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By Gerald L. Finlinger

This Bureau of Mines publication reviews underground methane drainage programs being conducted in various coalbeds. Equipment used in drainage programs such as drills, underground pipelines, and methane monitoring systems is described.

Jan 1, 1980

By Gary Almeraris, Vincent Jr Tirolo

Traditionally, “Means and Methods” were the sole responsibility of Contractors. However, because of a number of litigious projects in the 1970s, Owners and their Engineers began including Suggested Methods of Construction (SMC) in Contract Drawings. By the late 1990s these SMCs were becoming baseline “Means and Methods” with Contractor recommended changes often considered as Value Engineering proposals. By 2004, the word “Suggested” was sometimes changed to “Prescriptive.” Owners are also purchasing TBMs and other mining equipment for Contractors prior to bid. Is limiting the contracting community’s innovation in developing their own “Means and Methods” and selecting their own equipment in the best interests of the Owner? Does it reduce the Owner’s, Engineer’s or the Contractor’s risk? Are claims reduced and finally what is the impact on the bid? A questionnaire was sent to more than fifty senior engineering field and management personnel representing more than 30 heavy construction companies to ask their opinion on these questions.

Jan 1, 2005

By Holger Witthaus

There is more than a century of experience in multiple seam mining in Germany. In several mines up to 20 seams had been excavated within the last decades. Due to the nature of the deposit and the history of technical development the older panels cause a complex stress distribution for the lower seams and the current longwalls in descending order of mining. The depth of the longwalls reaches up to 4000 ft. This causes a maximum vertical stress that reaches between 30 and appr. 60 MPa. To handle these conditions several support systems are applied for roadway heading. A central knowledge management system for ground control is used for design and dimensioning of support within the DSK. This paper gives an overview to the nature of German multiple seam mining and the solutions in matters of panel layout and support design. It describes the full lifecycle for roadways in the seam starting with the geological and geotechnical evaluation, the basics of roadway deformation in great depth, the development of planning tools and standards for German coal mines, the range of alternative of support systems and roadheading techniques, as well as the reinforcement measures and the processing of support at the T-junction of the face entry. This paper uses exemplary descriptions that are consolidated in a specialized reference book ?Gebirgsbeherrschung von Flözstrecken? ? ?Ground Control in Roadways? which summarizes the standards of ground control based on the development of the past 25 years in German coal mines.

Jan 1, 2007

By Victor Benavente

La lixiviación es un proceso hidrometalúrgico que permite obtener el cobre de los minerales que lo contienen, aplicando una disolución de ácido sulfúrico, agua y agentes oxidantes. Este proceso consiste en que los minerales son sensibles al ataque de soluciones ácidas y oxidantes. En ese sentido, el objetivo del texto fue determinar la respuesta de los sulfuros secundarios de cobre a la lixiviación ácida y oxidante utilizando cloruro de sodio como portador de cloruro al sistema de lixiviación. El desarrollo de las pruebas y la ejecución de las mismas, definiió el proceso de lixiviación para minerales sulfurados de Minera Pampa de Cobre.

Sep 12, 2011

By D. M. A. Flight, P. M. Green, J. A. Plant, P. R. Simpson

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. The British Geological Survey's regional geochemical database is used to identify the patterns associated with the various mineral deposit types and to examine the extent to which their distribution reflects the presence of long-lived metallogenic provinces in the crust. Image analysis provides new insights into the setting of the mineralisation, geochemical constraints on tectonic models of Caledonide evolution and evidence for terrane amalgamation and large-scale processes. There is evidence that much of the mineralisation reflects the presence of long-lived provinces with a distinctive geochemistry reflecting their origins as zones of crustal extension. In the case of the Middle-Upper Dalradiam sedex deposits, the relationship between geochemistry and tectonic setting is direct. In other cases, rocks deposited in extensional zones appear to have acted as reservoirs of ore-forming elements which were further concentrated during later events

Jun 19, 1905

By W. J. Schlitt

The Namibian Copper Joint Venture has been formed to undertake development of the Haib copper deposit, one of the largest undeveloped copper resources in Africa. The development programme includes extensive hydrometallurgical testwork that is being managed by Kvaerner Metals (formerly Davy International).Various parts of the programme have been contracted to four third-party laboratories. The testwork involves sample selection and characterization, amenability tests, and a parametric study on the leaching variables. All portions of the programme are described and the results a represented. The ores selected for testing are quartz feldspar porphyries. The amenability tests include ?mapping? studies to assess optimum leach conditions, tests at high oxidation potentials, oxidation with various bacterial strains, and heap leach modelling. The parametric programme includes such variables as ore grade, leach temperature, crush size, pH, and ferric iron content of the lixiviant. Testing was done on both whole ore and concentrate. Results show that bacterial leaching is effective and that ore grade and temperature are key variables. Crush size and pH have less impact on copper extraction. For mid-grade ore, about 0.25 per cent copper, extraction is projected to reach 50 per cent after two years when heap leaching tertiary crushed ore at 60°C and pH 1.5. The heap leach operation would fit well with the proposed roast-leach operation used to treat higher grade ores. The latter could supply the low cost heat and acid needed in the heap leach.

Jan 1, 1999

By Ernst M. Cohn

The demonstrations of the "Silent Sentry" by Union Carbide Corp. in 1957 and of a special tractor-plow by Allis-Chalmers in 1959 ushered in the technology era of fuel cells. The idea for direct conversion of chemical to electrical energy, first published in 1801 by Davy in England and Ritter in Germany, has been kept alive by a few people through 150 years: Grove built the first hydrogen-oxygen fuel cell in 1839; Mond and Langer made electrolyte contributions around 1890 that are still used today; Baur worked on coal-based cells from 1900; Bacon started his work in the '30's, which resulted in the first multi-kilowatt unit in the '50's; Davtyan studied molten-salt electrolytes in the '40's, followed by Ketelaar in the '50's; and Justi developed highly active electrodes in the '50's, to name only some of the pioneers. Despite the tremendous increase in research and development of fuel cells, these direct energy converters are still in their infancy. They will find their functional application in space, where power density must be maximized and product water utilized. These early systems will provide valuable experience in system engineering and reliability.

Jan 9, 1964

New Zealand China Clays produces a unique halloysite clay product at Matauri Bay, Northland.   The company has licences over four deposits that were derived from the weathering of rhyodacite domes. Clay is mined and processed from two of the four deposits and is refined using a complex process based on gravity separation.   The product is almost entirely exported to niche markets in 24 countries. The main market is the fine ceramic industry where the product is used as a component in the manufacture of high quality porcelain and bone china bodies. The use of halloysite in these bodies gives the manufacturer the ability to achieve high whiteness and translucency. The other major market is for use in technical ceramics, where the product is sought after due to its high purity, fine particle size and stability at high temperatures.

Jan 1, 1997

Operating well designed and maintained surface mine haul roads is the key to minimising truck haulage costs - in itself a significant component of the total cost per tonne mined. Existing and proposed mining operations are subject to scrutiny, both from the economic and environmental perspectives. In the long run, this scrutiny returns improved efficiencies and leaner, 'greener' operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations - simply by virtue of their contribution to overall cost of operations and sustainability impacts. Whilst the end result - improved efficiency and contributions to resource sustainability - is not in itself problematic, it is the route, or process followed to achieve these improvements that needs to be carefully managed. We can be guided on this journey by our understanding of how a road is designed, and, critically, the technological solutions that can contribute to a company's sustainability initiatives. This paper examines the current state of mine road design and operation, together with the economic and environmental issues associated with under-performance. The paper serves as a basis for evaluating the economic and environmental contributions that technology in road design and management can deliver to sustainable operations. Utilising innovation is the key to long-term sustainability and as a means of positioning the industry for the imminent structural changes to the economy and environment, changes which are now within the operating life of many mines, haul roads and haul trucks.

Jun 1, 2010

By O. Acaroglu

Selection of the most suitable roadheaders (boom type tunnelling machines) for the galleries/tunnels to be excavated in certain rock and under known project conditions is important for avoiding problems during application. This research utilized a multiple attribute decision-making method and studied how this will be applied for the selection of boom-type excavation machines. The Cayirhan Coal Basin was used for selecting roadheaders using the analytical hierarchy process, which is one of the multiple attribute decision-making methods. To conclude, this study reveals that decision-making methods can be used in the process of selecting roadheaders for the excavation of galleries. Keywords: roadheaders, multiple attribute decision-making, analytical hierarchy process.

Jan 1, 2006

By Jiann-Yang Hwang

Microwave heating has been proved an effective method to rapidly heat iron oxide. This offers an opportunity to apply microwave heating in the steelmaking process. The reduction reaction of iron oxide is traditionally achieved at high temperature with reducing gases such as H2 and CO generated from various sources, including coke, coal, and natural gas. This study investigates the differences in iron oxide reduction using conventional and microwave heating under H2 and CO atmospheres. A special microwave thermal gravimetric device was designed and built to facilitate the investigation. With this device, iron oxides can be heated by electric resistance heating, microwave heating, or a combination of methods. The incoming CO and/or H2 also can be preheated to simulate a potential utilization of recovered heat. The iron oxide weight and temperature can be monitored during an entire reduction period. A series of reduction experiments have been conducted. The results are presented and discussed.

Jan 1, 2006

The Coal Resources Survey commenced in 1974 as a search for Huntly Power Station coal, but soon developed into the most detailed regional coal search programme to be instituted in New Zealand. The program was initially conceived as geological in nature, but later included geotechnical, geohydrological, mining assessment, coal use, and environmental considerations in its investigations. The programme never undertook development work but has provided Government and the private sector with a sound basis for identifying development options. The discovery of large-scale coal resources in the Mokau, Waikato, and Taranaki regions and the lignite resources of Otago and Southland are a measure of the Survey's success. The directive by Government to phase out the NZCRS to a large extent coincides with the completion stage of the program. With most of the detailed regional study finished, it now remains to collate the data and publish summary reports at Coalfield and Coal Region level, in order to maximise the use and value of the data collected over the years.

Jan 1, 1987

By L. du Plessis

The name FISH (Fully Integrated Sort House) refers to a class of technology deployed at Jwaneng Mine final diamond recovery. The FISH concept is based on three pillars, namely: ?Improved sorting efficiency FISH is based on laser technology, which is more efficient than hand sorting for certain product categories. Laser sorting is based on measuring in-elastically scattered light from molecules and this is referred to as Raman spectroscopy. The Raman scattered light occurs at wavelengths that are shifted from the incident light by the energies of molecular vibrations ?Availability of production information Roller gap diamond size distribution information is generated on line for upstream process optimization ?Improved product security A ?hands-off? philosophy reduces security risk during operation and maintenance of the plant. In addition, a number of lessons were learnt about the application of new technologies in the industry: ?The required human competency profile demanded by new technology should match the available competencies of the operational staff ?An integrated information management system should be fully functional for both production management and diamond control purposes ?Operational feedback must be correctly evaluated to identify design, maintenance, training and operational issues so as to accelerate the maturity of the new technology within the time span of the sustainable operations project ?Project execution and technology maturity risks have to be evaluated and married to ensure risk mitigation by means of suitable project resource and contracting model selection.

Jan 1, 2003

By B. C. Peterson

Calumet Division, Calumet & Hecla, Inc., whose operations are in Houghton and Keweenaw Counties, Mich., is a highly integrated and complex organization. This division operates mines, a railroad, a concentrating mill, a reverberatory smelter, and the auxiliary generating plants and shops to service these operations. In addition, it operates a sands reclamation plant, leaching plants, a foundry, and a machine shop that serves varied industries with castings and parts for many applications. Calumet & Hecla, Inc. has produced over 60 percent of all the copper that has been produced in Michigan since discovery of the ore in 1864, and in 1959 the company ranked eight among the country's producers with a production of 17,407 tons. To keep abreast of modern accounting systems developed elsewhere in industry and to combat increasing costs due to higher labor and supply costs, as well as increased costs due to deeper mines and lower grade ore, the company has developed a modern machine cost accounting system. This not only provides the usual bookkeeping and cost accounting facilities but offers accurate cost data for engineering evaluation of the mining operation. This system is credited with being instrumental in permitting continued operation of these high-cost mines in a period of increasing costs with no corresponding increase in the price of metal.

Jan 1, 1962

By John Smyth

Mining through in panel entries and the full face recovery method has been successfully practiced at U.S. Stwl, Mine 50. Suppat of the cut-through entries and recovery room is critical. Traditionally, concrete crib or fly ash cement backfill has been utilized. However, these traditional methods are not feasible at Mine 50 due to the difficulties of the plow face mining through these types of support. Recent development of new cable support systems provides an option for cut-through entry support. Mine 50 and Jennmar Corporation personnel have worked together to design and apply the cable systems in the cut-through entries and full face recovery room to eliminate standing support. To date, a number of full face recovery rooms and cut-through inpanel entries have been successfully mined. The results indicate that the cable systems combined with high capacity shields, have provided sufficient capacity to support the roof. Utilizing the Jennmar Finite Element Analysis (JFEA) computer program (Stankus and Guo, 1996), an analysis of the stress and roof deflection changes as the longwall gradually cut through was conducted. From the finite element analysis data, a supplemental support plan was designed. The history and experiences at Mine 50 are presented. Based on the case experiences and modifications made to the finite element analysis, an improved design criteria for future use has been formulated.

Jan 1, 1998

By Li Zhou

The kinetics of the dissolution of galena was studied by monitoring the mixed potential of a galena electrode in ferric sulfate solutions. The results show that the mixed potential of the galena electrode fluctuated with time in a regular pattern in a 0.1 mol/L Fe2(SO4)3 solution of pH 1.66 and in a 0.01 mol/L Fe2(SO4)3 solution of pH 2.33 at 35°C. The periodic accumulation and precipitation of lead ions at the galena electrode surface and the cyclical variation in pH at the galena electrode surface caused the oscillation phenomena.

Jan 1, 2008

By G. W. Josephson

WHILE methods of utilizing blast-furnace slag have been developing, a great deal of literature on the subject has accumulated, but no comprehensive summary of information that would be helpful to engineers, contractors, architects, chemists, and others in under-standing and more successfully using this byproduct of the iron and steel industry has been published in the English language. The National Slag Association recognized the need for such a publication, and the Problems Committee of the Association under-took in 1943 to accumulate the necessary material. Over a period of several years this committee compiled pertinent information in manuscript form, and in 1948 the Bureau of Mines and the National Slag Association made an agreement whereby the Bureau was to prepare the data for publication as a cooperative bulletin of the Bureau of Mines and the National Slag Association.

Jan 1, 1949

By M. M. Wong

The Bureau of Mines, under a cooperative research program with four lead companies, has investigated a nonsmelting process for the production of lead metal. The process, which would eliminate sulfur dioxide generation and minimize particulate lead emissions, involves ferric chloride leaching of galena concentrate to produce lead chloride, followed by molten-salt electrolysis of the lead chloride to yield lead metal and chlorine. This chlorine is used to regenerate ferric chloride in the leaching solution. The process was tested in an experimental unit with a capacity of 500 lb of lead metal per day. The tests were performed in three 10-day and six 5-day campaigns, during a period spanning 28 mo. The study was carried out using a southeastern Missouri lead concentrate. Typical lead recovery was about 98 pct. Process problems related to impurity buildup and control were studied. When copper and silver impurities were removed from the leaching solution, a lead metal purity of 99.999 pct was obtained. Lead-in-air levels and lead-in-blood levels of operating personnel were monitored. The process has potential for producing lead with minimum pollution, but is not ready for commercial utilization. Operation of a prototype commercial electrolytic cell and a full-scale pilot-plant investigation by industry are needed to evaluate the commercial viability of the process.

Jan 1, 1983

By Giovanna Valdivia Málaga

Dado que la comunidad de Michiquillay recibe una gran cantidad del canon minero a través de la gestión de la Municipalidad del mismo nombre, se planteó mejorar las relaciones de parentesco y la inmersión en la modernidad económica y socia de dicha comunidad y pasar de una economía informal a una economía social o solidaria. En ese sentido, el presente texto describe el proyecto de participación colectiva entre los miembros de la comunidad Michiquilllay y La Encañada, con el objetivo de construir una propuesta de privatización del proyecto minero Michicallay. El trabajo de campo se realizó en los ocho sectores y se desarrolló desde hace dos años, alcanzando la comunicación y sostenibilidad del mismo.

Sep 12, 2011

By K Firmin

The Mt Tom Price orebody of Hamersley Iron Pty Limited consists of a folded hematite - shale sequence capped by a layer of goethite. Consequently, variations in iron content occur within the ore body, and as the overall grade is below that required to make specification products, selective mining must be carried out. A necessary preliminary to quality control of products based on selective mining is the production of advance data on the tonnages and grades of material to be expected in future mining areas. Bench plans showing zones of different grades and types of material anticipated are prepared from structural geological information. The grades of materials on a bench are essentially governed by the positions and attitudes of the shale bands. Quality control is exercised by blending different grades and types of material in primary crusher feed. Iron grade is the prime grade consideration although sometimes the level of phosphorus content must be considered. Pre-production grades are determined from assay of samples taken from blast hole cuttings. As shales are more friable than hematite, product fines are always lower in iron grade than the lump product. The realisation of contract specification grade is more difficult with fines than with lump, so maintaining the correct fines grade becomes a prime factor in quality control. Control of fines grade is presently effected by aiming for an appropriate feed grade to the primary stockpile. Studies to estimate fines grade directly by qualitatively taking into account material types are in progress. Quality control measures are checked by monitoring the crushing and screening plant output, and taking appropriate compensatory actions in the mine when required. Minor fluctuations in quality of fines can be blended out on stockpiles. The quality control measures described ensure constant quality products, and a good recovery of high grade material from the deposit.

Jan 1, 1971