Search Documents

By A. L. Holley

The intention of this paper is not to discuss this important subject in all its bearings, but merely to point out why mechanical tests of steel, as ordinarily made, are not, alone, of any special value to engineers—certainly not to general mechanical engineers. The agents of the Barrow Hematite Steel Company, one of the largest and most successful Bessemer establishments in England, have recently distributed a report, made by Sir William Fairbairn,

By Andreas Rubo, Stephen Gos

In the days of increasing environmental and safety awareness many efforts have been made to prevent losses of both an evident economic nature and also less obvious losses. These losses could be associated with damages due to negative impact on the environment and also people coming into contact in a broader sense with any toxic chemical. This paper deals with how cyanide can be applied in a responsible manner at a modern gold mine. Responsible application is achieved by minimizing losses of reagent and avoiding negative impact on the environment as well as adopting a Responsible Care philosophy to the application of cyanide. It becomes evident that this is quite a complex system with a greater commitment than avoiding reagent losses for economic purposes.

Jan 1, 1997

By Martin F. Milligan

THIS short discussion of the effects of deoxidation on the mechanical properties of cast steels is intended to serve as general introduction to the subject of this afternoon's session. The subject is covered in detail in Mr. Carter's excellent paper. My material has been collected from the works of various investigators, several of whom are present today. For a definition of deoxidation, as applied to steel-furnace melting practice, we can best go to Briggs' book, "The Metallurgy of Steel Castings." Briggs says that deoxidation "includes all the phenomena in the final preparation of steel that would permit it to solidify free from gas cavities and from dissolved oxygen of all kinds." Various practices are used by welters to produce these end results.

Jan 1, 1947

By William P. Blake

At the August meeting of the Geological Society of America, I presented a paper on the occurrence of alunogen and bauxite upon the Upper Gila river, about 40 miles north from Silver City, New Mexico, together with observations upon the geology of that region." Inasmuch as the subject is specially interesting to metallurgists and mining engineers, and as our Transactions contain recent important papers, by Dr. Hayes, M. Laur, of France and others, upon bauxite, I venture to offer to the Institute, in more condensed form, an account of the deposits described in the paper above referred to. The only other published account of the alunogen locality which I have been able to find is a prospectus-pamphlet, issued in a small

Jan 1, 1895

By R. W. Raymond

THE important question of the metallurgical value of the coals of the Rocky Mountains and the Pacific Coast is to be settled, of course, by practical experiment. Meanwhile; as I have had occasion to point out, the proximate analyses of these coals throws little light upon it, and is, indeed, likely to mislead the metallurgist, if he compares it with the results of similar analyses upon bituminous and semi-bituminous coals. With the view of showing how large a proportion of the material usually classed as." volatile matters " consists of combined water, or oxygen and hydrogen presumably in chemical combination, I have collected a number of ultimate analyses from various sources, in the following tables. The numbered analyses in the first table are as follows

Jan 1, 1874

By William H. Love

ATLAS shaft was sunk to explore at depth a portion of the eastern end of the dry belt, or silver belt, of the Coeur d’Alene mining district. The Atlas mine is a mile east of Mullan and is on the south side of the Osburn fault. Equal partners in the venture are Hecla Mining Co., Newmont Mining Co., New Jersey Zinc Co. and Atlas Mining Co., the financing being equally shared by Hecla, Newmont, and New Jersey Zinc. As outlined the project had as its goal deep exploration of prominent structures developed in the Atlas in upper levels. Plans called for deepening the shaft from the 800 level to the 2400 level with subsequent drifting, crosscutting, and diamond drilling on the 2400.

Jan 11, 1954

By Shosei Serata

Conventional roof bolting may be giving ground to a new technique that utilizes only the ground itself to stabilize mine openings. This newly developed stress control technique (SCT) has initially been used in sedimentary ore bodies that are both overlain and underlain by weak strata. The technique is also suited to the design of production panels and main entry systems, and is readily adaptable to room and pillar as well as total- extraction mining, including both shortwall and longwall coal mining. In applications where the technique has been used, the requirements for roof bolting and floor renewal were virtually eliminated. The SCT comprises three basic methods and covers a wide range of problems associated with failing roofs and heaving floors in underground mines (see Table 1).

Jan 5, 1976

By Andrew Neale, Ari Supomo, Mike Mular, Rob Perry

A method is presented to measure and correct the performance of regulatory control loops. Freeport Indonesia treats over 220,000 dmtpd of copper-gold ore in a complex of four concentrators. More than 400 regulatory control loops are implemented throughout the operation. The performance of each loop is quantified by an index based on its time in automatic, the deviation of the measurement from the setpoint and a metallurgical assessment of its impact on overall plant operation. Index values are recorded in a plant-wide data acquisition system and analyzed to produce a report of loops requiring attention. Loop statistics are analyzed to show if the problems can be corrected with tuning. The practical application, benefits, management and staffing requirements of this method are discussed.

Jan 1, 2000

By Gang L

Seventy-nine gold deposits and prospects have been discoveried in the Jiamusi region of northeast China, and constitute one of the most important gold metallogenic belts in China. All these endogenic gold occurrences can be subdivided into three main deposit types: (1) porphyry related; (2) metamorphic-intrusive hosted, and (3) sediment-hosted deposit. The first two types of gold deposit are spatially and temporally related to Mesozoic Yanshanian granitoid intrusions with hydrothermal activity channelled along crustal-scale fissures. The ultimate cause of the Yanshanian magmatism is considered to be the subduction of Pacific oceanic lithosphere beneath the Eurasian continent. In contrast, The chemical sediment-hosted deposit is typified by the Dongfengshan gold deposit, and genetically related to Proterozoic sedimentation and Mesozoic igneous activities.

Jan 1, 1995

By Lovitt M

Ora Banda Gold Mine is located in the Eastern Goldfields of Western Australia. Mining is carried out underground by sublevel open sloping resulting in large open stopes. A Mass Blast of approximately 250 000 tonnes was carried out in July 1994 to recover a rib pillar between two stopes, and the crown pillar between the underground mine and the abandoned open pit above. Strategic development within 50 m of the blast consisted of two ventilation shafts and the main decline. This development required careful design and prediction of the blast results. This paper describes the design of the blast, the prediction of the likely effects, the measures taken to reduce the risk to important development, and the results of the blast.

Jan 1, 1995

By E. Gregory, C. G. Goetzel

The outstanding elevated temperature properties of materials made from sintered aluminum powder have been well established in recent years.1,2 and considerable investigation has been carried out on the structures which appear to be responsible for this type of strengthening.2,3 The maximum operating temperature of such materials is severely limited, however, by the low melting point of the aluminum matrix; and, therefore, considerable interest was aroused in methods of introducing the

Jan 1, 1959

By Raquel Húngaro Costa, Jonathan Tenório Vinhal

The demand for natural resources has grown over the years, however, the environment offers a limited amount of these resources for exploration. Then, the investigation of new methods for recovering and reuse some compounds and elements are essential to know later tailings purposes. Zinc is used in corrosion resistance as a protective coating for several products. One of the steps for the extraction of zinc is by flotation process to obtain the concentrated ore, in which a residue is generated. The aim is to characterize this residue, allowing the choice of recovery routes for compounds and elements in future stages. The methods of analysis were Malvern, VA, Eltra and ICP-OES, besides the water content. In this study, a characterization of elemental chemical analysis was performed, in which the main elements presented were: calcium (17.4%), magnesium (10.3%) and iron (7.97%); the water content was 27% and the grain size of the material presented an average size of 50μm. With the presented characteristics the material can be used, after treatment, in the recovery of other compounds for applications in the sector of fertilizers, ceramics and steel industry.

Oct 3, 2019

By Y. Hanada

Electrorefining at higher current density is desirable due to the increase in productivity attained without expanding the plant size. However, increasing the current density in common commercial practice causes problems such as anode passivation, dendritic deposition, cathode impurities and energy consumption. In general, agitation of the electrolyte is effective in suppressing these problems. To apply the agitation to commercial practice effectively, the method of agitation is important. One possible method is agitation by gas injection. In this study, fluid motion characteristics with gas injection between electrodes were investigated using a water model. Flow patterns were observed and fluid velocity was measured using a particle tracking method. It was found that the time-averaged velocity near the electrode walls was of the order of 0.1 m/s in the conditions. The flow was highly turbulent. The turbulent component of velocity was the same order as the time-averaged velocity. The mass transfer coefficient between the wall and fluid doubled when the effect of turbulent intensity was taken into account. The effects of gas injection on the electrolysis behaviour at high current density were discussed in terms of the mass transfer. It is suggested that gas injection could suppress the problems at high current density.

Jan 1, 2007

By Gary D. Babbitt

Facing an orchestrated assault from the anti-mining lobby and its congressional allies, the Mining Law of 1872 may soon be either dramatically changed or even repealed. In 1989, Sen. Dale Bumpers (D-AK) introduced Senate Bill 1126 entitled the "Mining Law of 1989." It has been through several hearings and is still in the Senate Committee on Energy and Natural Resources, where Sen. Bumpers is the number two ranking Democrat. In the House, Rep. Nick J. Rahall (D-WV) introduced the "Mineral Development and Exploration Act of 1990," HR 3866. This bill is in the House Committee on Interior and Insu¬lar Affairs. (The numbers on these bills, and perhaps some of their language, will be changed when they are reintroduced in early 1991. However, their substance is expected to remain substantially unchanged. Bill numbers here refer to legislation as it was numbered in the 1990 Congress.) In the eyes of its supporters, Bumpers' S 1126 appears to be more complete and has the inside track over the Rahall bill. Bumpers' bill includes provisions for royalties, bonding and reclamation. The Rahall bill is criticized by opponents of the Mining Law for its failure to include a royalty provision and for not having specific bonding and reclamation provisions.

Jan 1, 1991

In 1803 the purchase of the immense territory called the province of Louisiana wm arranged between Thomas Jefferson, President of the United States, and Napoleon Bonaparte, First Consul of France. This central portion of what is now the United States was claimed in 1682 by the explorer Robert de La Salle for France, who continued to hold her title to the vast domain until 1762, when it passed by treaty to Spain, only to be retroceded to France in 1802, in consequence of Napoleon's military domination of Spain. Jefferson did not care to see New Orleans and its extensive hinterland pass into the hands of France. Spain did not matter so much; she was quiet and feeble, whereas France was restless and aggressive under Napoleon, who had dreams of founding a French colonial empire on the American continent. The expression of American feeling that Jefferson elicited came as a surprise to Napoleon, who concluded that a contest was not worth while, for his navy had been shattered by the English, and it was evident that only maritime supremacy could enable him to retain this trans-Atlantic possession; so he resolved to put it out of the grasp of England and at the same time replenish his military chest by selling Louisiana to the United States. The price was 60 million francs. By the terms of the Louisiana purchase a magnificent territory was added to the national domain; it covered more than a million square miles, or more than the total area of the United States at that time. Louisiana included the present States of Louisiana, Arkansas, Missouri, Kansas, Iowa, Nebraska, South Dakota, North Dakota, Wyoming, Montana, Oklahoma, with parts of Colorado, Idaho, and Minnesota; but

Jan 1, 1932

By Donald P. Richards

West Elk Coal Company operates its Mt. Gunnison No. I mine on the western slope of the Rocky Mountains in Western Colorado. The mine is located along the north fork of the Gunnisson River near Somerset, Colorado as shown in Figure 1. The mine is designed for a sustained production of 1.4 million tons per year out of the "F" coal seam in the Mesa Verde formation. The coal seam is nominally 7 feet in thickness and dips at about 3 ½ degrees to the northeast. Mining of the seam is up dip with the entry portals on the north facing slope of Mount Gunnison. The mine is designed as a five entry system with four entries for ventilation and access and one entry for a coal-handling conveyor. The mine entry layout is shown in Figure 2. Initial mine planning began in 1979, with "permitting" complete and construction starting in the fall of 1981. A "turnkey" contract for design and construction of all five parallel mine entry tunnels was awarded by West Elk Coal Company to a Joint Venture of Jenny Engineering Corporation (design and contract management responsibility) and Affholder, Inc. (construction responsibility). The first entry access into the coal seam was completed in the early spring of 1982. The mine has been operating at full service (all five entries) for nearly 3 years.

Jan 1, 1984

By J. J. Geldenhuys

The Institute revived a valuable tradition when, on the 19th of March, 1983, it held its first 'annual' banquet in some fifteen years. It was such a sparkling success that it is sure to be held more frequently in future. The success of the occasion was borne out by the fact that the main banqueting hall at the Wanderers Club was filled to capacity, with over four hundred members and guests.

Jan 1, 1983

By R. C. O’Ferrall, W. G. Goulding

This paper describes the performance of a Robbins 52R Boxhole Borer from its introduction into the mine in July 1975 until late in 1977. As indicated by the costs involved, the performance has increased considerably and is expected to be even better once further envisaged modifications have been made. The average cost for the first half of 1977 was R275 per metre bored as against an average of R628 for 1975.

Jan 1, 1978

By F. Shaw, E. C. Chemaly, A. F. S. Schoukens

Steel-plant dusts are hazardous waste materials, containing toxic constituents such as lead, cadmium, and hexavalent chromium. These dusts can be treated by a number of thermal processes, which are described as used in Western Europe and the USA. A detailed description is then given of the thermal Enviroplas process, which as developed at Mintek and produces disposable slag and valuable byproducts such as ferroalloys containing chromium and nickel, and fumes high in zinc oxide.

Jan 1, 1993

By J. H. Bowden

On the night of January 23d, 1889, Erich C. Schaufuss, a member of the Institute, while engaged in making the regular mine-surveys in No. 4 Slope of the Susquehanna Coal Co, at Nanticoke, Pa., was killed by an explosion of fire-damp. The catastrophe, which cost another life also, is attributed to the carelessness of the " fire-boss" leading the party, who advanced with a naked lamp into a chamber

Jan 1, 1889