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By Chuanyao Sun, Zhenguo Song, Aijun Ren

"Lead-Zinc sulfide ore containing carbon is one of typical refractory resource. Because organic carbon has natural floatability, it has a great negative influence on flotation of lead-zinc sulfide ores. It is difficult to obtain qualified lead concentrate by flotation using conventional reagent system. In order to reduce the influence of organic carbon on lead and zinc flotation, two alternatives, i.e., removal carbon by pre-flotation or adding carbon depressant in lead and zinc flotation, can be adopted. If the flowsheet of removal carbon by pre-flotation is adopted, the lead and zinc recovery which are lost in the carbon tailings is often higher. If conventional carbon depressants are used in lead and zinc flotation, it has a certain depression effect on lead minerals. In the paper, the ore grading 1.49% Pb, 5.73% Zn, and organic carbon 3.14% has been carried out by flotation tests. In the bulk flotation of carbon and lead minerals, Pb concentrate is only about grading 21.00% Pb. In the pre-flotation of organic carbon, it’s hard to remove most of carbon, and the loss of Pb and Zinc recovery is too much in carbon tailings. New carbon depressant BK547 and three conventional carbon depressants including sodium lignosulphonate, Fe-Cr-lignosulfonate, and dextrin, are used in comparative tests of Pb flotation, and results show that BK547 have a good depression on organic carbon, and have almost no effect on Pb flotation. Using BK547 as carbon depressant, cycle test in flowsheet of two-stage Pb and Zn selective flotation and coarse concentrate regrinding have been carried out, and results show that concentrates grading 62.51% Pb and 41.33% Zn are obtained at recoveries of 70.24% Zn and 83.58% Zn.INTRODUCTION Lead and zinc mineral resources are still the main source of lead and zinc metal. For lead-zinc sulphide ore, lead concentrate and zinc concentrate are obtained by flotation. Minerals separation by flotation is a complex process and is dependent, along with other factors, on the relative distribution of hydrophobic (e.g. collector, polysulfide, elemental sulfide) and hydrophilic (e.g. metal hydroxide) species between different particles of the same mineral phase and between mineral phases (Piantadosi & Smart, 2002; Boulton, Fornasiero & Ralston, 2003). Organic carbon has natural floatability and is often associated with lead-zinc sulphide ores. If the content of organic carbon in the ore is more, the flotation index will become worse. The main problem is that the concentrates has too low grade to be qualified grade products for sale. At the same time, the consumption of reagents is more than ordinary ores without organic carbon. In order to solve the influence of organic carbon on the flotation of lead and zinc and other sulphide ores, a lot of research works have been carried out."

Jan 1, 2018

By O. K. Riegger, L. H. Van Vlack

The median angle of relatively few two-dimensional observations provides a satisfactory value for dihedral angle determinations. Those data that contain bimodal or non-equilibriated dihedral angle distributions are readily detected. THIS paper is concerned with a statistical simplification for determining dihedral angles in solids. Microstructures are partially controlled by relative energies of interphase boundaries and grain boundaries. smith1 has shown rather conclusively that such boundaries may be equilibrated to give a vectorial balance at grain and phase edges. Thus if an accurate measurement is made of the dihedral angle associated with grain and phase edges, an accurate calculation of the relative energies may also be made. The accurate measurement is difficult because the dihedral angle involves two planes in three dimensions, and only a two-dimensional cut through the dihedral angle is usually observed. Such a two-dimensional cut is statistically random provided there is no preselection or orientation. Harker and parker2 have shown that the mode of the frequency distribution of observed angles is within 5 deg of the true angle if the true dihedral angle is 120 deg. smith1 had calculations made to show that the same generalization could apply to dihedral angles of 30, 60, 90, and 150 deg. This procedure of requiring the determination of the statistical mode is time consuming because experience has shown that more than 200 angle observations are necessary before the mode is clearly indicated. It is possible to determine the dihedral angle with equal accuracy with only 25 angle observations if the median angle is used in place of the mode angle. Use is made of Harker and parker's2 basic equation tan =2 sin x cos

Jan 1, 1961

By S. Froes

Official daily output of the Reconcavo (Bahia) oil fields, which amounted to 300 bbl., increased by the end of 1944 to 500 bbl. The new productive wells are in the district of Candeias. This figure is expected to further increase during 1945. The Itatig Company, which had drilled five wildcats in the state of Sergipe, stopped in 1944, but intends to resume work during the current year, or as soon as the war is over, in order to try the Cretaceous areas around its salt deposits. Several concessions applied for in the states of Sao Paulo, Parana arid Santa Catarina were favorably considered by the Conselho Nacional de Yetroleo, which is interested in fostering prospecting activities in the country. Several national groups are interested in exploring the federal gas field of Aratu (Bahia), a proposal having been made to use the gas in the manufacture of Portland cement. Undoubtedly the most important fact in the 1944 activities was the visit by two outstanding petroleum geologists, who had the opportunity to examine some of the principal areas and reported their opinions to the Brazilian Government. By special courtesy of the U. S. Government, Mr. E. DeGolyer spent a few weeks inspecting the gas and oil fields of the so-called "Reconcavo" of Bahia (a large tract surrounding All Saints Bay, on whose shore lies the city of Salvador) Later he exchanged ideas with Colonel Joao Carlos Barreto, President of the Conselho Nacional de Petrolco, as to the most adequate measures to develop production. Considering the oil problem in the southern part of Brazil, in the sedimentary belt including formations from the Devonian to the Triajsic, Mr. DeGolyer suggested a visit there by Mr. Lemis MacNaughton. The latter traveled during the months of June, July and August, accompanied by Brazilian geologists Avelino de Oliveira, Vice-president of the Conselho Nacionial de Pctroleo, Pedro Moura, Annibal Bastos, Burdot Dutra and J. Felicissimo, and verified the actual possibilities of the region, thus confirming the opinion of Pedro Moura, Avelino de Oliveira and Froes Abreu as to the advisability of thoroughly prospecting the south of Brazil. It is to be hoped that on the recommendation of these proficient American experts the Brazilian Government will take the necessary measurcs to carry out a complete search 01 such areas, which hitherto have been unsuccessfully drilled because knowledge of the structure was not adequate. The old Government policy of monopolistic essence has now given way to the more enlightened tendency of reconciling official action with private enterprise, which should in no way be curbed but rather encouraged. Such trend is heartily welcomed by financiers and technicians alike, who realize how indispensable is the cooperation of private capital, both national and foreign, in

Jan 1, 1945

By A. W. Khair, M. Ahmad

"Bit wear has been proven to have a significant effect on respirable dust generation in coal cutting system. The mechanism of bit wear can be adhesion, abrasion. oxidation, or diffusion. depending on cutting conditions. This paper presents a portion of an extensive ongoing series of studies to better understand the principles of bit wear and dust generation. Used bits collected from underground coal mines were analyzed to identify the basic principle of bit wear in coal and rock cutting. Distribution of weight loss and conical height loss of worn bits were studied and bit wear was divided into four stages according to weight loss. Utilizing these worn bits, Laboratory experiments have been carried out to study the effects of bit wear on coal cutting system and respirable dust generation. An Automated Rotary Coal Cutting Simulator was use to perform the experiments. Acoustic emission monitoring is applied to study the effect of bit wear on fracture formation and dust generation. INTRODUCTIONContinuous miners were introduced in the 1950’s and became the major equipment in underground coal production. Now the larger production in the coal industry has increased the demand for continuous miners and their use. It is well known that serious dust problem is also introduced with the use of continuous miners, especially with recent increase in productivity. On the other hand, legal restrictions are made ·more strict by the Mine Health & Safety Administration for the respirable dust generated by the continuous miners to prevent coal workers from incidence of pneumoconiosis. The incidence of pneumoconiosis depends on dust concentration, exposure time, and physical properties of dust. Of them, dust concentration is the best parameter for the assessment of the risk of pneumoconiosis. Although a lot of research work has been done to reduce dust concentration substantially, some areas are still required further investigation to meet the strict regulations. One of the areas is about bit wear and dust generation. In this area, the principles of bit wear and effect of bit wear on dust generation are major concerns."

Mar 1, 1992

By J. Szekely, R. G. Carr

A method is presented which allows the extension of the Ergun equation for the description of gas flow through packed beds in a nonisothermal regime. The pressure profile in the packed bed is calculated by the establishment of a differential energy balance and the iterative integration of the integral equation thus obtained. The predicted values of the pressure distribution were found to be in excellent agreement with those measured experimentally, under carefully controlled conditions. MANY metallurgical processes are carried out in systems in which a gas stream and particular solids are contacted in a packed bed arrangement under strongly nonisothermal conditions. Ore sintering, the firing of pellets, the operation of regenerators, blast furnace technology may be quoted as examples. Although many aspects of these systems have been extensively studied, an important variable, the pressure distribution and the relationship between pressure head and flow rate, received only little attention to date. The purpose of the paper is to present a brief survey of relevant previous work, followed by a more rigorously formulated model, together with experimental results that afford ready comparison of theoretical prediction with measurement. PREVIOUS WORK A great deal of information is available in the chemical engineering literature on flow phenomena in porous media.' The experimental results pertaining to gas flow were generally interpreted in terms of models based on the analogy with the flow through a pipe of an incompressible, isothermal fluid. Of the numerous, semiempirical correlations that have been proposed to relate pressure drop to the volumetric flow rate, the Ergun equation2 is generally regarded as the most satisfactory: The strong nonisothermality of the metallurgical systems previously mentioned would render the direct applicability of Eq. [I] rather doubtful as both density and viscosity are temperature-dependent. Ergun has used Eq. [I] for estimating the pressure drop in the stack region in the blast furnace by neglecting the viscous term and evaluating the gas density at the integral mean temperature.3 His calculations showed a rather variable agreement with measurements and it was uncertain whether the discrepancy found was attributable to the model or to the inaccuracies often inherent in measurements on an industrial scale. Other work on nonisothermal systems includes studies of the pressure distribution in sinter beds, notably by Voice et a1.4 and Mitchell.5 Mitchell developed a method involving the subdivision of the bed into several zones and assigning average property values (temperature, gas density, and so forth) to each zone. The pressure drop was then calculated for each zone by using an expression analogous to Eq. [I]. This method was an improvement over that described by Voice et al., but even here prediction and measurement differed by as much as 30 pct in certain cases. It would appear that no really satisfactory methods are available for the prediction of pressure drop in packed beds with a strongly nonisothermal regime. The method involving subdivision of the bed into small enough sections, that may be regarded as isothermal, would show promise; however its validity has to be tested by both a rigorous formulation and comparison with experimental data obtained under controlled conditions. In the following a formulation is presented together with experimental data allowing ready practical evaluation of the theory. FORMULATION The mechanical energy balance over an infinitesimal section of a packed bed may be written as follows:

Jan 1, 1969

By P. W. Edwards

"This paper summarises many experiments conducted, and how in North American industry the use of aluminium in treatment and prevention has been adopted widely. The Pottery Insurance Co., Ltd., made it possible for me to investigate conditions in Canada and the U.S.A., and I thank them for permitting me to submit this short paper- an abstract of my report to them."

Jan 1, 1947

By Paul Worsey, Delbert Da, Eric Achelpohl

The University of Missouri-Rolla is currently researching the concept of using glass microspheres in explosives as taggants as part of a 3-year technical project funded by the Bureau of Alcohol, Tobacco, and Firearms. These taggants are intended to provide two functions, first explosive detection and second post explosive event identification. The key priority is being able to detect explosives used in terrorist acts prior to detonation. The research on the use of microspheres includes the development of indicator taggants for the purpose of revealing the presence of hidden explosives, by either emitting radiation when bombarded with neutrons or emitting selective vapors, such as DMNB which may be readily “sniffed”. Of secondary importance, after an illegal explosion, the tags serve to identify the lot number, etc of the explosive. This information is to aid in the tracking, arrest, conviction and imprisonment of the perpetrators.

Jan 1, 2001

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005

By J. Kitagawa

The principal objectives of a metallurgical test programme for a 'grass roots' mining project are twofold. The first requirement is to establish the metallurgical viability of the project by demonstrating that acceptable results can be obtained by processing of the ore. The second goal is to obtain essential supporting data to determine whether the project is economically feasible. This involves several functions, which include the establishment of a workable flowsheet, the obtaining of design criteria for the commercial plant, and the collection of the evidence necessary to convince management, and often a third-party expert, that the metallurgy predicted for the ore can be achieved in a full-scale operation. The latter task is facilitated if a coherent overall picture is presented considering the geology of the orebody, the mining plan, and the mineralogy and metallurgy of the ore. The purpose of this paper is to provide guidance in the establishment of a test programme to meet the above objectives.

Jan 1, 1978

By William C. Cooley

This volume contains copies of the 5 x 8 in. accession card file for all items collected which were judged to be relevant to underground hydraulic coal mining. In many cases, abstracts are included. Abstracts were taken from the source, from other reviews, or from the preliminary screening of Russian documents performed by Dr. A. L. Brichant. No attempt was made to write abstracts for every accession item.

Jan 1, 1975

By S. P. Singh

Destress blasting is commonly used in the mines to minimize the occurrence of rockbursts. The fracturing created by destressing in the vicinity of the face reduces the stress concentration by pushing the zone of high stress deeper into the rock mass. But the destressing practice by blasting may be devastating near the faults or other sensitive high stress zones. To avoid severe rockbursts in such situations, the application of chemical destressing has been proposed in this paper. A laboratory investigation was conducted on the rocks in the Sudbury basin to examine the change in the material properties with an aim of assessing the feasibility of destressing by chemical means. The favourable change observed in the rock properties led to the suggestion that the injection of surfactants in boreholes would enhance fracture propagation similar to what is currently done by blasting but in a safer, inexpensive and non-violent manner. The current destressing practices in Ontario mines have also been reviewed in this paper.

Jan 1, 1987

By S. O. Choi, H. -S. Shin, W. -K. Song

Nuclear waste should be disposed with the best warranty for the national health and welfare. Among the several repository systems, the deep underground disposal is considered to be a most suitable system in Korean peninsula. However it demands basically the comprehensive stability analysis such as the behaviour of discontinuities in rock mass, the behaviour of ground water, and the reaction of rock stress according to the heat from the nuclear waste. For these purposes, the underground nuclear waste disposal repository was simulated in two- and three- dimensions. It shows that emphasis will be given to the thermal conductivity of discontinuities and the thermal convection of ground water as well as the thermal stress generated by the nuclear waste for design and construction of repository system, and they should be obtained from the field measurements. Déchets nucléaires devront tre déposés avec la meilleure garantie pour la santé et le bien public. Parmi les plusieurs systèmes de dépôt, la disposition en souterrin profond est considérée au système le plus approprié en Corée. Pourtant ce système demande essentiellement l’analyse éten-due de stabilité comme le comportement des discontinues en masse rocheuse, le comportement de l’eau souterrin et la réaction des contraintes de roche selon la chaleur depuis les déchets nucléaires. Pour ce but, le dépôt des déchets nucléaires en sous-sol a étè simulé en deux et trois dimensions. Il montre que l’accent sera donné à la conductivité thermale des discontinues et la convection thermale de l’eau souterrin aussi bien que la contrainte thermale générée par les déchets nucléaires pour le plan et la construction du systèmes de dépôt, et ils devront tre obtenus depuis les mesures sur place. Die Kernwüste muß mit der besten Gewähr für die nationale Gesundheit und die Wohlfahrt angeordnenet werden. Unter einigem Fundgrubesystem, das tief unterirdisch Wegwerfen werde in Betracht das passendest System in der koreanisch Halbinsel gezogen. Jedoch, es verlangt grundzätzlich die umfassend Stabilitätsberechnung so wie das Behnehmen mangelnder Konti-nuität in der Felsmasse, das Behnehmen des Grundwasser, und die Reaktion der Felsenbelastung nach der Hitze von der Kernwüste. Für diesen Zwecke, die unterirdische Wegferfenfundgrube der Kernwüste wurde in der zwei und drei Dimensionen gesimuliert. Es beweist daß die Betonung wird zur thermisch Leitfähigkeit mangelnder Kontinuität und thermisch Konvektion des Grund-wasser sowie die thermisch Belastung ergezeugt durch die Kernwüste für den Entwurf und die Konstruktion des Fundgrubesystem gegeben werden, und sie müssen von den Feldmaße ergelangt werden .

Jan 1, 2003

By Hong Nguen Vu, Pavla Ovcarí, Peter Fecko, Barbara Tora

"The goal of the work was verification of bacterial leaching on the samples of black coal. From the results obtained it was clear that the coal is very well leached by Thiobacillus ferrooxidans and this technology can be used for coal desulphurization. A leaching time of one month is required, to remove 65% of total sulphur and 85% of pyritic sulphur.Microscopic evaluation of samples from Jaworzno showed, that it should be classed as a coal with low coalification, probably from black coal hemiphase. Macerals of the liptinite group were well distinguishable; they were of a dark brown colour. Evidence of coal mass oxidation was apparent on the fresh sample; in the test samples (during bacterial leaching) small grains were oxidised."

Jan 1, 2003

By E. C. Bohlen, H. l. Burghoff

THE work reported in this paper was carried out to supplement the existing information concerning directional properties and recrystallization textures of annealed brass sheet and strip. These characteristics are of direct interest when the forming and drawing properties of such material are being considered. Among those who have made contributions in this field are Bass and Glocker;1 Bauer, Göler and Sachs;2 Phillips and Samans;3 Pratt;4 Price;5 Cook;6 Richards;7 Brick;8 and Brick and Williamson.9 These investigators have found, in general, that in brass strip that shows directional variations in properties, tensile strength has a minimum value and elongation has a maximum value at 45° to the rolling direction. The most pronounced directional properties have been found in material given the greatest reductions in rolling followed by high annealing temperatures. Recrystallization texture of brass has been variously reported as (113)[112], (001)[100], and a combination of (110)[115] and traces of the primary rolling texture, (110)[112]. The directional studies have been very informative, but actual tests appear to have been confined to material in its final condition. Tests at intermediate stages have received little attention although previous history of some materials has been partly considered. Perhaps the most comprehensive investigation was made by Cook,6 who studied the directional properties of 70-30 brass strip for which the final and penultimate, or next to the last, anneals and the final reductions were varied. He found that, for any given combination of penultimate anneal and final reduction, the tendency toward the development of directional properties was reduced as the temperature of the final anneal was decreased. In addition to drawing cups and making tensile tests of the finished material at various angles to the rolling direction, he measured the frequency and the angles of twins in grains for several specimens. Plots of his twin counts showed directionality for the materials that produced eared cups. TEST MATERIALS AND EQUIPMENT For this investigation, one commercial heat of 68-32 brass was cast in the form of bars for cold-rolling, 13 ½ in. wide and 1 ½ in. thick. The analysis was as follows: 68.83 per cent copper, 0.04 per cent lead, 0.01 per cent iron, 31.12 per cent zinc (by difference). The bars were so processed to the final thickness, 0.020 in., as to obtain on this thickness all possible combinations of the variables listed below except those involving the sequence of 84 per cent penultimate reduction and 84 per cent final reduction: I. Penultimate reductions of 37 per cent, 50 per cent and 84 per cent; 2. Penultimate anneals at 800°, 900°, 1050° and 1200°F.; 3. Final reductions of 37 per cent, 50 per cent, 69 per cent and 84 per cent;

Jan 1, 1942

By Norman King

El texto aborda la importancia de las relaciones positivas con los sindicatos en América Latina a través de dos conceptos: las relaciones de poder y las relaciones humanas. Por ello, es necesaria la aplicación de las relaciones humanas que pueden existir en las negociaciones con los sindicatos. En este sentido, se evalúan los elementos que influyen en su esctructura como la negociación-fuerza, el conflicto; el acomodamiento; la cooperación y las ideologías. De otro lado, las relaciones humanas permiten comprender las difcultades de negociación y política que implican tanto la relación de los sindicatos como de la administración y así mejorar el problema económico y de preparación de los dirigentes sindicales.

Aug 20, 1963

By George A. Morgan

Output of mineral products was estimated to be unchanged in 1983 from that of 1982 with the exception of petroleum. The country began production of crude oil from the Seme Oilfield, and all output was exported. Wd and charcoal constituted 72% of Benin's total energy consumption, and imported petroleum products and electric power accounted for the remainder. Cement was produced from imported clinker. The gross domestic product (GDP) was $1,061 million in 1982, the latest year for which information was available.2 COMMODITY REVIEW Gold.-Exploration was underway at Perma by the U.S.S.R. as part of the United Nations development program. Gold had been produced previously at Perma, where a grade of 0.289 troy ounce of gold per ton was reported, An exploitation program for the deposit was to employ about 100 people, and output was targeted to reach 1,600 troy ounces per year. Recoverable reserves were put at 96,000 troy ounces.

Jan 1, 1985

By Upfold RW, Velzeboer MD

An underground mine fire will influence the ventilation equilibrium in several ways which results in a redistribution of the ventilating quantities and pressures throughout the whole mine. The ventilation carries the combustion products which constitute the greatest danger of mine fires through the mine and provides the oxygen on which the intensity of the fire depends. However, as a result of the ventilat- ion disturbances created by the fire, changes in airflow patterns can take place which are not always obvious, especially when the mine is being served by several fans. The use of com- puter simulation techniques allow for the likely effects to be tested and the different ventilation options to be evaluated as an integral part of the overall emergency/rescue planning and control procedures.

Jan 1, 1981

By Will Clark

HE who enters a mining claim within an Indian reservation of the United States of America acquires no rights thereby, because of the fact that the lands within such Indian reservation are not a part of the public domain, and cannot be located or acquired as mineral land. However, where such an entry is authorized as to a particular reservation by an Act of Congress, such claims as may be entered under such authorization are thereby segregated from the reservation, and the Indian title is extinguished. Under the Choctaw Constitution, any citizen of that nation, in other words any Choctaw Indian, who discovered a coal mine, acquired an exclusive right to all coal within a radius of 1 mile. The laws of the Chickasaw nation provided for the formation of corporations to develop coal and other mines, with authority to contract with others to develop and work the mines. Under these laws, leases were made; but Congress subsequently abrogated all existing leases, prohibited all persons from receiving royalties from such mines, and provided that all coal within the nation should remain the common property of the tribes. Such leases are now expressly prohibited by an Act of Congress (32 United States Statutes at Large, 655). All leases of mineral lands upon Indian reservations must now be made under regulations promulgated by the Secretary of the Interior, and the royalties must be paid into the United States Treasury for the benefit of the tribes. In Canada the Indians have no rights to the royal mines and minerals, and the government can make no stipulation with the Indians which would affect the rights of the Province in which the lands are situated. Therefore, while it is true that under our present law no rights can be acquired to a mining claim within an Indian reservation, it seems to be fully within the authority of Congress to make laws, giving such rights to mineral locators as it may deem necessary or expedient.

Jan 6, 1914

By R. L. Grayson, N. P. Reddy, D. A. Kinzler, S. Yuan, W. R. Myers, R. A. Wells

An examination was conducted on the impact of roof conditions and the mining cycle in determining a representative respirable mass concentration at the mid-shearer location on a longwall panel. Multiple personal gravimetric dust samplers, operated at a flow rate of 2.0 lpm, were used at different locations along the face to isolate the concentrations and variances associated with good and bad roof conditions under both the cutting and cleaning mode of operation. The number of samples needed to estimate the population variance at a given confidence level was analyzed. In addition, the statistical analysis showed that the coefficient of variation of dust concentrations at different locations and under different conditions ranged from 0.185 to 0.475, with an average value of 0.283. The estimates of the average dust concentration for a shift and the variance of the dust concentrations were calculated. A total of 48 data points were available for an [a x b] factorial ANOVA (analysis of variance). The estimates of the variance components were determined. The results from F-tests indicated that both the roof conditions and mining operations had a significant effect on the respirable dust concentration. There was no significant interaction effect between mining operations and roof conditions. In conclusion, this study shows that not only should sampling and analytical errors be considered in determining the required number of samples for a good estimate of the long-range exposures of miners, but also fluctuations of concentrations due to mining operations and geological conditions should be taken into account.

Jan 1, 1991

The U. S. Navy Department has perfected plans for the enrollment and training of considerable numbers of engineering officers. A school for this purpose, the U. S. Navy Steam Engineering School, has been established by the Department at Hoboken, N. J. The school is open to men between the ages of 21 and 40 who meet the physical requirements of the Navy, who are of thorough ability and officer-like character and who have completed the mechanical or electrical engineering course at certain recognized technical schools, or who possess an education and experience adjudged to be an equivalent thereof. Enrollment in the U. Naval Reserve Force of men properly qualified may be made at any Naval enrolling office, notation being made of the applicant's qualifications and desire to be detailed to this school. Applicants will be enrolled as Chief Machinist Mates, and during the course of instruction will draw the pay of this rating, $83 per month, plus $60 per month paid as subsistence. Upon graduation, men will be commissioned as Ensigns in the U. S. Naval Reserve, with a salary of $1700 per year. The duty to which a graduate of this school will be assigned will be that of an engineer officer in the auxiliary service of the Navy. Special provision has been made for the continuance of the school with proper material by a Navy regulation which permits undergraduates of the Freshman, Sophomore, and Junior Classes in recognized engineering schools to enroll in the Naval Reserve Force with the rating of Seaman 2d Class, and continue their courses at the institutions where they have matriculated. Such men will be called into active service after their graduation, and can at that time, if they are qualified to pass an officers' physical examination, apply for admission to the U. S. Navy Steam Engineering School. Men who are registered in the draft, either graduates or undergraduates, may enroll with the proper enrolling officer by securing from their draft board a letter of release, which in all probability can be obtained for this purpose. The aim of this school is not simply to produce engineers, but to produce naval engineering officers in the true sense of the word. The course of instruction covers a period of five months, arranged in four periods.

Jan 10, 1918