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By Denholm W. T

The SMELT-2 package is specifically designed to perform on-line simulation of smelting processes. This paper describes its application to the simulation of continuous matte converting followed by reductive slag cleaning in SIROSMELT reactors. The matte, containing 50% Cu is assumed to be produced at the rate of 20 tph in a continuous matte smelting furnace such as an Outokumpu Flash Furnace, Noranda or Sirosmelt reactor. Two alternative fluxing strategies in the converter are examined, namely: ò conventional silicate slags, ò calcium ferrite slags, and the flow sheets associated with each strategy are discussed. A regular solution model is used in the present study to account for the variations in the activity coefficients of components in the slag.

Jan 1, 1989

By J Aitchison, G Clarke

A reappraisal of the stratigraphy, new regional kinematic analysis and thermobarometric data allow a new interpretation of the metamorphic zoning and tectonic structure of the Upper Eocene high-pressure metamorphic core complex of northernNew Caledonia allow a three steps evolution to be proposed: 1. subduction and understacking of previously thinned continental crust elements; 2. subduction blocking due to the crustal thickening; and 3. crustal thinning and extensional detachment during the diapir-like uplift and unroofing of the eclogitic core. Steps 2 and 3 may be partly contemporaneous. Such a model accounts for the thermobarometric and radiochronologic data, and also for the weakness of substratum deformation during the emplacement of the ophiolitic nappe

Jan 1, 1995

At the LKAB, Iron Ore Mine, Kiruna, Sweden a preliminary investigation into the reliability characteristics of a fleet of load-haul-dump machines has shown that the hydraulic system is one of the most critical parts. Therefore, hydraulic system was selected for study and analysis through condition monitoring devices so that failure can be controlled or at least the failure consequences can be minimized.The hydraulic system has two different problems; one is that the contamination level is too high and the other is high temperature during operation. At high temperature, seals and tubes are a problem, because they stiffen due to carbonization, which leads to increasing leakage. The pumps and restrictions were responsible for the main temperature increase.

Jan 1, 1991

The Nelson province was chosen as the prime area for rhenium sampling, based on its mineral associations. Sample preparation involved benefication by grinding and flotation A modification of published procedures for rhenium analysis was developed and the results compared with those obtained for molybdenum on the same samples using atomic absorption spectroscopy. The results of the analysis for both metals is discussed and the relationships between rhenium and the molybdenum mineralisa- tion of this region is commented on. A metal- 1ngenic province is defined for molybdenum and r'.ienium and the tectonic setting for this is discussed. Some consideration has been given to rhenium possibilities in Fiordland and the Coromandel Range.

Jan 1, 1980

By M. R. Geer

THE increase in the number of coal-cleaning plants employing dense-medium processes occurring since 1946 is especially interesting when viewed historically. Both sand and magnetite were introduced as material for heavy mediums at about the same time, sand in the Chance process in 1921 and magnetite in the Conklin process in 1922, but from that point on their records diverge. The Chance process enjoyed a steady growth from its inception, whereas no additional magnetite plants were built in the United States for over 20 years. Then, following the close of the World War 11, magnetite was again introduced, this time with marked success. During the following years some 47 plants employing magnetite medium were built.

Jan 7, 1953

By D. T. Kinard, A. A. Schweizer

An operational 9 meter (30-foot) high gold heap leach pile was investigated by excavating test pits up to 6 meters (20 feet) deep, obtaining bulk and relatively undisturbed thin wall drive samples, and observing the ore distribution patterns exposed in the test pit walls. The clayey ore is crushed, agglomerated with lime and cement, and deposited on the leach pads using a radial stacker. Laboratory tests performed included moisture-density, gradation, compaction, Atterberg limits, permeability (constant and falling head), and triaxial strength tests. Discussion is presented on the effects of agglomeration on the permeability and strength characteristics of the in-place ore. Also discussed is the effect of deposition of the ore using the radial stacker.

Jan 1, 1987

By Yuta Yamamoto

Seafloor massive sulfides (SMS) which contain Au, Ag, Cu, Zn, and Pb have been interested in as a target of commercial mining these 15 years. Japan has large potential of SMS and a national R&D project for the mining has been active these 5 years. However, the economy of SMS mining is very bad, because the waste tailing disposal cost is very expensive in Japan. A slurry flushing method is experimentally examined in this study for the improvement of the economy. During the flushing, because of density difference between the metal-rich ore and the waste rock, a kind of gravity separation is possible. The results suggest a possibility of the actual application.

Sep 14, 2011

Cost reduction programs can focus on total cost or unit cost, but unit cost is usually the principal objective. The production cost per unit is: [Unit cost = Total cost Production volume] Consequently, any activity that reduces the total cost or increases the production volume will reduce the unit cost. Production volume is increased by (1) maximizing the availability of the production equipment and (2) maximizing equipment performance during periods of operation. Most operations managers routinely focus on volume because the factors influencing volume are generally well understood and congruent with the managers' technical skills. In fact, production volume (as a percentage of maximum achievable capacity) is widely recognized as one of the most significant measures of operational performance.

Jan 1, 1999

By M. E. Tyrrell

The purpose of the work leading to this report was two-fold: (1) To determine the properties of cemented tungsten carbide modified by the addition of one, two, and five percent of titanium diboride, and (2) to compare the properties of these mixtures when sintered, hot-pressed, and flash-welded (resistance-sintered). Minor additions of titanium diboride to mixtures of 94 percent WC and 6 percent Co decrease mechanical strength but increase oxidation resistance in proportion to the amount of the addition. One percent of titanium diboride increased the hardness by 2 Rockwell A units. Hot-pressing produced compacts with the highest density and the best mechanical strength, but losses of cobalt were high and grain growth was pronounced.

Jan 1, 1962

By Yusuf R

Many heap and dump leaching processes involve competitive, complementary and sequential reactions between multiple minerals and reagents. A comprehensive model has been developed to deal with these complex chemical interactions which is based on diffusion control of the reaction rates. All of the mineralogical and chemical data are obtained from representative samples of the ore or the chemical literature. These properties have been incorporated in a general way, making the model applicable to a range of ore-process systems. The simulation is used to predict the absolute reaction rates and can be used before any leach tests are carried out on the ore itself. The applicability of the model and some tests of its validity are presented.

Jan 1, 1984

By Mandzic E. H

The Dome Mine of Timmins Mining company is located in South Porcupine, N.W. Ontario. The orebody being mined partially lies in the No. 3 shaft pillar. Stability analysis has been carried out to establish the influence of nearby mining on ground movement in the shaft vicinity. Mathematical modelling of shaft displacement has been done for stope layout at depths from 180-210 m and distances of 10-50 m from the shaft. Analysis indicated that ground displacement around the shaft is below 1 mm/m and one third less for cut and fill than in the case of open stope mining. The result of the investigation was later confirmed by cut and fill mining of this orebody.

Jan 1, 1986

The Bendigo goldfield is centred on the urban area of Bendigo (population approximately 60 000) in central Victoria, 130 km north west of Melbourne, Australia. Gold was discovered at Bendigo in 1851 and production continued through to 1954. The Bendigo goldfield is the second largest goldfield in total gold produced in Australia, after KalgoorlieÆs Golden Mile with a total production of 22 million oz. The geology of the Bendigo Field consists of a series of tightly folded, interbedded sandstone and shale sediments. Within the sediments the gold mineralisation is hosted in quartz reefs or ribbons closely associated with anticline axes and reverse faulting. The gold within the quartz reefs is typically both coarse grained and erratically distributed.

Jan 1, 2002

This paper describes several sources of external dilution affecting the stope walls during underground sub-level and bench stoping. Factors which control ground behaviour such as the geometry of the openings, the influence of geological discontinuities, stress re-distribution and blasting practices are discussed. Crown stope instability due to stress concentrations induced by changes in the excavation geometry, is discussed and the most efficient ways to sequence blasting within a stope are analysed. Effects of undercutting by blasting, blast damage in the near field and cut-off slot blast designs are analysed. The influence of dynamic loading on the exposed walls as well as the practice of blasting fill passes within stope crowns are discussed.

Jan 1, 1995

By Tom Wynne

In order to shorten the time required and improve safety for a longwall face move, a 36-ft wide longwall recovery room was predriven. The room was supported with specialty bolts, trusses and concrete cribs. Rock mechanics instrumentation was implemented to evaluate the adequacy of the whole recovery system. This included instrumented roof bolts, entry convergence, load cells, and abutment stress in the surrounding pillars. This paper describes the methodology of support and instrumentation designs, and monitoring and evaluations. The results indicated that this method offers the safest and yet faster longwall recovery so far. But the rock mechanics monitoring also indicated some improvements are desirable in the truss system and concrete crib layout.

Jan 1, 1993

This Part is concerned with the theoretical study of UHF radio communication in coal mines, with particular reference to the rate of loss of signal strength along a tunnel, and from one tunnel to another around a corner. Of prime interest are the nature of the propagation mechanism and the prediction of the radio frequency which propagates with the smallest loss. Our theoretical results are compared with measurements made by Collins Radio Co. This work was conducted as part of the Pittsburgh Mining and Safety Research Center's investigation of new ways to reach and extend two-way communications to the key individuals that are highly mobile within the sections and haulage ways of coal mines.

Jan 1, 1974

By M. S. Raseroka

An experimental rig has been constructed to produce chloride stress corrosion cracks in Type 304L stainless steel tube samples. The samples are to be used to test possible in situ repair methods in future work. The factor which influences the time to failure most strongly is the sample temperature; the distribution of cracks within the sample is affected by local temperature variations and by the position of the water line. Low-frequency oscillations in stress, caused by the on-off temperature controller, did not appear to influence cracking in these tests.

Jan 1, 2009

On the following pages are abstracts of papers published by the Institute during the year 1934 as TECHNICAL PWLICATIONB, CONTRIBUTIONS, m bound volumes and in MINING AND METALLURGY. For abstracts of papers that appear In bound volumes in 1934 but that were published as TECHNICAL PWLICATIONS m 1932 or 1933, see the TRANSACTIONS for 1932 and the YEAR BOOK dated January, 1934. Many of the TECHNICAL PWLICATIONS have been reprinted In bound volumes Information regarding this disposition, and number of pages in each paper, may be found m the list beginning on page 92 Volume numbers are given as listed at the beginning of the index, page 99 The abstracts are grouped as follows:

Jan 1, 1935

This paper investigates the effects of solids concentration and the addition of Dispersant S40 on the flowability of original and ground limestone slurries. A rotational viscometer with a concentric cylinder geometry and a controlled-stress rheometer with a cone-and-plate geometry were used to characterize the rheological behaviors of limestone slurries. The rheological behavior of original limestone slurries (<100 µm) is transformed through different types of flows with increasing solids concentration. The use of Dispersant S40 can improve the slurry flowability by decreasing viscosity and eliminating Casson yield stress. It is therefore used as a grinding aid for the wet ultrafine grinding of limestone. The rheological behaviors of ground limestone slurries vary with grinding from a starting dilatant flow-ability to a resulting pseudoplastic one with an evident Casson yield stress in combination with a thixotropic character. The appearance of pseudoplastic flowability combining thixotropy is related to the fineness of a ground product and its specific surface area, which are both correlated to solids concentration and the additive amount of Dispersant S40. In addition, the accurate rheological characterization of time-dependent fluids is dependent on the instruments used and operation conditions.

Jan 1, 2007

A substantial proportion of current and historic West Coast gold production comes from deposits situated around the margins of æice ageÆ glaciers. Gold has been eroded and transported by glacial ice then deposited in till and outwash gravel. The interplay between fluvial and glacial processes, climate, basement geology, tectonic uplift, sediment supply and sea level dictates many aspects of the development of the West Coast landscape. The way in which the external forcing factors interact is crucial in determining the gold content of placer deposits in this region. The following is an outline of some of the factors that influence the gold distribution in vicinity of glacial margins.

Jan 1, 2000

By Llewellyn A. Rubin

Under Bureau of Mines Contract H0122007, Telcom, Inc., with the assistance of Fenix & Scisson, Inc., conducted a 17-month research and development project aimed at provid¬ing a field-test model of a guidance system for use with the Bureau of Mines Probe Drill. The Probe Drill is a part of the Bureau&apos;s Mine Rescue System developed under Contract H0101262. Volume I of this report is subdivided into seven sections. Volume II consists of a number of supporting appendices. In addition, there were delivered under the Contract, a number of other documents which are referenced in the text. Section 1 deals with essential contract information, Program Background, and a general system description. Section 2 covers the project chronology in brief. Section 3 is a digest of design considerations and implementation related to the requirements of the Contract. Section 4 is a description of the System, including illustrations of the hardware, and software. Section 5 is devoted to Operation and Maintenance. Para. 5.1 describes step-by-step field assembly and disassembly of the downhole unit. Para. 5.2 covers Operation. Para. 5.3 covers various aspects of maintenance from the lowest field echelon possible. Higher level maintenance must be accomplished in the laboratory, for the present field-test model. Para. 5.4 covers system calibration. Para. 5.5 covers detailed step-by-step operational sequences. Section 6 covers the results of the field testing, post-test evaluation, and recommendations. Essentially, we conclude that the present hardware (field-test model) has proven every aspect of system performance, but failed to provide reliable assurance of an operationally ready system. Telcom, therefore, recommends a three-phase continuing effort devised to provide the operationally-ready model of the system.

Jan 1, 1973