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By J. E. Lawver, R. R. Beebe, J. L. Wright

This paper describes a separation coefficient Ks useful as a "measure of goodness" to be used in factorial and response surface methodology. The use and limitations of the separation coefficient is discussed, and a computer program for calculating the coefficient is presented (in Fortran). The application of the coefficient is illustrated in terms of electro-dynamic separation of Mesabi semitaconites. Present Mesabi wash ores and gravity concentrates with an iron to silica ratio of only 5 or 6 to 1 are no longer readily salable, for the steel industry now demands concentrates with an iron to silica ratio of at least 10 to 1 and a structure comparable to pellets. THE ELECTRODYNAMIC-FLOTATION PROCESS Wash ores and gravity concentrates consist largely of hematite, goethite, and quartz. Several methods of beneficiation are being tested at the University of Minnesota Mines Experiment Station with a view to improving the salability of these materials. A process that looks particularly promising from an economic view is the combination electrodynamic-flotation process shown in Fig. 1. This process is designed to upgrade gravity concentrates to a 5% silica content and to provide fines — from the flotation circuit —to permit agglomeration. Although electrodynamic concentration of specularite is an established and well-understood process, the electrodynamic concentration of Mesabi goethite-hematite gravity concentrates presents interesting and enigmatic problems. The gravity concentrates are by no means assemblages of clean, free mineral particles. Instead, the concentrates to be retreated consist of a great variety of middlings. More or less complete liberation would require grinding to minus 325 mesh, at which size only flotation could be expected to function, and even then grades and especially recoveries would not be satisfactory. A close examination of the gravity concentrates shows that grinding to 100% minus 48 mesh will produce a product which is approximately 70 weight % plus 325 mesh (see Fig. 1). The remaining 30 weight % can be deslimed and floated by conventional methods, but the resulting iron concentrate is

Jan 1, 1964

By J. T. Ryan

POISONOUS, irritating, or explosive gases are found in almost every industry, and manufacturers of gas masks are called upon to provide gas mask protection for a great variety of conditions, such as operators in horseradish factories, fumigators of homes and ocean liners, and men engaged in the manufacture of tetra-ethyl-lead, the new motor fuel. The modern type of gas mask and respirator, to provide protection against all such industrial gases, is an outgrowth of the gas mask developed during the World War to protect the soldiers against the poisonous war gases. So far, it has been possible to develop ample mask protection from all known noxious gases and fumes present in atmospheres encountered in mines, metallurgical works, and chemical and other industries, so long as there is sufficient oxygen present to support the flame of an oil lamp. The most important development of the gas mask was in providing protection against carbon monoxide- which is the noxious gas that mining men are most concerned with and, in fact, is the noxious gas that man is most frequently exposed to. This paper will be con- fined largely to the discussion of masks for underground use in metal mines. Gases that contaminate the normal air in mines can be divided into two classes: those that are given off normally by the workings, and those that are produced in mine operation.

Jan 1, 1926

By Guy N. Bjorge, A. J. M. Ross, S. J. Staple, J. D. Johnson, J. F. Wiggert

In recent years the Homestake mine has been served by three shafts, the B. &. M., the B. & M. No. 2 and the Ellison, supplemented by an inside shaft, the Milliken, extending from the 2000-ft. level to the 3200-ft. level. In 1932, when a new operating shaft was under consideration, the bottom of the mine was at the 3200-ft. level. The B. & M. and the B. & M. No. 2 shafts were down to the 1550-ft. level and the Ellison was being deepened from the 2600 to the 3200-ft. level. All ore was hoisted at the B. & M. and Ellison shafts. Levels below the 2600 level, which were under development only, were served by the Milliken shaft. Below the 1550-ft. level, the mine was served only by the Ellison shaft from the surface. Within a few years, when ore reserves above the 1550-ft. level would be depleted, operation would be limited to the Ellison shaft and the auxiliary underground shaft. The Ellison shaft alone was not adequate for hoisting the entire output from the deeper levels and also handling all men and supplies. Furthermore, assurance of safety and uninterrupted operation required two fully equipped shafts to the deeper levels. Therefore a new operating shaft was authorized in November, 1932, and was named for A. J. M. Ross, the mine superintendent. Plans for New Shaft The B. & M. shaft, begun in 1878 before much was known of the form and extent of the orebodies, was too near the ore and was endangered by ground movement. In 1924 this shaft was seriously threatened and sinking of the B. & M. No. 2 shaft, to supplant it, was begun. The latter was completed to the 1550-ft. level in 1928. In the meantime ground movement at the B. & M. shaft had practically stopped and, though loss of the shaft constantly threatened, ore hoisting was con-

Jan 1, 1937

By C. N. Garman

Homestake-New Mexico Partners operate a 750-tpd carbonate leach uranium concentrate mill near Grants, N.M. The highly mineralized water available as process water leaves much to be desired. The 628 ppm as CaCO 3 makes the use of raw water very troublesome in pipes and on filter cloths. However, the residual sodium carbonate in the final filter cake going to tails makes an ideal softening agent. To take advantage of this fact, all makeup water used in the mill is first used as tailing slurry dilution water and comes to the mill from the tailings pond. The 5-acre tailings pond serves as a thickener and 100 to 150 gpm of nearly clear solution is decanted to a pump to be returned to the mill. Since this tailings water has small quantities of uranium in the solution an ion exchange scavenger unit was installed to remove as much uranium as possible. The ion exchange raffinate is then used as final filter wash ahead of the tailings slurrying step. In spite of the large settling area this return water is not clean enough for ion exchange feed. The solids present are very fine and composed of approximately 15 pct (by weight) burnable carbonaceous material common to the sandstone uranium ores in the area, 40 pct SiOz plus 45 pct CaC03. Laboratory work showed that this material responds very well to flotation. Before deciding to use flotation, various clarifying systems such as pressure leaf filters, sand filters, and continuous vacuum pre-coat filters, were considered. Each of these could have solved the problem but with much more operating labor, more reagents and greater installation costs than the flotation step. About 100 to 150 gpm of fouled water is fed to two 66-in. Fagergren cells, in series. Reagents used at the beginning were Arquad 2HT75 and Arquad C50, at the rate of about 1% lb per 8-hr shift, or about 0.0053 lb each per ton of ore. This did not completely remove the solids but does an acceptable job. Approximately 75 pct of the slimes are a size that can be caught on a 41-Whatman Paper are removed. Removal of these slimes also allows much better settling of the coarse nonfloatable material. Advantage is also taken of this fact in a small settling tank ahead of precipitation. Removal of this amount of the slimes makes the ion t:xchange feasible. PREGNANT SOLUTION CIRCUIT The carbonate? leach-caustic precipitation method of uranium concertration does not provide for any process purification step ahead of precipitation. Therefore, any fine solids getting into the pregnant solution through the filter cloth show up in the final concentrate. This, of course, lowers the grade, and, at times, the slimy nature of these very fine solids rendered final filtration of the concentrate difficult if not impossible At Homestake-New Mexico Partners a 75-ft thickener was available for gravity clarification of 100 to 120 gpm of this pregnant solution. However this did not sufficiently remove the slimes. Laboratory investigation of the whole range of flocculants that were suggested by literature, salesmen, and friends failed to turn up anything of consequence. A continuous vacuum pre-coat filter would do the job and was investigated. The capital cost and the operating labor and materials made this a last chance choice. Following work done in the metallurgical laboratory on the tailings return water, it was found that some changes in the reagent strengths and combinations made a very definite decrease in the solids in the pregnant solution. Concentrate grade improved about 5 pct anti the final product after drying had an appreciably greater bulk density. Compared to a cost of about 2.2e per ton for pre-coat filter opelation for cleaning just one circuit, flotation costs less than 1.0 per ton of ore for cleaning two circuits. While a pre-coat filter would do a more thorough job, the flotation does all that is required for either circuit. Gravity causes the froth produced to run back into the leach circuit. This does not appear to result in a build-up of objectionable slime. No extra manpower is required; the operators in the separate areas can observe the operation of the cells and mix the small quantities of reagents as needed. Normally the 66-in. Fagergren cell requires 15 hp per cell, but this very dilute slurry needs only 10 hp for both cells. Originally, a combination of the two Arquads mentioned previously served as frothers and promoters. As further testing

Jan 1, 1962

By A. Ojanen, T-L. Huggare, A. Kuivala

An electrolytic zinc plant with a capacity of 90,000 tons/year went on stream in Kokkola, Finland, in late 1969. It is a standard electrolytic zinc process plant; however, it has been subjected to several process improvements and enlargements during its time of operation. A fluidized bed roaster treats 500 tons/day of zinc concentrates which also contain mercury. Since the mercury evaporates completely in the roasting process, a mercury removal unit has been added to prevent, contamination of sulphuric acid produced in the neighbouring acid plant. The same unit also removes selenium from the roaster gases. In a separate unit, about 6 tons a year of metallic 99.999% mercury is recovered. The neutral leaching, originally a batch process, has been converted to a continuous operation, and a residue treatment system comprising hot acid leaching and jarosite precipitation has been added. Purification comprises a "hot arsenic-zinc dust" step and a cadmium removal step with zinc dust, both operated batchwise. Purification residues are used to make about 200 tons/ year of 99.99570 cadmium in a process developed by Outokumpu Oy. The electrolytic precipitation of zinc carried out at medium current density gives zinc of 99. 995% purity.

Jan 1, 1973

By R. Gilman Brown

INTRODUCTION. MINES are interesting by reason of what they have done for man, or of what has been done for them by nature. Not all are interesting on both scores. Many profitable mines are commonplace to the geologist; and many presenting unique geological conditions have been sad failures commercially. The Standard group at Bodie has produced in 25 years, $14,500,000, paying $5,000,000 in dividends.' On the other hand, this output has been mined (almost wholly above the 1,000-ft. level) from a system of more than 100 veins, ranging in thickness-from 0.5 in. of "specimen rock" to 30 ft. of clay and quartz; distributed through a zone about 2,000" ft. in width, and representing from three to five distinct periods of formation. This group, therefore, by reason of its industrial record as well as its geological features, may fairly be regarded as doubly interesting. The Bodie district occupies an island of recent (Tertiary) hornblende-andesite, surrounded by a complex of igneous rocks and breccias. It lies at the summit of the eastern foot-hills of the Sierra Nevada mountains, and within the Great Basin, a few miles from its western edge, marked here by Mono lake on the line of the Great Fault. The average elevation of the outcroppings of the veins may be taken at about 5,700 ft. The andesite projects from south to north in a great tongue, 12,000 ft. long and 5,000 ft. wide, reaching an extreme height at the northern end of perhaps 1,000 ft. above the adjoining small canyons. These separate it from the main mass of the foot-hill

Jul 1, 1907

By RICHARD MAIZE

IN this critical period of our history, the coal industry of the nation, faced with many obstacles, performed its work safely during the first ten months of 1943. Thousands of the younger mine workers were inducted into the armed forces of our country and in many instances their jobs have been filled by others without much if any experience and training. This situation alone would seem to be sufficient to interfere with the safe and orderly operation of the industry but the Government's demand for a substantial increase in coal tonnage over that produced in normal times introduced a hazard which always accompanies speed, regardless of the skill of the worker.

Jan 1, 1944

By J. S. Kasper, R. M. Waterstrat

IN view of the recent findings of a pronounced ordering of atoms in s phase alloys containing elements of the first long row of the periodic table (and including molybdenum),l it is of interest to resolve the question of ordering for s phases containing second and third-row elements. Examples of the latter have been provided recently by Greenfield and Beck2 and two of them, Re-Cr and Ru-Cr, would appear to be favorable for a study of ordering by X-ray diffraction methods because of the considerable differences in the scattering factors concerned. In addition, s phase is found to occur in the Os-Cr system, where the difference in scattering factors is even larger. Accordingly, X-ray powder intensities have been measured in an attempt to learn the nature of the ordering, if any, in these three v alloys. Since there is no reported work on intermediate phases in the Os-Cr system, an exploratory investigation was made in this system, and it was found that, in addition to the s phase, the phase with the A-15 or ß-W structure also occurs. Specimen Preparation—The alloys were prepared by compressing mixed powders of —200 mesh size and sintering in an atmosphere of pure dry hydrogen. All alloys were rapidly cooled from the annealing temperature to room temperature in a stream of cold dry hydrogen in a water-cooled chamber. Table I lists the sources and purities of the starting materials, as well as the details of processing for each of the alloys investigated. Intermediate Phases in the Os-Cr System—In the absence of information on intermediate phases in the Os-Cr system, it was suspected that this system would resemble that of Ru-Cr, where a s phase, RuCr2,2 and a phase with the A-15 structure, RuCr3,3,4 have been identified. Both these phases were found in the Os-Cr system and at compositions

Jan 1, 1958

"Located at Canyon Ferry on the Missouri River, 17 miles from Helena and 63 miles from Butte. River drainage area 15,570 sq. miles. Built in 1898.DAM: Rock-filled, wooden crib, 490' long and 39' feet at maximum head; also masonry core, earth bulk-head 300' long and granite masonry abutments.SPILLWAY: 473' long, crest elevation 3660.5; steel flashboard system 10' high.PENSTOCKS: 10 main penstocks, 12' diam., about 40' long, leading from canal to turbines, each supplying 1 pair turbines.WHEELS: 4 main center discharge, horizontal units, each 1 pr. of 42"" wheels made by Dayton Globe Iron Works, and 6 main units, each 1 pr. of 45"" wheels made by S. Morgan Smith Co., all 157 r. p. m., normal head 34', and direct coupled to generators.GENERATORS: 10 W. E. & M. Co., Kodak Type, revolving armature, 750 k-w., 157 r. p. m., 550 v., 3 phase, 60 cycle alternators.OPERATION: The plant has large water storage and can carry peak loads to 12,000 h-p. It is the central control station for the system."

Jan 1, 1913

By H. E. McKinstry

LIKE nearly everything else, mining geology has been reconverting. Many geologists had been in military and other government service. Many more, with mining companies, had been working primarily toward increasing production from known reserves. All of these are turning now toward their normal peacetime endeavor-the search for new ore; for most mining companies, finding themselves with accumulated deficits in development work, are more than ready to go ahead with their postwar plans made a year or more ago but still stalled at the close of 1945 for lack of man power. These plans include not merely development in the old home camp but also wide exploration for new prospects both domestic and foreign. Most of the large concerns have geologists and engineers in the field in the United States, despite the outlook for higher mining costs here, and at least half a dozen strong American companies are already investigating opportunities abroad, notwithstanding past unhappy experiences in certain Latin-American nations which have welcomed capital but later found means of preventing investors from reaping the reward of their enterprise. A few of these new foreign expeditions are following well-planned programs, but too many, in their haste to get any sort of footing, are proceeding without well-considered policy. with the result that their geologists can do little more than desultory scouting.

Jan 1, 1946

By R. B. Sosman, J. C. Hostetter

It is well known that ferric oxide, Fe2O3, is paramagnetic, while magnetite, Fe3o4, is classed among the highly ferromagnetic substances. But magnetic data on oxides intermediate in composition between Fe2o3 and Fe3O4 have been almost completely lacking. Fe2O3 and Fe3O4 form a solid-solution series, according to present evidence.' In this series the properties change continuously from Fe2O3 toward Fe3O4, as the percentage of FeO increases from zero toward 31.03, which is the percentage in magnetite. It is possible that there is a break in the series near Fe3O4, but it has not yet been possible to establish the existence of such a break experimentally. The occurrence of solid solution in this series is shown by the dissociation pressure, or oxygen pressure in equilibrium with the oxides, which falls continuously over the range from Fe2O3 to Fe3O4. The oxygen-pressure curves at 1100" and 1200" are shown in Fig. 1. The existence of solid solution is also demonstrated by the continuous change in optical properties from Fe2O3 over to a composition containing about 18 per cent. FeO, at which point the opacity of the oxide becomes so great that it is impossible to obtain measurements at higher percentages of ferrous iron. Natural oxides of iron intermediate in composition between Fe2O3 and Fe3O4 are much more common than is generally supposed. If a mineral oxide is not strongly attracted by a small hand magnet and if it gives a red streak, it is usually labeled "hematite." If it is strongly attracted by the hand magnet it is usually labeled "magnetite" without further tests. As we shall show later, oxides containing from 1 up to 31 per cent. FeO can be thus erroneously lumped together as "magnetite." It is a fact, nevertheless, that the great bulk of natural oxides of iron lie fairly near either Fe2O3 or Fe3O4 in composition. The reason will be

Jan 1, 1918

By B. Meddings

The technology involved in the Sherritt process for the recovery of nickel and cobalt from sulphide concentrates and mattes is presented in a manner which emphasises the chemistry of the process. The hydrometallurgical process takes advantage of the differing stabilities of the various oxy-acids of sulphur from thionates through thiosulphates to sulphate. Some separations are based upon stability differences, some upon kinetic differences and some upon valence state differences and similarities The engineering and economic factors involved in hydrometallurgy are not discussed in either detail or depth.

Jan 1, 1981

By R. C. Davis, R. F. Berry, G. W. White, B. T. O’Connell, L. A. Stacha

P,, and v, may now be solved for by trial and error between Eqs. 2 and 3, by assuming time approaching zero and equating PI, to P12. Observe that the pressure under the slug, P12 of Eq. 3, does not remain equal to the P1, at the valve in Eq. 2 as the slug proceeds up the hole. To plot the profile of pressure vs depth, it is necessary to express P12 in terms of P11. To do so, the extent to which the original submergence length S changes with respect to time must be analyzed. At the end of time t after injection, the actual value of L in Fig. 3 is The fall-back v,(t) is now distributed in the gas and exerts pressure on the bottom. This, in addition to the weight of the gas, amounts to the difference in pressures from point to point. With the average pressure profile calculable, a true numerical value for the average pressure in the tubing may be obtained. The value of v, must be obtained experimentally, and since v,, S and D are known, the basic Eq. 1 may be solved for the amount produced. Knowing P, and the actual volume of tubing occupied by gas (vat), it is possible to calculate the volume of gas at standard conditions which is present in the

(There are 70 Student Chapters in the United States, 2 in Canada) University of Alabama-University, Alabama, Mining and Metallurgical Society, Win L Mason University of Alaska-College, Alaska, Mining Society of the University of Alaska, E H Beistline University of Arizona-Tucson, Arizona, Miners Society Birmingham-Southern College-Birmingham, Alabama, Pick and Hammer Club, Daniel D Arden University of British Columbia-Vancouver, British Columbia, G M Dawson Club, H C Gunning University of California-Berkeley, California, Mineral Technology Association, W H Somerton Carnegie Institute of Teehnology-Pittsburgh, Pennsylvania, The Metals Club, Gerhard Derge Case Institute of -Technology-Cleveland, Ohio, Case Metallurgical Engineering Society, Robert F Hehemann

Jan 1, 1956

By Arthur F. Taggart, Herbert H. Kellogg, Nathaniel Arbiter

The experimental work herein described is presented in support of the following broad hypothesis: Conditioning of metals and metallic sulphides by amine collectors involves metathetic reaction at the solid surface between the collector and an oxidized metallic compound, to produce a coating comprising an amine-bearing compound of low solubility in the system. The type of reaction is different in acid and in basic solutions; both types may occur simultaneously in near-neutral pulps. Experimental The experiments comprise contact-angle tests with a variety of metals and metallic sulphides and extraction teats on ground chalcocite. Contact-angle tests were made principally on metals. Covellite paralleled metallic copper in amine solution at pH 8.8 (Table 3) and in alkaline water, but maintained an angle of about 70° in Io-3 HCl solution, where metallic copper lost its angle. The tests with anionic collectors (Table I) indicate that the behavior of metals in general is parallel to that of their minerals in anionic solutions. It is believed that this is generally true with cationic collectors also, but the covellite test is a warning against a broad assumption to this effect. All test specimens were mounted in Transoptic.* All tests in conditioning solution were preceded by a test in distilled water; cleaning and polishing were continued in every case until the angle in water was zero. Subsequent transfers into and out of solutions and test cells were made in such a way as to prevent exposure of the surface to air.1 The amine used was primary laurylamine, Armour and Co., AM-1120. It was used in the form of the hydrochloride, obtained by precipitation with gaseous hydrochloric acid from an ether solution of the amine, and purified by two recrystallizations from ether-alcoho1.2 Inorganic and other test reagents were standard laboratory grades. Temperatures were not controlled; the probable range of test-solution temperatures is 650 to 80°F.

Jan 1, 1943

By Herbert H. Kellogg, Nathaniel Arbiter, Arthur F. Taggart

The experimental work herein described is presented in support of the following broad hypothesis: Conditioning of metals and metallic sulphides by amine collectors involves metathetic reaction at the solid surface between the collector and an oxidized metallic compound, to produce a coating comprising an amine-bearing compound of low solubility in the system. The type of reaction is different in acid and in basic solutions; both types may occur simultaneously in near-neutral pulps. Experimental The experiments comprise contact-angle tests with a variety of metals and metallic sulphides and extraction teats on ground chalcocite. Contact-angle tests were made principally on metals. Covellite paralleled metallic copper in amine solution at pH 8.8 (Table 3) and in alkaline water, but maintained an angle of about 70° in Io-3 HCl solution, where metallic copper lost its angle. The tests with anionic collectors (Table I) indicate that the behavior of metals in general is parallel to that of their minerals in anionic solutions. It is believed that this is generally true with cationic collectors also, but the covellite test is a warning against a broad assumption to this effect. All test specimens were mounted in Transoptic.* All tests in conditioning solution were preceded by a test in distilled water; cleaning and polishing were continued in every case until the angle in water was zero. Subsequent transfers into and out of solutions and test cells were made in such a way as to prevent exposure of the surface to air.1 The amine used was primary laurylamine, Armour and Co., AM-1120. It was used in the form of the hydrochloride, obtained by precipitation with gaseous hydrochloric acid from an ether solution of the amine, and purified by two recrystallizations from ether-alcoho1.2 Inorganic and other test reagents were standard laboratory grades. Temperatures were not controlled; the probable range of test-solution temperatures is 650 to 80°F.

Jan 1, 1943

By S. R. Mitchell, M. Weissman, J. H. Brown

It has been demonstrated that for fine grinding operations, the energy input (E) and the product size modulus (k) are related by an equation of the form E = Ak1-n (1) where "A " and "n" are constants.(1) Also, it was suggested that "A" is determined by the comminuting device and that "n" depends primarily on the rock. It was the purpose of this investigation to study these constants by determining the form of an energy-size reduction relationship over an extreme range of energy inputs, and at the same time, to evaluate the minimum particle size produced during grinding. The comminution system consisted of a stainless steel laboratory ball mill in which quartz was ground at 60% solids for times ranging from 1 minute to 700 hours. The mill which measured 10" diameter by 12" long was loaded with about 60 pounds of balls ranging in diameter from 3/8" to 1-1/8" and was driven at 55 r.p.m. Quartz was selected for the tests because it is a brittle material for which size distribution data were expected to show a constant distribution coefficient regardless of product size.(1) This permitted specification of product size by a size modulus alone. The quantities measured were the time of grind (measure of energy input) and the specific surfaces of the products. Since no accurate method is available yet for determining particle size directly in the very fine size ranges specific surface data were used for this purpose. The relationship between these two quantities may be expressed as where Cis a constant which includes a shape factor, p is the specific gravity of the solid,_S is the specific surface and D is an equivalent particle diameter. For a material in which the distribution coefficient does not change with size the term (l/S) may be substituted for k in equation L if the proportionality constant "A" is changed correspondingly. This substitution was made in this work but in addition, screen analyses were made on several products to verify the equivalence of the two methods of size specification. EXPERIMENTAL DETAIL QUARTZ Quartz from two sources was tested. One series of tests was made on a clear, high purity crystalline quartz from Brazil and Arkansas, and another series was run on massive quartz fromNewHampshire. Grinding charges of the high purity material consisted of 2000 gram samples of -3-8 mesh particles, while the charges of the New Hampshire quartz were 500 gram samples of a -35+48 mesh screen fraction. The difference in the sizes of these two series of charges was not significant in view of the extreme size reduction accomplished, and the New Hampshire samples were smaller to permit ginding to finer sizes in shorter times than required for 2000 gram lots. SAMPLING AND ANALYSIS Separate charges were ground for all tests in which the grinding times were less than one hour and for all tests on New Hampshire quartz since these products were difficult to sample accurately without affecting the entire charge. During the long time grinding tests the mill was

Jan 1, 1961

The following is an incomplete list of members and guests who called at Institute headquarters during the period July 11, 1918 to August 11, 1918. John Carter Anderson, Tucson, Ariz. Edson S. Pettis, San Francisco, Cal. Lieut. Frank A. Ayer, Tyrone, N. M. Wm. H. Rettie, Yonkers, N. Y. W. R. Canton, McGill, Nev. J. T. Robertson, Port Richmond, S. I. Alden Crankshaw, Palmerton, Pa. Harry O. Robinson, Margarita, John Davenport, W. Norfolk, Va. Venezuela. A. Faison Dickson. C. K. Seng, Gilbert, Minn. F. A. Fahrenwald, Cleveland, C). E. S. Sheffield. L. Hall Goodwin, New York. H. G. Smith. W. H. W. Hamilton, Baker, Ore. Harry M. Spoor. Floyd D. James, St. Louis, Mo. H. H. Stoek, Urbana, Ill. George A. Laird. Arthur L. Tuttle, Copperhill, Tenn. J. W. McBride, Spokane, Wash. Thor Warner, Phoenix, Ariz. Arthur Notman, Bisbee, Ariz. Christopher G. Atwater, Manager Agricultural Dept., The Barrett Co., is in Washington serving the U. S. Navy Bureau of ordnance in connection with the Navy nitrate plant recently authorized by Congress. Edward Ludlam Blossom announces his marriage to Mabel Townsend, daughter of Mr. and Mrs. George Comings Mills, on Wednesday, July 17, 1918, at New York City.

Jan 9, 1918

By T. Egleston

DURING the year 1873, my attention was called to the frequent accidents, resulting from the breaking of rails, on the different railroads in this country, and I was requested to investigate the subject. The plan of investigation I proposed was to ascertain, in as many cases as possible, the exact history of broken rails, both in this country and in Europe; to collect information in Europe relating to the tests which rails used there were required to undergo, and to experiment upon the pieces of rails broken on the road, with a view to ascertain whether their fracture was due to their chemical constitution, bad manufacture, to a reduction in strength owing to temperature, or to physical changes in the constitution of the rail. The investigation was commenced by the collection of statistics, and for this purpose I spent several months in Europe, collecting information on the subject of broken rails, as well as the life of iron and steel rails generally, and inquiring into the systems of purchasing and of testing them employed by the railroads there, intending, on my return, to make a series of analyses of rails broken, both in this country and in Europe; to ascertain, if possible, how far great cold had an influence on the fracture ; to examine whether the rail broken, either on the road or afterwards, underwent, at or about the fracture, any physical change, and to make a series of experiments on the strength of rails manufactured in the United States or sold in the American market. Unfortunately, the panic of 1873 came on, just before my return from Europe, and prevented the carrying out of the larger part of the plan proposed ; as, however, I had collected in the meantime, a large number of statistics of different kinds from all parts of Europe, and had made a number of interesting experiments and investigations, I have thought it would be worth while to communicate some

Jan 1, 1875

By David W. Brunton

The list of our past-Presidents comprises the names of many who, in their official addresses, have sketched the current progress of the arts and professions with which they were familiar. Such addresses are, in my judgment, highly useful, setting forth the results of our own work as a society, and recalling to our minds the particular lines in which discussion would prove most fruitful. Following this course with some hesitation, I venture to offer an outline of the recent improvements and the present situation in mining and metallurgy in the Western United States. The wonderful advances in mechanics, chemistry, and electricity have all combined to aid these arts to such an extent that progress during the last decade has undeniably been more rapid than ever before in the history of the profession. In all mining countries improved transportation-facilities, in many instances called into existence by the traffic created by the mines themselves, have done much to enlarge the field of operations by the reduction of freight-, operating- and living-expenses, thereby bringing lower-grade properties into the producing class. Under normal conditions, as the age of a district increases, all these different factors should combine to off-set the augmented costs attendant on deep mining, and greatly tend to prolong the profitable life of the mines. The more recent and important improvements in our Western mining-practice which have contributed most towards the advancement of the art may be briefly summarized as follows; but, before beginning this portion of my address, I wish to thank most heartily the many engineering friends who have so

Jan 1, 1910