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By E. H. Greener, M. E. Fine

The internal friction (1/Q) of cobalt Fig. 1 (measured by an electrostatic dynamic method1) near 250°C begins to increase rapidly on heating and continues to increase until 560°C, the highest tem- perature measured. In the plot of log of 1/Q against 1/T, above 250°C the data nearly fit two straight lines intersecting at 400°C, approximately the temperature of the hexagonal-cubic transformation. The higher temperature branch corresponds to an effective activation energy of 6500 cal per mole, the lower temperature branch 11,000 cal per mole. Young's modulus Fig. 2 increases approximately

Jan 1, 1959

By Roger D. Sharpe

Oklahoma contains extensive resources of high-purity gypsum that were deposited in the Anadarko and Hollis basins during Permian time. The gypsum resources and reserves are estimated to be about 48 billion short tons and a; located in the western portion of the state. Oklahoma is the largest producer of gypsum products in the United States. The Blaine Formation and the Cloud Chief Gypsum contain several beds of minable thickness. Four stratigraphic units in the Blaine Formation are quarried in Oklahoma. The Shimer, Nescatunga, and Medicine Lodge Members are quarried in northwest Oklahoma. The Van Vacter Member, consisting of three gypsum beds, is quarried in southwest Oklahoma. The Cloud Chief Gypsum is quarried in the west-central part of the state. The gently dipping gypsum in the Blaine Formation generally crops out along low escarpments and is covered in the downdip direction by increasing overburden, consisting of sand, shale, and/or dolomite. Anhydrite occurs in the downdip direction under the thicker overburden. The Cloud Chief Gypsum crops out as hills, which are eroded remnants of a more widespread, massive sulfate unit. All of the gypsum produced in Oklahoma is extracted using quarrying methods. A variety of products are made from gypsum quarried in Oklahoma. The products are manufactured from uncalcined, calcined, and deadburned gypsum. Products vary from raw, ground gypsum used for agriculture, to high-value-added industrial plasters, cements, and fillers produced from calcined gypsum. A sampling of the many products manufactured from Oklahoma gypsumincludes: (1) agricultural-soil amendment; carrier for insecticides, pesticides, and herbicides; calcium supplement in animal feeds; (2) gypsum wallboard-common, fire-resistant, and water-resistant varieties; (3) industrialgypsum plasters-art and casting, pottery and ceramic, molding and tooling, crayons, wall patching; (4) industrial gypsum cements-oil-well cement, high-strength statuary, high-strength tooling, fiber-reinforced architectural, road and bridge repair; (5) food and pharmaceutical-filler and binder in aspirin and other medicines, yeast activator in brewing of beer, moisture absorbent in bread and pizza dough; and (6)portland-cement retarder-ground with clinker to control setting time.

Jan 1, 1999

By V. Songmene, R. Khettabi, J. Masounave, R. D. Njoya

L'augmentation régulière des règlements environnementaux et de la sécurité au travail deviennent de plus en plus strictes. L'usinage fait partie des opérations industrielles qui peuvent causer des problèmes de santé au travail et sur l'environnement. La plupart des particules de poussières produites pendant toutes les opérations d'usinage à sec ou lubrifie causent des nuisances environnementales graves. Le travail propose étudie l’influence des paramètres de coupe, des alliages et des états des matériaux sur la formation des copeaux et sur la génération de poussière lors de l'usinage à sec. Deux modes d'usinage (le fraisage et le perçage) sont abordés. Une loi reliant la ténacité des matériaux aux émissions de poussières est proposée. Les effets des matériaux et de leurs conditions, ainsi que des procédés d'usinage sur la génération des poussières ont été mis en évidence. Des mécanismes de formation de poussières sont identifiés et reliés à la formation des copeaux.

Jan 1, 2006

By Jack C. Haptonstall

This paper describes the analytical characteristics of Western subbituminous coal and the manner in which these characteristics apply to their use in a utility-sized steam generator. It compares these characteristics with those of typical Midwestern coal and Eastern bituminous coal. The paper also reviews in detail the design considerations that must receive attention when various blends of these three coals, or any combinations thereof, are planned to be used. This research paper describes variations in analytical and utilization characteristics when coals from different origins are blended in order to achieve a predetermined sulfur content for the purpose of predicting sulfur oxides emissions as they affect environmental regulations and the resulting alterations in utilization characteristics such blending would cause, and how such blends of coal would affect a utility-sized steam generator.

Jan 1, 1979

By Joseph A. Holmes

The public is already familiar with the general fact that the scope and the financial resources of the approaching St. Louis World's Fair are much larger than those of any of the preceding great expositions; and both the visitor and the exhibitor, when he comes to St. Louis in 1904, will find it to be a real World's Pair, with exhibits and visitors from every known country. Passing over the subject, as to the general Exposition, with this brief statement, I ask Sour attention to the consideration of a few important facts connected with the proposed mining exhibits at this Exposition. First of all, I may say that. reading- and writing-rooms and library facilities will be furnished in the Mines Building for miners and mining engineers, and it is expected that when they visit the Exposition they will make these rooms their headquarters, and give the Chief of the Department and his assistants an opportunity to extend to them such courtesies as may be possible. One of the exhibits in the Mines Department will consist of models and maps arranged to show the nature and extent of the mining operations in the United States at the time of the purchase of the Louisiana Territory in 1803, the event which

Jan 1, 1903

By Gene D. Clayton, Robert R. Dimock

A time-consuming and expensive preshearing program to minimize the adverse effects of blasting on slope stability at Kennecott Copper Corp.'s Ruth Pit in east-central Nevada has been eliminated in favor of down-the-hole, nonelectric delayed blasting which can produce a smooth wall effect and improve blast fragmentation. The new blasting approach resulted from a Kennecott engineering investigation aimed at improving the stability of the extremely variable rock conditions found throughout the pit by reducing the vibrational energy imparted to the walls with conventional bench blasts.

Jan 4, 1977

By Carthew SJ

The early period of South Australia's mining history was dominated by Cornishmen as large numbers of miners and their families migrated to escape closure of the Cornish copper mines. Records show that Carthew families migrated from Kent and Cornwall to South Australia. Those from Redruth, Cornwall, were miners and their family history provides an insight into the condi- tions under which early miners lived and worked. Carthews are one of the oldest surviving mining families in South Australia and their movement pattern has been typical of many other early Cor- nish mining families.

Jan 1, 1987

By Joe M. Short

More than eighty years ago, in what we generally consider a more leisurely age, workers and engineers began the construction of the longest railroad tunnel in the world. When completed, the Simplon Tunnel ran more than twelve miles through the alps to connect Switzerland and Italy. Work began in 1898 and the tunnel was completed in 1905. In all it took about seven years to build one of the world's great tunnels. More than seven years ago, in what was hoped to be a rapid and constructive to the deaths of 38 workers in two spectacular tunnel disasters in 1971, the secretary of Labor's Construction Advisory Committee on Safety and Health began in January 1972 a search for an effective standard on tunnel safety. Much hard and useful work has been done, especially by the construction advisory committee' but more than seven years later, we still don't have a tunnel standard. We may speculate that, when the Simplon Tunnel was completed, workers and their bosses assembled to celebrate their achievement and to count their casualities. We have no need to speculate on the lack of achievement up to this time. An so far as I know, the bureaucrats have suffered no casualities except perhaps some unreported cases of ring-around-the-color. The only moral I can draw from all this is thai it is easier to penetrate solid rock than it is to get through bureaucratic fog. We can only hope that OSHA will finally take advantage of the work which was finished years ago and complete the actions necessary to give us a tunnel standard. Having made my point, I could stop my remarks right now; but

Jan 1, 1979

A. R. Ledoux,New York City: The so-called combination method " is generally used in assaying bar copper for silver. It has been modified from time to time. Briefly outlined

Jan 1, 1901

By T. R. Curr, W. A. Gericke, J. Basson

South Africa is a leading player in the international ferro alloys industry. Historical factors that have contributed to this dominant position include an abundance of natural resources and relatively low cost electricity. A number of relatively recent developments are potentially threatening this position. These include new legislation affecting the mining and minerals industry, a shortage of some types of suitable reductants, depletion of surplus electricity generation capacity with resultant threat of real escalation of electricity prices and pressure resulting from the recent strengthening of the South African Rand. The industry is addressing these challenges in a number of ways to ensure long-term viability. Some of these measures include investments in more efficient technologies that have economy of scale benefits and are less dependent on expensive reductants and electricity. Local macro-economic impacts include new legislation regarding ownership of enter-prises, mineral rights and royalties on mineral sales, development plans for port and rail infrastructure, as well as initiatives to expand electricity generation and coke production capacity. The fundamentals for being a successful ferro alloy producer are still largely in place for South African producers. Therefore the South African ferro alloy industry will remain competitive and is well placed for continued growth in line with the international growth in ferro alloy demand. The industry should emerge leaner, more efficient and ready to respond to any future demands of the industry. This paper will cover the present status of the industry, the factors that are impacting thereon and a view on its future outlook.

Jan 1, 2007

By S. A. Willis

For over 150 years gypsum from Nova Scotia has been shipped via water to the United States east coast. The history of the movement has been one of continual improvements in quarrying, loading, and shipping. At the start, man-size rock quarried by hand auger and black powder was loaded into horse-drawn carts, hauled to the waterfront, and dumped into 100-ton sailing schooners. Last year the Canadian Gypsum Company completed the latest and most modern of these successive installations for the movement of this Nova Scotia product. The new system loads crushed gypsum into 11,600-ton vessels at Hantsport in two hours' time at high tide. At the head of the bay of Fundy are located vast deposits of gypsum. The tidal rise and fall of 45 feet twice a day, with its attendant swift currents, has always presented major navigation and shipping problems. When the tide is low, the Hantsport ship-loading pier is high and dry, with no water within 400 feet. Three hours later a large river has flooded in (running up hill) and large steamers can dock at the wharf. Before high water, the ship has been loaded and -there is a depth of 30 feet or more of water around the wharf. At high water, the ship sails away on the ebbing tide as the river runs in the other direction. Tides are caused by the gravitational attraction of the moon and sun on the ocean. When both celestial bodies are pulling together the 'spring tide' results, which means a 50-foot variation from high to low. This occurs at new and full moon. A week later, when the sun and moon work in opposition, the difference is only 32 feet between high and low water. The bay of Fundy, having a funnel shape (150 miles wide at mouth from Yarmouth to Portland, while the upper estuary at Hantsport is only one mile wide), builds up a tidal influence from 10 feet at the mouth to an average of 45 feet at Hantsport.

Jan 1, 1948

By G. Lindkvist

Roasting of concentrates with high impurity levels is normally done in multiple- hearth furnaces where the concentrates are heated with oilfired burners in order to remove As, Sb and Bi before the final sulfide oxidation. Although it is a countercurrent heat exchange process it uses a lot of oil. In order to develop an energy saving, and from a working environmental point of view a less harmful process than the multiplehearth process, pilot-plant tests have been done in a two-stage fluidized bed for partial roasting. The test materials have been As-rich concentrates with 8-25 % As some 5b and Bi. The Cu-content was 0-28 %. The tests have been successful with <0.3 % As,in the calcine and with an elimination of 5b between 80 and 90 %. In order to achieve the proper conditions for good impurity removal, 1.e. right temperature,residence time and sulphur potential, the tests were performed in a special designed roaster. The roaster consists of two beds with the facilities for recirculation of calcine, preheating of the blast, and possibility to use oxygen enrichment. The construction makes it easy to control the reactions that generate the heat in the bed and reduce the amount of dust that passes through the cyclones. As two roasting steps are used, the possibility to obtain optimal conditions for impurity removal is improved and the calcine can either be smelted to a normal matte, or after being dead-roasted in the second stage, be leached in the normal way for gold extraction. The calcine was smelted with slag. The matte and the slag obtained had low quantities of impurities in the matte and a favourable distribution of impurities to the slag.

Jan 1, 1983

By John Howe Hall

One&apos;s first thought, upon being chosen to deliver the Henry Mario Howe lecture, is of pride at being selected for this post of honor, but ther succeeds immediately a deep sense of the Obligation thereby incurre to give of one&apos;s very best in order to make a contribution worthy of hir in whose memory these lectures are given. One who had the goo fortune to be associated with Henry ill. Howe, upon sitting down t prepare such a paper as this, irnrnediately falls to musing upon thc day when his face and his footfall were familiar from constant association, an recalls with singular vividness his active figure, his mobile, alert face, an his keenness in penetrating to thc corc of the subject under discussior Like Dr. Mathews, I was a young man when I first worked under hi direction, now nearly a quarter of a century ago, and in those early day he oft,en seemed a hard taskmaster—a man whose standards it woul never be possible for me to meet. I well recall his insisting upon m proving for the third time the truth of a conclusion which I had brc unwilling to submit to him until it had been confirmed by two carefull planned experiments. To my impatient protest that thc third .demor stration he asked for was but a repetition of the second, with differer samples, he replied, "Yes, that is true, but the inherent improbability ( your conclusions is so evident that I can not accept them until you prov your case again." "Shall I ever do a thing well enough to suit him? I thought. Looking back today upon many similar incidents, 1 suspect that h never expected me to attain the excellence he preached, and held up t me and to himself as a model, but knew out of the fullness of his experienc. that in no other way could he so impress upon me the necessity in researc of the patient, never-failing attention to detail and to accuracy tha distinguished his own work. How painstaking he was in the preparation of his many books an professional papers, as well as in his experimcntal work, was ncvcr s

Jan 1, 1929

By Dale T. Peters

Conductivity, both electrical and thermal, are attributes accounting for about 70% of the applications of copper and its alloys. This paper presents results of on-going research into two new applications that depend on copper&apos;s excellent conductivity. The Copper Development Association (CDA), together with materials and motor company partners, is working toward a solution to the key problem preventing pressure die casting copper for the conductor bar/end ring structure of the induction motor rotor, i.e., lack of a durable high-temperature mold material. Work is showing that a combination of high- temperature materials and elevated temperature processing gives much improved mold life compared to die steels. Substitution of copper for aluminum in the rotor can result in a 20% decrease in electrical losses in motors consuming 35% of electrical power generated in the U.S. The second development uses the excellent thermal conductivity of several high-strength high-copper alloys to simultaneously improve productivity and part quality in the injection molding of plastic parts.

Jan 1, 1999

By T. E. Breaux

Repair of large rotating apparatus such as ball mills is uncommon but under certain circumstances is achievable. This paper describes the successful repair of trunion on a 14 foot diameter by 20 foot long ball mill. Diagrams of the repair are included for visual perspective and non-destructive test procedures are outlined.

Jan 1, 1988

By Thomas R. Kuesel

Just south of the L&apos;Enfant Station in Seventh Street, the WMATA system splits into two branches, each comprising twin single-track soft ground tunnels. Immediately at the beginning of the section, Interstate Route 95 crosses transversely over the alignment in open cut, removing most of the cover over the tunnels. Seventh Street spans I-95 on a bridge whose abutments and pier also cross transversely over the four tunnels, with their footings as little as 7 feet above the tunnel crown (Figure 1). Soil investigations revealed that the tunnels would have to be driven through mixed face, with a clay invert and a waterlogged sand crown. Thus, there was a good chance that the roof would fall in, leaving 1-95 and the Seventh Street Bridge in a crater. Since there was no roof that could be counted on, these were figuratively (and potentially truly) Washington Metro&apos;s Topless Tunnels (Figures 2 and 3). DESIGN ALTERNATIVES Faced with this situation, the designers considered several options, including temporary detours that would permit demolition of the bridge and building tunnels under the 1-95 Freeway by cut-and-cover methods. They also investigated structural underpinning of the bridge and freeway pavement, and strengthening the bridge abutments and center pier by post-tensioning to enable them to span over any subsidence trough.

Jan 1, 1976

By V. R. Bovino

In the early 80&apos;s, the cover of a major weekly magazine proclaimed the "Death of Mining." A few years ago, mining conventions, similar to this, around the country sported the theme, "The Survival of Mining." Today, the SME announces that "Mining is Alive." Being part of an industry that is simply alive is not very exciting. We can do better! Our challenge must be to flourish, blossom, maximize our potential and expand our horizons. The pace of rejuvenating this industry is still woefully inadequate. The new generation of mining industry leaders recognizes the urgent need for bold operational changes?changes in the way we deal with our employees? changes in the way we achieve productivity? and changes in the way we reward our employees for productivity.

Jan 1, 1991

The Jundee gold mining operation is located in the Western Australian Yandal Greenstone belt. Jundee is a mature operation encompassing multiple and complex underground ore resources, dwindling open pit reserves, large surface stockpiles, small satellite resources and two near-mine but stand alone process plants. The imminent completion of continuous open pit mining and the associated drop-off in total mill feed precipitated a review of the strategic mine plan and development of options that would optimise the exploitation of the remaining mineral resources and the utilisation of the existing plant and infrastructure.An initial review of the strategic decisions to be made, available options as well as the quantity, complexity and co-dependency of the strategic variables quickly led to the conclusion that an Operations Research style modelling approach would be appropriate. An &apos;off-the-shelf&apos; program engine by the name of WHATSBEST! (LINDO Systems Inc.) was chosen on the basis of price, reputation and ease of use. The model was formulated with the unknown variables (being the ore mining rates) expressed as a proportion of the maximum achievable ore mining rate from each source. Costs were defined as variable or fixed, with this definition being a key aspect of the modelling process. The critical application of the model was in determining the optimal extraction rate of ore, the destination (ie Jundee or Nimary mill) and the sequence of extraction of each ore source that maximized the cash flow of the operation. The program was designed to be able to quickly derive an optimal result from the many variables, replacing the previous laborious iterative process of arriving at an acceptable answer by means of several large and static spreadsheet models. This paper presents the process of selection, formulation, application and scope of operation of the turn-key linear and non-linear program strategic model now used as part of the Jundee Operation strategic decision making process.

Jan 1, 2002

By Terry B. Linde, William M. Dowall

The recently completed In-Pit Crushing and Conveying Project at Phelps Dodge&apos;s Morenci Mine is rated among the world&apos;s leading materials handling projects. The operation involves the crushing and transport of more than 109,000 tonnes per day of copper ore, utilizing regenerative conveyors capable of providing over 5.5 megawatts (7,000 hp) of equivalent electrical energy. This paper describes the key aspects of the project and includes: Original project objectives; System design criteria; System description; Optimization studies; Major design features; Equipment description; and System commissioning.

Jan 1, 1993

By Takaaki Shibata

The Tamano Refinery has developed two new processes for removing the impurities, arsenic, antimony, and bismuth from an electrolyte. The first process involves bleeding the surface electrolyte in the electro-refining cells. The copper concentration level in the outermost layer is lower than that in any of the other layers, while the impurity levels are almost the same in all layers. Bleeding the surface electrolyte increases the amount of impurities removed in the liberator by approximately 20%. The second process involves adsorbing antimony and bismuth from the electrolyte by means of chelating resin. As the electrolyte passes through the packed column of chelating resin, antimony and bismuth are selectively adsorbed. They are then desorbed by means of hydrochloric acid, and then recovered in the form of a highly concentrated antimony chloride solution by means of evaporation. This process almost doubles the capacity for removing antimony from an electrolyte.

Jan 1, 1987