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By Seth C. Schaefer

As part of the Bureau of Mines, U.S. Department of the Interior, effort to provide thermodynamic data for the advancement of minerals technology, the Gibbs energy of formation of sphalerite (zinc sulfide) was investigated with a high-temperature galvanic cell employing stabilized zirconia as the electrolyte. In the temperature range 948 to 1,210 K, potential measurements were obtained for the cell Pt, ZnS + ZnO, S02 = 1 atm // Zr02 // Cu20 + Cu, Pt, with the overall cell reaction ZnS(c) + 3 Cu20(c) = ZnO(c) + 6 Cu(c) + S02(g). (1) These results, combined with the best available values of ?Gf° for ZnO, S02, and Cu20 from the literature, give the Gibbs energy of formation of zinc sulfide for the reaction Zn(l,v) + 1/2 S2(g) = ZnS© (2) ?Gf° = -64.223 + 24.02 X 10-3T ± 0.650 kcal/mole (3) (948-1,180 K; standard states - pure liquid zinc and S2 gas at 1 atm), and ?Gf° = -92.720 + 48.17 X 10-3 ± 0.650 kcal/mole (1,180-1,210 K; standard states - pure zinc vapor and S2 gas at 1 atm). A third law analysis yields for the formation reaction Zn(1) + 1/2 S2(g) = ZnS(c), (5) a standard enthalpy of formation as follows: ?Hf298.15 = -63.64 ± 0.700 kcal/mole.

Jan 1, 1978

By Balmer Neilly

In these days of arrested prosperity, when patience is tried and the future but dimly outlined, Canada's gold mining industry stands out as a beacon light shedding its rays of hope and confidence and demonstrating that there is still one product unaffected by Customs barriers and eagerly sought by all the people of the world. Some other forms of industry have hesitated and side-stepped. Some have cried for help, and in spite of public assistance, generously extended, they are still unable to demonstrate definitely their ability to resume the onward march. But gold mining has never hesitated. As an industry, it has bad an unique experience. When prices are high and conditions are generally referred to as prosperous, this industry is adversely affected. The cost of production goes up; profits are diminished; public sympathy is lacking; and, thrown upon its own resources, the industry tightens up its belt and throws its whole energy into an effort to improve operating conditions, and offset high prices by increased efficiency. When, in due course, depression follows inflation and prices ebb, the gold miner, through necessity, finds himself physically and mentally prepared to meet the situation.

Jan 1, 1932

By José A. Rios, José A. Vidalôn

The case study of a highland area in the Central Andes of Peru, where many abandoned polymetallic mines are found, is presented. Some of these mines generate metal leaching and acid rock drainage (ML/ARD) or have potentially ARD generating (PAG) tailings/waste rock storage. Effluents are discharged into the first of two lakes in line, which act as reservoirs for irrigating an important valley in the desert coastal region. Drainage fees, their relationship with the deposit and the solid-wastes mineralogy are discussed, as well as variations in water and sediments composition, the benthos, and the aquatic/riparian flora/fauna in these lakes.

Jan 1, 2000

When most people think of coal mining, they envision men in soot-covered clothes and hard hats digging at deposits in deep underground caverns. These mental images commonly include coal cars rumbling on rails as they emerge from the earth, filled to the brim with rocky ore. The world of modern, longwall coal mining is a far different place. Yes, it?s underground, the miners still wear hard hats and the environment is filled with soot. However, today?s mining operations are carefully monitored and the entire process is highly automated. Five kilometers (3 miles) underground, a sophisticated, high-powered mining machine moves steadily through a 2-m (6-ft) high tunnel at an average speed of 3.2 km/h (2 mph), carving out coal, then conveying it to a crusher and carrying it to the surface. Instead of digging out the ore, a longwall mining system slices it from the exposed tunnel face, using giant rotating shears. The shorn coal tumbles onto a conveyer below the shears and is conveyed to the stageloader, where it is crushed and dumped onto the main conveyer belt that eventually hauls it out of the mine. Integral to the longwall shear and conveyor is a moving metal roof that protects it from the thousand plus feet of ground above. The ceiling panels automatically advance above the shears, powered by hydraulic roof supports that stand on the other side of the tunnel, moving in a slow, sideways lock-step with the shears. This complex and massive machine makes longwall mining the most ef?cient and productive method for excavating coal. In fact, it produces 2.7 kt to 22.6 kt (3,000 to 25,000 st) of ore per shift, versus 544 to 907 st (600 to 1,000 st) for the conventional room-and-pillar mining. Using that method, miners develop one section of a mine at a time after carving out load-bearing columns of coal to support the roof above their heads. Longwall mining also is considered safer than the room-and-pillar method, largely because the process is mostly automated, requiring fewer workers. Still, longwall mining has its drawbacks: The equipment is expensive and the mining conditions are harsh. An entire longwall system can cost between $50 million and $100 million, while the electrical controls used to operate it can cost an additional $1 million to $2 million. These investments grind away all day, every day, in hot tunnels filled with coal dust.

By Kenneth S. Ritchie

TOO often, many foremen; superintendents, managers, and executives, "The Bosses" of the oil and mining industries, do not fully realize: (1) How much personal actions '.on the job" may reduce their effectiveness in getting work done; and, (2) The importance of harmonious relations with their fellow men. Today. these qualities of personality in the people entrusted with the positions of responsibility are more important than ever with the shortages of labor so critical in vital war production. Likewise, many engineers do not fully realize that their work is essentially executive in character; i.e., other people do the actual labor. Without their help. the engineer's work would not be done. A clearer appreciation of this fact would increase their interest: (1) in the nontechnical aspects of their work. and, (2)in their relations with others, particularly the individuals in their own organization. Consequently, these engineers would be more successful in equipping themselves for greater responsibilities and increased remuneration.

Jan 1, 1944

By Jun Ohbayashi, Yoshiyuki Yagiura, Hiroaki Miyatake, Masuo Kondoh, Naotoshi Shinkawa

"Reducing the improvement ratio of ground improvement is an extremely efficient way to reduce the construction cost and construction period of mitigation measures for soft ground. The Arch Action Low Improvement Ratio Cement Column (ALiCC Method) is one method for this, and it is being increasingly applied to sites. This method enables us to rationally evaluate the embankment loads that are acting on cement improved soil columns and unimproved ground, by considering the arch action generated in the embankments and from there thusly allocate improved soil columns in spans of a greater distance than those needed for conventional methods. As a result, it serves to reduce construction costs and the construction period, while also minimizing the settling of the embankment and differential settlement, by placing numerous improved soil columns in the ground immediately beneath the embankment at equidistant intervals. In this report, we give a basic overview of the ALiCC Method, report typical construction results from real life cases that have been carried out, and make comparisons with other construction methods in order to report on the effectiveness of this design method.OVERVIEW OF ARCH ACTION LOW IMPROVEMENT RATIO CEMENT COLUMN (ALiCC) METHODIn the area of mitigation measures for soft ground, a significant role is played by ground improvements using improved materials such as cement. For this reason, a reduction in construction costs and construction period required for ground improvements has become of greater importance. The Public Works Research Institute carried out joint research with Kiso-Jiban Consultants Co. Ltd., Kitac Co. Ltd., and Fudo Tetra Co. Ltd. over a period from 1998 through 2002, and, from that, developed the ""Arch Action Low Improvement Ratio Cement Column Method"" (hereinafter referred to as the ""ALiCC Method"") that enables ground improvement with a lower improvement ratio (the improved area ratio is approx. 10% to 30%) than is required for conventional methods, while also ensuring stabilization and minimizing the settling of embankments.In the area of mitigation methods for soft ground by deep mixing, the dominant method until now has been that (50% or more of improvement ratio) shown in Fig. 1. This method comprehensively improves the area under the face of the slopes of both sides of the embankment. This is based on the calculated stability against rotational slip, which states, ""the most effective way to ensure the stabilization of the embankment environment is to carry out improvements of the area under the face of the slope."" Therefore, for the area under the face of the slope, ground improvement by deep mixing was done, and for the soft ground in the area under the middle part of the embankment, accelerated consolidation methods (hereinafter referred to as ""conventional method"") such as sand draining method and paper draining method were used. Mitigation measures that combine these improvement methods have also been mainstream for a long period of time and are used to prevent side deformation around the embankment. However, there have been some problems that have occurred, such as a situation where consolidation settling occurs in the center area under the embankment where no improvement had been carried out. This phenomenon leads to a situation in which the improved soil columns in the area under the face the of slope are pushed to the outside, which results in side deformation occurring around the area of the embankment, and additionally the occurrence of a step due to a situation of differential settlement between the improved ground and the consolidation advancing part, which results in cracks in the embankment."

Jan 1, 2015

By F. R. Hensel

PURE silver and silver-lead alloys have been studied as to their suitability for bearings.1-8 A review of the properties of thallium and the silver-thallium constitutional diagram was made by the author to analyze the possibilities of silver-thallium compositions for antifriction materials.† The silver-rich end of the diagram as reported in the literature9-11 was found to be sketchy and it was necessary to carry out considerable experimental work to arrive at definite conclusions. Some of the results of this work are reported in this paper. TEST MATERIALS In the beginning of the work, only fused alloys were investigated. Later, research [TABLE I. Composition of Fused Silver thallium Alloys Tested for Antifriction Properties PERCENTAGE ALLOY No.OF THALLIUM 15330.48 153406 231 HT2.04 2312.10 232 HT3.83Balance 2324.07Silver 233 HT5.86 2336.38 2349.84 234 HT10.07] was carried out on electroplating methods and diffusion processes. In preparing the fused alloys, care was taken to exhaust the toxic fumes caused by the thallium content. The compositions of the series of fused alloys are listed in Table I. The silver-thallium alloys were melted in clay-graphite crucibles and cast into preheated steel molds of 3/4-in. diameter. In the cast condition, they showed a cored structure, as indicated by the micrographs of Figs. I to 3. The etching reagent used was a mixture of 2 grams K2Cr2O7, 8 c.c. H2SO4, and 100 c.c. H2O. The cored structure is unsatisfactory for the type of corrosion resistance required for bearing applications, and homogenizing experiments were carried out at various temperatures, the results of which are shown in Figs. 4 through 8. The alloys with a lower thallium concentration, which were heated for 2 hr. at 525°C. show an almost completely homogenized solid solution type of structure. With higher thallium concentration, the homogenizing temperature was dropped to 475°C. to eliminate the formation of a liquid phase. It is evident that heating for 2 hr. at this temperature did not result in complete elimination of the cored structure. As would be expected, cold-working of the cast structure is an expedient in establishing equilibrium conditions. The fine homogeneous grain structure shown in Fig. 7 corresponds to the cold-worked area under the Rockwell ball penetration when the hardness was taken before heat-treatment. A detailed structural study was made on a cast silver-thallium alloy containing 3.67 per cent thallium. Three micrographs (Figs. 9, 10 and 11) show the transition

Jan 1, 1945

By Randall M. Wheeler

Many of us have used a seismograph to measure peak particle velocity and frequency. But do we really understand why? Also, why do we measure particle velocity instead of displacement and/or acceleration? What is the vector sum? How do these items relate? Where does frequency fit in? This workshop will attempt to answer these and other questions. Some of the answers may surprise you, others may not.

Jan 1, 1997

The Midvale Slag Site covers 300 acres in Midvale, Salt Lake County, Utah. Midvale (population 10,000) is part of the Salt Lake City metropolitan area (population 936,000). Between 1902 and 1971, United States Smelting, Refining and Mining Co. smelted ores on the site to produce copper, gold, lead, and silver. Figure 1 shows a picture of the historical Midvale smelter operations. [ ] When operations ceased, the site was estimated to contain 2 million tons of slag from these operations. The smelter no longer exists. In 1971, Valley Materials, Inc., acquired the site to process the slag into materials for railroad beds and asphalt highways. During the 1980s, the U.S. Environmental Protection Agency (USEPA) raised concerns regarding environmental impacts associated with the historical site operations. The Midvale Slag Superfund Site was listed on the NPL in 1991. The Site consists of two Operable Units (OUs): OU1 covering the properties north and adjacent to former ore smelting operations; and OU2 covering the smelter site itself. OU1 had historically been affected by wind blown slag dust and stack emissions occurring on OU2 and the Sharon Steel site further to the south. These emissions resulted in elevated levels of arsenic and lead in the native soils. The EPA issued the final Record of Decision (ROD) for the OU1 Site in 1995. The OU1 ROD required the implementation of institutional controls for the undeveloped portions of OU1 in order to restrict future land use to commercial/industrial purposes unless additional remediation was performed. Hence, the land comprising OU1 was originally considered in the ROD to be suitable for commercial or industrial purposes without the need for remedial action. However, development of OU1 for other land uses, including residential or recreational, would require additional assessment and probable remediation. The OU2 parcel was remediated by EPA to allow future land development, and the Sharon Steel site was remediated by EPA and deleted from the NPL. PROPERTY TRANSACTION AND REDEVELOPMENT In February 2006, a private development company, Mercer Bingham Junction, LLC. (MBJ) purchased 130 acres of the OU1 property for the purpose of performing environmental remediation, and developing mixed residential and commercial real estate. Development of the property was conducted in cooperation with USEPA Region 8 (EPA), the Utah Department of Environmental Quality (UDEQ) and Midvale City. The guidelines under which residential development could occur were defined by EPA. The 130 acres was to be developed for open space, residential and commercial use as part the Midvale City Bingham Junction development. Figure 2 shows the general layout of the proposed land uses. [ ] In May 2005, MBJ began pre-acquisition due diligence activities to purchase the 130 acres of OU1 north of 7200 South Street, which now comprises the Bingham Junction Development. This included the completion of Phase I and limited Phase II investigations. The Phase II investigations were performed to evaluate arsenic and lead concentrations in the planned residential areas of the site, and to explore the contents of the historic landfill on the property. The historic landfill area was on the far west side of OU1, adjacent to the Jordan River. Soil samples collected during the Phase II investigation showed that the planned residential parcels did not currently meet the criteria established in the Tech Memo and that additional placement of fill or soil excavation would be required for residential development in this area. An evaluation performed by the previous owner of the property, Littleson, Inc., showed similar results.

Jan 1, 2009

By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By Jacques J. Eksteen

Metallurgical accounting around toll treatment smelters pose a number of challenges. This paper reviews the requirements for good sampling practice, and how conflicting requirements for good furnace operation and design often makes reliable closure of the metallurgical balance tenuous at best. Typical physical causes of variance and bias will be identified. The propagation of error (in the form of variance) will be discussed for a copper smelter.

Jan 1, 2006

By M. Javier

Management is a major part of sustainability research. Many different aspects of sustainability have already received significant research attention, but the management processes in mining from the perspective of their impact on society are less understood and integrated as a holistic frame. It is evident that mining technology has received major blame in past ecological disasters and major mining-induced environmental hazards, but the management-mining process has escaped unscathed. This should not have happened. Instead, the management processes should share equal blame with obsolete technology for the failure to identify and monitor potential environmental hazards before their inception of mining. We will present an emergent style of management for the future of mining. It challenges the actual ?mind-set? of mining management. It describes balance and equilibrium: physical, chemical, and biological in nature as an understanding of nature?s language, which is Geomimic along side ?the bottom line?. The goal is to minimize loss instead of maximize profits (waste design) at the design stage of mining and to develop clean technologies (nature's values) to achieve non-social environmental impacts that provide a prosperous legacy to future generations.

Jan 1, 2010

By M. M. Wong

Beryllium possesses attractive properties for use in the nuclear and space fields. Since fused-salt electrorefining can be employed to produce this metal in high-purity form from low-grade or scrap metals, the Bureau of Mines investigated electrorefining of beryllium in electrolytes composed of a LiC1-KC1 eutectic mixture plus varying amounts of BeC12. Results showed a 99- percent or better reduction of oxygen and magnesium and a substantial reduction of other minor metallic impurities. Extremely pure beryllium metal was produced. Operating variables, including BeCl2 concentration in the bath (3.5 to 16.5 mole-percent), temperature of operation (450° to 550° C.), and cathode current density (45 to 770 a,/sq, ft.), were studied; their effects on the deposition of metal, working condition of the bath, and purity of the refined metal are discussed. The safety precautions used in handling beryllium in the laboratory are also described.

Jan 1, 1962

Abbey. Robert Graham, District Mgr.. The W. W. Sly Mfg. Co., 50 Church St., New York, N. Y. '21 Abbott, Clarence E., V.P., Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg., Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Consolidation Coal Co., Watson Bldg., Fairmont, W. Va. '15 Abeel, George H., Jr., Cons. Min. Engr 12S1, S. Canon Dr., Beverly Hills, Cal. '18 4 -Abel, Raymond L., Asst. Prof., Dept. of Pet. Refin.. Univ. of Pittsburgh. Pittsburgh, Pa. '28 Abel, Walter D., Cons. Engr 650 S. Grand Ave., Los Angeles, Cal. '82 Abele. Louis T., Min, & Met. Engr., Supt., Texas Hill Mine Coulterville, Cal. '31 Abell, Leo M Sullivan Concentrator, Chapman Camp, B. C., Canada '31 Abernathy, George Elmer, Prof. of Geol. & Min., Kansas State Teachers College. Pittsburg, Kan. '20 Aborn, Robert H., Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., Member, Geological Staff of Burmah Oil Co., Ltd., Nyaunghla, Upper Burma, India. '28 Abstein, Henry T., Engr. & Mgr., Profile-Tamarack Mines Co Yellow Pine, Idaho '27 Acker, E. O'C., Met 128 East Washington Lane, Germantown, Philadelphia, Pa. '86 Ackerman, D. E., Met., Research Lab., International Nickel Co., Inc Bayonne, N: J. '24 Ackerman, George F., Engr., Real del Monte y Pachuca Min. Co., Apt. 3, Pachuca, Hgo., Mexico '29 *Acres. T. H.. Geol. Dept., Valuation & Pet. Engrg., Richfield Oil Co., 555 S. Flower St., Los Angeles, Cal. '29 Adachi, Jinzoo Address Wanted '88

Jan 1, 1934

How Particles Stick to Bubbles - The Influence of pH and Hydrophobicity in Flotation

Sep 13, 2010

By John A. E. M. Church

THE prospector's pan was the first implement used for saving gold, and its action is so effective that it has never been equalled for thorough work. Copper plates, blankets, sluices, and amalgamators of several patented designs have thrust it aside, but in spite of all the advances made there is no dispute among experienced men as to the comparative thoroughness of the work done by it and its rivals. When its rivals are doing their best, the pan can take their discarded refuse and prove their inefficiency by producing from it not only gold, but even the mercury which has been lost from the machines themselves. The trouble with the pan has always been that it was only a tool. Man was the machine that moved it. His work was high-priced, the quantity treated small, and it was impossible to use the pan for any but the richest sands. As a consequence the best gold-saving appliance known has been discarded for years and replaced by machines of inferior excellence, but which could more than make up for their limited ability in saving gold by their capacity for treating great quantities of ore. Mr. Peck is one of the old-time amalgamators of the Comstock district, and the first idea of the new machine came to him as he used to pan below the tailrace of his mill. No matter how fine the work of the mill was, the pan invariably proved that better could be done. The tailings always contained gold, silver, and mercury. This state of things is just as true to-day, after all the improvements that have been made, as it was then, and the much-vaunted method of the " Washoe process" consists in extracting 72 per cent. of the gold and silver by one operation, and then repeating this operation half a dozen times to get out about one-third of the remainder. With all the advances of twenty years in milling, there is nothing more crude in metallurgy than the treatment of tailings in many of the large mills of the West.

Jan 1, 1880

By John A. Church

Jan 1, 1880

By Ender Keskinkilic

Continuous casting of slabs is conducted with two successive steel flows: first from ladle to tundish, then from tundish to mold. There are certain process abnormalities related to ladle, tundish and mold. For example, change of submerged entry nozzle (SEN) is the one encountered during steel flow from tundish to mold. Tundish exchange is the abnormality taking place due to replacement of processed tundish with the new one at rest. Another example is the flow of steel from ladle to tundish without a ladle shroud. In this study, a statistical analysis was conducted related to the process abnormalities in slab casters of a steel plant. Slab surface defects observed in slab yard was incorporated in this analysis.

Mar 1, 2018

By Brent A. Slaker, Michael Murphy, John Ellenberger, Erik Westman

"Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technologies such as laser scanning are unsuited, undesired or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were photographed during four visits over a 63- day period. Using photogrammetry, point clouds of the mine geometry were obtained and triangulated surfaces were generated to determine volumes of change over time. Pillar spalling in the range of 0.29–4.03 m3 of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band, were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully applied to multiple ribs in quantifying the pillar geometry change over time.IntroductionAdequately measuring underground rock mass movements is integral to understanding how rock masses behave and how to interact with them safely and efficiently. Many modern measurement techniques employed in underground mining environments rely on point measurements, such as through extensometers or borehole relief methods (Christiansson, 2006). These techniques, while commonplace, do not provide a comprehensive view of how the rock mass is behaving. The dynamic changes in stress states underground, coupled with the mechanical uncertainty of rock masses, near active excavations, creates a need for measurement systems which better capture the behavior of the rock mass. Photogrammetry is a technology capable of producing the wide-area displacement measurements required for a comprehensive understanding of rock mass movements.Digital photogrammetry is a means of obtaining threedimensional point clouds from digital photographs. By finding the same point across multiple images, all viewing an object from different angles, the location of that point in three-dimensional space can be inferred. Close range digital photogrammetry (CRDP) is photogrammetry applied to measuring objects or scenes less than 100 meters away (Atkinson, 1996), and is used for various functions in underground mining environments. These uses include, but are not limited to, mapping fracture networks (Kim, Kim, & Won, 2005)(Somervuori & Lamberg, 2010), characterizing fractures (Styles et al., 2010) and measuring volumes of blast rock (Heal, Hudyma, & Potvin, 2004)."

Jan 1, 2015