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By Se-joon Kim, Jong-hwa Chun

"‘Gas hydrate’ is the common term for a solid material formed from the combination of various gases as ‘guest’ and water as ‘host’. A series of large-scale scientific drilling and coring programmes conducted since 2000 revealed that natural gas hydrate exists in a wide variety of accumulations in the sediments. The scaled-up onshore and offshore field production tests during the last decade show that gas production technology will be realized to make gas production from gas hydrates viable in the future, recognizing its potentials as one of the future sustainable energy resources.The total produced gas was approximately 470 m3 by the hot water circulation method over 6 days of operation in the permafrost-associated Mallik 2002 project in the Mackenzie Delta of Canada. In the Mallik 2007-2008 project, the gas was successfully produced stably by the depressurization method for 6 days, up to 13,000 m3 cumulatively. The depressurization method applied in the Mallik test was shown to be an effective way to produce gas from gas hydrates. The Alaska field trial to inject mixed gas of CO2 and N2 to exchange CH4 in 2012 was successfully done for the first time to produce maximum 1,270 m3 per day. A remarkable achievement was made by Japan when it completed its first offshore production test in the Eastern Nankai Trough, producing approximately 120,000 m3 of methane by the depressurization method over 6 days in March 2013. The technical challenges and scientific uncertainties obtained from Nankai Trough production test provide Korea with more considerations as to the aspects of well completion, reservoir formation and seafloor stability, sand control, flow assurance, environmental monitoring, and etc., due to the different geological setting and geomechanical properties of the Ulleung Basin in Korea."

Sep 1, 2014

Some major mineral deposits in northern Australia are found in preconsolidation slump disturbances in the sediments.In the retransported marine sediments at Tennant Creek, breccia beds and disturbances are found which have localized later mineral deposits such as the Peko copper orebody. These disturbances are thought to result from slumping, turbidity flow and various types of "semi-fluidized" subaqueous slides intermediate between slumps and turbidity currents.Movements are found to ~ause widespread disturbances in the sediments such that subsequent mineralization can spread through a large volume of rock giving rise to orebodies greater than those localized by tectonic structures.A similarity is noted between the sedimentary disturbances at Tennant. Creek and those at Mount Isa and Mary Kathleerr. It is suggested that disturbed beds which are host rocks to ore minerals in these mines may also be due to movements of the sediments before compaction.Certain characteristics of the slumped rocks can be recognized and limited generalizations can be made about the shape, extent and habit of these host rocks and the orebodies they contain.INTRODUCTIONSubmarine slumping and· turbidity current retransport are almost entirely responsible for some types of deep marine sediments.However, little attention has yet been drawn to slump deposits and associated disturbances bedded in the sediments as features localizing later mineralization.A study. has been made by the writer of the slump and associated phenomena of the ,Tennant Creek field where many mineralized bodies, including some gold and copper orebodies, occur as replacements of coarse fragmental slump...

Jan 1, 1960

By Tom Meikle

Long tendon support systems provide several challenges when used in-cycle as part of the secondary or primary support cycle. A two-component pumpable resin, Carbothix, has been in development for use with self-drilling rock bolts, but many of the attributes of this new resin system make it ideal for grouting long tendon support systems. While neat Portland cement grouts or polyester resin capsules have been used with long tendon support systems for many years, two-component pumpable resin systems overcome many of the shortcomings in these systems. The two-component systems dramatically improve the set-time to enable mining face advance with fewer delays, enable longer pumping distances, improve quality control, and enhance load transfer mechanisms. This paper describes the key benefits associated with a new pumpable resin and details the Australian Department of Mines and Petroleum department atmospheric testing results and cable load testing completed by Minova personnel to date. It also details the results of the Australian mine site trials and the introduction of these systems into production use.

Jan 1, 2012

By Mohamed Yusuff

Modern transportation systems are one of the most important achievements of our civilization and provide us with tools for broadening individual and social freedom of choice. The transportation system initiated today is handed dawn to the next generation, probably with little choice because of the enormous expenditure of monies involved, and influence their way of life as to where they should live and where they should work. The ever increasing antagonism between the citizens and the planners of the transportation systems necessitates a careful review of the entire planning process. The planning process can be broadly classified into: the goal formulation and decision making process; the plan development process; and the plan implementation process. THE GOAL FORMULATION AND DECISION MAKING PROCESS Goal formulation and decision making is one of the vital phases of the planning process and is primarily based upon social values. In measuring social values, the planner must employ an appropriate scale of measurement since in the absence of this yardstick, these values tend to became vague and abstract ideals. The need for major social programs and concerns (poverty, etc.) of the urban areas should be analyzed to determine the type of transportation system which would contribute to the solution.

Jan 1, 1974

By Yue-yuan Li

China has abundant magnesite resource, but the low-grade and powder ores have always been rejected, which influences the comprehensive utilization of resource and often causes circumstance problems. The present work investigated the preparation of magnesia whisker using magnesite tailings as starting materials by preparation magnesium carbonate whisker as precursor firstly in the route of calcination, hydration, carbonation and pyrolysis, follows by second calcination of the precursor. The influence of pyrolysis conditions and additives on morphology of magnesium carbonate crystal as well as the influence of calcination conditions on morphology of magnesia whisker was investigated. The results showed that thermal decomposition products was MgCO3?3H2O. Magnesium carbonate whisker with length of 10~60 µm and the length-to-diameter ratio of 10~20 was prepared when soluble magnesium salt was added. While temperature was elevated at 1°C?min-1, magnesia whisker with length of 10~60µm was obtained.

Jan 1, 2010

By Greenwood J. N

This is the fourth paper in the series on Australian w,ar materials and the work was undertaken as part of the programme for producing hard carbides. It had been intended to determine the influence of tantalum and columbium' carbides in mixtures with tungsten carbide. Owing to other, urgent developments, it has not been possible to proceed with that programme.1. THE PROCESSING OF A TANTALITE ORE(a) The OreThe minerals in which tantalum and columbium most commonly occur are tantalite and columbite. These two minerals are the end members of an isomorphous series of tantalates and columbates of iron and manganese, but in nature the series grade into each other.Some of the best deposits of tantalum and columbium ores in the world occur in the north-west of Australia. Until recently tantalite low in columbium was the only mine~al in demand but discoveries of extended uses for columbium, e.g., addition of ferro-columbium to high chromium I steels inhibits intergranular corrosion (weld decay), have created a demand for columbite low in tantalum as weB. Both of these types of' ore occur in the Pilbara district in Western Australia and most of the ore mined is exported to America after a preliminary grinding and concentration by gravity.A sample from the Bynoe Harbour locality, west of Darwin, was used in this investigation. It consisted of coarse lumps of tantalite with quartz in minor amounts. Cassiterite w.as also present. A recent investigation!l) gave the analysis as:

Jan 1, 1943

By Lawrence S. Darken

STAFF: Editor, Gerhord Derge Cornegie Institute of Technology Schenley Pork Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: J. S. Smart, Jr., President; C. C. Long, Past-President; K. L. Fetters, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: C. L. McCabe, Chairman; H. L. Bishop, K. L. Fetters, J. J. Harwood, W. A. Krivsky, F. C. Longenberg, R. E. Lund, W. 0. Philbrook, L. L. Seigle, R. L. Smith, and F. L. Vogal. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: C. L. McCabe, Chairman; R. E. Lund, Vice-chairman; D. H. Baker, Jr., W. A. Krivsky, R. A. Lewis, Paul Qusneau, A. S. Russell, R, E. Shinkoskey, W. W. Stephens, and M. E. Wadsworth. Institute of Metals Division: L. L.Seigle, Chair-man, P. A. Back, J. J. Backer, l.l. Bessen, J. 0. Betterton, Jr., J. 8. Clark, R. S. Davis, A. E. Dwight, R. W. Fountain, R. B. Gordon, C. D. Graham, Jr., R. W. Guard, J. C. Gurland, E. L. Harmon, J. J. Hager, A. A. Hendrickson, M. Harmon, J. N. Hobstatter, H. H. Johnson, Jr., H. 5. Kolish, R. R. Nash, T. N. Rhodin, R. H. Richman, W. Rostokar, P. G. Shawmon, C. W. Spencer, L. Slifkin, J. K. Stanley, C. D. Starr, R. Steinitz, and H. C. Stumpf. Iron and Steel Division: H. L. Bishop, Chairman; 2. E. Boni, F. C. Langenberg, J. B. Wagstaff, and T. V. Wainwright. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription PetroleumEngineers,$30 per year for non-AIME members in United States and North, South, and Central America; 332, foreign; $5 for AlME members. Single copies, $4.00, single copies foreign, $5.00. The AlME is not responsible for any statement mode or opinion expressed in its publications . . . Copyright 1%1 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address; AIME New York ..Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts.. .Second class postage paid at New York, N. Y., and Ann Arbor, Mich. Volume 221, Number 4.

Jan 1, 1962

By D. Wolfe, K. Reid, T. Nunn

"The Aurora North mine has been operating for more than ten years, and is the source of over half of Syncrude’s bitumen production. In order to minimize front-end rejects, and to allow for high throughput, the ore top size at Aurora has been set at a nominal 125 mm. These relatively large lumps have a significant effect on both pump performance and pipeline pressure gradient. Current design methods underestimate the solids de-rating effect of lumpy slurries in pumps, and do not accurately describe the distribution or magnitude of the lump effect on pipeline pressure gradient. Data from the Aurora hydrotransport systems has been compiled, to quantify the effect of lumps on the pump head ratio and pipeline pressure gradient, and how this effect changes as lump ablation occurs along the length of the pipeline. A model has been built, using a logarithmic curve, which predicts the effect of 125 mm lumps on pipeline pressure gradient as a function of velocity and the distance from the start of a hydrotransport pipeline. This model is applicable only to Aurora hydrotransport operation, but similar models could be developed for other operations using the same methods. Using accurate pipeline pressure gradients and pump head ratios when designing future hydrotransport pipeline systems will help improve their reliability and operability."

Jan 1, 2014

By G. J. Hasenfus

This paper presents the results of an extensive hydrological and geomechanical monitoring program which Gas conducted at a longwall coal mine in W. Va. The field program included monitoring of groundwater levels. overburden hydraulic conductivity, overburden movement, and surface subsidence relative to the passage of the longwall. Overburden geology and rock strength characteristics were evaluated prior to mining. A postmining corehole was drilled to evaluate main roof fracturing. An overburden response model is proposed based on the correlations between hydrological and geomechanical data.

Jan 1, 1988

By Fulvio Tonon

And Rabcewicz said ?tunnels should be driven full face whenever possible.? ADECO, which stands for ?Analysis of Controlled Deformations in tunnels,? now allows us to fulfll Rabcewicz?s dream in any stress-strain condition. In order to achieve that dream and its consequent control over cost and schedule, however, NATM must be abandoned for the ADECO. The paper presents the basic concepts in the ADECO approach to design, construction and monitoring of tunnels together with some case histories, including: full face excavation for Cassia tunnel (width of 22 m, height of 14 m) in sands and silts under 5 m cover below an archeological area in Rome, Italy; Tartaguille tunnel (face area > 100 m2) advanced full face in highly swelling and squeezing ground under 100 m cover where NATM led to catastrophic failure, France; and 80 km of tunnels (face area > 100 m2) advanced full face in highly squeezing/swelling ground under 500 m cover for the high-speed railway line between Bologne and Florence, Italy (turnkey contract).

By Jackson R. Pressley, Bruce Vandenberg

The knowledge of how and when your explosives go off can help you make intelligent decisions regarding future application of explosives thus removing some of the black magic associated with blasting. The net result will be intelligently set-up shots with timing, explosive charges, and placement more accurately done. Lower operational costs can be achieved when the correct combinations are applied.

Jan 1, 1992

By Madgwick J. C

A novel, microaerobic, heterotrophic microbial leaching system for manganese dioxide is described. Mixed natural microflora were enriched by addition of sugars and crude plant nutrItIOnal supplements. Between 84 and 104 mg MnH was solubilized per gram sugar at I per cent (w/v) concentrations for fructose and galactose in the presence of 0.03 per cent w/v dried microalgae (a Chlamydomonas species). Some 42 per cent soluble manganese was dissolved by microbial action on MnO, (3 per cent (w/v) pulp density) using a 10 per cent (w/v) molasses growth substrate.

Jan 1, 1983

The greater part of this paper comprises the material used in a lecture delivered to the South Queensland Branch of the Australasian Institute of Mining and Metallurgy in September, 1949. It contains little in the way of original matter, its main purpose being to call attention to the need for research into the properties of Queensland coals and to indicate some of the lines such investigations might profitably follow.Since the lecture was given the Powell Duffryn (1949) 1 report, which has made an excellent start along these lines, has been printed. This report is, however, only a beginning, though a big one, and there is ample room for many years of work along similar lines.The paper is based largely on the work of de Jersey (1946, 1949)2,3,4,5 and Jones and de Jersey (1947)6, but these workers in turn owe a debt to the work of many British and American investigators, too many to enumerate. The subject is a very large one-to deal with it fully would require not a paper but a book; all the author can hope to do is to discuss very briefly some of the main lines of investigation and indicate some of their applications.The reason for selecting Queensland coals in particular is the widespread ignorance of the extent of the coal resources of that State and the almost complete ignorance, to within the last year, of the modern industrial purposes to...

Jan 1, 1950

By AIME

Burton J. Westman-Besides decreasing the diamond size, there appear to be two other approaches open to overcome excessive diamond loss and, more particularly, the rapid diamond polish that took place in this quartz-feldspar rock. First, however, a short discussion of the diamond characteristics should be made in order to discuss the situation more clearly. The West African diamonds which we can assume were used. for this drilling have two disadvantages when drilling hard, exceptionally fine-grained rocks. These are rapid polishing and, if .the bit isn't "drilled in" carefully, a tendency to damage, resulting in excessive diamond loss. The normal wear resistance of any diamond is inversely proportional to the compressive strength of the diamond, therefore only the highest grade, of diamonds free from insipient fractures should be employed. Using upwards of 90 diamonds per carat instead of the20 to 30 per carat not only decreases the total projected area of the cutting points but increases the stress per point which, in turn, causes greater depth of penetration into the rock. Considering this depth of penetration, therefore, suggests an approach other than increasing the, number of diamonds per carat and that is to decrease the actual number of diamond points (also the carat weight per bit) so that the penetrating force on an individual diamond is increased. This penetration increases the chipping or rock shearing action.

Jan 1, 1950

By P. W. Godbehere

"INTRODUCTIONMagnetic mill linings have been developed from an invention by Mr. Bertil Brandt, the originator of the Skega rubber lining. The OREBED magnetic mill lining is a concept in which rubber covered strontium ferrite permanent magnets are arranged on the inside wall of a mill shell so that they attract magnetically susceptible material be it ore, media or tramp, to form a protective layer over the magnets and to serve as an operating surface with indefinite life.Noranda Mines Ltd. through its associate Norcast Division of Noranda Metal Industries formed a joint venture with the inventors to market magnetic mill linings in North America. For the past twelve months trials have been undertaken in conjunction with Orebed Inc. to test and develop these linings for grinding mill applications at the Horne Concentrator. Two independent milling circuits are currently being operated, one treating a siliceous gold ore and the other a copper slag.This paper presents the results of the magnetic lining test programme to date."

Jan 1, 1983

By R. D. Pehlke, J. V. Gluck

AS a portion of a general study of liquid-metal thermodynamics, high-temperature galvanic cells were used to study the effect of added dilute solutes on the activity of zinc in dilute solution with molten bismuth in the range 450° to 650°C. 1,2 The cells were of the type The experimental procedures have been described previously.1 In the course of studies conducted in the bismuth-rich corner of the systems Bi-Zn-Au and Bi-Zn-Cu, marked discontinuities were observed in the electromotive force-temperature relations for a number of the experimental compositions. Above the discontinuity temperatures, the relations, which were linear, exhibited slopes similar to the binary alloy of the same mole fraction zinc, as shown in Figs. I and 2. Below the discontinuity temperatures, the slopes were markedly different, but the relations remained linear. In general, as the amount of the third eletnent was increased, the slope of the lower portion of the relations tended to become less positive. The slopes of electromotive force-temperature relations reflect the entropy of mixing of zinc and, therefore, the occurrence of a discontinuity marks the transition between two different equilibrium situations involving the solution of zinc. A number of other investigators3-5 have used such observations to determine liquidus boundaries in binary alloys. Since the upper portions of the ternary electromotive force-temperature relations of this study had the same slopes as the binary alloys, the discontinuities are interpreted as marking the transition between the single-phase liquid region and the underlying two- and three-phase regions. Reference to the Zn-Bi equilibrium diagram6 confirms that the binary alloys were single-phase liquids at the experimental temperatures. Fig. I shows the electromotive force-temperature relations for the alloys containing Bi-Zn-Au and Fig. 2 shows similar relations for the Bi-Zn-Cu alloys. In the lower portion of each figure, the temperature of the discontinuity is plotted vs the mole fraction of the added solute at the various levels of zinc concentra- tion. Cross-plots from these curves at constant temperature permitted the construction of the partial liquidus surface isotherms shown in Figs. 3 and 4.

Jan 1, 1967

This paper presents the results of a unique study conducted by the National Institute for Occupational Safety and Health (NIOSH) from 2016 to 2019 to evaluate the effects of longwall-induced subsurface deformations on shale gas well casing integrity and underground miner safety and health. At both deep and shallow cover instrumentation sites, surface subsidence measurements, subsurface in-place inclinometer measurements, and underground pillar pressure measurements were conducted as longwall panels were mined. Comparisons of the deep and shallow cover test site results with those from a similar study under medium cover reveal an interesting longwall-induced response scenario. Under shallow and medium covers, measured horizontal displacements within the abutment pillar are one order of magnitude higher than those measured under deep cover. Conversely, measured vertical compressions under deep cover are one order of magnitude higher than those under shallow and medium covers. However, FLAC3D simulations of the casings indicate that, in all three cases, the P-110 production casings remain intact under longwall-induced deformations and compressions, which has serious implications for future mine design in areas where shale gas wells have been drilled ahead of mining.

Jan 7, 2020

The compilation of the sampling nomogram is an essential tool in the optimization of a sampling protocol and allows the operator to track the change in relative variance of the sampling error (the Fundamental sampling error) during steps of comminution and mass reduction in the process of recovery of the aliquot for analysis. The data required for the compilation of the nomogram are centred on the sampling constant K and the exponent, alpha (a) of the nominal fragment size. Five methods for establishing K have been identified, but two of them, the duplicate sampling analysis method and the heterogeneity test method purport to provide such constant. The step by step procedure for each of these two methods was examined using broken ores from three mines, Mponeng mine, Kloof mine, and Lily mine. Two of these mines (Mponeng and Kloof) are typical Witwatersrand-type gold mines, and the third is an Archaean-type shear related gold deposit situated in the Barberton Greenstone belt. The results suggest that the factor K derived using the heterogeneity test is very accurate, but applies only to a single size fraction in the spectrum of comminuted materials. The calculation of gold grain sizes using this method appear to be too small and do not conform with the results from detailed mineralogical studies. The factors K and alpha derived using the duplicate series analysis are appropriate for use across a wide spectrum of comminution sizes and also provide realistic gold grain sizes, comparable with the equivalent circular diameter of gold grains identified in mineralogical studies of the ores.

Jan 1, 2010

By M Stevens, M P. Simpson, J L. Mauk

The Karangahake deposit was the second largest producer of gold-silver bullion in the Hauraki Goldfield, New Zealand. New mapping of a 2 + 3 km (6 km2) area demonstrates that hydrothermal alteration surrounds productive veins. Wallrocks proximal to veins are intensely altered and alteration decreases toward the margin of the system.   At Karangahake, distinct zonation of adularia, calcite, epidote, illite and illite-smectite surrounds gold-bearing lodes with unaltered rocks containing magnetite and plagioclase occurring on the margins. Adularia, illite, illite-smectite, and calcite zonation defines hydrothermal alteration extending 2 km to the east of productive lodes. Epidote and adularia zonation occurs proximal to veins. The adularia zone compares well to potassium/thorium studies conducted in the area. Illite zonation is well developed to the east of the veins grading into interstratified illite-smectite containing 5 to 40 per cent smectite 1.5 km from the Maria Lode. Calcite is restricted to the east of the study area occurring in 18 per cent off surface samples. Less altered rocks containing plagioclase and magnetite occur distal to veins. The magnetite occurrence compares well to aeromagnetic studies conducted in the area.   Adularia and coexisting adularia and albite indicate the host rocks were highly permeable. Epidote, illite, illite-smectite and previous fluid inclusion evidence implies temperatures graded from >240¦C in the core of the system to approximately 150¦C on the periphery. The alteration association of quartz, adularia, calcite, pyrite, chlorite, illite and illite-smectite reflects a near-neutral to weakly alkaline water. Calcite occurrence and the absence of zeolite imply the fluid contained significant dissolved CO2.

Jan 1, 2005

By D. M. Mubita

Dilution reduction is one of the areas that offer metal mines an opportunity to increase revenue and reduce costs, resulting in enhanced profits. Effective dilution control programmes require interaction on a multi-disciplinary level. This paper outlines recent initiatives undertaken at Konkola Mine to reduce dilution and increase revenue. The increase in revenue arising from reduced dilution and high factors between in situ and delivered to mill grades were quantified and amount to close to U$ 1.0 million per one per cent improvement in grade factor at a 75c/lb copper price. Sources of dilution from open and in?stope mining methods practised at the mine were identified and a multi-disciplinary dilution control forum set up to control these. Among the major achievements were the introduction of low dilution in-stope mining methods; the introduction of Gemcom geological and mining planning software to replace traditional pencil and paper methods, leading to better in situ estimation and production planning; enhanced control in open stopes through dilution awareness among mining production personnel; location of critical secondary development ends in correct positions; enhanced blast hole control; tracking of development waste by metal tracers and monthly tally; implementation of a cavity monitoring system to check over-breaks in open stopes; and setting up of a stope history database. The results from the cavity monitoring system showed that stopes with over-breaks of 5 metres or less could be controlled to break along the hangingwall contact.

Jan 1, 2005