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Question 1—1s Structural Deformation of Some Character Always Necessary for the Migration of Mineralizing Solutions. Especially in Limestone or Other Dense Rocks Discussion by: A. M. Bateman.........120 S. F. Kelly........... 125 C. H. Behre. Jr........118.123 G. B. Langford......... 123 T. M. Broderick.........121 H. E. McKinstry......... 116 R. H. Clarke.......... 123 D. H. McLaughlin........ 118 J. D. Forrester for M. H. Gidel . . 11.4 W. H. Newhouse......... 123 G. M. Fowler......112. 116. 121 R. H. Sales.......... 116 L. C. Graton..........121 Edward Sampson......... 122 R. D. Hoffman.........120 J. 8. Stevenson.......... 117 I. B. Joralemon.........121 L.B.Wright........... 112 Question 2—What Are Some of the Chemical and Physical Characteristics in Certain Beds within a Limestone Formation that Determine Their Favorable or Unfavorable Aspects as Reservoirs for Ore and Other Introduced Minerals? Drscussion by: G. W. Bain....... 127 G. M. Fowler....... 131 C. H. Behre, Jr. ..... 131 L. C. Graton....... 128 J. S. Brown. ...... 126 G.. F. Loughlin...... 128 E. L. Bruce ....... 129 R. H. Sales........ 129 R. H. Clarke...... 130 A. K. Snelgrove....... 130 Question 3—Are There Any Criteria by Which One Can Determine When Mining Operations Have Reached the Roots of an Ore Deposit? Discussion by: J. M. Boutwell...... 139 G. B. Langford..... 139 T. M. Broderick..... 138 . G. F. Loughlin...... 135 E. Y. Dougherty..... 137 R. H. Sales...... . 134 G. M. Fowler....... 132 F. A. Thomson..... 136 I. B. Joralcmon...... 132 Edward Wisser:..... 140 General s. F. Kelly................. . ...........145 References...............................146

Jan 1, 1941

By W. S. N. Waring, E. C. Bain, E. S. Davenport

The more familiar compositions of both the iron-carbon-chromium' and the iron-carbon-tungsten2 systems have been investigated with a degree of thoroughness which has permitted the construction of their three-dimensional equilibrium diagrams; and it is probable that these equilibrium diagrams are sufficiently accurate for the present metallo-graphic needs. Strangely enough, in spite of their importance, the alloys of iron, carbon and manganese apparently have not been investigated in the same systematic manner, and so far as is known, no three-component equilibrium diagram for this system is available. Even iron-carbon-nickel alloys3 have been studied rather more thoroughly; for these the solidus and liquidus surfaces have already been determined, but the solid transformations in this, as in the manganese system, have not been reported systematically. The present paper deals with the constitution at equilibrium of a series of 36 iron-carbon-manganese alloys of commercial purity limited by 1.5 per cent carbon and 15 per cent manganese, a range of compositions including most of the manganese steels. The temperature range of melting has not been determined, nor has the high-temperature (delta iron) ferrite equilibrium been included in the study, it being considered that the more important characteristics of the manganese steels are their ordinary transformations in the solid state. The delta iron region is almost certain to be a small tetrahedron not very different in magnitude or contour from that in the iron-carbon-nickel diagram. It is probably true

Jan 1, 1932

Question 1—1s Structural Deformation of Some Character Always Necessary for the Migration of Mineralizing Solutions. Especially in Limestone or Other Dense Rocks Discussion by: A. M. Bateman.........120 S. F. Kelly........... 125 C. H. Behre. Jr........118.123 G. B. Langford......... 123 T. M. Broderick.........121 H. E. McKinstry......... 116 R. H. Clarke.......... 123 D. H. McLaughlin........ 118 J. D. Forrester for M. H. Gidel . . 11.4 W. H. Newhouse......... 123 G. M. Fowler......112. 116. 121 R. H. Sales.......... 116 L. C. Graton..........121 Edward Sampson......... 122 R. D. Hoffman.........120 J. 8. Stevenson.......... 117 I. B. Joralemon.........121 L.B.Wright........... 112 Question 2—What Are Some of the Chemical and Physical Characteristics in Certain Beds within a Limestone Formation that Determine Their Favorable or Unfavorable Aspects as Reservoirs for Ore and Other Introduced Minerals? Drscussion by: G. W. Bain....... 127 G. M. Fowler....... 131 C. H. Behre, Jr. ..... 131 L. C. Graton....... 128 J. S. Brown. ...... 126 G.. F. Loughlin...... 128 E. L. Bruce ....... 129 R. H. Sales........ 129 R. H. Clarke...... 130 A. K. Snelgrove....... 130 Question 3—Are There Any Criteria by Which One Can Determine When Mining Operations Have Reached the Roots of an Ore Deposit? Discussion by: J. M. Boutwell...... 139 G. B. Langford..... 139 T. M. Broderick..... 138 . G. F. Loughlin...... 135 E. Y. Dougherty..... 137 R. H. Sales...... . 134 G. M. Fowler....... 132 F. A. Thomson..... 136 I. B. Joralcmon...... 132 Edward Wisser:..... 140 General s. F. Kelly................. . ...........145 References...............................146

Jan 1, 1941

By J. A. Harrison

The physical composition of coal and the distribution of its physical constituents will partially determine the efficiency of the process chosen for coal preparation. Distribution and concentration of coal macerals will, to a degree, be controlled by preparation processes. A number of preparation processes have been evaluated to determine this interrelation. These evaluations will help provide information needed for the production of coal that meets definite petrographic composition specifications. etrographic composition and degree of coalifica-tion of coal can determine the choice of cleaning processes and equipment used in coal preparation. The purpose of this paper is to present data on studies of the preparation processes of breakage, sizing, cleaning, and blending and to show the effect coal's petrographic composition has on these processes. Herrin (No. 6) and Danville (No. 7) Coals from Illinois were used in these tests. Nomenclature used herein is that approved in the Glossary of the International Committee for Coal Petrology,' based primarily on the Stopes-Heerlen system of classification2 and used in coal petrography laboratories throughout the world. BREAKAGE TESTS Breakage tests of Illinois coals related to petrographic composition have been conducted at various times at the Illinois State Geological Survey. These tests have been classified under two headings -impact tests and compression tests. Impact tests, as the name implies, consisted of breaking the coal by a sharp, sudden force. Impact tests were further divided into fall tests and block tests. Compression tests consisted of applying a constant pressure on a piece of coal until the coal fractured.

Jan 1, 1963

By C. Baldwin Sawyer

During the last half century, much time has been devoted to investigations of the effect of nitrogen on the physical properties of steel, but in all discussions of results there is considerable doubt as to the accuracy and interpretation of analyses. No conclusions concerning the effects of nitrogen on the physical properties of steel can be more reliable than the methods used for determining the quantities of nitrogen present. The work described in this paper endeavors to establish some additional conditions required by the customary distillation method for reliable and nccurate determinations. Results by a combustion method of analysis for total nitrogen content are presented; these indicate that all of the nitrogen in steel, exclusive of that contained in blowholes, may be determined by the distillation method. Based on these more sound and more reliable analyses, results havc been obtained that bear on the following divisions of the general subject, nitrogen in steel: Nitrification of steel by melting in nitrogen, nitrification of steel by heating in ammonia, decomposition of nitrified steel by heating, and thermal analysis of nitrified steel. Consideration of Two Methods of Analysis and Some Results The details of the distillation and combustion methods are chemical in character and of little interest to most readers. They are therefore described in an appendix. The distillation method is essentially that described by Hurum and Fay1 and was generally used throughout this work. It is capable of the greatest accuracy and all results given are significant to the last, figure. Where analyses do not check, the samples

Jan 1, 1923

By C. Baldwin Sawyer

During the last half century, much time has been devoted to investigations of the effect of nitrogen on the physical properties of steel, but in all discussions of results there is considerable doubt as to the accuracy and interpretation of analyses. No conclusions concerning the effects of nitrogen on the physical properties of steel can be more reliable than the methods used for determining the quantities of nitrogen present. The work described in this paper endeavors to establish some additional conditions required by the customary distillation method for reliable and nccurate determinations. Results by a combustion method of analysis for total nitrogen content are presented; these indicate that all of the nitrogen in steel, exclusive of that contained in blowholes, may be determined by the distillation method. Based on these more sound and more reliable analyses, results havc been obtained that bear on the following divisions of the general subject, nitrogen in steel: Nitrification of steel by melting in nitrogen, nitrification of steel by heating in ammonia, decomposition of nitrified steel by heating, and thermal analysis of nitrified steel. Consideration of Two Methods of Analysis and Some Results The details of the distillation and combustion methods are chemical in character and of little interest to most readers. They are therefore described in an appendix. The distillation method is essentially that described by Hurum and Fay1 and was generally used throughout this work. It is capable of the greatest accuracy and all results given are significant to the last, figure. Where analyses do not check, the samples

Jan 1, 1923

By R. W. Raymond

HAVING had recently the opportunity of examining a transit and a plummet-lamp, manufactured by Messrs. Heller & Brightly, of Philadelphia, and intended for the use of mining engineers in under-

Jan 1, 1873

By R. W. Raymond

HAVING had recently the opportunity of examining a transit and a plummet-lamp, manufactured by Messrs. Heller & Brightly, of Philadelphia, and intended for the use of mining engineers in under

By M. C. Fuerstenau, R. K. Price, R. D. Wellik, B. M. Wakawa

Median lethal concentrations of pure and commercially available ethyl xanthate, isopropyl xanthate, amyl xanthate, diethyl dithiophosphate, dibutyl dithiophosphate, and isopropyl ethylthionocarbamate for rainbow trout have been established utilizing static bioassays.

Jan 1, 1975

By Arch J. Alexander

This paper is a resume of a study undertaken by the West Virginia Department of Mines. The underlying and direct causes of accidents are determined in each occupational group. Then from this study, accident prevention courses, visual and written, are to be taken to the various working groups in the mines. THE causes of accidents in West Virginia mines follow the main pattern of coal industry accidents in the United States—falls of roof, ribs and face, 56 pct; from haulage, 25 to 30 pet; blasting, 3 pet; electrocutions, 3 pct; explosions, 2 pct; and other causes, about 10 pct. To arrive at some satisfactory conclusions regarding causes and prevention of mine accidents, the Department of Mines has made a study of all mine accidents, from 1945 to 1948, inclusive. During the last two years of this period, we did not have a major explosion, one that took the lives of as many as five men. The direct cause of these accidents is apparent in the reports but we who are making a close study into their frequency think that the virus lies much deeper, and we want to suggest an underlying cause. The rapid growth of the coal industry in West Virginia, the largest producer of bituminous coal, has resulted in a demand for manpower which probably has never been equaled in mining history. At the turn of the century, West Virginia had 24,635 men employed in and about her mines, and they produced 21,153,341 tons of coal a year. In 1948, there were 125,669 men employed, and coal production for the year was 168,589,033 tons, an average increase of 35 pct for each year since 1900. Over 100,000,000 tons of this increase were mined in the southern counties of the state. A safety analyst might read into the history of this development an underlying cause for accident occurrence. He might say that in such a vast, rapid development the available supply of trained miners became exhausted and that young, inexperienced men were employed in the mines by the thousands. Being unacquainted with the hazards of mining, it would be only natural for these young men to be injured or killed in too great a number. This assumption would not be borne out by the records. Men were not injured or killed in disproportionate numbers during their first years in a mine. The only reason we can give is that, during these years, they possessed an attribute of safety—CAUTION—to a much greater degree than in the years following. The coal companies in West Virginia that have been operating over a number of years have a nucleus of employees who have been with them ten, twenty, thirty, and forty years; many of them having gained all of their mining experience with one company. Their habits of work have been

Jan 1, 1951

By Arch J. Alexander

This paper is a resume of a study undertaken by the West Virginia Department of Mines. The underlying and direct causes of accidents are determined in each occupational group. Then from this study, accident prevention courses, visual and written, are to be taken to the various working groups in the mines. THE causes of accidents in West Virginia mines follow the main pattern of coal industry accidents in the United States—falls of roof, ribs and face, 56 pct; from haulage, 25 to 30 pet; blasting, 3 pet; electrocutions, 3 pct; explosions, 2 pct; and other causes, about 10 pct. To arrive at some satisfactory conclusions regarding causes and prevention of mine accidents, the Department of Mines has made a study of all mine accidents, from 1945 to 1948, inclusive. During the last two years of this period, we did not have a major explosion, one that took the lives of as many as five men. The direct cause of these accidents is apparent in the reports but we who are making a close study into their frequency think that the virus lies much deeper, and we want to suggest an underlying cause. The rapid growth of the coal industry in West Virginia, the largest producer of bituminous coal, has resulted in a demand for manpower which probably has never been equaled in mining history. At the turn of the century, West Virginia had 24,635 men employed in and about her mines, and they produced 21,153,341 tons of coal a year. In 1948, there were 125,669 men employed, and coal production for the year was 168,589,033 tons, an average increase of 35 pct for each year since 1900. Over 100,000,000 tons of this increase were mined in the southern counties of the state. A safety analyst might read into the history of this development an underlying cause for accident occurrence. He might say that in such a vast, rapid development the available supply of trained miners became exhausted and that young, inexperienced men were employed in the mines by the thousands. Being unacquainted with the hazards of mining, it would be only natural for these young men to be injured or killed in too great a number. This assumption would not be borne out by the records. Men were not injured or killed in disproportionate numbers during their first years in a mine. The only reason we can give is that, during these years, they possessed an attribute of safety—CAUTION—to a much greater degree than in the years following. The coal companies in West Virginia that have been operating over a number of years have a nucleus of employees who have been with them ten, twenty, thirty, and forty years; many of them having gained all of their mining experience with one company. Their habits of work have been

Jan 1, 1951

By G. E. Archie

Data given in this paper indicate that certain relations exist between different characteristics of sandstone. These relations are not rigid, for all sandstones are more or less heterogeneous. Not every increment of a given horizon follows exactly the relationship; however, studying a reservoir as a whole from a large number of samples, definite trends are found to exist. Apparently nature's processes of sedimentation and diagenesis are such as to give some degree of uniformity. Average relationships are valuable because electrical measurements in a borehole comprise a considerable volume of rock near the hole. Also, it is desirable that a given producing reservoir be studied as a unit. In a permeable reservoir whose pores are filled with a saline solution, it was found that the total porosity and the type of sandstone influence the relationship between its electrical resistivity and the RO and the resistivity of the brine R,. The relation can be expressed by the following empirical equation, Ro = R10O— [i] where 0 is the porosity expressed as a fraction and the numerical value of the exponent lies between 1.8 to 2.0 for consolidated sandstones, and is about 1.3 for clean, unconsolidated packs. This equation indicates that an appropriate electrical log can be used to estimate the porosity of a saline water-bearing reservoir when Rw and the type of rock are known. The fraction R0rw, is called the "formation resistivity factor." It reflects the effect of the nonconducting rock structure on the resistivity of the salt water that fills the tortuous paths through which the electricity must pass. The formation resistivity factor F is found to be related to permeability k. In this case the type of rock plays an important role, as shown by the relation F = ak-b [2] where the values of a and b must be determined experimentally for each horizon. Therefore Eq. I rather than Eq. 2 is used when it is desired to determine the value of F, because small changes in rock structure particularly in the pore size are not critical. Another useful relation, R = R0S- [3] where R = resistivity of rock when partially saturated with brine and partly with oil or gas, S = fraction of the pore space filled with brine, and n equals approximately 2 for both unconsolidated and consolidated sandstone, shows that the connate water of an oil or gas reservoir can be estimated in situ from a resistivity log. Equation 3 shows that in order to estimate the water content of a reservoir a knowledge of R and Ro is essential. The first value can be obtained from the electrical log when all factors influencing the resistivity curve can be properly taken into account. The latter may be obtained when a log is available on the same horizon where it is entirely water-bearing and has

Jan 1, 1946

By G. E. Archie

Data given in this paper indicate that certain relations exist between different characteristics of sandstone. These relations are not rigid, for all sandstones are more or less heterogeneous. Not every increment of a given horizon follows exactly the relationship; however, studying a reservoir as a whole from a large number of samples, definite trends are found to exist. Apparently nature's processes of sedimentation and diagenesis are such as to give some degree of uniformity. Average relationships are valuable because electrical measurements in a borehole comprise a considerable volume of rock near the hole. Also, it is desirable that a given producing reservoir be studied as a unit. In a permeable reservoir whose pores are filled with a saline solution, it was found that the total porosity and the type of sandstone influence the relationship between its electrical resistivity and the RO and the resistivity of the brine R,. The relation can be expressed by the following empirical equation, Ro = R10O— [i] where 0 is the porosity expressed as a fraction and the numerical value of the exponent lies between 1.8 to 2.0 for consolidated sandstones, and is about 1.3 for clean, unconsolidated packs. This equation indicates that an appropriate electrical log can be used to estimate the porosity of a saline water-bearing reservoir when Rw and the type of rock are known. The fraction R0rw, is called the "formation resistivity factor." It reflects the effect of the nonconducting rock structure on the resistivity of the salt water that fills the tortuous paths through which the electricity must pass. The formation resistivity factor F is found to be related to permeability k. In this case the type of rock plays an important role, as shown by the relation F = ak-b [2] where the values of a and b must be determined experimentally for each horizon. Therefore Eq. I rather than Eq. 2 is used when it is desired to determine the value of F, because small changes in rock structure particularly in the pore size are not critical. Another useful relation, R = R0S- [3] where R = resistivity of rock when partially saturated with brine and partly with oil or gas, S = fraction of the pore space filled with brine, and n equals approximately 2 for both unconsolidated and consolidated sandstone, shows that the connate water of an oil or gas reservoir can be estimated in situ from a resistivity log. Equation 3 shows that in order to estimate the water content of a reservoir a knowledge of R and Ro is essential. The first value can be obtained from the electrical log when all factors influencing the resistivity curve can be properly taken into account. The latter may be obtained when a log is available on the same horizon where it is entirely water-bearing and has

Jan 1, 1946

By R. J. Mellen

IN a chloridizing roasting and cyanidation plant treating a manganese-silver ore, certain experiments pointed out the way to an improvement in roasting conditions by a change in the degree of crushing. The following short article is simply a description of the various changes that were necessary throughout the plant and of the results obtained. There is nothing unusual in these changes but they are of some interest in that they constitute a good many of the alterations usually resorted to in increasing production. In the beginning, the changes were brought about by an experiment that was not successful, but which clearly pointed to means of improving the operation, and is an example of the fact that often experimental work may result in failure and still be of value in arriving at correct fundamentals. This experiment also shows how far a metallurgist can get out of line in his deductions, particularly in a field with which he is not thoroughly familiar. The ore at the plant of Compania Minera Kildun y Anexas is crushed through a 13-in. gyratory, a 3-ft. standard Symons cone crusher and a set of 16 by 42in. rolls, the latter in closed circuit with two Tyler 400-mesh screens. The crushed ore is then conveyed to two fine-ore bins. These provide storage and feed for two 6 by 90-ft. kiln roasters, which discharge directly to coolers. The coolers in turn discharge to a 6 by 12-ft. ball mill, where the ore is ground for cyanidation. Laboratory and pilot-plant tests previous to the mill construction had indicated that minus ¼ -in. crushing was satisfactory for roasting, although results did not vary greatly with some coarser or considerably finer crushing. The plant was designed for a capacity of 300 tons per day on this basis. After a few months operation, the initial operating problems were overcome and the anticipated milling rate was reached but the results being obtained were not really good. The plant seemingly did not have much excess capacity in any department but the roasting operation was the most critically limiting factor both as to tonnage and the results obtained. If this could be improved there seemed some possibility of improving the total tonnage rate to some extent. Segregation of the calcine into various screen sizes showed that the coarser sizes ,were not giving the expected recoveries. In all of the laboratory and pilot-plant testing, any limiting conditions as to the percentage of salt used, temperatures, feed rates, etc., had affected the fine material more than it had the coarse, and even in making laboratory tests at this time the mill conditions could not be exactly duplicated. Further laboratory testing indicated that a segregation of the crushed ore into a coarse and fine product for roasting might result in some improvement in roast-

Jan 1, 1945

By S. C. Sircar, B. K. Dhindaw

KINETICS and mechanism of sulfation reactions have been studied extensively. Qualitative and quantitative data are reported for the kinetics and mechanism of sulfation reaction of copper oxide pellets;''2 yet it remains a controversial Subject. The mechanism and kinetics of the sulfation of zinc oxide powder (B.D.H. analar quality) were studied by gravimetric technique. A spring of high-carbon steel wire with accuracy well within 0.2 mg was used for measuring weight change. The sample was taken in a Pyrex glass bucket, hanging freely inside a Pyrex glass tube reactor, with a gold wire attached to the spring, the reactor being surrounded by a movable furnace (double wound type) with a temperature control within *5"C. Flow of oxygen, 60 cu cm per min, and sulfur dioxide, 45 cu cm per min, were measured through calibrated flowmeters and the mixture dried over PZ05 before entering the reactor. The experimental results are presented in Figs. 1 and 2. The plot of weight change of zinc oxide, giving the amount of zinc sulfate formed, was found to be linear over the temperature range of 500" to 700° C and up to a conversion of approximately 60 pct, as beyond it they divert from linearity.' The rate of sulfation was found to be affected by total flow rate of gases at a fixed ratio of SO2/O2, up to 60 cu cm per min, and was found to be linearly dependent on quantity of total powdered sample taken. The plot of rate of sulfation of zinc oxide, 70 mg, with varying amounts of vanadium pentoxide, at a constant ratio of gases as mentioned above, and at a constant temperature of 625"C, was also found to be linear as seen in Fig. 2. Extrapolation to zero V2O5 addition gives the same rate of sulfation, as in case of pure zinc oxide, 70 mg. Vz05 was prepared by heating ammonium vanadate at 600°C for 15 min in a muffle furnace. The available literature points out that the theory of sulfation that has received the maximum support postulates the following mechanism for sulfation of ZnS: 2ZnS + 30, = 2Zn0 + 2SOZ; the ZnO formed acts as a catalyst for the reaction, 2 S02 + O2 = 2S03. This SO3 reacts with ZnO to give zinc sulfate. It is suggested here that the above widely supported mechanism is operative in the sulfation reaction and that the rate-controlling step in the sulfation reaction of ZnO is the formation of SO3 from SO, and 0,. The authors are carrying on further work in this line, and the details will be published later. The authors wish to acknowledge the facilities provided and the help extended by Prof. P. R. Dhar, Head, Department of Metallurgical Engineering, and the permission granted to publish this note by the Director, I. I. T., Kharagpur.

Jan 1, 1969

By J. W. Stewart

The aim of this paper is to point out the various ways in which design is taught in standard four-year mining engineering curricula in American colleges and universities; to discuss the reasons apparently justifying the great diversity of procedure that exists along this line; and to indicate possible solutions to the difficulties now attending the teaching of design. A study was made of typical four-year mining engineering curricula in 15 colleges and universities of the United States (Table I). Great diversity in content of the various design courses, if taught as described, became apparent immediately. It appeared that it might be both interesting and instructive if the cause for this colorful variety could be found. Was the cause local mining conditions, departmental individuality, or actual necessity? Study of the school catalogues revealed that the various design courses could be classified into two fairly distinct types; namely, (I) those dealing with mine equipment or structures, and (2) those dealing with underground layout of mine workings. It seemed reasonable to label the first type of course "mining design" and the second type "mine design." Some such distinction must have been in the minds of mining educators, for we find both names (i.e., mine design and mining design) used to designate the design courses included in the various mining curricula Unhappily, the name and the apparent content of such courses do not, in all instances, conform to the classification made here, although in most instances such conformation does obtain (Table I). It is possible that in the exceptional case the method of teaching a design course, and consequently the content of it, may have been changed at some time without change in the name of the course. Apparently only 3 of the 15 schools made an effort to cover both types of design in their curricula (Table I). Two other schools did not list or describe any course of study that could with certainty be taken as a design course. Of the remaining 10 schools, 9 gave a mining-design type of course and one gave a strictly mine-design type. Obviously, the preponderance of design courses afforded are of the mining-design type. Why? To answer this question, it is necessary to make a study of the prerequisites for the two types of design courses taught. In all schools the design courses were taught in the senior year; in eight, design was taught throughout both semesters; in two, it was taught during the first semester only; and in three it was taught during the second semester only. Consequently, excepting the last three cases noted, it is obvious that all prerequisites for a design course should be completed by the end of the junior year PREREQUISITES What are the probable prerequisites for the different kinds of design courses as they appear to be taught? Let us take first the case of the mine-design type of course, having to do with layout of underground workings. Here it would seem that logical

Jan 1, 1943

By James Norman, Benjamin S. Lindsey

BaritE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the 'more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to 100 per cent through 325 mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, II.II per cent SiO², and 2.85 per cent R²O3. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.' The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of non-metallic minerals in the presence of a large amount of slime is usually very difficult, and when done is an innovation calling for conditions different from those under which granular material is scparated. Laboratory Flotation Work Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1942

By H. Landsberg

The curriculum presented here is an outgrowth of discussions by the Committee on Geophysics Courses of the A.I.M.E. in previous years. It had to be a compromise between the desires voiced by employers of geophysicists, professional geophysicists and the possibilities at an average college. There one has to face the questions of the available teaching staff, the inertia of administrators and teachers set in their ways, and the red tape involved in modernizing antiquated curricula. It is, of course, not ideal to have colleges and universities lag Io years behind the times. Rather, instead of being prodded by industry, they should be ahead of industrial needs. There should also be a certain amount of leeway for the student in any college curriculum. All these points had to be considered in drawing up a curriculum, which, instead of being narrowly termed "geology" or "geophysics" was rather called "earth science." It gives the student a chance to specialize in one of the various branches represented by teachers on the faculty of The Pennsylvania State College, giving as options Geology (with subdivisions of Mineralogy and Paleontology), Geophysics, Geography, and Meteorology. Table iA represents the option of geophysics in the curriculum that envisages that a student may want to make his career in any of the fields encompassed by the American Geophysical Union or in geoexploration. This is, of course, only the start of an education that in most cases will have to be followed by graduate work for complete professional training. The outlined curriculum is definitely of an engineering type and is identical for all of the four options mentioned for the first two years. Specialization will start in the junior year but even thereafter the branches are kept as closely allied as feasible in order to permit a student to change from one tO the other (e.g., because of a different aspect in the mployment situation) with a minimum of additional work. Table IB shows the geophysics option according to subject matter, indicating the considerable amount of work in the fundamentals of mathematics, physics and chemistry with a liberal number of geology courses, and some engineering. The courses in the field of geophysics are limited—just two lecture courses as a general introduction and one field course, to permit the student a visualization of the correlation between mathematically analyzed physical data and the geological realities. Thesis work is considered essential to teach the student, while he is still in college, some things S. F. Kelly has mentioned as desirable: (I) following of instructions for somewhat independent work; (2) organizing of material, and (3) producing a readable report. This, together with the personal contact with the advising faculty member, will help in forming a student's personality. The seminar course attempts to get the student into the habit of reading current literature, so that he can keep abreast of the times.

Jan 1, 1946

By H. Landsberg

The curriculum presented here is an outgrowth of discussions by the Committee on Geophysics Courses of the A.I.M.E. in previous years. It had to be a compromise between the desires voiced by employers of geophysicists, professional geophysicists and the possibilities at an average college. There one has to face the questions of the available teaching staff, the inertia of administrators and teachers set in their ways, and the red tape involved in modernizing antiquated curricula. It is, of course, not ideal to have colleges and universities lag Io years behind the times. Rather, instead of being prodded by industry, they should be ahead of industrial needs. There should also be a certain amount of leeway for the student in any college curriculum. All these points had to be considered in drawing up a curriculum, which, instead of being narrowly termed "geology" or "geophysics" was rather called "earth science." It gives the student a chance to specialize in one of the various branches represented by teachers on the faculty of The Pennsylvania State College, giving as options Geology (with subdivisions of Mineralogy and Paleontology), Geophysics, Geography, and Meteorology. Table iA represents the option of geophysics in the curriculum that envisages that a student may want to make his career in any of the fields encompassed by the American Geophysical Union or in geoexploration. This is, of course, only the start of an education that in most cases will have to be followed by graduate work for complete professional training. The outlined curriculum is definitely of an engineering type and is identical for all of the four options mentioned for the first two years. Specialization will start in the junior year but even thereafter the branches are kept as closely allied as feasible in order to permit a student to change from one tO the other (e.g., because of a different aspect in the mployment situation) with a minimum of additional work. Table IB shows the geophysics option according to subject matter, indicating the considerable amount of work in the fundamentals of mathematics, physics and chemistry with a liberal number of geology courses, and some engineering. The courses in the field of geophysics are limited—just two lecture courses as a general introduction and one field course, to permit the student a visualization of the correlation between mathematically analyzed physical data and the geological realities. Thesis work is considered essential to teach the student, while he is still in college, some things S. F. Kelly has mentioned as desirable: (I) following of instructions for somewhat independent work; (2) organizing of material, and (3) producing a readable report. This, together with the personal contact with the advising faculty member, will help in forming a student's personality. The seminar course attempts to get the student into the habit of reading current literature, so that he can keep abreast of the times.

Jan 1, 1946

By R. W. Raymond

to same extent, the assumptions tinderlying Dr. Ilu?ley's con alusions. These amrrmptions are: that 'the loss of metal per million tons of trafffc, depends, first upon the circrtnistances under which the rail is worn; secondly, upon the proportions of its various constituents, ancl that the anlorlnt of loss is afEect~d by eacb constitnent in a cer tain ratio, so that if the circunlstances were the same for all tlie mils, the wear per nliilion tons might he upproxi91ately expre~sed by an equation of the form I + Cc + Pp + SR + Mm = R, io wtlioh I is an unknown valne, dependi~.rg on the quantity of iron (and other ingre dients not determined) in the rail, and assumed to be constant for all the rails ; c, p, s, and m are the experimentally determined quan tities of carhon, phosphorus, sulphur, and manganese, as tabulater1 in YIates VT and VII of Dr. Dudley's paper; and R is the experirnen tdlly dcterlnincd wear per million tons; while C, P, S, and M are onknown wfficients. In other words, it is assunled that the differ ence in wear is proportional to a difference in c, p, s, or m, and that the effects of a change in the amonnt of either are independent of the amount of the rest-—within the experinlental limit5 of the problem. It is also assr~med that sulphar, copper, and other ingredients, not determined, are qually present in all the rails, or at least {lo not affect the wear, since I is taken as constant. Dr. Dudley tacitly assumes the coefficient6 C, P, S, and M to be positive; and assigns certain valries to them, by means of which he redom t.he equation to the form I + Pa: = R, x being equal to cc + Es +Mm i Pp, or tjje uanjbe,. of so-called phosphorus units in the rail. But we do not have R directly given under constant circumstances. The varying weights (per engine, car, or train) and the varying epds, we must neglect for lack of data, and assume that in these rwpects the rails examined have been treated srlbstantially alike. But there remain the varying conditions as to track, which mnst he elirninsted. Dr. Dudley gives six clrlsses, four of which contain 8 rails each, and two 16 rails each. Beginning with the 6~st (tangent grade), take the mean of the figures expressing wear for that clam; and continaing tliis process through the other five, we obtain six expressions in quantity of loss 'by wear, which we assome tc, represent, in their differences, the varying conditions of the trarli, with respect to grade and direction. We now take the mean of these moans (giving double weight to the gmiip containing 16 ohwrvafieras). This general rnean is the 10 of metal per million tons of trafio for a rail of avorage constitution under mean ciroumstances.

Jan 1, 1881