from Wyoming fields included the conversion of an existing oil line to a gas line to serve towns in southeastern Wyoming and western Nebraska. Colorado The decline of 132,501 bbl. in the production of oil in the Colorado fields during 1931 from the figure of 1930 is due to the natural decline of existing wells, partly offset by the increased production in the Greasewood area. New exploration was limited largely to northeastern Colorado, where attempts were made to find oil in areas adjacent to the Grease-wood field. Powder Wash, Moffat County.—The Ohio Oil Co. is to be credited with the discovery of a gas field in the Power Wash structure in Moffat County, Colorado. The initial well drilled in sec. 5-11-97 encountered a sand at a depth of 2152 ft. which produced 34,188,000 cu. ft. of gas on an open-flow test. The rock pressure was reported as 630 Ib.

Jan 1, 1932

By E. Z. Lajtai

The probability distribution of fracture data from a rock mechanics test contains information about the effectiveness of the testing procedure and/or about the nature of the operating failure mechanism. The tensile strength of Lac du Bonnet granite forms a bimodal probability distribution when determined through line loading as in the Brazilian test. The same data obtained from three point bends tests are unimodal. The bimodality can in part be removed by distributing the line load over a finite area. Moisture has the anticipated effect in lowering both the average compressive and the average tensile strength of Lac du Bonnet granite. The reduction in strength however is not uniform within the probability distribution; the change is the largest at low and the smallest at high strength. Conversely, long-term loading is more damaging to the high strength members of the distribution. The large scatter of failure times in static fatigue experiments can in part be removed or even utilized when the probability distribution of instantaneous strength is taken into account.

Jan 1, 1982

Jan 1, 1920

By H. J. Hager, P. H. Haskell

For the past 20 years Alabama has probably led all other coal-producing districts in the proportion of coal prepared by wet washing. All rail mines, with one exception, and a high percentage of truck mines now wash all coal under 3 or 4 in. Most of this coal has been cleaned by jigs, though within the past few years one or more wet-table plants have been installed for cleaning some of the coal from practically all the major seams. These tables supplement either single or multicell jigs usually for one of the following purposes: (I) to wash the finer sizes of raw coal, (2) to rewash the finer sizes of washed coal after they leave the jigs, (3) to re-treat jig middling products. The main purpose of this paper is to present cleaning data and operating factors involved in the preparation by tables of the finer sizes of raw coal. The specific information and data pertain to the Mary Lee seam of coal as extracted at three of the mines of the Alabama By-Products Corporation, which produces coal for both byproduct coke-oven consumption and the general steam market. The Mary Lee seam has long been recognized by coal-preparation authorities as presenting a very difficult ash-reduction problem. Washing characteristics and physical structure of the seam vary widely. Its thickness ranges from 32 in. with no rock parting to 100 in. with from one to three partings. Over the entire field the bed contains bands of bone and rash. These are distributed throughout the seam cross section. A portion of this bone or bony coal occurs as definite bands I in. or more thick; however, some bone is interlocked as layers within the coal and consequently breaks into flakes when the coal is broken. This material is relatively high in ash and its specific gravity varies widely. It has been observed that in most cases in the washing of Mary Lee coal from 10 to 18 per cent of the raw coal is within +0.10 specific gravity of the attempted point of separation. Therefore with the average wet jig, only with extreme difficulty can a low-ash product be obtained without loss of much marketable coal in the refuse. Without entering into the controversial question as to whether modern washing equipment can efficiently handle simultaneously all sizes up to a given maximum, suffice it to state that the comparatively old-type jigs in service at the Alabama By-Products Corporation's mines could not clean the he sizes satisfactorily. Therefore, in 1931 that company installed six diagonal-deck tables at the Barney mine, which were installed as an addition to a complete plant cleaning all coal below minus 3 in. The primary washed product is shipped as steam coal and another portion may be prepared as washed nut for domestic trade. These tables are washing 9 tons per hour of raw coal sized to ¼ in. to o. The washed table coal is mixed with the 3 to ¼-in. jig product to constitute a 3 in. to o steam coal.

Jan 1, 1942

By H. J. Hager, P. H. Haskell

For the past 20 years Alabama has probably led all other coal-producing districts in the proportion of coal prepared by wet washing. All rail mines, with one exception, and a high percentage of truck mines now wash all coal under 3 or 4 in. Most of this coal has been cleaned by jigs, though within the past few years one or more wet-table plants have been installed for cleaning some of the coal from practically all the major seams. These tables supplement either single or multicell jigs usually for one of the following purposes: (I) to wash the finer sizes of raw coal, (2) to rewash the finer sizes of washed coal after they leave the jigs, (3) to re-treat jig middling products. The main purpose of this paper is to present cleaning data and operating factors involved in the preparation by tables of the finer sizes of raw coal. The specific information and data pertain to the Mary Lee seam of coal as extracted at three of the mines of the Alabama By-Products Corporation, which produces coal for both byproduct coke-oven consumption and the general steam market. The Mary Lee seam has long been recognized by coal-preparation authorities as presenting a very difficult ash-reduction problem. Washing characteristics and physical structure of the seam vary widely. Its thickness ranges from 32 in. with no rock parting to 100 in. with from one to three partings. Over the entire field the bed contains bands of bone and rash. These are distributed throughout the seam cross section. A portion of this bone or bony coal occurs as definite bands I in. or more thick; however, some bone is interlocked as layers within the coal and consequently breaks into flakes when the coal is broken. This material is relatively high in ash and its specific gravity varies widely. It has been observed that in most cases in the washing of Mary Lee coal from 10 to 18 per cent of the raw coal is within +0.10 specific gravity of the attempted point of separation. Therefore with the average wet jig, only with extreme difficulty can a low-ash product be obtained without loss of much marketable coal in the refuse. Without entering into the controversial question as to whether modern washing equipment can efficiently handle simultaneously all sizes up to a given maximum, suffice it to state that the comparatively old-type jigs in service at the Alabama By-Products Corporation's mines could not clean the he sizes satisfactorily. Therefore, in 1931 that company installed six diagonal-deck tables at the Barney mine, which were installed as an addition to a complete plant cleaning all coal below minus 3 in. The primary washed product is shipped as steam coal and another portion may be prepared as washed nut for domestic trade. These tables are washing 9 tons per hour of raw coal sized to ¼ in. to o. The washed table coal is mixed with the 3 to ¼-in. jig product to constitute a 3 in. to o steam coal.

Jan 1, 1942

By H. F. JR. Miller

(Butte Meeting, August, 1913.) THE major cause of the deterioration of the open-hearth furnace as its length of service increases, is the melting down, or rather the slagging, of the checker-brick, together with the deposition of dirt in the form of iron oxide, etc., which helps to close the openings, as well as to slag the brick by chemical action. Any construction that will do away with the necessity of having the waste gases come down through the checkers will eliminate the main reason for their deterioration. There are some other well-defined reasons which are subordinate to the main one given above. Some of the defects of the present type of regenerator chambers are as follows: 1. The checkers cannot be cleaned while the furnace is in operation, nor can they be cleaned at the end of the run without taking out all of the checker-brick. This causes high costs for labor and brick. The labor cost is high because all checker-brick have to be handled twice. The brick cost is high because many of the bricks are spalled in the double handling, rendering them useless because a spalled brick will not stand up. 2. The top courses of brick become coated with iron oxide, etc., melt clown, and large amounts of dirt are deposited throughout the checkers, especially at the bottom. The draft of the furnace is decreased by the closing of the top and bottom openings, especially the top ones, and the entire working of the furnace is affected. If an effort is made to clean the checkers the dirt and brick falling down into the holes still further diminish the draft. 3. The distribution of the air or waste gases through the checkers is in many cases uneven, resulting in a lower temperature of pre-heated air and therefore a slower working furnace. Also, the passage of air and waste gases is so crooked that sometimes the chimney is not powerful enough to overcome the friction.

Jan 6, 1913