Search Documents

By Ben L. Seegmiller

The artificial stabilization of a pit slope at the Twin Buttes Mine near Tucson, Arizona has been completed as part of a practical rock mechanics program. The research program began in June 1971 as a result of the three million ton South Slope slide(1) which caused significant economic and operational problems. Hydrological studies, field and laboratory testing and investigation of various stabilization systems(2)occupied the first year of research. In July 1972 a design for an artificial stabilization test using post-tensioned cable bolts was completed and the selection of an outside contractor was made the following month. The project began in mid-September and was completed during the first week of January 1973. The test site is located adjacent to the South Slope slide in a zone of high potential failure. When the site was initially selected it was thought that it would remain stable at least until the test could be completed. However, heavy rains which fell in late October induced displacement in the half of the test site adjacent to the South Slope slide. Prior to this stabilization test it was thought both impractical as well as improbable that a moving slide could be stabilized with an artificial support system(3). Because the project was nearing the half-way point it was decided that an attempt should be made to complete the test as originally planned. This meant, in effect, that an attempt would be made to stabilize the moving section as well as the stable section.

Jan 1, 1973

By A. J. MacEachen

"LIKE ALL OTHER NOVA SCOTIANS, I have been thrilled during the past few years with the growing evidence that substantial reserves of oil and gas are being discovered off the Atlantic coast of Canada. There are those in this province who believe that large-scale commercial production is just around the corner, and that when it starts Nova Scotia will begin to float on a sea of royalties. These overly optimistic people, of whom I am not one, are convinced that with the first barrel of oil shipped to market, Nova Scotia can forget its financial problems while its people take on the luxurious lifestyle of the shieks of Kuwait or Saudi Arabia. You and I know, however, that even though offshore oil and gas may turn out to be the greatest gift nature has ever bestowed on Eastern Canada, it may take some considerable time before the reserves can be accurately assessed, before the industry can become fully operational, and before the benefits of production can be translated into royalties and tax revenue, improved public services, new industrial facilities and more jobs. While it is premature for the ordinary Nova Scotian to take on the habit of buying expensive cigars and lighting them with ten-dollar bills, it is not too early for him to insist that governments and industry plan intensively and well for the beneficial exploitation of undersea resources."

Jan 1, 1973

By L. A. Haas

Hydrogen sulfide was decomposed to elemental sulfur in an electrical discharge. With He, N., or Ar diluents, a threshold voltage between 1 and 3 kV was required for the decomposition reaction to occur in a laboratory ozonizer. Above the threshold voltage, the HAS decomposition rate increased with increasing voltage, but the increase was more pronounced with argon diluent than with either nitrogen or helium. In common with other reactions in an electrical discharge, the B2S decomposition decreased with increasing temperature in the range of -410 to +61° C. The reaction did not appear to be rate-controlled by a solid-gas sorption step because the introduction of activated charcoal into the electrical discharge zone did not significantly affect the decomposition yield. In the presence of polymeric chlorofluoro-carbon oil, 90 pct conversion of the 3 pct H2S in helium was obtained at 14 kV, 60 Hz, a 2-mm electrode gap, and a gas-residence time greater than 1 min. Under the same experimental conditions in the absence of oil, the conversion was only about 50 pct.

Jan 1, 1973

By H. E. Powell

This Bureau of Mines study describes two processes for recovering zinc, copper, silver, and iron from the magnetic fraction of a waste generated by the primary smelting of zinc in horizontal retort distillation furnaces. The laboratory-scale procedures include reduction melting to produce a high-copper iron and matte smelting to produce a copper-silver-iron matte and metallic iron. Zinc is fumed in each process and recovered as the oxide. Direct reduction melting yields a metallic iron high in copper and a small rich matte from the sulfur contained in the waste. The products of the second process are a matte containing essentially all of the silver, about 80 pct of the copper and 37 pet of the iron, and an iron-copper alloy containing all of the remaining copper. Extraction with metallic lead or sodium sulfate recovers essentially all of the copper from the molten high-copper iron and yields an acceptable foundry iron.

Jan 1, 1973

By A. G. Kim

Methane and other hydrocarbon gases, byproducts of coalification, are emitted from coal at widely varying rates and often present ventilation problems during mining. The air in some coal mines apparently contains no methane. To determine if coals from mines which bid no history of detectable gas emission contained adsorbed methane, samples of coal at the shaft bottom and at an active face were obtained and placed in sealed metal cylinders. The atmosphere around the coal was sampled and analysed by gas chromatography. Methane, ethane, ethylene, propane, propylene, and butane were found to have been desorbed from these coals. Hydrogen and helium were also detected. An estimate of the amount of residual gas per ton A coal indicated that coal samples from the active face generally contained more adsorbed gas than coal samples obtained from the shaft bottom, although in both instances the total amount of gas was relatively small.

Jan 1, 1973

By Lewis. Clifford J.

The purpose of this article is to present design information and operating data on a pilot gas scrubber which is believed to be a new approach for removing noxious gases and particulate matter from the off gases of coal burning power plants and smelters. This principle of scrubbing gases, particularly, scrubbing with an aqueous slurry of lime, was conceived by the author early in 1972. The National Lime Association financed the design, fabrication and initial operation of the unit. The unit was fabricated by Hazen Research Inc. of Golden, Colorado. It has been tested on the off gases of two coal burning power plants and one smelter. The current environmental program has stimulated research and development activity directed toward the removal of sulfur oxides, oxides of nitrogen, particulate matter and other undesirable substances from gases discharged into the atmosphere. At present, most of this effort is focused on the removal of sulfur dioxide and particulate matter by aqueous scrubbing of the gases. This presentation deals particularly with the removal of sulfur dioxide using an aqueous slurry of lime as the scrubbing medium. In recent papers, the author has called attention to-the sludge problems resulting from aqueous scrubbing and to some earlier data on the pilot scrubber about to be discussed.1/

Jan 1, 1973

By Tapio Leskinen, Jouko Koskinen, Timo Nlltti, Lappalainen Seppo, Pentti Vanninen

"The Courier 300 on-stream analysis system manufactured by Outokumpu has now been in operation at five of the company's concentration plants long enough to give a reliable basis for closer examination of the benefits achieved in control of these processes. The first system was installed at the Pyhiisalmi mine at the end of 1967. Since November 1970, two analyzers have been in operation at Pyhiisalmi feeding the assay data to a process computer which controls the whole plant and does the optimization of the process. In October 1970 the Courier 300 analysis system was installed at S. T. O. LESKINEN J. KOSKINEN the Keretti concentrator of the Outokumpu mine, followed soon by installations at the Vihanti Mine in May 1971, at the new Vuonos mine in November J 971 and at t he Kotalahti mine in December 1971. Since installation of the Courier analysis systems, considerable improvements have been achieved in the control and the economy of the plants. Immediate knowledge of the changes in the process and the possibility for rapid action has resulted in evener production and higher capacity and recovery. The recovery has been increased most significantly at the Vihanti concentrator, which operates on a complex ore. Consumption of chemicals has been reduced at all concentrators. Due to the fact that process control and partly also bilance analysis are not achieved by conventional methods any more, it has been possible to reduce the personnel of the laboratories drastically. Two of the plants, viz. the Pyhiisalmi and the Vuonos concentrators, are computercontrolled. The Vuonos concentrator started operation in January 1972 under computer control from the very beginning. The Pyhiisalmi concentrator has been computer-controlled since 1970. The Courier 300 analysis system was described in detail at the AIME Centennial Annual Meeting (1971). In this paper, less attention is paid to the analysis system. Only the sampling system of the Courier 300 is described in more detail. In the development of sampling equipment, effective use has been made of the company's wide knowledge of the problems involved and the test field offered by its concentrators. The sampling equipment includes secondary samplers and six basically different types of primary samplers, with which most sampling situations can be managed."

Jan 1, 1973

By D. Randolph Berry

This manual was prepared to provide essential information to be used when critical decisions pertaining to mine fire recovery or other disaster situations become necessary. It is a state of the art report based upon technology and instruments developed, under a Bureau of Mines Research Contract. A detailed description of the development work and results of full-scale field testing is contained in the Technical Report, Vol. II, of USBM Contract Report H0122045, "Extinguishing Coal Mine Fires by Remote Scaling." Further research and development work has been programmed; consequently, a more complete manual providing detailed instructions and describing available instruments and equipment will be published. Those instruments and special equipment described in this manual must be considered prototype; methodology and applied technology will require special expertise. Consequently, any prospective application of this remote sealing technique will require assistance by the United States Bureau of Mines Research organization and experts from the contractor who developed the basic technology and instruments.

Jan 1, 1973

By P. L. Wright

"This is a brief history of the development of the mining project, with a description of the proven geology. The paper describes how the experiences gained progressively demanded change in the mine design. The equipment used is described, together with methods of working. Interesting facts have been proved regarding gas emissions and roof. supi;iort. The. working cycles evolved are completely flexible m operation and lend themselves to maximum utilization of the most productive units. The two underground mines are compared, showing the variance in conditions already experienced. Programs currently in operation to improve standards and production are: the training of miners, maintenance men and officials; experiments in floor consolidation and continuing roof support trials; and the effect of comparative stability of working crews on the performance of the operation."

Jan 1, 1973

By James S. Browning

For the past several years, the Bureau of Mines has conducted laboratory and continuous process development work on weathered mica pegmatites and micaceous schist ores to determine the feasibility of recovering commercial-grade mica concentrates by flotation. The research has resulted in the development of two processes for flotadon of mica: an acid cationic method for recovery of coarse mica, and an alkaline anionic-cationic method for recovery of fine mica. The research indicated that the two processes may be effectively utilized separately or in combination for flotation of mica from weathered pegmatites and micaceous schists. Concentrates containing over 98 percent mica, with recoveries ranging from 77 to 92 percent, were obtained from the pegmatite ores. The micaceous schist ores yielded concentrates containing 95 to 98 percent mica, with recoveries ranging from 70 to 83 percent. Part 1 of this report summarizes the process development work and demonstrates the feasibility of producing commercial- grade mica concentrates. The report also includes details of commercial beneficiation and grinding of .mica.

Jan 1, 1973

By Allan F. Smith

The Bureau of Mines studied toxic products produced by burning eight fire-resistant mines conveyor belts, a brattice cloth, and an electrical cable insulation obtained from laboratory-scale burning experiments under various air-flow conditions. Generally, CO product concentrations for most materials were noticeably higher then the NO2 and HC1 levels that were measured; also, no phosgene was detected. However, several of the fire-resistant belt samples yielded HC1 concentrations that were above the reported lethal level for 1/2 to 1-hour exposures, although these data were limited to flow conditions where air dilution effects were small; the belt materials that showed this behavior included samples of polyvinyl chloride, styrene butadiene, styrene butadiene blends, and a British neoprene which yielded the greatest amount of toxic vapor. In addition, some results are presented on the phosphoric acid concentrations that may be produced from the decomposition of ammonium dihydrogen phosphate when dispersed on a burning coalbed.

Jan 1, 1973

By F. E. Armstrong

This Bureau of Mines publication reviews 237 papery on radiometric prospecting, which is the measurement of naturally occurring radioactivity in the earth's surface and its application to petroleum and natural gas exploration. Many theories and documented surveys are listed in both support and refutation of this reported phenomenon, and the Bureau of Mines is conducting research to obtain direct field information in order to determine the statistical credibility of a radiometric method of predicting petroleum accumulation.

Jan 1, 1973

By J. B. Janus

In connection with the purchase of coal under specifications for Government use, the Bureau of Mines in this report has compiled data on 81 mines located in 15 States. This annual report lists analytical data on the composition and quality of tipple and delivered samples of coal collected during fiscal year 1973. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. Ultimate analyses are given for most of the coalbeds listed. The deliveries were sampled at destination in accordance with instructions issued by the Bureau of Mines. All samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

By E. L. Piper

Natural graphite has been known for many centuries, having first been reported as a distinct mineral form by Gessner in 1565. At that time, graphite was used extensively as pencil "lead" because of the ease with which it marks paper. It is a black, unctuous material found as flakes, lumps, or needles in scattered locations throughout the world. The less crystalline, or "amorphous", natural graphites are thought to have been formed from coal under conditions of high temperature and pressure. The more crystalline varieties, such as those mined in Ceylon, probably were precipitated from molten solutions or were pyrolyzed from gaseous carbon compounds. Recognition of the good thermal and electrical conductivity of graphite, together with its highly refractory nature, led to an increasing number of appli¬cations for this material. Clay and pitch bonded natural graphite has been used in crucibles, refractories, foundry facings, and other high-temperature appli¬cations. These forms constitute the most important current uses for natural graphite in the United States. Other products containing natural graphite include batteries, lubricants, pencils, brake linings, etc.

Jan 1, 1973

By William J. Cavanaugh

In 1967, Lone Star Industries, Incorporated, established a program to carry out the necessary Research and Development work to bring the Snyder Process to commercial application. The purpose of this paper, is to present the detailed metallurgical results gathered in comparing the Snyder Process of Comminution to conventional grinding techniques for the milling and beneficiation of certain ores and other materials. The ore primarily dealt with in this paper is a fine-grained magnetite ore, containing approximately 23% acid-soluble iron, from the Lake St. Joseph ore body of Steep Rock Iron Mines, Ltd., (Canada). This particular example was selected for presentation in this paper because extensive comparative results with conventional methods of grinding were available. Also briefly described in the paper are the comminution of other ores and materials such as porphyry copper ore and alumina.

Jan 1, 1973

By J. R. Hoskins

Method - A direct approach to instrument users, initially by letter and later by telephone or personal contact was made. The resultant data was compiled to give specific use information on the seven instruments. During the course of the study attempts to evaluate the Griswold Gage were abandoned when it became apparent that the gage was not being commercially produced. One company is developing the gage for its own use. The information presented is the result of over 1200 inquiries.

Jan 1, 1973

By H. A. Zollinger

The Hallmark Distribution Center is one of the most sophisticated material handling and order filling facilities in the world. The 53 million cubic foot facility houses an ultra-modern, computer- monitored distribution complex that handles as many as 1/4 million orders per day. The Distribution Center replaces 16 leased buildings scattered through- out metropolitan Kansas City and, in addition, re-leased 4 floors in mid-town Kansas City needed for creative and administrative expansion. This new facility is the nerve center for distribution of Hallmark products in United States and Latin America. The size and gross numbers of all parts of the system is a significant accomplishment, but the purpose of this paper is to explain the technical advancements in the state-of-the-art of material handling and controls. The system iteself is made up of seven sub-systems including receiving, warehousing, picking rack stocking, towline, order filling, order sorting, and shipping. Significant techniques were used in each of these areas as well as technical advancements in the state-of-the- art. The most significant points are in 4 of the areas and are discussed in this paper.

Jan 1, 1973

By G. Wilson

"Satisfactory hydraulic performance of a centrifugal slurry pump is not the only design criterion. If abrasive wear exists the severity of any damage can be reduced and the life of the wearing parts prolonged by selecting the correct pump to suit the conditions of service. This paper is concerned with the design and construction of centrifugal pumps for handling abrasive solids. The wear phenomena due to the slurry being pumped and the materials used to combat abrasive, wear are outlined. The hydraulic design of the impeller and casing and their relationship to wear and the hydraulic radial and axial unbalance are discussed. The prediction of abrasive wear in pumps can not be precise, as many factors are involved - and this is the object of current research."

Jan 1, 1973

By C. G. Tester

Automatic tripper control systems can be reliable and as such are suitable for use in the mining industry. Proper application of fundamental engineering principles provides the means for the reliability. Some of the principles are: (1) Be sure the system designer designs a system that does the job operations people want done; (2) Use sound logic design practices to avoid internal electrical problems; (3) The design must be maintenance oriented; and (4) Use good quality components. I would like to discuss a tripper control installation at Kennecott Copper Corporation, Chino Mines Division, in Hurley, New Mexico, and how these principles apply to this tripper control system. First, however, I will expand on the principles to clarify just what is meant. First, "Be sure the system designer designs a system that does the job operations people want done.? Operator acceptance is often the key to the success or failure of an automatic control system. One of the best ways I know of to get operator acceptance is to give him a system that he wants. I don't mean to imply that if bad practices or procedures exist that they should be incorporated in the control system. I do think that many designers feel they haven't done their job if the control system doesn't do things drastically different than the old manual method. Good engineering principles dictate that the job should be done right and if the manual method was right it can very likely be right for the automatic method.

Jan 1, 1973

By Martin P. Corriveau

It is not news to anyone in the mining industry that federal action in the prevention and abatement of air pollution has seriously affected the industry both directly and indirectly. It is the purpose of this paper to review how the development of federal action is directly affecting the coal mining industry's number one customer, the fossil-fuel-fired steam generating power plants and, consequently, the industry itself indirectly. In essence, Public Law 84-159 of 1955 as amended by the Clean Air Act of 1963 and its revisions in 1967 and 1970 progressively tightened federal coordination and management of air pollution control programs throughout these United States. The Environ- mental Protection Agency (E.P.A.) set up to direct the programs was charged to establish National Air Quality Standards, Standards of Performance for New Stationary Sources, and National Emission Standards for Hazardous Air Pollutants.

Jan 1, 1973