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By N. N. Clark

Pachuca tanks are used widely as reactors for treating gold slimes, and for alumina digestion and uranium leaching. In some designs, slurry mixing in the tank is achieved by introducing air at the base of a draft tube, which is the full height of the tank. A buoyant air-slurry mixture rises in the draft tube and is discharged at the top. The slurry flows back through the bulk of the tank volume. Little information is available to predict the relationship between slurry flow rate in the draft tube, and the volume of air added at the base of the tube. Most current designs are based on the energy balance proposed by Lamont 25 years ago. Recent two-phase flow theory is used to develop a momentum balance for the flow in the draft tube, and a new, accurate design equation is derived. Bubble slip, frictional (wall) losses, entrance losses, and acceleration effects all contribute to the pressure gradient in the draft tube. None of these factors may be neglected under typical operating conditions. The new design equation accounts for all of these factors, and finds good agreement with Lamont's experimental example. Also, the new equation demonstrates that it is uneconomical to operate the draft tube with high airflow rates.

Jan 1, 1985

The Committee on Nominations begs to submit the following names as its nominees for the respective offices indicated: For President, SIDNEY J. JENNINGS, New York. For Vice-Presidents. C. W. GOODALE,* Butte, Mont.; MARK, L. REQUA, San Francisco. For Directors, J. E. JOHNSON, JR., New York; ALLEN H. ROGERS, Boston; HOWARD N. EAVENSON, West Virginia; ROBERT AI. RAYMOND, New York; WILLET G. MILLER, Canada. The nomination for President has attracted the attention of a large number of members, as is evidenced by the receipt of many hundreds of letters and postcards. Most of these favored either Sidney J. Jennings or Philip N. Moore, each of whom received many cordial endorsements. Such a wide interest on the part of the members is a very wholesome sign, but where there is so much activity it is natural to expect a certain amount of criticism. Some of the letters indicate that the authors feel that the nomination of President should be left entirely to the Committee on Nominations without any effort by the members at large to influence them. Others feel that the nominations are largely controlled by a small group and that the members at large can have little influence. As the result; of the experience of the last few months; a majority of the Committee on Nominations begs leave to suggest that the method of making nominations be changed so that two candidates, at least, for the various offices to be nominated, and suggests that the Directors appoint a committee to investigate this question thoroughly with. a view to making definite recommendations. In accordance with its opinion that the best interests of the Institute would be served by a change in the Constitution, allowing the nomination of two candidates, and in view of the fact that this Committee has no authority to make more than a single nomination for each office, considering the high standing of both Mr. Jennings and Mr. Moore and the large number of members favoring each of these gentlemen, this Committee respectfully suggests the desirability of ,the immediate nomination of Philip N. Moore by a petition of 25 members in accordance with the present Constitution. This Committee regrets, its inability to make two nominations. Respectfully submitted, S. W. MUDD, Chairman.

Jan 1, 1917

GENTLEMEN: Submitted herewith are the report of the Treasurer for the year 1940 and reports for the same year of the following standing committees: Admissions, Membership, Pa¬pers and Publications, Mining and Metal¬lurgy (Magazine), Library, and Student Relations. These reports present additional details. MEMBERSHIP For the third year in succession member¬ship reached a new high level for all time, as indicated in the accompanying tabula¬tion in which "Members" includes all categories except Student Associates.

Jan 1, 1941

By J. E. Lawver, J. D. Raulerson, J. P. Bernardi, R. S. Hearon, D. Lynch, G. F. McKereghan

Despite recent economic problems, the future of the Florida phosphate industry appears optimistic. Florida has enormous reserves and will continue to produce a third of the world's phosphate supply simply by making changes in the present system of mining, beneficiation, waste disposal, and land reclamation. The geology and mineralogy of future deposits are discussed with reference to specific deposits. Lower ore grades, increasing power costs, and environmental regulations are necessitating development of new concepts of mining and matrix transportation. Because one of the ores to be mined in the future contains appreciable amounts of dolomite, research and development efforts are being concentrated on new techniques in beneficiation. Changes are being made in plant design to meet environmental and regulation standards. However, the expected new technology outlined for the industry depends on the geology and mineralogy of future reserves.

Jan 1, 1985

By C. A. Hartnagel

The year 1944 marks the eightieth anniversary of the discovery of petroleum by drilling in New York State. It was in 1864 that a half dozen shallow wells were drilled at Limestone in Cattaraugus County, in a region that now forms the northern extension of the 82,000-acre Bradford pool. These early wells found oil, but not in paying quantities. They did, however, attract attention to the district and were a factor in the development of the still active Bradford pool of Pennsylvania and New York. During 1943, the production of petroleum in New York amounted to 5,029,000 bbl. This represents a decrease over the previous year, in which 5,421,000 bbl. was produced. The flush production for the New York fields occurred in the early eighties shortly after the discovery of oil in the Richburg pool of Allegany County. During the flush period, production was in excess of five million barrels annually. By 1887, however, the output had decreased to an amount only slightly more than two million barrels, and through the early years of the present century the annual total was often less than one million barrels. Flooding of the oil sands for increasing productioil was made legal in 1919, and in 1927 the output once more reached the two million mark. Two years later it had increased to over three million barrels. In Table r is shown production since 1935, in which year for the first time the output under flooding methods was in excess of four million barrels. From this table, it is evident that oil production in New 'I'ork is rather well stabilized, and since most of the oil is obtained by the flooding, or water-drive, method, with little or no prospect of discovery of new oil territory, rapid changes in yield from year to year are not to be expected. In thickness, the oil sands have a maximum of about 50 ft., and by means oi flooding may produce 10 to 12 thousand barrels an acre and proportional amounts for thinner sands. In some cases, floods have been developed in sands only 12 ft. thick. Under good flooding conditions a yield of 2000 bbl. an acre is about the lower limit at which oil can bc produced at the present price of $3.00 a barrel. The average cost for the physical development ol a lease, not including the cost ol the lease itself, is $5000 an acre. Since several months must intervene before the flood begins to act on the oil wells, and a year or more is required to bring thc wells to maximum daily production, it is evident that a considerable interval occurs before maximum returns are realized. Once a flood is developed and the wells

Jan 1, 1944

By C. A. Hartnagel

The year 1944 marks the eightieth anniversary of the discovery of petroleum by drilling in New York State. It was in 1864 that a half dozen shallow wells were drilled at Limestone in Cattaraugus County, in a region that now forms the northern extension of the 82,000-acre Bradford pool. These early wells found oil, but not in paying quantities. They did, however, attract attention to the district and were a factor in the development of the still active Bradford pool of Pennsylvania and New York. During 1943, the production of petroleum in New York amounted to 5,029,000 bbl. This represents a decrease over the previous year, in which 5,421,000 bbl. was produced. The flush production for the New York fields occurred in the early eighties shortly after the discovery of oil in the Richburg pool of Allegany County. During the flush period, production was in excess of five million barrels annually. By 1887, however, the output had decreased to an amount only slightly more than two million barrels, and through the early years of the present century the annual total was often less than one million barrels. Flooding of the oil sands for increasing productioil was made legal in 1919, and in 1927 the output once more reached the two million mark. Two years later it had increased to over three million barrels. In Table r is shown production since 1935, in which year for the first time the output under flooding methods was in excess of four million barrels. From this table, it is evident that oil production in New 'I'ork is rather well stabilized, and since most of the oil is obtained by the flooding, or water-drive, method, with little or no prospect of discovery of new oil territory, rapid changes in yield from year to year are not to be expected. In thickness, the oil sands have a maximum of about 50 ft., and by means oi flooding may produce 10 to 12 thousand barrels an acre and proportional amounts for thinner sands. In some cases, floods have been developed in sands only 12 ft. thick. Under good flooding conditions a yield of 2000 bbl. an acre is about the lower limit at which oil can bc produced at the present price of $3.00 a barrel. The average cost for the physical development ol a lease, not including the cost ol the lease itself, is $5000 an acre. Since several months must intervene before the flood begins to act on the oil wells, and a year or more is required to bring thc wells to maximum daily production, it is evident that a considerable interval occurs before maximum returns are realized. Once a flood is developed and the wells

Jan 1, 1944

By Ronald K. Linde

Metastable Ag-Cu solid solutions at two compositions beyond the maximum limits of solubility obtainable by quenching from the solid state were obtained by rapid quenching from the liquid state. The process of transformation of the metastable solid solutions into the equilibrium phases was studied by means of X-ray diffraction intensity measurements and electrical-resistance measurements; metallographic examination was also performed. Results are compared with those for an alloy quenched from the solid state at a composition which exists as a solid solution at elevated temperatures. Activation energies for the trans-formation were computed to be 33,600 * 2500 and 33,100 * 2000 cal per g mole for the 60.1 and 75.0 at. pct Ag;Cu compositions, respectively THE kinetics of precipitation in supersaturated solid solutions obtained by quenching from high temperature has been thoroughly studied in many alloys, and detailed investigations of the early stages of nucleation and subsequent growth of the equilibrium phases have been carried out. All of these studies have been made on alloys quenched from the solid state, however, and it is the purpose of this paper to present some of the results on the kinetics of transformation of metastable solid solutions in Ag-Cu binary alloys whose compositions lie outside of the solid-state limits of solubility. Limits of solubility in the solid state can be increased by rapid quenching from the liquid state. This was first demonstrated by Falkenhagen and Hofmann, who obtained appreciable increases in solubility limits of the elements of the first transition series in aluminum by rapid cooling of liquid alloys through contact with a copper mold maintained at liquid nitrogen temperature.' The same basic idea of cooling a liquid alloy by conduction onto a substrate rather than by convection of a gas or liquid (conventional quenching) has been recently revived and extended to very high rates of cooling by Duwez and his collaborators. The new technique was first applied to Ag-Cu alloys because the existence of a eutectic in this system is not predicted by the Hume-Rothery rules of alloy phase formation. Rapid quenching from the liquid state resulted in metastable solid solutions at all concentrations. The kinetics of decomposition of these metastable solid solutions containing 60.1 at. pct Ag;Cu (eutectic composition) and 75.0 at. pct Ag;Cu is the subject of the present paper. EXPERIMENTAL TECHNIQUES Alloys were made in 10- to 20-g heats using silver of purity 99.99 pet and copper of purity >99.999 pct. Components were weighed accurately to 0.1 mg and melted by induction heating in an alumina crucible under an atmosphere of hydrogen. Weight losses amounted to less than 0.02 ~ct in all cases. Rapid cooling from the liquid state was achieved in an apparatus of the type described by Pietrokowsky. 3 In this technique a freely falling drop of molten alloy is caught between a stationary anvil and a fast moving piston, both anvil and piston being lined with copper. The resulting foils were approximately circular (about 2 cm in diam) and from about 50 to 150 u in thickness, depending on the pressure driving the piston. Metallographic samples were prepared for polishing by edge-mounting foils in Quickmount. The mostef-fective etching procedure was found to be: 10 parts NH4OH (concentrated), 1 part H2O2 (30 pct), 5 parts H2O, swab for 5 to 10 sec. The transformation of the metastable alloys to equilibrium was followed by X-ray diffraction and electrical-resistivity measurements. The peak intensity and the integrated intensity of suitable Bragg reflections of the metastable and stable solid solutions were studied with a Norelco dif-fractometer, using nickel-filtered copper KO radiation. The peaks were step-scanned at intervals of 0.05 deg. Using either a Kelvin bridge or a null circuit with a Leeds and Northrup K-2 potentiometer, the changes in electrical resistance due to phase transformation were measured for specimens cut into strips about 20 mm long and 4 mm wide. All resistivity measurements were carried out at liquid-nitrogen temperature. The isothermal heat treatment was accomplished by sealing the samples in argon-filled aluminum containers with stainless-steel O-rings. Containers were then suspended in wax baths with temperatures in the

Jan 1, 1967

By Y. Shimomura, M. Serizawa, Y. Takahashi, K. Miyagawa

The "semi-pellet" sintering method developed and currently being used at the Fuji Iron & Steel's Hirohata Works is discusssd. It is shown that the method makes fine-sized material easily sinterable and increases sinter production. The operation can be incorporated readily into conventional sintering plants. Sintering plant raw materials currently being used in the Hirohata Works consist of 40 pct pyrite cinder, 40 pct fines resulting from crushing and screening of imported ores, and 20 pct others, such as mill scale and iron sands. Pyrite cinder, a major component in the sinter feed, has been getting finer since 1952, due to the increased grinding required for the improvement of the results in the iron sulfide flotation and to the adoption of FluoSolid roasters in sul-furic acid plants; some fines pass 100-mesh sieve almost completely. Increased use of the fine-sized pyrite cinders in the sinter raw mix resulted in such difficulties as decreased bed permeability, uneven firing conditions, and low yield. In an attempt to study the cause and to find a remedy for this problem, a series of experiments were made, using an 80-kg experimental sintering pan. As a result it was established that, by rolling the fine-sized pyrite cinders into small balls of 10 to 3 mm diam (hereafter called semi-pellets) and mixing them into the sinter raw mix, the bed permeability was improved, the sintering time shortened, and the yield and production rate increased. It is proposed that this new method be called the semi-pellet sintem'ng. In recent years the pelletizing process has taken the spotlight in the agglomeration field for treating fine-sized ores here in Japan as well as in the U.S. and Europe. This process produces pellets suitable for the blast furnace charge as such, and consists of three major operations: fine grinding, balling, and firing. With regard to the firing technique, some problems still appear unsolved. In the semi-pellet sintering, however, several ad- vantages can be claimed: the balling operation is relatively simple because only small-sized balls are shown to be acceptable and the operation can be readily incorporated into the conventional sintering plant, since only balling, not grinding or firing, equipment is needed. Basic test work on the process was initiated in 1954 and favorable results were obtained. Accordingly a pilot plant was built in 1955 and the test work was continued. The semi-pellets thus prepared in the pilot plant were tested further by USing them in the actual sintering pan and their beneficial effects ascertained. In late 1956 a drum-type balling machine (2.4X4 m) was installed and it went into operation in April 1957 in conjunction with the Greenawalt sintering plant (8 pans having dimensions of 7.2 m in length, 3 m in width, and 0.3 m in depth). In October 1958 a cone-type pelletizer, with a 2.2 m diam, and later a disk-type pelletizer were further added in the plant. In the DL sintering plant (2000 tpd), newly built in July, 1960, four disk-type pelletizers (3.2 m diam, 10 tph capacity) were installed. By mixing the semi-pellets thus prepared with the feed, the sintering operation was found to be greatly improved. The results of the basic test work, and the equipment and operation of the semi-pellet sintering operation at the Hirohata Works will be described. ON THE SINTERING CHARACTERISTICS OF FINE SIZED PYRITE CINDERS To ascertain the effect of addition of fine-sized pyrite cinders on the sintering characteristics, a series of measurements on bed permeability was carried out by varying the size distribution of pyrite cinders. The composition of the raw mix used in the tests was fixed at 50 pct pyrite cinder, 20 pct Larap magnetite fines, 30 pct sinter return, and 5 pct coke; only the size distribution of the pyrite cinder was varied. Also the moisture content was changed at each size distribution. The results are given in Fig. 1. For all pyrite cinders tested the bed

Jan 1, 1961

By C. Y. Garber

INTEREST in the sink-float plant operated by the Bunker Hill and Sullivan Mining and Concentrating Co. at Kellogg, Idaho, has recently been largely confined to the preparation and reconditioning of the galena medium. The ease and simplicity of these operations in a concentrating mill producing a flotation lead concentrate has occasioned enough comment to possibly justify a brief description. The subject is treated from an operator's viewpoint only; no effort is made to discuss it in a theoretical or technical manner. PLANT AT BUNKER HILL The sink-float plant was first operated in December 1941. It was built for the purpose of quickly increasing mill capacity with a minimum of equipment. It is the Huntington-Heberlein sink and float process using galena medium and is operated under license from the Sink and Float Corporation, New York city. Lead-zinc ore from the Bunker Hill mine is crushed to pass a I ¼ in. screen and is then washed and separated on vibrating screens having 4 ½ -mm. round-hole punched plates. The screen undersize, amounting to 33 per cent of the mill feed, is dewatered and sent to the ball-mill feed bins. The screen oversize goes to the sink-float plant, where 50 per cent of the oversize, or 33 per cent of the mill feed, is float, which is washed free of medium and disposed of as a tailing. The remaining 33 per cent is sink, which, after washing, is crushed to pass ½ in. and joins the undersize in the ball-mill feed bins. The normal plant capacity is 1700 tons per 24 hr. About 1.7 per cent of the total lead and 3.3 per cent of the total zinc in the feed is lost with the sink-float tailings (Table I). [ ] More complete descriptions of the H. H. process and Bunker Hill sink-float plant are given in several recent articles, listed at the end of the paper. PREPARATION OF MEDIUM AT BUNKER HILL New medium is made intermittently as needed, usually 12 hr. in each 6 days. A small portion of the current mill flotation concentrate is diverted from the lead cleaner cells to a I-in. vertical sand pump and pumped to a two-cell 36-in. Agitair flotation machine, where NaCn and ZnSO4 are added and the grade of concentrate is improved as shown in Table 2. Tailing from this operation is returned by gravity

Jan 1, 1946

THERE are many kinds and varieties of earth* that are used for the loam compositions for making the moulds for casting bronze, brass, or other metals. Since this is a very necessary thing, you must try to have the best kind and one that resists the fire well. It must be disposed to receive the metals well, must make a neat casting, and must not shrink or break with cracks on drying or baking. Aside from actual trial, I believe that there is little that can help you, since the clay in itself has no color or [77] visible sign that I know of to show how satisfactory it is. Understand that their colors are no less varied than their natures, for, as you see, one is white, one black, one yellow, and another red. Perhaps none will show by its color that it is good for this work, yet it might also happen that all colors are good. But all that I can say about it is to show you by their effects how the good ones should be in their nature; and so by trial you will choose among those that come into your hands. All earths are either sandy or tufaceous, either argillaceous and lean or pasty with unctuous viscosity. The lean ones make the loam powdery and without toughness and hold together poorly by themselves when they are dry. The unctuous and viscous ones shrink and break. Becoming smaller by shrinking, they often twist the forms and they stick together badly. They swell up again in the fire and produce works that are neither exact-a nor neat. Therefore, the good ones must be those that are neither unctuous nor lean, neither wholly tender nor rough, and with a grain that is fine, without pebbles or shells. When applied to a work they easily dry out without fractures and, when dry, hold their own shape well. Above all they must resist the fire well. These are usually of a yellow or red color, but whatever their color may be, the color does not force me to say that the yellow are really better than the black, and the red than the white or gray. Their quality depends on what trial shows. Thus, to summarize, whenever you have to do this work, you must try to have the best clay that you can, because it is to be the foundation of

Jan 1, 1942

By H. J. Maguire

(Presented by invitation at a meeting of the Spokane Local Section, Feb. 17, 1912.) THOSE familiar with mill-practice understand the work required of an average bucket-elevator, but I wish to call special attention to the wear on the buckets. I have been studying in what manner the life and service of the bucket might be improved, and I feel that an adjustable lip, attachable to each bucket without the aid of rivets, will be of material advantage. For illustration, consider the feed-elevator of a typical mill in the Cur d'Alène district. The ore is carried by water in a launder from the feed-rolls and dumped in the "boot" of the elevator, directly in front of the ascending bucket. Middlings from the return-rolls are similarly handled. Under this condition the bucket not only carries the ore, but also picks it up, and this latter requirement determines the life and service of the bucket. It might be said that it would be better practice to convey the feed to the elevator and dump it directly into the bucket, but at one mill at which this plan was tried the results were disappointing and the rubber belt was badly worn. The wear of the bucket is confined to the lip and the corners which have to pick up the material. When the lip on a corner of a 7- by 12-in. malleable cast-iron bucket is worn down about 3 in., the bucket is of no further value as a carrier and has to be replaced. The worn bucket, containing about three¬quarters by weight of the metal of the original bucket, has a scrap value of about 10 per cent. of that of a new bucket. To the cost of the bucket, however, should be added the time-cost of replacing the old bucket by a new one. This time-cost is considerable when the loss per hour, to cease operating the mill, is about $200. It is out of the question to put lips on a bucket unless the latter was originally fitted with this device. For if it is attempted to fit lips upon buckets not originally provided with

Sep 1, 1912

By A. A. Gustafson

IN diamond or churn drilling for the prospecting of ore bodies, two products can be used for quantitative analyses; i.e., the core and the cuttings, or sludge. Some operators prefer an assay of core; others insist that the sludge be sent for analysis. Both must recover the sludge for check samples or for assays if there is no core recovery for any particular section of the diamond-drill hole. The Freeport Sulphur Co. found that numerous cumbersome sludge boxes or barrels were inconvenient and delayed drilling. The sludge settled slowly in the ordinary shallow, rectangular diamond-drill boxes and its total removal from the container was difficult, time-consuming and unsatisfactory; and sampling of deposits of which the metal contents are easily concentrated, as in ores containing cinnabar, gold and silver, is subject to error if the boxes are not thoroughly cleaned. Mr. Charles Ballard, dredge superintendent at Freeport's operation at Grande Ecaille, Louisiana, developed a portable cone while he was in charge of prospecting a mercury property near Tonopah, Nevada, in 1040. Ballard later improved the design while the settler was being used at a manganese property in New Mexico. The operation is based on the "free settling" of comminuted particles in a quiescent liquid. The ordinary sludge box discharges over a lip 8 to 12 in. wide and consequently the water has sufficient velocity so that the discharge water is never clear. The cone settler used by Freeport Sulphur Co. discharges over the entire circumference, which gives a discharge lip of 9 ft. in the size of cone used at the cinnabar and manganese prospects. Consequently, the velocity of the discharge water is slow enough so that all fine material settles and the discharge water is clear. When the drilling of a sample interval is complete, the sludge can be drawn off by the time the driller is ready to cut another sample. Thus, only one cone is needed per drill. The cone has been used by Freeport successfully in churn-drilling a manganese deposit, in diamond-drilling a mercury deposit, and in diamond-drilling a deposit of ore containing tin, copper, gold and silver. The cone is greatly superior to the old methods of collecting sludge and is now used on all Freeport drilling campaigns in the western states, both for surface and underground drilling. Fig. I shows the important details of a cone designed for average operating conditions, 30 in. in diameter and 36 in. high. Abnormal conditions may require some revisions in design. Fig. 2 shows a working drawing. A hose or pipe larger than the one used to convey water from the pump to the swivel head of the string of rods is connected to the stuffing box at the collar of a diamond-drill hole. The usual T-connection is used. It is not necessary to use a stuffing box if the top of the cone can be placed lower than the collar of the hole. Then the return water and cuttings can be made to flow by gravity. This hose or pipe discharges the cuttings of the drill bit and the return

Jan 1, 1943

By C. E. Lesher

COAL has been fighting a rear-guard action since the last World War. The battle against competitive fuels has been largely guerilla warfare with more sniping within the ranks than of organized opposition. Oil and natural gas are the fuels that over these twenty odd years have driven coal backward and out of many profitable markets. Now, somewhat timidly, the coal industry is trying a new weapon; namely, Research, or let us more properly say, Organized Research. Engineers have been designing this weapon for many years, supported by those interested in coal, including some coal producers. A part of this pioneer work has been Fundamental Research, the Ph.D. kind that is over the heads .of most of us. Another part has been aimed at immediate objectives and realizable profits, the practical, man-in-the-street sort. That is Industrial Research. Enough has been accomplished to make a fair exhibit, but whether this new weapon will have sufficient fire power to rout the opposition, whether the industry will really go into production and use it, the next few years will tell. NEED FOR COAL RESEARCH To utter "Research" is to use the modern magic word; to conjure up the miraculous-rubber from weeds; radar; magnesium from sea water; yes, even gasoline from coal. Research is a very general term. It means something different to every man. What is the coal industry seeking with its research; or what should it seek? And, specifically, how is it going about the job; and is it taking the best way? There are many who say that Coal has been asleep at the switch, while Oil and Gas have been taking the energy business. In an organized way this is true. Large-scale, privately financed research is just started in the Pennsylvania, anthracite industry, and it is still a dream for bituminous coal. What has been done so far collectively is purely defensive; as, for instance, to improve mechanical devices for burning coal so as to be able to recover markets for house-heating fuel long since abandoned to oil and gas. To appreciate just how seriously bituminous coal has slipped back in the national economy in the past 25 years, one has only to recall that, in the last war the Navy required for its operations all the high-grade, low-volatile coal that could be produced, and that anthracite was withdrawn from the middle and northwest markets to keep the eastern seaboard warm. All coal was "rationed" by zones, if not to individuals. Now the Navy, the Armed forces and the Merchant Marine are propelled by oil and gasoline. Gasoline and heating oil are rationed to individuals. Production of all coal in this country in 1918 reached the historic figure of 678,200, 000 tons, and in 1943, after 25 years, it is expected to reach a special wartime total of 660,000,000 tons. Meanwhile, production of crude oil this year may exceed 1,500,000,000 bbl., and like that of natural gas, reach four times the amount produced in 1918.

Jan 1, 1944

By Charles H. Jacoby, Leo E. Read

IN diamond coring salt beds to evaluate deposits, special techniques are applied to standard slim hole drilling to obtain a representative sample of the water soluble sodium chloride. Industrial consumers generally require a run-of-the-mine material of 98.0 pct sodium chloride. Since no commercial beneficiation has yet been devised to upgrade the lower quality salt beds, the only processing is crushing and screening to the size required by the customer. Coring salt sections has recently become important not only in dry mining, but also in the development of brine cavities by hydraulic fracturing and the formation of jugs for storing liquid petroleum products. Drilling Fluid: The fluid used in coring salt beds in New York, Ohio, and Michigan is a thoroughly saturated brine made from 3.0 lb rock salt per gal of make-up water. This mined rock salt, -4 mesh +10 mesh, is dissolved in a lixator, a double-bottomed cone hopper that turns fresh water to fully saturated brine.

Jan 5, 1957

By C. M. Shigley

Tan record of the largest magnesium plant in the country utilizing sea water as a primary raw material stands as another victory in the struggle for large-scale production of pure chemical elements from the oceans. Bromine was the first element to be economically and commercially recovered when, in 1933, a six million pound per year unit was built on the Atlantic Coast near Wilmington, North Carolina, by the Ethyl-Dow Chemical Co.1 The bromine was reacted with ethylene to produce ethylene dibromide, a necessary associate of tetraethyl lead in ethyl antiknock fluid. Within eight years that plant was doubled and redoubled, and another large unit was put into operation at Freeport, Texas, taking bromine from the Gulf of Mexico. In 1940, in fortunate anticipation of the impending demand for magnesium and the limitations of the production from natural brines, the Dow Chemical Co. turned again to the sea, and designed and erected a plant at Freeport to produce 18,000,000 lb. of magnesium per year from sea water.2 In March 1941, two months after the new plant had been put into successful operation, construction of an 18,000,000-lb. Government-financed addition was started. Late in 1941, as a part of the $400,000,000 defense program intended to produce 600,000,000 t0 700,000,000 lb. of magnesium per year, Dow was asked to build and operate for the Government a 72,000000-lb. plant near its original plant at Freeport. Within a few days after the Japanese made their attack at Pearl Harbor, preparation of a site was started at Velasco, Texas, for the construction of the Texas plant of the Dow Magnesium Corporation-the largest known magnesium plant utilizing sea water as its raw material. Less than six months after the first piling was driven, urgently needed magnesium was in steady production. Five months later, the plant had exceeded its rated capacity. It remained above rated production until the general magnesium curtailment was applied to Government-owned plants in September 1944. Credit for the construction and operation record of the Dow magnesium plant must be divided among the efforts of a very determined group of men, an extremely favorable location, and a simple process. It is with the two latter aspects of the plant that this article will deal. The site for the new enterprise was chosen near Velasco, Texas, on property bordering the Brazos River at a point approximately 6 miles inland from the original magnesium plant and y miles inland from the Freeport Harbor on the Gulf of Mexico. This location was far enough away from the operating units to reduce both interference from construction and the vulnerability of closely bunched manufacturing operations to the then feared air attack. Yet the distance inland was not too great for the economical construction of a barge canal from the harbor to serve both the transportation of raw

Jan 1, 1945

By C. M. Shigley

The record of the largest magnesium plant in the country utilizing sea water as a primary raw material stands as another victory in the struggle for large-scale production of pure chemical elements from the oceans. Bromine was the first element to be economically and commercially recovered when, in 1933, a six million pound per year unit was built on the Atlantic Coast near Wilmington, North Carolina, by the Ethyl-Dow Chemical Co.' The bromine was reacted with ethylene to produce ethylene dibromide, a necessary associate of tetraethyl lead in ethyl antiknock fluid. Within eight years that plant was doubled and redoubled, and another large unit was put into operation at Freeport, Texas, taking bromine from the Gulf of Mexico. In 1940, in fortunate anticipation of the impending demand for magnesium and the limitations of the production from natural brines, the Dow Chemical Co. turned again to the sea, and designed and erected a plant at Freeport to produce 18,000,000 lb. of magnesium per year from sea water.2 In March 1941, two months after the new plant had been put into successful operation, construction of an 18,000,000-lb. Government-financed addition was started. Late in 1941, as a part of the $400,000,000 defense program intended to produce 600,000,000 to 700,000,000 lb. of magnesium per year, Dow was asked to build and operate for the Government a 72,000- ooo-lb. plant near its original plant at Freeport. Within a few days after the Japanese made their attack at Pearl Harbor, preparation of a site was started at Velasco, Texas, for the construction of the Texas plant of the Dow Magnesium Corporation—the largest known magnesium plant utilizing sea water as its raw matcrial. Less than six months after the first piling was driven, urgently needed magnesium was in steady production. Five months later, the plant had exceeded its rated capacity. It remained above rated production until the general magnesium curtailment was applied to Government-owned plants in September 1944. Credit for the construction and operation record of the Dow magnesium plant must be divided among the efforts of a very determined group of men, an extremely favorable location, and a simple process. It is with the two latter aspects of the plant that this article will deal. The site for the new enterprise was chosen near Velasco, Texas, on property bordering the Brazos River at a point approximately 6 miles inland from the original magnesium plant and 7 miles inland from the Freeport Harbor on the Gulf of Mexico. This location was far enough away from the operating units to reduce both interference from construction and the vulnerability of closely bunched manufacturing operations to the then feared air attack. Yet the distance inland was not too great for the economical construction of a barge canal from the harbor to serve both the transportation of raw

Jan 1, 1949

R. V. Norris, Wilkes-Barre, Pa. (communication to the Secretary*):—Mr. Stow's paper presents a series of arguments, numbered from 1 to 18, concerning the relative merits of four systems of colliery-ventilation, designated by the author as " plain pressure-ventilation," " plain exhaust-ventilation," " obstructed pressure-ventilation," and " obstructed exhaust-ventilation." These arguments are subsequently compared by means of tables, in which an arbitrary numerical value is assigned to each, and which consequently serve no other purpose than that of showing his opinions and predilections, as indicated by his assignment of the said numerical values. In addition to this general summary, Mr. Stow intimates his preference for a fifth method of colliery-ventilation—namely, what he calls " alternating pressure-ventilation," which consists in the running of the fan at "pressure " during working-hours, and as an " exhaust" between shifts—a system which he proposes as, perhaps, new, yet which he thinks deserves recognition " as a standard form." This proposed " standard form " is not to be found in practice ; and I think it would be impracticable in gaseous mines of large extent, for the following reasons: 1. It takes considerable time to reverse the air-current in a large mine; and the reversal would involve a period of complete stoppage of ventilation, long enough to permit serious accumulations of gas. 2. In shaft- and slope-mines, at least, it is hardly practicable to have " every man out of the mine" during the night, and certainly impracticable to avoid keeping mules and horses inside. 3. The doors necessary to divide and direct the air-current are properly hung to open against the air-pressure; and, unless

Jan 1, 1910

By Merrill F. McCarty, Robert S. Olson

New organic flocculants of high-molecular weight are replacing lime, glue, and starch in liquid- solid separation. Of these synthetic materials, polyacrylamides are outstanding. Polyacrylamides form a class of compounds varying widely in composition and activity. Separan 2610H, one of the first of these flocculants' released to the mining industry in 1954, is described' as a high- molecular weight polymer of acrylamide with or without a copolymer material and with some replacement of amide by carboxylic groups.

Jan 1, 1959

TO THE BOARD OF DIRECTORS AND MEMBERS Of THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN Submitted herewith are the reports of the Treasurer for the year 1947 and the reports of the following standing committees Membership, Admissions, Papers and Publications, MINING AND METALLURGY (Magazine), and Library 75th Anniversary Celebration The founding of the Institute at Wilkes-Barre, Pa, in 1871, vas appropriately commemorated by a three-day Celebration, March 17, 18 and 19, 1947, at The Waldorf-Astoria, in New York City The Celebration had been scheduled for the preceding September but had been postponed, perforce, because of conflict with meetings of the Assembly of the United Nations The Celebration immediately preceded the Annual Meeting which was deferred from the usual February dates The proceedings took the form of a "World Conference on Mineral Resources " More than three thousand people, including eight hundred ladies, participated in the proceedings in one way or another Twenty-eight foreign countries were represented, some of them by five or six individual delegates Likewise, official representatives were designated by fifty institutions of higher learning in the United States A special 820-page Anniversary Volume entitled "Seventy-five Years. of Progress in the Mineral Industry,".(which

Jan 1, 1952

By Stanley M. Miller

The probabilistic nature of appropriate geologic variables can be included in analyzing the stability of potential slope failure modes. Random variables in the two-dimensional plane shear analysis of a specified structural discontinuity include the shear strength and waviness angle of the discontinuity and, in some cases, the rock mass density. Estimated probability density functions that describe these random variables are combined by Fourier analysis to produce an estimate of the safety factor probability density function, which appears to approximate a gamma distribution. The probability that sliding will occur along the specified structure is equal to the area under this density function where the safety factor is less than one.

Jan 1, 1982