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By W. L. Dare

Tri-axial strains in pillars, created by pillar robbing, were measured in an experiment at the Dysart No. 1 uranium mine near Grants) New Mexico. At this mine, room-and-pillar stoping is used on the advance, and pillars are recovered on the retreat. The are deposit is, for all practical purposes, horizontal. Measuring devices were installed in pillars approximately 90 to 200 feet from the break line, and strains were recorded over a 4-to 6-week period. The measurements indicate that, in general, the algebraic magnitude of vertical strains increased, and the horizontal strains decreased, in turn, indicating that vertical (or near vertical) loads on the instrumented pillars lessened as pillars were recovered.

Jan 1, 1962

By J. Kraemer, A. Preusse

In the federal state of North Rhine Westphalia (Germany) small and medium sized companies are beginning to extract the related gas via old shafts or boreholes and to use it as a source for the production of electricity and heat. More than 100 applications for the separate mining right on mine gas had already been filed by beginning of 2002, since mine gas is treated as a mineral resource under the Federal Mining Law. Meanwhile more than 40 mine gas concessions have been granted and first projects are being developed with encouraging results so far. To enhance the applied techniques and their efficiency Aachen University has formed a research team in this discipline. Scope and goals of this research activities are being presented in this paper. Keywords: extraction mine gas, Renewable Energy Act, Ruhr District.

Jan 1, 2003

By André de Albuquerque Vicente

Foram estudadas as microestruturas de quatro juntas soldadas de aço inoxidável austenítico produzidas através do processo MIG/MAG com diferentes gases de proteção, dentro de um projeto que visava estudar o comportamento de juntas soldadas de aços inoxidáveis austeníticos a altas temperaturas. Utilizou-se o metal de adição 22.12.HT e diferentes gases de proteção: 100% Ar, Ar + 2% CO2, Ar +4% CO2 e Ar + 20% CO2. Para cada mistura gasosa, foi soldado um corpo de prova. Estudouse a variação das frações volumétricas de ferrita delta em função dos diferentes gases de proteção utilizados. Observou-se aumento no teor de carbono e consequente diminuição das frações volumétricas de ferrita delta nos metais depositados com gases de proteção com maiores concentrações de CO2, evidenciando-se que o carbono é um forte estabilizador da austenita nos aços inoxidáveis austeníticos.

Aug 17, 2017

Research and Application of Vertical Screw Stirred Mill

Sep 13, 2010

By S. J. Rodgers

MSA Research Corporation, Division of Mine Safety Appliances Company, was awarded a contract to conduct a survey of past and present methods used to control respirable dust in noncoal mines and ore processing mills. The survey covered information reported in mining journals, and U.S. Bureau of Mines Circulars, dust inspection reports, on-site evaluation of dust control methods and systems, and contact with manufacturers of dust control equipment. Both surface and underground mining operations were visited. Fifty mines and 51 processing plants were included in the survey. Dust control methods for the following types of ores or mines were studied: [ ]

Jan 1, 1974

By Michael Rieber

An analysis of coal slurry pipelines was presented in our May 1976 study, Route Specific Cost Comparisons: Unit Trains, Coal Slurry Pipelines and Extra High Voltage Transmission (4]. The present study extends that analysis. The earlier work included technical and economic cost descriptions of the black Mesa and ETSI pipelines as well as some hypothetical pipeline routes. Water problems, safety and environment, required resources, and labor impacts were discussed at some length. Additionally, pipeline impacts on competing railroads, slurry-rail comparisons, and cost escalation. were analyzed. The difference in pipeline profitability to an owner-operator versus a promoter-builder was suggested. These aspects are not redone in this study. Here, we present a synopsis of the previous results and a general statement of coal slurry pipelines. Extensions of the arguments are presented where they appear warranted. New material is developed in the area of pipeline branching and tapping. This would appear necessary if slurry pipelines are to function as more than private lines; if they are, for example, to be responsive to common carrier requirements.

Jan 1, 1977

By R. W. Mei, R. A. Strombom, D. J. Moore

"Heat-shrinkable cable accessories are solving problems in the mining industry. This paper describes a range of products used by the industry, including low-voltage splices, high-voltage splices to 8.7 k V, cable repair sleeves, mining cable terminations used on system voltages up to 25 kV and motor connection kits up to 8 k V. Technical procedures and designs are illustrated.IntroductionThe development of high-performance heat-shrinkable materials slightly over 20 years ago proved to be one of the major technological breakthroughs in power cable accessories. Heat-shrinkable products were introduced initially for use as low-volt age cable accessories in the aircraft and electronics industry. A program of continuous development and product introduction now enables the manufacturer to offer a broad range of products for mining, industrial and utility electrical systems.With the advent of atomic energy, an important discovery was made-exposure of some plastic materials to high-energy electrons can cause the permanent crosslinking, or intermolecular joining, of adjacent molecules. Once the material has been crosslinked, it will not melt or flow at any temperature.The unique properties of heat-shrinkable products also result from the exposure of special thermoplastic formulations to high-energy electrons. Because of crosslinking, these products have perfect elastic memory. The heat-shrinkable products are supplied in expanded condition. When heated, they will shrink and tightly cover the object over which they have been placed. 'The functional and operating demands of mine cable accessories exceeded the classic electronic applications of heat shrinkable materials. These demands required a very sophisticated program to develop materials and adhesive systems that could endure the operational environment associated with the mining industry,Ease of assembly, low installed cost and operational reliability are among the main reasons for the acceptance of heat-shrinkable mine cable accessories in electrically powered mines. For over a decade, these systems have been demonstrating proven performance."

Jan 1, 1980

By S. R. Zimmerley

As a result of the drilling program of the :Mining Division, Bureau of Mines, large amounts of manganese ores have been blocked out in the Drum Mountain District of Utah. The ores, as mined, would not be acceptable for the production of ferromanganese, and this investigation was made to determine their amenability to concentration by ore-dressing methods and the amount of

Jan 1, 1942

By S. R. Zimmerley

As a result of the drilling program of the Mining Division, Bureau of Mines, large amounts of manganese ores have been blocked out in the Drum Mountain District of Utah. The ores, as mined, would not be acceptable for the production of ferromanganese, and this investigation was made to determine their amenability to concentration by ore-dressing methods and the amount of

Jan 1, 1942

By G T. Kukla

A Seam deposit User oriented Mine Planning System (SUMPS) was developed by The Broken Hill Proprietary Company Limited (BHP) at its head office in Melbourne. It is one of the computer mine planning systems developed by the Corporate Data Processing (CDP) section of BHP. To date it has been employed in the feasibility study of four coal prospects for the BHP Group, including Gregory in central Queensland û Ham and Van Hoorn (1978). It was also used in detailed short term mine planning for Gregory. A recent application was in the feasibility study of Saxonvale, a multi seam coal deposit in New South Wales with seams up to 20 m thick. The other two applications of SUMPS were also on thick multi seam coal deposits. Development of programs for the underground subsection of SUMPS is continuing. SUMPS was developed and implemented on mini computers with graphics and plotting peripherals. The company's philosophy towards computing is one of centralized development and project planning, with transfer of hardware and software to site once the mine becomes operational. Support of the site's system continues from head office which is continually involved in development of SUMPS and issuing revision updates to sites. The users, as well as programmers, were mostly geologists and mining engineers. This helped to ensure rapid, successful implementation. The broad approach of this system was to use interactively the specialist skills and interpretative abilities of the user mining engineers and geologists with the data manipulation abilities of the computer. It is an integrated system which covers geological exploration, deposit modelling, mine planning and production scheduling. An important feature of the system is that the user has full interactive control over each function through a graphics terminal where applicable.

Jan 1, 1980

By H. Kotzé

Titania slag is used as feedstock in the production of titanium dioxide pigment. It (titania slag) is the product of ilmenite smelting,a process whereby ilmenite is reduced at high temperature utilizing anthracite as a reducing agent. Although various slag tapping configurations are employed throughout the ilmenite smelting industry, the method of tapping the slag from the furnace into bell shaped cast steel pots, was the subject of investigation in this study. The paper describes the formulation of a cooling model used to calculate and subsequently predict the temperature profile of a slagblock during its cooling within the various cooling environments of pot cooling, air cooling and water cooling. The model was calibrated against actual internal slag temperature measurements and verified with information obtained from both pilot and industrial scale blocks. The paper concludes with solidification results and their practical implication.

Jan 1, 2010

By Jim Britton

Sustained elevated metal and coal prices in 2011 continued to drive mining projects across British Columbia. The province is the top producer of copper, exporter of coal and the only producer of molybdenum in Canada. The province also produces significant amounts of gold, silver, lead and zinc and more than 30 industrial minerals. The total 2011 value of solid metal production is an estimated $8.6 billion and the outlook for 2012 is positive. British Columbia is poised to bring several new mines onstream in the next few years. Construction continues at the New Afton and Mt Milligan copper-gold projects that are anticipated to be open in 2012 and 2013, respectively. The provincial Environmental Assessment Office indicates there are 26 mine proposals in process with three currently under review and 23 in the preapplication stage. The following text briefly describes 2011 metal and coal mining activities in the five regions reported on by the provinces? regional geologists (Fig. 1).

Jan 1, 2012

Two coal seams were selected and the conceptual designs were based on the geological and physical conditions typical of these seams. As a result of the screening process presented below, the two coal seams selected were the Lower Kittanning Seam in central Cambria County, Pennsylvania and the Pittsburgh Seam in northwestern West Virginia and southwestern Pennsylvania. SELECTION PROCESS FIRST SCREENING OF LONGWALL OPERATIONS The list of longwall operations prepared in Phase I and included in the Phase I report, was used as the basis for a first screening. From this list it was determined which longwall operations were not in the Appalachian coal fields and not in a coal seam of the thickness range of 42 to 72 inches. The first screening eliminated 30 of the listed operations, leaving 48.

Jan 1, 1976

By Dana T. Updyke

An evaluation was made of one of several improved underground communication systems sponsored by the U.S. Bureau of Mines. The system evaluated was installed in a typical metal/non-metal room and pillar mine and utilized UHF repeaters connected to a unique distributed antenna and passive reflector system which provided mine-wide communications. A microprocessor controlled data collection system was assembled and installed for the evaluation. Data consisting principally or times and durations of messages and identities of the originating transceivers was collected between February and August of 1982 (6 mos.). Analysis of the data shows that the principal benefits are reduction in time required for unscheduled maintenance and repair, enhancement of safety, and better coordination of production activities. A cost benefit analysis shows a net benefit over cost, although it is also concluded that the capacity of the system is greater than can be justified by current activity in the mine.

Jan 1, 1983

By Firth B. A

The classification performance of a Dutch State Mines (DSM) Rapped Sieve Bend has been investigated in a series of experiments. Coal slurries of a nominal 0.5 mm size were classified in the separation range of 0.10 to 0.14 mm at pulp densities from 6 to 21 per cent by mass of solids, and flow rates of 110 to 1375 litre min-1.The results obtained showed that the partition curve and water split io oversize was dependent on the solids flow rather than slurry flow rate or pulp density. For most of the operating conditions considered an accurate classification of the fine coal was obtained. The undersize efficiency was susceptible to solids flow rate, and was less than 70 per cent for solids flow rates greater than 16.7 tonne hour-1 metre-1 width of screen.

Jan 1, 1983

Table A-1. Number of underground coal mines and samples collected for underground occupations, 1988-92 [ ]

Jan 1, 1997

By Neil T. Russo, Peter M. Kandaris, Jogi S. Gadok

"Assessment of subsurface data for foundation design in support of long high voltage electric transmission lines is best accomplished using a probabilistic strategy since only a small portion of structure locations are typically sampled. Probabilistic approaches provide a tool to evaluate site uncertainty in a systematic and rational manner. This paper provides a case history of a risk-based design approach for a recently completed 191-mile long 69/161/345kV steel monopole transmission line traversing Central Iowa. The project owner made available limited subsurface information at project initiation, requiring the design team to obtain additional data within a constrained budget for 1067 large diameter, laterally-loaded deep drilled shaft reinforced concrete piers. The team commissioned a geologic desktop study to reduce uncertainty in subsurface evaluations and aid in selecting additional sample sites. In total, investigation programs tested approximately 15 percent of structure sites. The paper details the probabilistic approach used to estimate foundation geotechnical design parameters, with information from the various studies categorizing strata both laterally and with depth. Low-bound parameters were estimated via a statistical approach at a predetermined reliability level. Significant savings resulted from this approach when compared to conservative deterministic processes. Project QA/QC logged subsurface soil conditions during foundation excavation, then compared as-found conditions to the conditions assumed for design. The team redesigned foundations if either a non-conservative variance in soil conditions was observed or if bedrock elevation differed significantly from design assumptions. As a result, only 22 out of 1067 foundations required modification during construction (2% variance from initial design) with negligible impact on the construction budget and schedule.INTRODUCTIONFoundation design for long high voltage transmission lines presents a unique challenge in that the assessment of subsurface conditions typically requires substantial data that may or may not be obtainable. Investigations are usually performed well in advance of construction, often with limited access to structure sites and typically in remote areas. Probability and risk-based investigation and design strategies offer an opportunity to systematically estimate subsurface profiles and geotechnical design properties with limited data. Risk can be further reduced with dedicated field inspection of foundation construction along with good field and design team communication during construction. This paper presents a case history of probabilistic methods used for the investigation and design of electric transmission line foundations."

Jan 1, 2017

By C. Taschereau, G. A. Vickell, A. R. Laplante

Evidence in support of an iron-gold corrosion cell during the high-temperature/highpressure elution of loaded carbon is presented herein including, but not limited to, its discovery, mode of genesis, and confirmatory laboratory testwork. A discussion of metallurgical and economic impacts, remedial investigations, plant design considerations, and future work including mitigative possibilities is presented.

Jan 1, 2006

Interest in mining narrow, vein-type ones has increased world-wide during the last few years despite the fact that prices of metals have not risen in proportion as production costs of mining, such as labour and energy. In many mines, where narrow ones are mined, the mining technique and equipment used have been poorly mechanised. The mining methods have been cut-and-fill or shrinkage stoping. Pneumatic jack-legs have been used for drilling and slushers have been used for loading. The methods that have been used can be called the 'first-generation' methods. Work has been very hard for miners. It has been dangerous and exhausting. Production volumes of mines, and a s a result of that, also profits have been low.

Jan 1, 1990

This Bureau of Mines publication contains the texts of the four papers presented at the May 6-7, 1980, seminar on the role of overburden analysis in surface mining. Coverage includes the geologic distribution of pyrite and calcareous material and its relationship to overburden sampling, overburden sampling and analysis, use of soil-overburden data in mine planning and development, and minesoil classification.

Jan 1, 1981