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A SELF-RESPECTING miner doesn't wash the cuttin's off his hard hat until he quits his job but, on the other hand, he keeps his lamp clean and a "spot" focus on the work at hand; the former habit is a matter of pride and the latter serves for efficient operation. During 1949, the mining engineer got all the "wet raises" for the problem of cutting costs to meet the drop of metal prices and keeping research work up to schedule when strikes tied up his work were his headaches. We note, not without admiration, that he hasn't washed the muck off his hat in token of surrender but, on the contrary, his light shines bright on the job to be done as can be seen in the following pages. Few people have any conception of how much ore and rock have to be mined and how much sorting it takes to cull a pound of copper from a 1 % ore body. These people would be even more startled to picture the problems faced by the engineer in mining and extracting, profitably, .2 oz of gold from a ton of ore as is done at some of our lode mines. Strikers have sometimes kept our researchers from their pilot plants and research laboratories, but the end of the year shows progress in making ore out of taconite and ferruginous sandstone, with a pilot plant in operation at Aurora, Minn., and plans for one near Birmingham. Unfortunately, it looks as though the mining engineer will have to make John Doe secure in mineral resources in spite of himself. Coal for steel, power, and to warm our homes is still economically possible, in spite of Mr. Lewis, through development of mechanized tools for mining. During the year, the use of continuous mining machines has extended, transport systems are being adopted to keep the ore flowing from the face to the tune of 40 tons per man-shift. Experiments in the gasification of coal are going forward in several places and may eventually extend our fuel reserves by the addition of coal seams now too lean for mining. Liquid fuel from coal, oil shale, or natural gas will become economic when oil consumption exceeds our supply; but, at less than 30 cents a ton direct cost for mining oil shale, the engineer is almost making it competitive under present market conditions. In this age of specialists, the mining engineer is still holding his own as a broad-gauge man. As a matter of fact, he is emerging from a stage of semispecialization as a coal, nonmetallics, or metal mining man to the realization that, with mechanization, mining is fundamentally materials handling whether it is fluorspar, coal, or copper ore. From the coal business come rubber-tired mechanical loaders to the iron mines of Birmingham. Shuttle cars are also finding application in the lead mines of the Tri-State. Open-pit methods are universal. Belt conveyors, trucks, Diesels, and mobile, jumbomounted drills are finding application in all types of mining. In preparation, such methods as flotation,- heavy density, electrical, and centrifugal are finding application in coal, nonmetallics, and metals. These concepts have been recognized by the mining engineer who has kept himself informed and has been quick to seize a method, machine, or a process from another operation and, with ingenuity, applied it to his problems. This, our Annual Review issue, is written by mining engineers. In gathering these separate articles under one cover for publication, we think of it as a trrbute to the tireless energy and skill of these men. They get little of the publicity accorded physicists, medical men, labor leaders, or company executives, but they supply raw materials without which industry would die.

Jan 1, 1950

BUSTS of James Douglas and his friend, Ben Williams, placed in front of the library at Bisbee, Ariz., were unveiled there on April 8, and the connection of the two men with the development of the. Copper Queen mine was reviewed. Judge Bisbee, the brother-in-law of Ben Wil-liams, secured an option on the Copper Queen claim, financed its development and sent Ben Williams in to build the smelter, which turned out its first copper in November, 1880. Dr. Douglas, who was then superintendent of the Chemi-cal Copper Co., at Phoenixville, Pa., had a refining plant and, looking for more metal to refine, came to Bisbee early in 1881, where he negotiated a contract to refine the Copper Queen copper.

Jan 5, 1928

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

Jan 8, 1919

By H. A. Winne, B. R. Prentice

THE announcement of this World Conference on Mineral Resources briefly traced the development of the metals industries over the past 75 years The various phases were characterized as iron and steel for the railroad era, then copper and the electrical age, through alloy steels to the age of light metals in World War II, ending with the curtain rising on the atomic age at the end of the war The interests of mining and metallurgical industries in the atomic age may perhaps be divided broadly into three - groups (1) production of the special materials required by atomic-energy installations and processes, (2) use of atomic power in the mining or refining of materials, (3) use of radioactive isotopes and radiation in metal and chemical processes both for laboratory study and in the production of materials for use in any field In the production of special materials, the mining and metallurgical, scientific and industrial groups have already contributed much to the start of the atomic age The mining, refining and fabrication of the basic uranium to a degree of purity and form suitable for production of plutonium in the Hanford Engineering Works is just one example. The production of graphite for the Hanford piles, sufficiently free of neutron-absorbing impurities to allow a chain reaction with natural uranium, was a signal achievement These, together with many

Jan 1, 1947

By AIME AIME

AN outstanding session of the Annual February Meeting was one held under the joint auspices of several groups on Tuesday afternoon, Feb. 22, as a symposium on the question of preserving peace in the postwar era through the control of the supply of sundry minerals vital to the Axis nations. D. H. McLaughlin and R. C. Allen were associate chairmen. And C.K. Leith led the discussion.

Jan 1, 1944

By S. Usui, I. Iwasaki

The effect of pH on the adsorption of dodecylamine at the mercury-aqueous solution interface was investigated by differential capacity and electrocapillary measurements. With dodecylammonium acetate, the differential capacity curves showed two desorption peaks in the cathodic branch with their relative intensities varying with the solution pH. With dodecyltrimethylammonium chloride, only one cathodic de-sorption peak was observed in the same pH range. Through thermodynamic analysis of the electrocapillary curves, the adsorption density of undissociated amine was evaluated separately from that of aminium ion. The adsorption densities of the un-dissociated amine and of the total amine increased with increasing pH. The ratio at the interface of undissociated amine to aminium ion was several orders of magnitude greater than the ratio in the solution and increased with increasing pH. The potential at the closest distance of approach of counter ions to the mercury surface was compared with values of zeta potential on quartz previously reported. The most important variable in the flotation separation of minerals is probably the pH of the pulp, and a number of theories have been proposed to explain its effect on the condition of the mineral surfaces, on the dissociation of collectors and of inorganic and organic species (accidentally present or intentionally added) in the pulp, and on the mineral-collector interaction. In the development of a theoretical background for oxide flotation systems, an experimental approach based on electrokinetic measurements has been of much value, although the effect of pH becomes confounded since it governs both the electrochemical conditions of the oxide surface and the dissociation of the collector. For investigation of the adsorption behavior of long-chain collectors on oxide minerals, however, electrokinetic potential measurements are the most widely used technique. Hydrogen and hydroxyl ions are found to be the potential determining species, thereby governing the interfacial electrical conditions. The electrostatic interaction between the charged mineral surfaces and ionized collectors is regarded as the driving force for the adsorption of the collectors. An association of alkylamine collectors adsorbed on quartz surfaces has been postulated from streaming potential measurements, and a term "hemi-micelles" has been proposed.' The possibilities of coad-sorption of undissociated amine along with aminium ion has been inferred from contact angle measurements? and from adsorption studies.~ Electrochemical titration as applied to silver sulfide provides a more quantitative approach to the analysis of the electrical double layer at an ionic solid-solution interfaceqG and the electrochemical evidence for the adsorption of amine at pH 4.7 indicates a specific affinity of dodecylammonium ion towards silver sulfide surfaces, whereas at pH 9.2 the adsorbed species might be free arnine." A combination of differential capacity and electrocapillary measurements on a dropping mercury electrode was reported to be a sensitive method of provid- ing reliable information on the adsorption behavior of dodecylammonium acetate (DAA) at a natural (near neutral) pH.? It was also shown that there were striking similarities in the properties of the double layer and in the adsorption behavior of the amine on mercury and on such ionic solids as quartz, silver sulfide, and silver iodide. The effect of pH on the differential capacity curves at a mercury-sodium fluoride solution interface has been investigated by Austin and Parsonss who reported that between pH 7 and pH 11 there was very little effect. In the present paper, the adsorption behavior of DAA was investigated as a function of pH through differential capacity and electrocapillary measurements and the information gathered was correlated with that available in literature on quartz and silver sulfide. Experimental The apparatus and the method used for determining the differential capacity and the electrocapillary curves were identical to those described previously.' The ionic strength of the supporting electrolyte was fixed at 0.1 M with potassium fluoride, and the pH of the solution with potassium hydroxide. Only the neutral to alkaline range was covered in order to avoid the dissolution of the glass vessel with hydrofluoric acid. Results In Fig. 1 the differential capacity has been plotted against the applied potential at a DAA concentration of 10-' M at three different pH values. The curves are characterized by one capacity peak in the anodic branch, by two capacity peaks in the cathodic branch, and by a marked depression in capacity between the peaks. The depression indicates an adsorption of the arnine in this potential range. One of the cathodic peaks appears at pH 7.3 near -1.4 v and decreases with increasing pH. The other appears at pH 8.9 near —1.2 v and increases with increasing pH. At pH 9.6 only the latter peak is observed. Beyond the cathodic peaks, all the curves tend to converge with the curve in the absence of DAA, implying that two different species are being desorbed in this potential region. The anodic peak near 0.0 v increases markedly with increasing pH. The well-defined anodic peaks at pH 8.9 and 9.6 were accompanied by an appreciable increase in the current flow (in excess of O.luA), and, therefore, is a "pseudo-capacity"'" due to a

Jan 1, 1971

NEW MEMBERS The following list comprises the names of those persons who became members during the period Feb. 10 to Mar. 10, 1915: Members BANKS, HAROLD PURDY, Min. Engr 61 Broadway, New York, N. Y. BARAGWANATH, JOHN G., Min. Engr., Morococha Mining Co.; Morococha, Peru. BEESON, JOSEPH JOSIAH, Min. Geol Stanford University, Cal. CALLOWAY, ALFRED W Pres., Davis Coal & Coke Co., Cumberland, Md. DEETRICK, JAMES W., Mgr., Republic Iron & Steel Co., 826 Pennsylvania Ave., Youngstown Ohio.

Jan 4, 1915

By Henry M. Howe

Preparing the Metals.—Ordinary silver wire was hard-drawn to No. 23 Brown and Sharp gauge; it was cut in two, and one piece was carefully annealed in the ordinary way. The wire was prepared by Messrs. Guild and Delano, jewelers, Boston. The Ansonia Brass and Copper Co., Ansonia, Conn., kindly furnished me with some hard-drawn copper wire No. 31, A. W. G., and some of the same wire after annealing in the ordinary way.

Jan 1, 1885

By P. D. I. Honeyman

CHANGING trends in concentration, involving regrinding with the subsequent production of a finely divided, high-grade flotation product, presents a real problem to the modern copper smelter. In the treatment of such a material, handling difficulties are numerous and potential possible losses may be very great. In many plants, of course, preliminary roasting of the furnace charge remains an economical necessity. Under such circumstances, the operator has no alternative except to follow orthodox roaster reverberatory practice, though taking all possible precautions to avoid excessive dust losses and bad working conditions. In other plants, roasting is not only unnecessary but would be highly undesirable, and at best the charge would be merely dried before entering the reverberatory furnace. In the latter case the possibilities of raw charging loom large. The Miami plant of the International Smelting Co. handles the entire output of concentrates of the several mining companies operating in the Globe-Miami district. All of these companies produce a flotation concentrate which, at the Miami Copper Co. particularly, is all reground and is high in grade. In addition, the Inspiration Copper Co. ships a substantial tonnage of high-grade cement copper to the smelter from its leaching plant. Following the flow sheet of the original plant, all such material received was bedded, dried in Wedge furnaces and smelted in reverberatory furnaces. At times during the history of the plant it has been necessary to carry the drying operation further, to a partial roast, before reverberatory smelting. Since the charge contained over 80 per cent flotation concentrates, the handling of which in a dried condition was at best a dusty job, unusual precautions were taken to cut down dust losses. The Wedge furnace plant was equipped with a Cottrell treater and all hoppers and calcine cars were carefully designed to cut down dust loss in transferring the so-called calcine from hoppers to car and from car to furnace. In the furnace itself the dusting problem was a severe one. Arch erosion was very rapid and flues and waste-heat boilers rapidly filled up with a partly smelted flue dust.

Jan 1, 1932

By Charles Legrand

The problem of mine pumping is so much affected by local conditions, and those conditions are so liable to changes during the life of a mine, that the best system to use is difficult to determine. The experience of the writer has been that, in general, for copper mines, electric pumping is most satisfactory unless the quantity of water to be pumped is great or the mine does not use electric power for any other purpose. As a rule, however, figuring on the cost of necessary power plant, the total cost of installation is greater with electric pumps than steam pumps. As the water is liable to be gritty, outside-packed plunger pumps are to be recommended, and if the water is not acid, or only slightly so, chilled cast-iron plungers pay for their extra cost very quickly in diminished cost of packing. With chilled plungers it is possible to use metallic packing instead of soft packing, if the water is not too gritty or the lift too high. In vertical pumps this packing is satisfactory for lifts up to 400 ft., in the experience of the writer, and may be found satisfactory for higher lifts. For water slightly acid, cement-lined pump bodies have given good satisfaction. For acid water, both plungers and puhp bodies should be made of acid-resisting bronze. For high lifts, especially with gritty water, a satisfactory pump valve is difficult to find. To reduce the unbalanced pressure on the valve at time of opening it is advisable to have narrow seats; this, however, brings high pressures on the seats when the valve is closed. On large valves for lifts of 600 to 1,000 ft. we have used leather, hard rubber, vulcanized fiber, and soft brass; for clear water the latter has given best satisfaction. The difficulties due to grit make it advisable to have large sumps where water can settle, and if possible, to have two of them so that they can be cleaned alternately. At the mines of the Old Dominion Copper Mining & Smelting Co., Globe, it was found that a small air ejector discharging into a mine car provides a very convenient way to clean mud and sand from a sump.

Jan 1, 1916

By Orville R. Lyons, A. C. Richardson

DURING the past few years there has been a growing demand by coal operators for detailed information about the performance characteristics of the various dryers now being manufactured, preferably in such a form that the information could be used to determine the type of dryer best suited to a particular drying problem. A few operators have been desirous of going even further, because they are of the opinion that present-day dryers are not properly designed and that fundamental studies of dryer design should be undertaken. This growing demand for a method of dryer evaluation and the indicated need for fundamental research resulted in the sponsorship by Bituminous Coal Research, Inc. of a project at Battelle Memorial Institute to investigate the thermal drying of coal. In investigating this problem, the most feasible method of attack appeared to be a survey of active operations to determine the present status of the thermal drying of coal. Data were obtained, usually by actual plant tests with the cooperation of the various preparation engineers and their staffs, for Q screen-type dryers, 8 rotary- type dryers, 3 continuous-pallet-type dryers, 2 flash-type dryers, I tray-type dryer, and I cascade-type dryer. The testing program provided: (I) data for 24 coal- drying operations, (2) information about dried, (3) information about the previous treatment that the coal had received, and (4) information about operating costs. The data obtained through the dryer survey and relationships determined from the data make it evident that all of the types of dryers included in the survey can be operated with the same degree of effectiveness if each type of dryer is used to dry the sizes of coal for which it is best suited. It should be noted that it is usually undesirable and often impossible to dry different sizes of coal in one type of dryer. By use of the data in the report, any prospective dryer user, having determined the surface moisture percentage and screen- size analysis of the coal to be dried, the tons of water to be removed per hour, and the final surface moisture percentage desired, should be able to determine with a fair degree of accuracy: (I) the difficulty of the drying problem, (2) the approximate cost of drying, (3) the required dryer inlet gas temperature and volume and exhaust gas temperature and volume, (4) the type of dryer to use, and (5) the size of dryer required. The method of testing the dryers and determining the difficulty of drying can be used by operators already having dryers to check the performance of their particular dryer and determine whether they are operating effectively. Considerably more information was obtained from the survey of thermal drying than was anticipated when the survey was first considered. However, a great deal of work still remains to be done in the field

Jan 1, 1948

By D. Muraoka

Introduction Soda ash, anhydrous sodium carbonate, is produced from underground trona deposits occurring in the Green River Basin of southwestern Wyoming. Stauffer Chemical Co. of Wyoming, a jointly owned subsidiary of Stauffer Chemical Co. and Rocky Mountain Energy Co., mines the trona and processes it into high-purity soda ash. Stauffer Wyoming has been in operation since 1962 with a current production capacity of about 1.8 Mt (2 million st) per year of soda ash. The refinery has five parallel operating trains using the monohydrate process which is a series of chemical processing unit operations described below. Screening and Crushing The mined trona is brought to the surface in two counterbalancing ore skips. The ore is initially screened with refinery feed (less than peagravel size material) entering the process. Oversize is conveyed to an outdoor stockpile. Ore is recycled from under the stockpile via cone feeders as the refinery needs require. The ore is conveyed to hammer type crushers and screened. The refinery feed enters the process and the oversize is recycled to the crushers. Calcining The first step in refining trona to soda ash is calcining the trona ore. This is accomplished in concurrent flow, rotary kilns that are direct fired with natural gas. [2 (Na CO NaHCO 2H O) Heat 3Na CO + 5H20 + CO 2 3~3~ 2 ~~2 32] The trona ore is fed to the kiln at the burner end and is intimately mixed with the hot exhaust gases from the burner. Direct contact with the flame is avoided. The ore moves down the kiln by gravity and rotation aided by the kiln's internal lifters. The exhaust gases are cleaned to 99 + % particulate removal and discharged to the atmosphere. Dissolving the Calcined Trona The calcined trona is conveyed from the kiln discharge to a rotary drum dissolver where it is mixed with water and weak solution (unsaturated solution of calcined trona in water). The calcined trona is soluble whereas the impurities, primarily shale, are insoluble. The discharge from the dissolver is a slurry containing saturated solution (about 30% dissolved calcined trona in water), some undissolved calcined trona, insoluble impurities, and organic impurities. The dissolver discharge enters a rake classifier that makes the first solid/liquid separation in the process by removing the heavy undissolved material from the saturated solution. This undissolved material is conveyed to a second rotary drum dissolver and mixed with water to dissolve any remaining calcined trona. The secondary dissolver discharges to a second rake classifier that separates the solids from the liquid. The solids are now primarily insoluble impurities with very little unrecovered calcined trona. These wastes are conveyed to evaporation ponds for disposal. The liquid from the secondary rake is recycled to the primary dissolvers' weak solution system. Returning to the primary rake classifier, the saturated solution which contains suspended insoluble muds is pumped to a thickener. Flocculant is added to aid settling of the suspended muds. The flocculated muds are collected at the bottom of the thickener and pumped to vacuum cloth filters. The adhering saturated solution is separated from the muds that remain on the filter cloth. The recovered solution is returned to the dissolvers' weak solution system. The muds are reslurried and pumped to the evaporation ponds for disposal. Saturated solution, containing some suspended insoluble muds along with the organic impurities, overflows the thickener. Filtering the Saturated Solution The saturated solution overflowing the thickener enters a holding tank where it is pumped to a bank of pressure leaf filters. The suspended muds are captured on the filter leaves while the cleaned saturated solution is pumped to polishing filters. The polishing filters are also leaf pressure type, intended to remove any suspended solids that may pass the primary filters. Organic impurities are removed with activated carbon. The purified solution is now free of insoluble muds and has most of the organic impurities removed. Crystallizing and Drying the Monohydrate The purified saturated solution is pumped to evaporative crystallizers. The solution is circulated from the crystallizer vessel through a heat exchanger. Indirect contact with steam in the heat exchanger causes the saturated solution to boil, thus crystallizing the soda ash in its monohydrate form. Slurry crystal density is maintained in the crystallizer by simulta¬neous feed of fresh saturated solution and drawoff of the slurry.

Jan 1, 1986

Arizona F. P. MATHEWSON, Chairman F. W. MACLENNAN, First Vice-chairman _CLYDE F. WEED, Second Vice-chairman F. D. GARDNER, Secretary-Treasurer Box 4097, University Station, Tucson, Ariz. ARTHUR CROWFOOT G. H. DOWELL HENRY F. FASTER R. D. LEISK Boston Meets first Monday each month, October to May, inclusive FREDERICK K. MORRIS, Chairman DANIEL CUSHING, Vice-chairman F. LEROY FOSTER, Secretary-Treasurer Rooms 6-202, Mass. Inst. of Tech., Cambridge, Mass. WILLIAM H. COBURN RUSSELL 01550K

Jan 1, 1934

By R. W. Raymond

THE question, what is the best proportion among weight, fall, and speed of stamps, is one which has not yet received thorough and systematic examination. In considering the economical application of stamping machinery, we meet, at the beginning, with serious difficulties in obtaining accurate data for comparison. The weight and fall of stamps vary as the shoes and dies wear out; and this may lead to a change of speed also. Moreover, defects in engines, boilers, or machinery for the transmission of power, may occasion serious losses, which cannot fairly be charged to the arrangements of the stamps proper. Again, the capacity of stamp-mills is directly dependent, in some degree, upon the nature and extent of discharge, fineness of screens, and other peculiarities of the battery. Finally, the hardness and tenacity of the rock crushed varies so much that comparisons between different localities cannot be implicitly trusted. The safest experiments are those made in the same mill, by changing first one and then another condition of working; but this is seldom possible for such conditions as weight and lift of stamps, and only within narrow limits for their speed. We may eliminate questions of friction, transmission, and generation of power, in the case of stamps, by measuring the power actually developed by their fall. Thus, the weight, multiplied into the fall in feet, and the number of drops per minute, gives us exactly the number of foot-pounds exerted by each stamp. Dividing by 33,000, the number of foot-pounds per minute in one-horse power, we have the horse-power per stamp, from which the effective power of the whole mill may be obtained. Dividing the amount of rock crushed daily by the effective horse-power, gives us the daily amount per horse-power; and this is the best measure that can be obtained for the effectiveness of the stamps. A complete discussion of the subject would require us to determine the exact influence of the discharge, etc., and the exact resistance offered by different classes of rocks, for both of which points the data are wanting. Professor J. D. Hague, in the third volume of the United States Geological Exploration of the Fortieth Parallel, gives a valuable

Jan 1, 1873

By Charles Legrand

(San Francisco Meeting, September, 1915) THE problem of mine pumping is so much affected by local conditions, and those conditions are so liable to changes during the life of a mine, that the best system to use is difficult to determine. The experience of the;, writer has been that, in general, for copper mines, electric pumping is most satisfactory unless the quantity of water to be pumped is great or. the mine does not use electric power for any other purpose. As a rule, however, figuring on the cost of necessary power plant, the total cost of: installation is greater with electric pumps than steam- pumps. As the water is liable to be gritty, outside-packed plunger pumps are to be recommended, and if the water is not acid, or only slightly so, chilled cast-iron plungers pay for their extra cost very quickly in diminished cost of packing. With chilled plungers it is possible to use metallic, packing instead of soft packing, if the water, is not too gritty nor the lift too high. In vertical pumps this packing is satisfactory for lifts up to 400 ft., in the experience of the writer; and may be found satisfactory for higher lifts. For water slightly acid, cement-lined pump bodies have given good satisfaction. For acid. water, both plungers and pump bodies should be made of acid-resisting bronze. For high lifts, especially with gritty water, a satisfactory pump valve is difficult to find. To reduce the unbalanced pressure on the valve at time of opening it is advisable to have narrow seats; this, however, brings high pressure on the seats when the valve is closed. On large valves for lifts of 600 to 1,000 ft. we have used leather, hard rubber, vulcanized fiber, and soft brass; for clear water the latter has given best satisfaction. The difficulties due to grit make it advisable to have large sumps where water can settle, and if possible, to have two of them so that they can be cleaned alternately. At the mines of the Old. Dominion Copper Mining ,& Smelting Co.; Globe, it was found that a small air. ejector discharging into a mine car is a very convenient way to clean mud and sand from a sump. .

Jan 9, 1915

By Jack Fox

Although this is going to appear in the December Issue of &E, it is being written long before the end of the year. December, of course, is the time for a summing up of the year's activities. Perhaps, the best way to begin is to report on what went on at the SME Board of Directors Meeting in St. Louis on October 20. This won't be a chronological report, and I shall take time to comment on some of the items we cover as we go along. You should be encouraged to know that your Directors take their duties seriously. Of the 21 current Directors, 19 were present, and three of the new 1971 Directors came to observe what goes on at an SME Board Meeting.

Jan 1, 1970

By H. R. Deeth, C. J. Koenig

ABOUT ten years ago nepheline syenite was introduced to the ceramic industry and the material has now found application in the various branches of the industry, namely, as a vitrifying agent in white-wares and as a source of alumina and alkalies in glasses, glazes, and porcelain enamels. Spence1 described the early mining and processing developments regarding this material. Since the time of his article many research papers have appeared relating to the usage of nepheline syenite but little has been published relative to subsequent mining and processing methods. A complete indexed review of the literature was issued recently by Ohio State University.2 Since "Lakefield" nepheline syenite from Blue Mountain, Ontario (Fig I); is the only commercial ceramic-grade nepheline syenite now being marketed on this continent, discussion is limited to this operation carried on by American Nepheline Limited, Lakefield, Ont., and its subsidiary in the United States, American Nepheline Corp. at Rochester, N. Y. THE DEPOSIT Blue Mountain is a long ridge rising to an elevation of about 350 ft at its highest point above the surrounding country and extending for about six miles in a northeasterly direction across Methuen township, Peterborough County. The rock of the Blue Mountain central alkaline intrusive is fine grained, light colored and of even granitic texture. The solidified mass consists predominately of the minerals albite, nepheline and microcline in order of abundance. The average mineralogical composition for the deposit obtained by a study of 112 samples taken regularly over the whole formation is as follows:3 [VOLUMETRIC MINERAL PER CENT Albite54 Microcline20 Nepheline22 Muscovite2 Mafics2 (Biotite, hastingsite, magnetite) Total100] The mineral nepheline (or nephelite) belongs to the feldspathoid group but is lower in silica content than are the feldspars. It is a silicate of soda, potash, and alumina (NaKAl2O32SiO2). Its presence with albite (Na2O A1203 6SiO2) and microcline (K20 A12O3 6SiO2) gives the Blue Mountain deposit an alkali content of 15 pct and an alumina content of approximately 24 pct. While this huge alkaline mass is somewhat variable mineralogically, it has a uniform chemical composition. When the iron, mostly in the form of magnetite, is removed during processing, a remarkably uniform finished product is obtained. Geological surveying has disclosed many million tons of nepheline syenite in the Blue Mountain deposit. Diamond drilling in the area where mining is now being carried out indicates a block of about one million tons.

Jan 1, 1947

By A. L., Bailey

All who are even generally aware of the tremendous rate of increase in coal washing operations must realize the growing importance of the float-and-sink test. I believe it is conservative to estimate that, in the past decade, the dollar volume of float-and-sink testing has increased tenfold. It is a simple matter of economy, then, to examine the factors that determine the cost of adequate float-and-sink testing. When the Coal Preparation Section of the Bureau of Mines entered upon a greatly expanded program of such work in connection with the synthetic liquid fuels investigations, it seemed advisable to examine these factors experimentally. The principal consideration that differentiates float-and-sink test sampling from general purpose sampling, is that the original particle size must be preserved. Therefore, the total cost of the test will be directly affected by any standard that might be proposed to limit sample bulk reduction at any given particle size. For this reason, the relationship of sample size to variability of results was the first factor to be studied experimentally.

Jan 1, 1949

The President was authorized to appoint a committee comprising himself and five others, to draft an amendment to the Constitution for the purpose of bringing before the membership the suggested change in qualifications for members. The President thereupon appointed the following Committee: Edwin Ludlow, Chairman, B. B. Thayer, J. W. Richards, G. C. Stone, C. F. Rand, and P. N. Moore. The President was authorized to arrange with the Bureau of Mines for the payment of the necessary clerical assistance to copy the inventory of

Jan 8, 1917

By C. A. Heiland

MEASUREMENTS of gravity with gravimeters have come into increased use in this country and abroad in the past five years. Probably 100 to 125 gravimeter parties are working in the United States alone. In oil exploration, gravimeter methods have relegated the gravity pendulum definitely to second place, if not third, and now closely rival and possibly surpass the torsion balance in many applications. Gravimeters have lately been applied in mining, although it is doubtful whether they will ever replace electrical or magnetic methods in this work. Notwithstanding the widespread application of gravimeters, there has been no article covering the entire field in the domestic or foreign literature. The purpose of this paper is to meet the demand for com-prehensive engineering information on the subject. The working principles of a number of gravimeters will be, illustrated and treated in relation to the action of corresponding seismometers and astatization methods. The mathematical discussion of theory has been confined to the most necessary fundamentals and been given in as ele-mentary form as possible. A description of calibration methods con-stitutes the last part of the paper. The symbols shown at the top of page 2 will be used in equations throughout the paper.

Jan 1, 1939