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[A Aall, Christian H., M49 B VP, Dir of Smelt & Refin, Am. Metal Climax Inc., 1270 Ave. of the Americas, N.Y. Aaroe, Stanley L., A54 B VP, The W. S. Tyler Co. of Can. Ltd., St. Catharines, Ontario, Canada Abalos, Toodulo Q., J57 A Prod Foreman, Lepanto Cons. Mng. Co., Mt. Province, Philippines Abbass, G., M55 P. O. Box 680, Hong Kong, China Abbitt, James M., A54 770 Sole Blvd., Bartow, Fla. Abbott, Raymond C., J59 3442 Greenwich Ave., Columbus 24, Ohio Abdullah, N. Y., J53 Dept. of Mines, Res. Div., P. O. Box 1016, Tiger Lane, Ipoh Perak, Malaya Abel, John F., Jr., J53- 100 Maple, Littleton, Colo. Abell, Leo M., M31 B Conc Supt, Phelps Dodge Corp., Morenci, Ariz. Abendroth, Harry E., A57 A Geol, Union Carbide India, 183 Brabourne Rd.. Calcutta. India]

Jan 1, 1961

By W. S. Ayres

A BRIEF history of the growth of the anthracite-coal preparation will give a better view-point from which to judge the present problem of separating slate from coal. At the beginning of the commercial value of anthracite, 70 years ago, only the pure portions, or " splits," of the veins were mined and shipped to market, and without any preparation or screening other than the selection, while loading, of the glassy lumps, and the rejection of the fine material and the slate that had strayed accidentally into the coal. The next step was the crushing or breaking of the coal (hence the name Lt breaker" as applied to the preparation-building), and the sizing of it by means of bars or revolving screens. This stage of its development marked the advent of the "breaker-boy " as a slate-¬picker, with his ever-increasing capriciousness. As the richer veins or ? splits " became exhausted and the market demanded a still greater output, the less-pure " splits " and the thinner veins were utilized to produce the coal. Carrying as they do a far greater percentage of impurities; particularly when removing the pillars, it became necessary to build new and better equipped preparation-plants. Finally, we are now at the highest stage of complication yet known to the art of coal-preparation. We are dealing with varying specific gravities, frictional difference, hardness, structure, and form in the pieces of coal and slate coming from many different veins, and

Dec 1, 1909

[A Aall, Christian H., M49 D Mgr, American Metal Climax, Inc., 61 Broadway, New York 6, N.Y. Aaroe, S. L., A54 B Sales Mgr, The W. S. Tyler Co. of Can. Ltd., St. Catharines, Ont., Canada Abalos, Teodulo Q., J57 A Foreman, Lepanto Cons. Ming. Co., Mt. Province, Philippines Abbass, G., M55 P. O. Box 680, Hong Kong, China . Abbitt, James M., A54 770 Sole Blvd., Bartow, Fla. Abdullah, M. Y., J53 Dept. of Mines Res. Div., P. O. Box 1016, Tiger Lane, Ipoh Perak, Malaya Able, John F., Jr., J53 A Ming Engr, USA SIPRE 1215 Washington Ave., Wilmette, Ill. Abell, Leo M., M31 B Conct Supt, Phelps Dodge Corp., Morenci, Ariz. Abenius, Hakan Wilhelm, M52 A Mng Dir, Stora Kopparbergs Bergslags AB, Falun, Sweden Abenoroth, Harry F., A57 Natl. Carbon India Ltd., 18A Brabourne Rd., Box 217, Calcutta, India Abercrombie, Harry W., J56 1645 Camphor Dr., Lakeland, Fla.]

Jan 1, 1961

By C. A. Rowland

The rising costs for and the possibility for limited availability of electrical energy are emphasizing the continual conflict faced in the selection of comminution circuits used in preparing ores for concentration, namely; capital cost vs. operating cost. Frequently, the circuit with the lowest capital cost is not the most efficient in the use of electrical power and wear resistant materials. The simplest circuit in terms of flow, pieces of equipment and capital cost is the single stage autogenous or partial autogenous circuit used to grinding primary crusher discharge or run of mine ore to the desired product size. (Fig. 1) From this circuit, complexity increases to multi-stage crushing circuits preparing feed for multi-stage grinding circuits. Fig. 2 showing a three stage rod mill ball mill arrangement is an example of a complex grinding circuit. Stage concentration further complicates the flow. Multi-stage circuits being the most expensive to install, often give the greatest operating flexibility and offer the best possibilities for the most efficient use of available power and wear resistant materials. Within available grinding circuits, other comparisons such as high speed vs. low speed mills, grate discharge vs. overflow discharge, metal liners vs. rubber liners, high charge vs. low charge, etc. all add to the conflict

Jan 1, 1977

By Guilherme Liziero Ruggio da Silva

Uma marcha estável do alto-forno (AF) está ligada à consistência das propriedades químicas, físicas e metalúrgicas das suas matérias-primas (MP), especialmente, as do coque. As propriedades do coque são reflexos das propriedades dos carvões que lhe deram origem. Em termos de propriedades ligadas à natureza do carvão, a qualidade do coque é bastante influenciada pelo rank dos carvões, que compuseram sua mistura, ou seja, quantidades de macerais reativos e inertes, bem como suas propriedades coqueificantes, que é, exatamente, a habilidade inerente aos carvões aglutinantes de quando aquecido, amolecer, tornar-se plástico e solidificar em uma massa coerente. Neste contexto, o presente trabalho se propõe a evidenciar as mudanças no modelo de britagem de carvões da Gerdau Ouro Branco, bem como a operacionalização do padrão criado. Após a implantação, verificou-se a elevação de 1.8% em DI.

Aug 17, 2017

By Jilai Xue, Shuming Huang, Zengie Wang

The corrosion behaviors of chrome corundum/magnesia in laterite nickel slag were investigated by static crucible method. The results show that the molten slag can penetrate into chrome corundum or magnesia which are used as lining materials in smelter furnace, and the corrosion can occur at the slag-refractory interface and the inner area of the refractories as well. Both the penetrated amount of slag and the penetration depth of Fe, Si increase with increasing FeO content (10–25 wt%) in slag. Such penetration in magnesia is stronger than that in chrome corundum under the same corrosion conditions, as more pores in magnesia may provide channels for slag penetration and corrosion product transportation. A damage of the refractory linings and short service life of smelter furnace may happen during metallurgical processing slag with high FeO content.

Mar 1, 2017

By E. P. Youngman

Before the World War the use of zirconium and its compounds was largely experimental and confined almost wholly to Germany and Austria . Occasionally small lots of zirconium ore had been produced in the United States ( 1,000 pounds in 1869 , 26 tons in 1883 , and 3,000 pounds in 1903 ) and used (with monazite ) in the manufacture of various lighting devices , especially incandescent gas mantles ; but it was not until 1906 that the discovery of the natural zirconium oxide in large quantities near Sao Paulo , Brazil , first gave promise that a zirconium industry eventually might be developed . Edward Rietz , who worked the Brazilian deposits , interested German chemists in extending the use of zirconium , and by 1911 trade journals were listing German firms as manufacturers of compounds or products derived therefrom . For a time zirconia was one of the various oxides used in the Nernst lamp . It was used also for crucibles and hearths as refractory material ; in the manufacture of chemical utensils ; in enamels ; in the place of bismuth subnitrate for defining Röntgenray pictures of the stomach ; as a pigment ; in medicine ; and in a number of other ways . The Germans were credited also with producing a remarkable zirconium steel , which , it was claimed , was much superior to other alloy steels . During the World War the United States Government investigated the possibilities of zirconium , as well as those of other steel -hardening elements , and a large automobile manufacturer actually purchased a substantial quantity of ore with the purpose of employing zirconium in automobile steels . Immediately after the armistice the Government ceased its investigations ; but despite the difficulties experienced by various investigators in reaching concordant results , interest in the use of zirconium as a steel -hardening agent , as well as in other uses of the element and its compounds , continued . In 1918 the Foote Mineral Co. , which had been interested in zirconium for several years , was exploiting the deposit in Brazil formerly worked by the Germans and was supplying zirconia in the form of ore , brick , and cement for refractory and other purposes . About the same time the Electro Metallurgical Co. , which before the entrance of the United States into the war was experimenting with zirconium alloys , supplied in tonnage quantities the demand for these alloys . In 1919 it was reported that American manufacturers , after several years of research, were producing in commercial quantities pure zirconium oxide , which was finding a place in the manufacture of small refractory articles , scorifying dishes , crucibles , tubes , and one- piece furnace linings . In 1920 the lowering of the price of zirconium metal powder ( because of improved metallurgical methods ) promised the production of the metal on a semicommercial scale . In 1924 the Titanium Alloy Manufacturing Co. introduced a new opacifying agent , " Opax , " made from zircon . A year or two later some of the large pottery manufacturers became interested in the use of zirconium oxide as an opacifying agent , the increased production of titanium pigments having resulted in the production of zirconium as a by-product at a price that could compete with tin oxide . In 1928 it was reported that the industrial use of zirconium oxide was increasing steadily in the manufacture of brick , crucibles , and other refractory products , such as high- temperature cements . However , the reluctance of producers to install additional and more suitable

Jun 1, 1931

By Jack Bedder

"Editor’s note: We would like to thank those who make this annual issue possible. A special thank you goes out to the industrial minerals annual review editor, to the Industrial Minerals & Aggregates Division Technical Committee chair and vice chairs, and to the authors of the individual commodity profiles.Jim Norman, member SME, of Tetra Tech, is the industrial minerals annual review editor.Ebrahim K. Tarshizi, member SME, of Michigan Tech, is chair of the Industrial Minerals &Aggregates Division’s Technical Committee.The technical committee vice chairs include: • Hyunjung Kim, member SME, of Chonbuk National University, agricultural materials.• Xihui Yin, member SME, of Kemira, ceramics and refractory materials.• Nikhil Gupta, member SME, of Virginia Tech, chemical raw materials.• Jasson Giddens and Swadhin Saurabh, members SME, of Oil Dri Corp of America and Mill Creek Engineering, respectively, chemical raw materials.• Snehamoy Chatterjee, member SME, of the Michigan Tech.• LeDeana Roberts and Shubham Verma, members SME, of Imerys and U.S. Oil Sands, respectively, fillers and pigments.• Thomas Hilderbrand and Kaiwu Huang, members SME, of Thiele Kaolin Co. and Virginia Tech, respectively, sorbents, filters and process aids.• Rhaghav Dubey and Edgar Blanco, members SME, of Outotec and FL Smidth, respectively, specialty mineralsAntimony generally occurs along with gold, lead, copper and silver. There are more than 100 antimony minerals, although the sulfide mineral stibnite is the main one.Antimony enters the supply chain either as a result of mining (primary production) or recycling (secondary production). China has by far the largest antimony resources and is, as a result, the world’s center for antimony mine production. In 2016, it accounted for more than three quarters of the global mine supply out of a world production figure of 130 kt (143,000 st), according to the U.S. Geological Survey. The biggest, and most high-grade deposits are found in southern China, with the largest mines located in Hunan, Guangxi and Yunnan provinces. Tajikistan, Russia, Australia and Bolivia are the largest mine producers outside China. A new antimony project in Oman made progress in 2016, producing first metal in April 2016 in test facilities, and then ordered three furnaces for a 26 kt/a (28,600 stpy) antimony metal and oxide smelter that is due on stream in late 2017.Antimony ingot production is not as widespread as is antimony mine production, owing to the high levels of pollution that are associated with antimony smelting. It is for this reason that smelting has been largely confined to China and other Asian countries, where environmental legislation is less stringent.Antimony oxide production is undertaken on four continents with China being the biggest producer. There is also a considerable amount of oxide production in Europe — which relies on imported feedstock, mostly from China. Antimony also enters the supply chain through recycling. Lead containing antimony is produced in a number of countries, mainly in secondary lead smelters. Typically, a blast furnace charge containing used or discarded battery plates, type metal or bearing metal is reduced to lead bullion, which is refined in reverberatory furnaces and melting pots. In the main, the antimony recovered is consumed in metallurgical applications. China was the biggest secondary antimony producer in 2016, and accounted for 25 retardants and lead-acid batteries. Flame retardants accounted for roughly 50 percent of consumption in 2016 with batteries representing about 25 percent. Other end uses include plastics and heat stabilizers, ceramics and glass and a variety of metallurgical applications. Demand has been sluggish since the global financial crisis, mostly because key markets failed to recover strongly from the downturn, particularly in Europe."

Jan 7, 2017

By N. W. Bliss

"Bauxite has been the almost universal ore of aluminum for about 100 years, with most of the world's reserves oc¬curring in the developing countries. As a result of fiscal and political activities prompted in part by the energy crisis, the formation of the IBA combined with increasing freight and labour costs, these reserves are no longer as competitive or as secure as they once were. This has given fresh impetus to the development of processes for alumina production that utilize raw material other than bauxite. Canada has no bauxite and it is prudent to look for alter¬native raw materials within our own boundaries suitable for one of these processes.Of the three igneous rocks that have been used as a source of alumina, only anorthosite is considered as a potential source in Canada. The Al content would be extracted by a sinter process, which currently requires a raw material with a. minimum of 28% Al2O2. Thus, about 4 tons of anorthosite and 10 to 12 tons of limestone are needed to produce one ton of alumina. There are two petrologically distinct types of anorthosite, one containing the plagioclase andesine-labradorite and around 26% Al2O3, and the other containing upwards of 30% Al2O3, in by¬townite-anorthite; for our purposes they may be con¬sidered as low- and high-alumina anorthosite respectively. The high-alumina anorthosites are somewhat rare; the low-alumina anorthosites are much more common, partic¬ularly in Eastern Canada. Geologically speaking, there is no shortage of anorthosite in Canada. The reserves are im¬mense, although their low Al2O3 content coupled with con¬siderations of location, access and proximity to limestone could be constraints to their development. Fly ash from coal-fired thermal power stations and nepheline syenite can also be used in a sinter process, but neither is likely to be utilized in Canada in the immediate future.The H+ process utilizes an acid attack to leach Al from a raw material with at least 20% Al2O3. One of the best raw materials is kaolinite-bearing clay; not only is it high in Al, but most of it can be extracted. With the possible exception of the Whitemud clay in Saskatchewan, Canada is apparently deficient in clays with sufficient reserves to support an alumina plant utilizing the H+ process. Low-alumina clays with illite and montmorillonite may also prove to be a suitable raw material if advantageously sited with respect to industrial centers. The average shale con¬tains only 15% Al2O33, much of which may be contained in minerals, such as feldspar, not amenable to acid leaching. If shale is used as a source of alumina, it will be because it contains some other valuable commodity, such as oil or uranium, the extraction of which leaves the spent shale upgraded in extractable Al2O3 and lowers the over-all costs to a point where it is economic, Thus, rejects from coal washing plants are most commonly considered as a source of alumina; they are already mined, are available in large and ever increasing amounts, and may contain significant amounts of combustible material which upgrades the Al2O3, content of the resulting ash. Coal rejects from existing and developing coalfields in Alberta and British Columbia are a possible source of raw material, but present data indicate they may contain insufficient Al2O3."

Jan 1, 1976

By Syd S. Peng

According to accident statistics (l, 2), roof fall accidents occur quite frequently at the intersections of underground? openings and account for up to 30% of the roof fall fatalities. But this figure will certainly go up considerably if roof falls not associated with any fatal accident are included in the analysis. Unfortunately, nonfatal roof falls are seldom documented. In the underground coal mines, there are two types of entry intersections. One is the three-way (V type) and the other is the four-way (T type) intersections. A three-way intersection occurs whenever the mainline track haulageway turns at an angle into a section haulageway. The four-way intersections by far the most common type in the U.S. under-ground coal mines are formed by the intersections of two entries which are oriented perpendicular to each other or by the intersections of entries and crosscuts. However, crosscuts are frequently driven at an angle to the entry to facilitate machine movements. The four-way intersections formed by this method of crosscut development are angled. At the intersection of two underground openings, the diagonal roof span is wider than the width of each individual opening. This is one of the major reasons why roof falls occur more likely at the intersections than in the entry between pillars. Consequently, special intersection support plans are usually employed (Figs. 1 and 2) for intersections. The most popular practices are to decrease roof bolt spacing 1 ft. less than or to increase roof bolt length 1 to 2 ft. longer than those employed in the entry between pillars (3). The increase in bolt length or decrease in bolt spacing can be applied to all of the bolts in the intersection or employed only for the strategically located bolts depending on the individual mine practices. These rather generalized practices seems to be adequate for some areas but in many cases inadequate for others. Occasionally, the neighboring two lines of chain pillars are staggered such that the crosscuts in one row of chain pillars face the centers of the chain pillars in the neigh-boring rows. This layout forms T-type three-way intersections which are also inadequate for most weak roofs (3, 4). A study was therefore initiated to develop special techniques for intersection supports. The first phase of the study was the analysis of the stress fields for the underground entry intersections. A three-dimensional stress analysis was necessary for this purpose. Unfortunately, the three-dimensional problems of complicated boundary conditions are beyond the existing analytical methods. The three-dimensional finite element method (FEM) was therefore employed in this study. In the analysis, square pillars of 40 feet wide and an entry height of 8 feet were assumed while entry widths varied at 14, 20 and 26 feet. This model was selected to simulate the mine where roof falls data were collected. The second phase of the study was the collection of field data. The sizes of the roof falls including heights, lengths and widths were collected and analyzed. In the third phase study, the results of the first and second phases were compared and discussed. The analysis of field data revealed an arching zone within which roof falls occurred. The arching zone above an entry obtained empirically was compared with the calculated stress contours. Assuming that the bolts must be anchored in the rock strata outside the arching zone, the preferable systems of bolting were proposed. Also the amount of pretension required to inhibit sliding between layers was discussed.

Jan 1, 1978

By M. A. Reyes, J. Bickson, J. R. Srednicki

Federal laws mandate the presence of refuge alternatives (RAs) in underground coal mines and provide guidelines for harmful gas removal. After an explosion, harmful gases can follow survivors into an RA and can reach a deadly concentration. Investigators from the National Institute for Occupational Safety and Health (NIOSH) tested 12 ventilation system configurations (VSCs) to purge sulfur hexafluoride (SF6) tracer gas from a built-in-place (BIP) RA in the Experimental Mine in Bruceton, PA. Using a borehole air supply, tests were conducted with airflows of 750 and 1,000 standard cubic feet per minute (SCFM). Excluding a VSC where the air inlet was 1.98 m (78 in) from the air outlet, the results show that the time to purge the SF6 concentration from 1,000 parts per million (ppm) to 25 ppm ranged from 26 to 29 minutes for an airflow of 750 SCFM and ranged from 18 to 23 minutes for an airflow 1,000 SCFM. Mines can use this information to reduce purge time in case of a mine disaster and determine which VSC to avoid. INTRODUCTION After a fire or an explosion in an underground mine, the concentration of carbon monoxide can reach a fatal level. In a mine disaster, the main goal is to escape. However, if miners cannot escape, they have to migrate to a location to find refuge and, if possible, communication, and a borehole source for a fresh air supply. To ensure survival of the miners, Federal laws mandate the presence of a refuge alternative (RA) within 304.5 m (1,000 ft) of the nearest mining face. In addition, Code of Federal Regulations Title 30 CFR Section 7 sets the guidelines for personnel tracking, RAs, and the removal of noxious gases in underground coal mines (Mineral Resources, 30 CFR, 2014). Federal regulations define an RA as a protected, secure space with an isolated atmosphere and integrated components (Mineral Resources, 30 CFR, 2014). There are three types of RAs: portable metal RAs, portable tent-type RAs, and built-in-place (BIP) RAs. A BIP RA is constructed using masonry or other stoppings to create an isolated space in a mined-out area. Blast doors are installed in one or both of the stoppings for the miners to enter the RA. Furthermore, RAs must provide the following components: breathable air, food, water, air monitoring, and harmful gas removal. Federal regulations have emphasized the mandate for breathable air and harmful gas removal in the following words: “Purging or other effective procedures shall be provided for the airlock to dilute the carbon monoxide concentration to 25 ppm” (Mineral Resources, 30 CFR, 2014). The purpose of the mine ventilation system is to provide a sufficient quantity of air to the underground mine workings, to dilute methane and other contaminants, to maintain a suitable working environment, and to prevent accidents from happening (Cheng and Wei, 2014). In addition, the organic nature of coal amplifies risks from poisonous gases, explosions, and fires (Engström et al., 2018). If an underground coal mine ventilation system fails after an explosion, the concentration of toxic gases, most notably carbon monoxide, will increase. Carbon monoxide is dangerous because it creates tissue hypoxia by binding to hemoglobin (Özmen and Aksoy, 2015).

Jan 1, 2019

By J. R. Tonry

In the grinding of dry non-metallic materials such as rocks, ores, gypsum, lime, and cement clinker, it is recognized that only a relatively small portion of the energy is utilized for actual size reduction, and the major portion of the energy used is converted into heat. As a result, heat is generated inside grinding mills imparting to the ground product a higher temperature than that of the mill feed. In some cases, as for instance in grinding cement clinker and gypsum into finished cement, it may be desirable to keep this temperature increase within certain limits, to avoid any change in the properties of the product and, because consumers may specify a maximum temperature of the finished product for reasons associated, with the tulimate use of the cement. The actual proportions of heat and useful work are somewhat indefinite. Some tests have indicated that nearly all the energy is converted into heat, and. other investigators have found that they could account for "everything except the noise." Investigations sponsored by the American Institute of Mining and Metallurgical Engineers, and carried out with an adiabatic calorimeter, indicated that a surprisingly high 19 percent of the energy might actually be used for size reduc¬tion. However, for the purpose of the following discussion it will be assumed that: (Fig. 1) 10% is lost in motor and gears 10% is lost by radiation and convection from the mill body 10% is used for size reduction, and. that 70% of the energy input leaves the mill as heat in the ground. product. A typical example (Fig. 2) would be a 7x22-ft tube mill operating in open circuit, driven by a 400 hp motor, charged with 77,000 lb of grinding media and producing 70 bbl or 26,300 lb of cement per hour. Reducing this cement from a clinker size of 96 percent passing a No. 16 mesh sieve to a specific surface of 3,230 sq cm per gm (Blaine) will increase the temperature of the cement approximately 143F above the temperature of the feed, as explained later. If the tempera¬ture of the clinker therefore is 125F, the finished cement will be 268F, which in some cases may be too hot. : When cement temperatures approach a range during grinding where dehydration of the gypsum becomes a problem, a logical consideration would be some means of reducing the temperature before it attains the range conducive to gypsum dehydration. Regardless of the varying degrees of heat generated within the mill or mills during grindingto various finenesses, consideration of the maximum safe limit for any type of cement being ground, which may vary fromplant to plant, govern in refining the mill circuit to obtain a safe temperature range. All plants are not necessarily required to do the same cooling job, and may or may not use cement coolers following the grinding circuit. (Not discussed in this paper). In the past, various means have been employed for controlling this temperature increase, Such means have included water cooling of the outside of the mill shell; equipping the shell with cooling fins; injection of moisture inside the mill; ventilation through the mill; and., in cases of closed-circuit grinding, drawing cooling air through the classifier; the purpose in all such cases being to remove heat from the grinding system.

Jan 1, 1958

By Jerold Bishop, Grant Bearss, Aleksey Egorov

"When a shock wave is released in the bottom of a drill hole filled with wet concrete slurry, the result is called an electrohydrodynamic effect, or EHDE. The energy is carried through the fluid with minimal loss because the slurry is an incompressible medium. Repetitive discharges provide a series of energy pulses that compact the soil along the pile shaft and at its base. The process is analogous to repeated applications of low-energy blast densification or to dynamic compaction. In general, the process is not depth dependent. EHDE was identified in the 18th century by an American scientist who observed that a spark between two electrodes placed under water induced a burst of pressure. In 1957, two Russian engineers formulated a process and received a patent for a method of creating a pressure wave by transforming power from an electrical discharge to a mechanical impact. They derived more than 200 applications for technical and industrial processes.In the 1970s, civil engineers at the Engineering and Building Institute in St. Petersburg, Russia, began to look at EHDE to improve the capacity of drilled piles. Early experiments showed that electric discharges in a wet concrete slurry mix could create a pressure wave of up to 26 MPa (3700 psi). Later tests demonstrated that this pressure level could be created in a drilled pile hole. The researchers devised equipment and in the early 1990s began to study pulse technology as applied to drilled piles.This application was accepted into the Russian Federation Building Code in the 1990s. The code treats “regular” drilled piles with equivalent bearing area as having roughly half the capacity of a driven pile. However, the code considers drilled piles treated with the EHDE technique a direct “one for one” substitution for driven piles and allows higher values if the capacity is established by static load testing. Hundreds of projects have been completed in Russia using this technology to value engineer drilled pile projects. In several instances, the number of drilled piles installed was fewer than half of the number originally planned for due to the capacity increase that EHDE-treated piles provided.Drilled PilesIn drilled pile construction, the EHDE process creates a mechanical pressure wave that impacts the base and sidewall of a drilled pile shaft. Soft, poorly consolidated or loose soil is compacted by successive pulses of pressure created by electrical discharges. These mechanical impulses are made by inserting a discharge probe into the wet concrete slurry. A discharge across the tip of the probe creates the pulse that travels outward to the sidewall and base of the drilled pile through the incompressible medium of the slurry. The power pack ratings for equipment presently in use are 35 and 50 kJ (kilojoule).Each pressure wave strikes the soil, causing compaction and expanding the hole. Workers apply the pulses until the size of the hole stops increasing. They watch the slurry level during pulsing. When the level quits dropping, further soil compaction in the drill hole sidewalls and base is not possible. After the pulse process is complete, workers insert a rebar cage and the pile is finished.The process does not alter the soil mineralogy. The electrical discharge is internally grounded and does not arc to the sidewalls of the drill hole. Soil is not scorched or altered in any manner; it is only compacted by the pressure wave. This technique has been used in urban areas with no effect on electrical or electronic equipment."

Jan 1, 2009

By Dell P. Williams, Howard G. Nelson

The tensile behavior of magnesium single crystals at a temperature of 26º ± 2ºC was investigated at varying pressure levels from 760 to 8 X 10-8 tow. For crystals deformed at a constant linear strain rate of 0.061 min-1. there was no apparent effect of the vacuum environment down to 10-8 torr. However, from a vacuum of 10-5 torr down to the lowest pressure attained (8 x 10-8 tor,), the effect of the vacuum environment was to increase the strain at the end of the first linear (or easy-glide) stage and to decrease the slope of this stage; the magnitude of this effect was found to be dependent on pressure. The slope of the second linear stage was also decreased at the lower pressure levels; however, this effect appears to be caused primarity by the vacuum effect on the first linear stage. The magnitude of the vacuum-environmrnt effect was also found to be dependent upon strain rate. The reduction in flow stress at 5 x 10-8 torr, as compared to the stress in air, was obserced to be about 10 pct for a strain rate of 0.0250 min-' and 70 pct for a strain rate of 0.67 min-1. No systematic effect of pressure on the critical resolvled shear stress was observed. The data interpreted in terms of a modified form of Mott's work-hardening mechanism for hexagonal metals. It has long been known that surface conditions influence the mechanical behavior of materials. Roscoe 1 demonstrated the importance of surface conditions on mechanical behavior by testing cadmium crystals with oxide layers. He found that the "apparent" critical resolved shear stress for cadmium was increased approximately 2.5 times by the presence of an oxide layer 1000 atoms thick. The magnitude of this effect was dependent on film thickness with crystals having films less than 20 atoms thick still showing a definite increase. This observed strengthening could not be attributed to any strength of the oxide film because of 1) the thinness of the films and 2) an observed increase in the flow stress as deformation proceeded. Harper and cottrel12 obtained similar results on zinc crystals which had been etched and steamed to give artificially thick oxide films. However, in the course of this study, they also carefully examined the very early stages of plastic flow for zinc crystals which in one case had been electrolytically polished and in the other had been lightly etched to produce a thin film. They then found that the critical resolved shear stress for both surface treatments of the crystals was actually identical but that the etched crystal exhibited a much more rapid initial hardening rate. This had not been noted previously. This result indicated that, in fact, the film caused an increase in the stress for continuation of slip, rather than for the initiation of slip. Lipsett and King3 investigated the effect of evaporated gold films on the plastic behavior of cadmium single crystals. For large angles (=75 deg) between the specimen axis and the normal to the slip plane, they found that the stress-strain curve of the coated specimen always lies above that for a clean specimen. The shear strain at the end of the first linear stage was greater in clean specimens than in coated specimens and the slope of the second linear stage was

Jan 1, 1965

By G. M. Crosby

Seven mines with important production records in the Coeur d'Alene lie adjacent to the Gem stocks —the Frisco (Gem), Hercules, Interstate, Rex (Sixteen to One), Success (Granite), Sunset, and Tamarack. Old records are incomplete, but available data given in Table I show these mines have produced 10.550,721 tons of ore containing more than 50 million oz of silver, more than 1.5 billion lb of lead, and about 1 billion lb of zinc (approximately 1.25 million tons of lead and zinc combined). Average ore grade is 4.8 oz of silver per ton, 7.2 pct Pb, and 4.6 pct Zn. This impressive production represents about 12 pct of the District's yield. At present metal prices, with modern beneficiation, the gross value would be more than $400 million. THE GEM STOCKS The Gem stocks, considered to be outliers of the Idaho batholith of Late Cretaceous age, are located in the northern half of the Mullan quadrangle, and extend from the town of Gem, Idaho, along a strike of N30°E for a distance of approximately five miles. They occur as two major masses of monzonitic rocks commonly referred to as the North stock, which covers an area of 1.1 sq miles, and the South stock, which covers 2.6 sq miles. The areal pattern is roughly club-shaped, the North stock representing the handle and the South stock the head of the club. Two and a half miles west and five miles northeast are two groups of smaller stocks, isolated from the main masses but of the same general rock type. This discussion is limited for the most part to the North and South stocks. At the north end, where the intrusion is about 3200 ft wide, the walls are about parallel and dip very steeply west. At the south end, where the mass is about 7000 ft wide at surface, the walls dip away from each other at moderately steep angles. An aeromagnetic survey' detects and outlines with surprising accuracy the two main stocks. as illustrated on the magnetic contour map (Fig. 2). Of particular interest is the location and shape of the magnetic anomaly representing the South stock. The anomaly is centered over the south end of the outcrop, and a westerly extension joins it with a smaller anomaly over the Dago Peak stocks. The latter anomaly, likewise, is located over the south end of the isolated stocks. This pattern suggests the intrusion has greater extent at depth to the south and west. Though correlation between the Dago Peak stocks and the larger masses is suggested, the controversial aspects of the Dobson Pass fault, which separates the two areas, casts doubt on a correlation. Topographically the monzonite stocks are ignored by the drainage pattern indicating these rocks, and the invaded rocks of the Lower Belt Series react similarly to erosion. The drainage patterns of Nine Mile and Canyon creeks cut indiscriminately across the monzonite-Belt contact, resulting in both valleys and ridges in the southern end of the intrusion. Nine Mile Creek traverses diagonally the entire five-mile length of the stocks. The monzonite rocks of the intrusion are referred to locally as granite, but granite is rare and the rocks comprise a wide variety of types. Their characteristics, described in detail by F. L. Ransome and F. C. Calkins,' are summarized by P. J. Shenon.' The principal rock type is coarse-grained, light gray, porphoritic monzonite containing black crystals of hornblende. Pyroxene, epidote, and titanite

Jan 1, 1960

1. Book reviews Physiochemical properties of molten slags and glasses, by E.T. Turkdogan. London, Metals Society, 1983.516 pp. £35. Reviewer: A.F .S. Scboukens Microstructural characterisation of metals and alloys, by P.E.J. Flewitt and R.K. Wild. London, Institute of Metals, 1984. £14. Reviewer: M.P. Sbaw Metallurgical applications of magnetohydrodynamics, edited by H.K. Moffatt and M.R.E. Proctor. London, Metals Society, 1984.346 pp. U.K. £35, U.S. $70. Reviewer: N.A. Barcza Extractive metallurgy symposium. Proceedings of a meeting on 12-14 November, 1984, organised by the Melbourne Branch. Parkville (Victoria), Australasian Institute of Mining and Metallurgy, 1985. Reviewer: B.K. Loveday Conference on gold mining, metallurgy and geology. Proceedings of a meeting on 9-11 October, 1984, organisedby the Perth and Kalgoorlie Branch. Parkville (Victoria), Australasian Institute of Mining and Metallurgy, 1985. Reviewer: B.K. Loveday Corporate policies for the 1980's in the steel industry, by Patrick Genevaz in collaboration with B.A. Bloom. La Chambre des Cartes, 26 rue de Piepus, 75012 Paris (France). U.S.$7oo, additional copies $140. Reviewer: D.C. Maree Mineral processing technology, by B.A. Wills. Oxford, Pergamon Press, 1984 (3rd edition). 629 pp. Hard cover £31.50, soft cover £9.75. Reviewer: B.K. Loveday Ma1lllgement information-ma1lllging for improYement, volume 2: symposium proceedings and additional papers. edited by M. Hammond. Doncaster (England), The Institution of Mining Engineers, 1984. 86 pp. £60 for vols. 1 and 2 (124 pp.). Reviewer: M.J .R. Meyer 2. Recent publications Tins and its and its uses no. 144, 1985. This issue by the International Tin Research Institute (Fraser Road, Greenford, Middlesex, UB6 7AQ, Canadian minerals yearbook 1983-84. Department of Energy, Mines and Resources Canada, Mineral Report 33. Ottawa, Canadian Government Publishing Centre, 1985. $35.40. 82 Year 1984, edited by 1.0. Jones and RM. Louthean. Kalgoorlie (Australia), Western Australian School of Mines, 1985. 100 pp. Johnson Matthey Chemicals 1984-85, issued by Matthey Catalogue Sales (Orchard Road, Royston, Hertfordshire SG8 SHE, England). 416 pp. South Africa's mineral industry 1984. Johannesburg, Minerals Bureau, 1985. 190 pp. Coal 1985. Operating and developing coal mines in the Republic of South Africa. Johannesburg, Minerals Bureau, Directory 2/8S. 1985. 72 pp. Gold 1985. Operating gold mines and gold recovery plants in the Republic of South Africa. Johannesburg, Minerals Bureau, Directory 3/8S. 98 pp. 3. New journal Pergamon Press, New York, have announced the publication of a new quarterly known as the International Journal of Plasticity. 4. Mintek reports Report M93D Hydrochloric acid leaching and low-temperature roasting of tin-tungsten concentrates from Van Roois Vley. (First issued April 1983.) Report M99D The upgrading of coarse kyanite crystals. (First issued Report M105D The development and installation of a microcomputer based data logger, and the analysis and evaluation of data. (First issued July 1983.) Report M109D The remelting ofsi/iconfines. (First issued July 1983.) Report M180 An assessment of available corrosion inhibitors for the reticulation systems of South African gold mines. Report MW1 Quantitative assessments of abrasive and impactive wear from ball-size distributions in rotary mills.

Jan 1, 1985

By John M. Kelly

New Mexico produced 39,751,868 bbl. of oil in 1941 and ranked seventh among the oil-producing states. Its 1941 production established an annual record, exceeding the 1940 record year by 854,498 bbl. The average daily production for the year was 108,909 bbl. The average daily non-marginal well allowable for New Mexico on Jan. I, 1941, was 36 bbl.; at the close of the year it was 43 bbl. The average daily pipe-linc runs were approximately 3 per cent less than the allocations of the New Mexico Oil Conservation Commission, which followed closely the recommendation of the United States Bureau of Mines in setting the daily outlet demand. The production in Lea County was 34,333,448 bbl.; Eddy County, 5,009,354 bbl.; and northwestern New Mexico (San Juan and McKinley Counties), 406,306 barrels. The total number of completions in the state was 402, of which 301 were oil wells, 19 gas wells, and 82 dry holes. Drilling during 1941 was 68 per cent of 1940, and the ratio of dry holes to producers, I to 4, was the greatest since 1935. Of these dry holes 43 were drilled in proven fields and 39 were wildcats. One new oil field and one new gas field were discovered as a result of the 1941 wildcatting program. However, numerous extensions were made to the existing fields, which, although they were called extensions to proration areas, were in reality field discoveries, being on separate geologic structures. Southeastern New Mexico Lea County The Monument field was the largest producing field in Lea County, with 6,973,808 bbl. It was closely followed by the Eunice field, with 6,644,181 bbl.; Vacuum field, with 4,800,608 bbl. and Hobbs, with 3,624,159 bbl. Hobbs field, however, still has the largest total recovery, this being 97,407,929 bbl. at the end of 1941. The new oil-field discovery in Lea County during 1941 was the Salt Lake field, T. 20 S., R. 33 E. The discovery well was Leonard-Welch State No. I, NW. NW. of sec. 18, T. 20 S., R. 33 E. This well was drilled to a total depth of 3103 ft. and was completed for an initial production of 250 bbl. per day pumping. The oil is 26" gravity and the producing horizon is in the San Andres limestone of Permian age. The discovery well was completed on June 22, 1941, and since that date four more producers have been completed, with no failures. The area is about 10 miles north-west of the Lynch pool, to which the oil from this field is being trucked because there is no pipe-line connection. The greatest drilling activity during 1947 was in the Maljamar field of western Lea County, with 62 completions, 59 being oil wells and 3 dry holes. The limits of this pool are now being defined on the north and south but to date have not been defined either to the east or west. The total number of 40-acre oil-producing units in the field at the close of the year was 158. On April I, 1941, a pressure-maintenance project was installed at the southern end

Jan 1, 1942

By C. A. Hartnagel

The production of petroleum in New York state in 1942 amounted to 5,410,000 bbl. This represents an increase over each of the four preceding years, and, with the exception of 1937, is the largest production since the peak of over six million barrels in 1882, shortly after the discovery of oil in Allegany County. The oil industry in New York is virtually stabilized and there has been little or no exploration for new sources of supply in recent years. The boundaries of the present fields were established more than 30 years ago and since then no additional reserves have been found. Deep drilling for natural gas during the past 10 years both within and without the oil fields has failed to find oil in quantity below the present producing sands of Devonian age. Oil Since 1882, the New York fields have produced approximately 140 million barrels of oil. Of this amount, 65 million was produced up to the year 1919 by ordinary pumping methods; that is, without flooding by water or the use of other secondary-recovery methods. In the year 1919, when a law was passed making the use of water-flooding methods legal, the oil production, of the state amounted to only 851,000 bbl. In the 23 years since 1919, there have been produced in the state 75 million barrels, or 10 million more than in the previous 37 years, which included the period of flush production. Price.—On March 26, the price of crude oil was raised from $2.75 to $3.00 per barrel, hut this increase had little or no effect on the number of wells drilled. In the Allegany field, which accounts for three fourths of the state's oil production, 1259 wells were completed in 1942, 7 less than in 1941. The smaller number of wells drilled was not only due to the shortage of labor but also was caused by the fact that in water-flooding territory a definite program for drilling wells is followed, and the flush period of an oil well is not usually reached in time to profit by any given price increase. Daily Production.—All of the oil wells in New York state, some 21,000 in number, are small producers. The average daily oil production is 7/10 bbl. per well. Under good flooding conditions, a maximum production of 5 to 8 bbl, a day is reached about one year after the flood begins to act on the well. In 5 years the daily production usually is less than one barrel. Although most of the oil in New York is produced by flooding, an estimated 2500 old wells produce without flooding. Some of these produce as little as 1/20 bbl. a day and are pumped only at intervals. The small producing Wells are mostly on lands leased to the larger oil companies and later will be included in a flooding program. At present, they are pumped only because the owners of the land insist on the royalty. Government Aid Needed.—Because of its good lubricating qualities, New York oil is one of those for which there is an insistent and growing demand, but even at its present price of $3.00 per barrel, many of the operators are producing at a loss.

Jan 1, 1943

By John Griffen

This paper records over twenty years' experience with the use of the Rheolaveur system in the United States, showing its ability to meet changing conditions caused by the dirtier mine output of present-day mechanical mining methods. Data are given on size ranges handled, number and capacity of units installed, maintenance experience, and operating results on two-product and three-product separations. IT is not the purpose of this paper to discuss the principles employed in the Rheolaveur system of fine-coal cleaning as these have been fully covered in the technical literature of the Institute."2 Rather, our purpose will be to record the highlights of over 20 years' experience in the United States with Rheolaveur fine-coal launders, which will indicate their capabilities and costs of cleaning and their adaptability to meet the changing conditions caused by present-day mechanical mining methods. Rheolaveur fine-coal launders are used in the United States to treat a wide variety of size ranges of fine coal, the coarsest being 1/2 in. to 0 and the finest about 1/8 in. to 0. In Europe feeds as coarse as 5/8 in. and as small as 1/2 mm (28-mesh) to 0 are being cleaned. The size ranges usually handled in this country are 3/8 to 1/4-in. round to 0. Thirty five units with a combined hourly feed capacity of 3200 tph have been installed in the United States. Individual units are cleaning as little as 25 tph, while others are cleaning as much as 200 tph. Rheolaveur fine-coal launders offer cleaning units of high capacity and are outstanding in requiring a minimum of building space per ton of input. Experience has shown that maintenance costs are low. Several installations were made in the Pittsburgh district from 1928 to 1930, and since that time operation has been largely two shifts per day. Minor repairs to liner plates and Rheo boxes have been required during the intervening years, but no major replacement of launders was required until 1947 and 1948. At one of these plants, launders operated for 17 years before they were replaced and during that period over 26,000,000 tons of —5/16-in. coal were cleaned. The effect of the much dirtier raw coal produced by mechanical loading of the Pittsburgh seam is shown by the following tests. The data in table I summarize the performance of a Rheo fine-coal unit when cleaning hand-loaded raw coal. The —4-in. raw coal fed to the cleaning plant analyzed only 8.16 pct ash and 1.31 pct sulphur and contained 4.6 pct sink, 1.55 sp gr. Two years later, in 1945, mechanically-loaded coal from the same mine was cleaned in the same plant. The feed, —4 in., then analyzed 20.10 pct ash and 1.53 pct sulphur and contained 20.2 pct sink, 1.55 sp gr. The performance of the Rheo fine-coal unit when cleaning this coal is given in table 11. It will be noted that the +48-mesh coal is cleaned almost as thoroughly as in table I. The large amount of high-ash slimes produced from the dirtier feed are responsible for the higher ash of —--48-mesh washed coal in table 11. In this plant the Rheo fine-coal unit did not get the full load of refuse resulting from mechanical

Jan 1, 1951

By L. K. Jetter, C. J. McHargue

The use of axis charts for representing the texture of cold-rolled thorium sheet was compared with conventional pole figures. Four texture components were deduced from the axis charts and shown to be consistent with the pole figures. It was shown that consideration of the pole figures alone could lead to an apparent component which is the average of two actually present. It was also shown that the spread about the "ideal" textures and the amount of material associated with each could be readily obtained Fom the axis chart method. BECAUSE of the crystallographic nature of the deformation mechanisms in metals, plastic flow results in the alignment of certain crystallographic directions with the primary flow directions. In the study of the "preferred orientation" thus developed, one wishes to discern the distribution of the crystallographic directions with respect to some reference direction, usually a direction related to the fabrication procedure, such as the rolling direction. The pole-figure method, introduced by ever,' involves the plotting of the distribution of the poles of some family of planes on a stereographic projection which places the reference direction(s) at the north pole and/or in the center. By noting the angles between the reference directions and concentrations of poles on several such pole figures, one can deduce the crystallographic directions which are aligned with the reference directions. If the preferred orientation is relatively simple and well-developed, one to three pole figures may be sufficient for obtaining the desired information; if there are several texture components, more pole figures may be needed. A significant improvement in the method of representing the textures in wires and rods resulted from the introduction of the "inverse pole figure" or axis-distribution chart by Harris.2 Such a chart gives directly the distribution of the reference axis relative to the standard stereographic projection. There has been widespread acceptance of this method for the representation of fiber textures, and methods have been proposed for converting observed diffraction intensities into axis densities.2-6 The suggestion by Mitchell and Rowland3 and Jetter, McHargue, and williams5 that sheet textures could be represented as distributions of rolling, normal, and transverse directions have been criticized on the basis that they offer no significant advantage over a combination of two ordinary pole figures and that it has not been proved that sheet textures can be treated as quasi fiber textures.6 If the purpose of a texture determination is to study some property which is related to the orientation of a particular crystallographic plane or direction, then conventional pole figures certainly are sufficient. For example, the distribution of the slip planes in face-centered cubic metals (the (111) pole figure) serves to indicate the variation in mechanical properties of sheet. On the other hand if the study is directed at an understanding of the factors influencing texture formation, it is desirable to know not only the preferred orientation but the kind and degree of spread from it and the relative amounts of material in each component, if there are more than one. Axis charts give this information as well as the orientation distributions. Consider the procedure for deducing a texture component from a pole figure for the (111) planes

Jan 1, 1961