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By J L. Mauk

The Martha epithermal Au-Ag deposit contains multiple generations of quartz veins with a range of textures. We examined: +        vein textures, +        crosscutting vein relationships, and +        the paragenetic sequence within the pit walls as well as a wide range of hand specimens. Samples include host rock, breccia, and veins, but these groups are not distinct; instead, they form a continuum.   Veins at Martha mine show a wide range of textures on a local scale; these textures also change significantly over both the lateral and vertical extent of the pit. Common textures include crustiform bands, comb quartz, colloform bands, platy quartz, massive quartz, drusy quartz, sedimentary textures and brecciation.   Vein grades relate to textures. Many textures, including crustiform, platy, cherty, and sedimentary textures display predominantly low grades, but some textures are linked with high grades, such as ginguro, massive and comb quartz where they are associated with visible base metal sulphides and/or electrum. Host rocks and most breccias are low grade, as most samples contain <2 ppm Au.

Jan 1, 2006

By Walter E. Dean

Deep-sea manganese nodules are considered to be potential ores of manganese, nickel, cobalt, and copper. Considerable time, effort, and funds have been applied to the study of Se distribution of nodules on the sea floor and the location of economically important areas, but little effort has been spent in understanding the origin of nodules. Most theories that have been proposed to explain the origin of manganese nodules have been based on inorganic physicochemical processes. It is not by coincidence, however, that the area considered to be most economically feasible is in the zone of high biological productivity in the eastern equatorial Pacific Ocean and underlain by siliceous biogenic sediment. The genesis of manganese nodules and the concentration of many trace elements are intimately associated with biological processes.

Jan 1, 1982

By G. L. Gates

The comments by George L. Gates are appropriate to the characteristics that we sought to feature in our study and they are appreciated by the authors. In our laboratory deposition tests the smoothness of the surface seemed to be more important than the type of surface. However, we also noted that even where very smooth glass, plastic or polished metal coupons were used, scale deposition still occurred though the rate varied. Much more information is needed, however, and new work to solve the mineral scale deposition problem by mechanical and chemical means is expected to continue.

By George White

On June 25, 1876 Lt. Colonel George Armstrong Custer led the Seventh U.S. Cavalry Regiment., comprising 31 officers and 637 enlisted men, into the valley of the Little Big Horn River in southern Montana. His assigned mission was a reconnaissance-in- force to locate the Indians reported to be assemblying in that area. Custer was extremely successful in locating the Indians. Unfortunately he located more than 3000 Cheyenne and Sioux under the leadership of the great war chiefs Crazy Horse and Gall. Custer's entire battalion of more than 200 men was annihilated; there were no survivors. While I don't seriously suggest that things will be all that bad in the uranium industry, I do suggest that some very fundamental changes have occurred in the uranium market. Conventional thinking based on past truths will no longer suffice. Geology, economics, politics, nuclear growth pat terns, technology, and utility attitudes have all changed. New thinking is in order. It is at this point that I would offer my usual disclaimer. My views regarding the future are simply that--my personal views. My belief that certain events will come to pass does not mean I view those events as appropriate, wise, good, equitable, or economic.

Jan 1, 1985

A simulation of the fluid flow, minera- logical and chemical aspects of in situ leaching is being developed for application to the recovery of metals from unbroken, naturally jointed rock. The fluid flow aspect has been developed. The rock is assumed to have a double-fracture property. A major joint set is responsible for bulk flow of solution, while a minor joint set, intersecting with the major set, allows the solution to contact the reactive minerals. The two-dimensional fluid flow through the major joint set is analysed by a streamline model for a particular well pattern. The other important components of the model are described briefly.

Jan 1, 1984

By J. Persson, N. G. Bliss

Electric furnaces used for smelting and those used for scrap melting exhibit different performance profiles in terms of electrical characteristics. However, the underlying principles are the same for either case. The rationalization of these variables is a major concern for furnace operators and designers. This paper presents the results of a two year study of high speed real time data from a number of electric furnaces around the world, covering a very wide range of design philosophy and product manufacture, to provide a better mathematical insight into rationalizing the furnace operation.

Jan 1, 2004

The only significant iron ore deposit in Hungary could be found in Rudabánya. The mine was closed in 1986. The area of Rudabánya was always the home of heavy mining activity. In former times, mainly silver and other non -ferrous metals were excavated.

Jan 1, 2011

By John L. Morning

Although faced with a slowdown in the world economy, continued inflation, and rising costs, the mining industry exceeded its 1974 raw mineral production value of $55.1 billion by 13%. The increase was due to value increases in the production of fuels and nonmetals; metals reported a decrease in value. Of 23 metals produced, 14 showed value increases; of 44 non-metals produced, 26 reported value in-creases. Because of increasing costs and depletion of high-grade reserves, the mining industry continued to rely on new technologies to maintain its profit margins. In the surface mining sector, the development of new tools and equipment played a large part in increasing production and maintaining this goal. Some of the types of equipment developed were instrumentation for control of pit slope stability, shovel power transmissions, electric wheel trucks, and single-flight conveyor systems.

Jan 1, 1977

By Taylor RN

A simple apparatus for delivering pulverized coal as fuel to a SIROSMELT lance is described, and its performance in smelting tests is evaluated. Using the pulverized coal as fuel, the SIROSMELT furnace performed well in both oxidative copper smelting and reductive smelting (zinc fuming). In both cases the evidence suggests that part of the combustion occurred by indirect oxidation of coal particles entrained in the bath. Oxygen potential measurements made during the zinc fuming tests confirmed the general features of the the non-equilibrium mechanism for zinc fuming proposed by Richards and Brimacombe. The zinc level in the slag during continuous fuming was lower than was predicted using an equilibrium model.

Jan 1, 1987

By Clif Kettle

The paper will detail the design and execution of passive and active settlement control measures, the means adopted to overcome the various physical and operational constraints, and to meet specified allowable settlement criteria. The paper will highlight the close integration between the tunnelling and geotechnical contractors, designer, and Client, and demonstrate how particular practical difficulties were overcome by both the design and the construction methods.

Jan 1, 2008

By Thomas Fenner

Surface and underground mining operations are often hindered by unknown tunnels and slopes and the precise locations of adjacent workings. Mine safety and planning are adversely affected especially in previously undermined areas where historical records are incomplete or nonexistent. The results of several ground penetrating radar (GPR) studies for the detection of known mine tunnels in underground coal, salt and gold mines are presented. A case study to locate unknown, abandoned mine workings at a surface gold mine successfully located all workings to a depth of 11 m (36 ft).

Jan 1, 1996

The use of systematic review methods, derived from System Safety approaches used in the North American nuclear power industry, have become an accepted approach for seeking "approval" for new coal mining equipment and operational changes in NSW. Based on risk analysis, they provide a valuable and needed framework for the reduction of losses related to people, equipment and production.

Jan 1, 1991

By R. C. Ferguson, B. Bernstrom

R.C. Ferguson (District Manager, Hardinge Company Inc., Hibbing, Minn.) — In the opening paragraph of Mr. Bernstrom's paper he stated that the Cascade mill performance information is preliminary. With the completion of the 1962 operating season, more reliable performance information became available. The main bearings, which had been damaged, were reconditioned at the factory. New Gatke bearing bushings with a 120° are of contact were supplied. Provision was made to introduce high pressure lubricant at two points in each bearing. New spherical bearing balls that operate in spherical seats were aligned at the factory and held in place by several setscrews to aid in installing the bearings in the field. The screws were not loosened prior to, or during, operation; therefore, the bearings operated as rigid bearings. The lubricant cooling system was changed to the cooling tower type to provide lubricating water of a suitable temperature. Another refinement consisted of installing a device to add a set percentage of soluble oil to the make-up water.

Jan 1, 1963

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Jan 1, 1938

By G. R. Hopkins

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Jan 1, 1927

By Arthur F. Taggart

ENGINEERING education today is like a crazy quilt of somber wools and gaudy shoddy, chain-stitched on an academic assembly line, and sold at ever mounting prices to inexperienced youths for lifetime use. Each engineering school offers a half-dozen or so patterns with essentially the same skimpy wool content. Sales appeal is in the color of the shoddy, denoted by the hopeful adjectives chemical, civil and the like. This article is argument for an all wool product made by slow, careful handwork. Bluntly it proposes a thorough four-year undergraduate drill in fundamental science and general engineering empirics, leavened by continuing study of the third of the engineer's troubles: Man. It is not contended that existing methods of engineering education have failed to start men on the path to successful engineering practice (too many of you have started that way); rather, social conditions and the bounds of knowledge have changed tremendously, and corresponding alterations in the pattern of engineering education are overdue. We'll Teach the Specifics The first part of this contention is illustrated by excerpts from a letter received recently from an officer of one of the largest corporations: "We are interested in employing two or three outstanding young engineers to be placed on a special training program to develop them as design and construction engineers.... "We propose to put these men on a four-month indoctrination and orientation course after which they would be given job-training assignments for a period that will vary from about six months to about a year and a half depending upon the aptitudes, abilities and intelligence of the candidates.... "I am not too fussy about what kind of engineers the men might be insofar as academic courses are concerned. They could be.. . in almost any engineering classification.... We can furnish the additional training beyond the academic fundamentals. "The starting rate for these jobs would be $326 per month...." This letter is not unique; rather it is representative of a practice that has become common. It is industry's enforced response to the general refusal by young graduates to submit to union domination in order to gain operating experience at the labor level. The message to engineering schoolteachers is plain: You teach the fundamentals; we'll teach our practice and pay the graduate to learn it. The letter means to the student that time spent in school studying the specific practices of particular industries is waste compounded. The school can't give the equivalent of what industry teaches, wherefore industry will still demand apprenticeship. The student must pay for the specific instruction at school instead of being paid to take it later. And time-consuming specifics crowd out drill in basic scientific and technical subjects as well as liberal arts.

Jan 1, 1952

For his achievement in building the Panama Canal, Major-Gen. George W. Goethals was presented, on May 22, the John Fritz medal, the highest mark of distinction in the engineering profession. In the absence, in Europe, of Clemens Herschel, chairman of the Board of Award, Charles F. Rand presided over the meeting. Col. John J. Carty, who was chairman of the Board of Award at the time the medal was awarded to Gen. Goethals, and who ordinarily would have presented the medal, was detained in Paris by Government work, so the presentation was made by Ambrose Swasey. When calling the assembly to order, the Chairman said: This medal has been awarded by a Board representing four of the National Engineering Societies: American Institute of Mining and Metallurgical Engineers, American Society of Civil Engineers, American Society of Mechanical Engineers, and American Institute of Electrical Engineers. The medal was established in 1902, in honor of that great American engineer, John Fritz, and has never been awarded except to very distinguished men. In. 1902, the first award was made to John Fritz for scientific and industrial achievement. In 1905, to Lord Kelvin for his work in cable telegraphy and other scientific attainments. In 1906, to George Westinghouse for the invention and development of the air brake. In 1907, to Alexander Graham Bell for the invention and introduction of the telephone. In 1908, to Thomas A. Edison for the invention of the duplex and quadruplex telegraph, the phonograph, the development of a commercially practical incandescent lamp, the development of a complete system of electric lighting, including dynamos, regulating devices, underground system protective devices and meters. In 1909, to Charles T. Porter for his work in advancing the knowledge of steam engineering and in improvements in engine construction. In 1910, to Alfred Noble for notable achievements as a civil engineer. In 1911, to Sir William H. White for notable achievements in naval architecture. In 1912, to Robert W. Hunt for his contributions to the early development of the Bessemer process. In 1914, to Professor John E. Sweet for his achievements in machine design. In 1915, to Dr. James Douglas for notable achievement in mining, metallurgy, education, and industrial welfare. In 1916, to Dr. Elihu Thomson for achievement in electrical invention, in electrical engineering and industrial development, and in scientific research. In. 1917, to Dr. Henry M. Howe for his investigations in metallurgy, especially in the metallography of iron and steel. In 1918, to J. Waldo Smith for achievement as engineer in providing the City of New York with a supply of water. And now to General Goethals for achievement as the builder of the Panama Canal_

Jan 7, 1919

Jan 1, 1928

As longwall shields are lowered in preparation for advance, dust from the canopy falls directly into the air stream with the potential of becoming entrained. Historical dust sampling data from the early 1980s shows that shield advance contributed an average of 12 percent to the airborne respirable dust levels found on longwalls in the United States. Data from the 1990s indicates that shield dust liberation had increased to an average of 23 percent. Increased longwall production levels over this time resulted in the need to move a larger number of shields during each shift, while an increase in air velocities on the face was also occurring. These factors combine to suggest that greater quantities of shield dust are being entrained into the face air. A series of controlled laboratory tests were conducted in a test stand simulating shield dust entrainment to evaluate changes in airborne respirable dust levels at different air velocities. Significant differences in respirable dust entrainment were observed. The test facility, test methodology, and dust sampling results will be reviewed and discussed

By Boyack DJ

DEFINING AN ECONOMIC TARGETExploration usually begins with the corporate goal of finding a minimum tonnage and grade of a selected mineral. Sometimes this is expressed more simply as a minimum quantity of contained metal without any indication of the desired grade or implied profitability. Such a goal is useful in the selection of exploration areas and the planning of initial drilling programs. However, it should be reviewed as soon as significant mineralisation has been identified. To make rational decisions about exploration expenditure, the potential return from a deposit must be estimated from the outset and re-esti-mated frequently.The potential return will depend on:1. The proportion of mineral which can be economically recovered from the deposit by mining (the mining recovery).2. The quantity of valuable constituent that can be recovered after dilution with waste rock during mining and losses due to incomplete metallurgical recovery.3. Expectations of price and markets.4. Capital and operating costs applying to the selected mining and processing methods, and to transportation and marketing. Increasingly, environmental costs and constraints must also be considered.

Jan 1, 1990