Search Documents

By D. A. Greenwood

Dr David Greenwood opened the first technical session of the conference by highlighting the diverse nature of the papers in this session but drawing attention to the common theme that each solved a particular problem. PAPER 1.1 Tony Elliott introduced his paper on deep mix-in-place soil/cement stabilisation by stressing its simplicity. The engineering solution adopted at Elland was detailed in his paper and had formed the key to success of the project. The process itself is not widely used or known in the UK, although it has the potential to achieve significant benefits, subject to proper engineering control being exercised. It was explained that although the concept was not new, development of the technique for soil modification was relatively recent. The alternatives to mechanical mixing are injection, which is very dependent on soil type, site geometry, etc, and jet grouting; both processes are soil-responsive, and not easily monitored or programmed, difficulties which can largely be overcome by mixing. To achieve this at depths to say 30m requires high-powered, high torque machines and has resulted in significant equipment development.

Jan 1, 1991

By A Jewbali, J Phillips, C Boyle

Normal practice in the mining industry is the creation of a single geological model. These models provide a single interpretation of the geological and mineralisation domains. These interpretations infer the exact behaviour of ore domain contacts at shorter scales when resource definition drilling is done on wider scales and are thus locally highly uncertain. The interpreted geological model provides a single number for the volume and tonnes of mineralised material enclosed by the mineralisation envelope. It is on this single number for volume and tonnage that capital intensive mine development decisions (mine design and scheduling, stockpile strategy, waste management, closure planning, dewatering strategy, product quality, etc) are based. Some of these decisions require knowledge of grade variability for small volumes of material such as quarterly production periods. It is generally recognised that this information cannot be derived from single kriged geological models, but can potentially be modelled by conditional simulation techniques. Uncertainty in the extent and continuity of the mineralised envelope and its effect on grade variability for shorter production periods is thus recognised as a major source of uncertainty in new mine development.CITATION:Jewbali, A, Boyle, C and Phillips, J, 2013. Quantifying domain uncertainty for an iron ore deposit, in Proceedings Iron Ore 2013 , pp 157-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By M R. Stevens

The Kauri Block (Hauraki Hill) andMatawai Valley epithermal vein systems, near Coromandel township, are hosted by hydrothermally altered Miocene andesites and Mesozoic greywackes of the Coromandel VolcanicZone. The hydrological setting of both geothermal systems was probably that of an andesitic volcanic arc. Two types of veins are recognised: 1. Simple veins composed of fine comb quartz, and 2. Complex (breccia) veins composed of vein fragments of sulphide-bearing, chalcedonic silica cemented by saccharoidal and fine comb quartz.   Pyrite, arsenopyrite, marcasite, and gold form the ore minerals. Both deposits historically exploited hypogene and supergene bonanza gold.   At Hauraki Hill, breccia veins up to 7m wide contain abundant fragments of recrystallised colloform banded-crustiform textured quartz veins ('Golden Cross' style) and were probably major channels for ascending deep mineralising fluids. Alteration assemblages are zoned with the higher elevations of Hauraki Hill-Bunkers Hill characterised by strong kaolinite alteration whereas deeper levels are dominated by illitic clays.   At Matawai, complex veins and hydrothermal breccias pinch and swell, and inflect, within a total width of veining and alteration that exceeds 50 m. The greywacke host rocks are altered to an assemblage of illitesmectite, quartz, chlorite and pyrite although there are pockets of kaolinite.   The proposed genesis of veins and ores in both deposits invokes episodic rapid mixing (quenching) of hot mineralising reservoir fluids with cool acid condensate waters, whilst acidification and increased fO2 triggered gold deposition. These hydrothermal systems heated up during their later stages and at Matawai visible gold was deposited from a late mesothermal stage. The main conclusion is that the northwest CVZ has excellent potential for large gold deposits (= 30 tonnes contained gold).

Jan 1, 1993

By P. Falcão Neves

A detailed analysis of the geomechanical behaviour in rock cutting with a diamond saw is provided to obtain a better understanding of the mechanisms involved in the process. The energy of elastic deformation (before failure) and plastic deformation (post failure) was determined in uniaxial compression tests as well as the energy consumed per unit volume in the cutting process. The test samples are White and Ruivina marbles from Borba - Vila Viçosa in Portugal. Correlations between total deformation specific energy and cutting specific energy, normal and tangential forces and diamond indentation are analysed, and some conclusions are presented.

Jan 1, 2012

By L. B. Davidson

The petroleum literature contains many reports on the relative permeability properties of porous media. However, only recently have studies of relative permeability at elevated temperatures been made.1 -5 Each of these studies presents relative permeability data on water-oil systems in linear sandpacks or sandstone cores under isothermal conditions. The results of these investigations are dissimilar. Edmondsonl found that in Berea sandstone a temperature-dependent effect was present, while Shilobod,2 using the same material, found no temperature dependence after normalizing for initial water saturation. Workers at Texas A&M U.3-5 found that the ratio kw/ko was temperature dependent in an unconsolidated system. The differences in results of these studies are probably a consequence of differences in the material employed, in the experimental procedures followed, and in the properties of the porous systems used. This paper describes an experimental investigation of permeability ratio temperature dependence, conducted to clarify some of the results obtained by previous workers. Each experiment described in this paper involved the isothermal displacement of Chevron No. 15 white oil by either nitrogen, steam, or distilled water and displacement of water by nitrogen. All permeability ratios were calculated using the Welge procedure. Values of the water-oil permeability ratio were obtained over the temperature range 75OF to 540°F. Results indicate the ratio is temperature dependent at low water saturations, probably due to interfacial effects. However, as the saturation is increased, temperature dependence decreases until, above some minimum saturation, the ratio becomes insensitive to temperature. Previously published work indicates that the dependence reappears at very high water saturations, a region of the ratio curve not completely examined in the present study. It appears that water-oil permeability ratios are temperature dependent at the extremes of the ratio curve where changes in interfacial tension with temperature induce variations in residual saturations. Between the extremes, there is a region in which the permeability ratio is insensitive to temperature. The size and location of this region is probably a function of the characteristics of the porous system. Gas-oil permeability ratios calculated from nitrogen-white oil displacement experiments indicate a definite temperature dependence over the range 75OF to 500°F and over the entire gas saturation range studied. Evidence discussed in this report indicates that this dependence is a consequence of molecular slippage in the gas phase. This is an extension of the Klinkenberg effect6 to two-phase systems at high temperatures (the existence of slippage in two-phase systems at room temperature has been demonstrated7). Evidence for a similar source of temperature dependence in superheated steam-white oil experiments

Jan 1, 1970

By Y X. Xue, J Pan, D Q. Zhu

In order to reveal the correlation between the fundamental sintering characteristics of iron ores and their real sintering behaviours, a comprehensive evaluation index is proposed based on the measurement of four high temperature indexes, ie assimilation temperature, liquid phase bonding strength, liquid fluidity and calcium ferrite formation percentage, and the sintering pot tests of single ore fines and their blends. The results show that both the lowest assimilation temperature and liquid fluidity of ore blends appear to be the linear superposition of those of single iron ores except for the liquid phase bonding strength and calcium ferrite formation percentage. Furthermore, the tumble index of the sinter product obtained from blended iron ores also corresponds to a linear superposition of that of single ores, but not for the solid fuel rate and productivity. The comprehensive strength index YT exhibits a credible linear positive correlation with the four high temperature reactivity indexes, whereas the comprehensive productivity index YP possesses a lower correlation with the four high temperature reactivity indexes. The comprehensive strength index YT developed can predict the tumble index of the sinter product quite well, but the comprehensive productivity index YP cannot be used to evaluate the productivity effectively.CITATION:Zhu, D Q, Xue, Y X, Pan, J and Shi, B J, 2017. Correlation between high temperature sintering characteristics and sintering behaviours of iron ore fines, in Proceedings Iron Ore 2017, pp 123–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

During the past decade, the miner-al industries have been faced with an increasing shortage of engineers. The point has now been reached where the shortage may be termed critical. This shortage may be attributed directly to declining enrollment in the mineral science programs offered by the universities on this continent. Although the reasons for declining enrollment are undoubtedly many, two major hypotheses may be postulated. The first is that high-school graduates are either unaware of the mineral industries and the opportunities in them or that they are aware of them but have somehow obtained a false image of their true nature. The second is that they are aware of the true nature of these industries and the opportunities they offer but find them exceedingly unattractive. The problem of dwindling enrollments has, in recent years, been subjected to a concerted attack by the industries and professions concerned. However, their efforts to date have been based essentially on the first hypothesis. Sufficient results are now available to suggest that either the methods of attack are inappropriate

Jan 1, 1965

By Tapio Leskinen

"l. IntroductionA reliable sampling system is the basis for an on-stream analyzer. This was realized in Outokumpu company when the development work of the Courier 300 On-Stream X-ray analysis system was started. Because Outokumpu Oy is a mining and mineral processing company, its engineers have been able to thoroughly test sampler prototypes in actual operating situations. The sampler development has been going for several years in close co-operation between company's concentrators, the Institute of Physics and the Instrument Division of Outokumpu Oy. The most active part of the work was done between 1969- 1972. Besides the reliable operation of a sampler special attention was paid to the representatively of the samples taken by the samplers. 2. The Courier 300 Sampling SystemThe sampling system comprises up to fourteen sampling circuits in one Courier analysis system. Each circuit consists of the following components:1. Primary sampler 2. Secondary sampler 3. Cleaner screen 4. Feeding tank5. Sample cell6. Timer-controlled sampler7. Pumps, sumps and pipesSecondary samplers, cleaner screen and feeding tanks are included in the secondary sct1npling system. The sample cells are located in the spectrometer cabinet of the analyzer."

Jan 1, 1976

By Jürg Schlumpf

Concrete is one of the decisive construction materials, also for the AlpTransit Gotthard Tunnel. The client has many requirements, and many are the solution possibilities that concrete systems can offer. Cement producers and concrete admixture manufacturers have been challenged to design and test jointly concrete systems for cast and sprayed concrete. The testing operation followed the scenario laid out by the Gotthard AlpTransit Project management?s instructions ?Testing system for concrete mixes.? Various supplier teams have applied for the concrete systems for sections Amsteg/Erstfeld, section Sedrun and/or sections Bodio/Faido and have also followed through with the tests. As was to be expected, the rate of failed mixes matched the level of the requirements. Thanks to this system, it was nevertheless possible to test complete concrete systems for all sections and to get them approved. The joint ventures tendering for the contracts were allowed to include only approved mix designs in their bids. Workability and durability are of paramount importance for cast and sprayed concrete mixes. Durability is influenced by the chosen mix design where binder concept and well-defined water content, i.e., impermeability, are determinant. Aggregates for AlpTransit are to be considered as given. The concrete mix design also determines workability. Because ambient conditions and also requirements with respect to workability are subjected to change, it is necessary that the mix designs include control measures. The choice and number of components for the concrete systems (cement, additives and admixtures) allow adaptation to changing conditions. For AlpTransit such adaptive measures must meet very strict requirements.

Jan 1, 2008

By Randy R. Huberty

Although originally designed with deep foundations consisting of all driven steel H piles and drilled caissons, a unique application of Augered Cast-in-Place (ACIP) piles as an alternate design resulted in a significant cost savings for the Midfield Terminal Project at the Pittsburgh International Airport. The project was enormous in scope covering an area two miles long by one mile wide, with changes in elevation of over 200 ft. The varying geology combined with the large amounts of fill required resulted in a complex set of geotechnical design parameters that had to be evaluated through both load testing and analyses. A total of almost 400,000 lineal feet of ACIP piles were installed for this project.

Jan 1, 2001

By P. Schmieder

"The close vicinity of mining companies to other sites that are used for commercial and residential purposes or to areas under conservation as well as the fact that the people become more and more sensitive to emissions have led to a negative attitude towards mining operations in the neighborhood. It is above all the use of drilling and blasting techniques that give rise to objections, in the course of which demands for more environmentally-friendly production methods have been voiced. It is in this context that production methods without the use of explosives are considered as an option. After all, the use of such production methods is the only alternative for some quarry operators. The question is what are the true benefits of these techniques and what is the relation between a possible improvement of the environmental effects on the one hand and the technological potential as well as the costs on the other. It is intended to assess the mining techniques for solid rock in their entirety. This paper will therefore look at the aspects for assessing mining techniques in the context of their environmental impact and the costs."

Jan 1, 2005

De Beers? Finsch diamond mine began operation in the 1960s as a surface project using the latest technology available. During the 1990s, the operation, located about 160 km (100 miles) west of Kimberley, South Africa, began its move as an underground mine. The earlier stages (Blocks 1, 2 and 3) of underground work at Finsch used open stope mining methods, also using the latest in technology. The mine began developing Block 4 in 2004. How-ever, studies on this level showed that block caving was a more efficient mining method than open stoping. It was during those studies that De Beers determined that Block 4 would be a good candidate for testing Sandvik?s automated truck haulage technology.

Jan 1, 2008

The income of the Institute is derived mainly from dues, advertising in MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization.

Jan 1, 1939

THE old mill erected by the .Irvinebank Company consisted of 10 heads of stamps (850 lb.), rock-breaker, Hartz jig, two Krupp tables, two Luhrig vanners, three sand-pumps, one mixer; six flotation vessels, and the necessary settlers. Power was supplied by a small colonial-type boiler, and 10-in. x 15-in Tangye engines. The ore was darted from the mines to the mill and hand-fed, into the rock-breaker, and the broken product elevated into the batter bins and fed into the stamps, the pulp from the stamps passing to a classifier, the spigot to jig, tables, and vanners, the overflow from the classifier passing to settlers. After the removal of bismuth-wolfram concentrates, the pulp was pumped to the molybdenite flotation plant and the olybdenite recovered by flotation.A commencement was made with the erection of the first unit (20 heads) of the new mill in August, 1917, and milling and concentrating commenced in February, 1919.

Jan 1, 1920

By Jia-Shyan Shiau, Chung-Ken Ho

An uneven gas distribution through the burden layers inside a blast furnace (BF) results in abnormal gas resistance or pressure changes. Rapid variations in the abnormal gas resistance will lead to the occurrence of channeling. A visualization technology mainly made of pressure distribution was developed to predict BF channeling phenomena in this study. The real-time data of BF shaft pressure was used to create a 3D visual model by neural network algorithms and 3D real-time BF pressure changes were observed. The root mean square deviation (RMSD) of the BF shaft pressure was used as an index to set up the predicting criteria of channeling occurrence with the opening of BF Annular Gap Element (AGE), and a predicting system based on the criteria was built. The two criteria for the channeling alarm are the RMSD of the BF shaft pressure (> 0.15 kg/cm2 ) at the upper two levels, and the AGE opening being greater than 60%. This system has been installed in the China Steel Corporation (CSC) BFs, and the test results showed that a prediction can be obtained 8 to 16 min ahead of channeling allowing sufficient time for the operator to adjust the BF operation in order to avoid the occurrence of channeling.

By Robert W. Bergwall

The $58,000,000.00 Columbia Heights Metro Station project (Section E3-a) forms a part of the Washington Metropolitan Area Transit Authority's (WMATA) Greenbelt Route - Green Line subway system. The Greenbelt route is one often segments that make up WMATA's subway system. Construction of the "cut and cover" reinforced concrete station includes 600 linear feet of an underground center platform, two ancillary service areas totaling 466 linear feet, two surface entrances, and vent shafts (See Figure No. 1). Station subgrade is approximately 60 feet below existing grade. The project can be divided into five main areas: 1. North Service Rooms and Passageway; 2. West Entrance and West Passageway; 3. East Entrance; 4. Center Platform; 5. South Service Rooms. Station dimensions are approximately 1068 feet long by 64 feet wide. Construction commenced at the site in January of 1995 and is expected to be completed by December of 1999. Franki Northwest Company, Crofton, Maryland, was awarded a subcontract by general contractor Blake Construction Company, Washington, D.C, to install the support of excavation and temporary decking systems. Franki's scope of work included the installation of 490 drilled soldier piles plus two elevator shafts totaling 29,700 linear feet of drilling; 1,150 tons of steel decking covered by 37,000. square feet of precast concrete deck planks; 120,000. square feet of timber lagging; 2,500. tons of struts and wales; and temporary support of underground utilities. In conjunction with Franki's work, Bencor Corporation of America, Dallas, Texas, constructed parallel, 600 foot long slurry walls which serve as permanent walls for the center platform portion of the station.

Jan 1, 1997

Undisturbed minor sedimentary structures-cross-bedding, ripplemarking, scour-and-fill, slumping-are present in most of the rock types in the Willyama Series of the Broken Hill district and in the orebodies.This indicates that there has not been any significant movement of mineral matter within or into the rocks during or after metamorphism, that the rocks have not flowed during tectonic deformation or during metamorphism, and that the ore is an original sedimentary deposit in its sedimentary position.Sedimentary processes, depositional and mechanical, are indicated to explain the deposition of sedimentary metallic minerals and their concentration into large masses. The Broken Hill orebodies show evidence of these processes.INTRODUCTIONI visited Broken Hill for one week in May, 1958, at the invitation of Mr. Haddon F. King, Director of Consolidated Zinc Pty. Ltd. He asked me to examine the rocks and orebodies in the mines and outcrops at Broken Hill for:1. Sedimentary structures that might be used to determine the facing of the banding;2. Indications of the original nature of the rocks if I considered they may have been sedimentary; and3. Indications of any possible sedimentary origin for the ores.It has been stated (Gustafson et al., 1952, p. 30) that there was no indication, in the banding, of the facing of the banding, but recently B. P. Thomson had found examples of what he had interpreted as graded bedding (personal...

Jan 1, 1959

When perusing articles which treat of mining geology, and when talking with miners on the field, one is at times unable to follow the exact thoughts intended to be expressed, owing to the introduction of occasional technical words, the meanings of which are not thoroughly understood either by the speaker or by the hearer, or possibly by both and laymen at times accuse their technical brethren of attempting to confuse them by employing unusual words in their conversations and writings. Technical words are necessary adjuncts to all arts and sciences. They creep into our language, frequently unnoticed by those who employ them, as being more concise and convenient than longer sentences to explain frequently recurring expressions. In many cases these words give the finest shades of meaning, such as aglomerate and congzomerate, but in others they are extremely ambiguous, for instance black sand, which in some places means ilmenite, in others, chromite, tourmaline, cassiterite, in fact, any black mineral occurring in the form of sand. Then, again, much confusion is cansed by the same rock or mineral having different names, e.g, jlu01'spa'i', which is known as cand, cann, cauk, kawk, blue-John, Derbyshire spar, &c. The multiplicity of local names is of course chiefly found among the more common minerals, which are widely distributed some people have a propensity for using words the meanings of which they understand as little as' they do how to pronounce them. We have heard such persons speak 'of vughs as "bugs," and oxides as "ox hides," and to show that there was no mistake in their intentions, we have seen these and other words written in the same way as they were pronounced. Then, again, some persons, relying more on examples than definitions, get a very vague idea as to what the true meaning of a term may be the word dimite is an example in point, which we have frequently heard applied to any dyke rock that the miner was unable to recognise as granite in fact, he uses the word in a general sense, just as the field geologist provisionally employs the word " greenstone " for certain rocks, until he has an opportunity of thoroughly investigating their character.

By F Gervilla, J Laukkanen

The Kevitsa Ni-Cu-PGE deposit in northern Finland contains disseminated Ni-Cu-Fe sulfides, and platinum-group minerals (PGM). The 2.05 Ga-old ultramafic-mafic, funnel-shaped intrusion is intruded into a volcanosedimentary sequence. The major ore minerals are pentlandite, hexagonal pyrrhotite and troilite, chalcopyrite, cubanite and magnetite. Pyrrhotite and pentlandite are replaced by pyrite, millerite and heazelwoodite near the surface. Nickeline, maucherite and gersdorffite are locally abundant. A pilot feed sample of 575 t of the main orebody at Kevitsa had average grades 0.45 per cent Cu, 0.36 per cent Ni, 1.85 per cent S, 0.33 g/t Pt, 0.34 g/t Pd and 0.19 g/t Au, with 0.06 per cent Ni contained in silicates. Higher PGE contents (2 - 27 ppm) occur in a vertical N-S bearing fault zone. The PGM (n = 6022) mapped in specimens of four drill holes, consist of sperrylite 34.7 vol per cent, braggite and cooperite 18.5 vol per cent, geversite 17.2 vol per cent, moncheite 14.7 vol per cent, merenskyite 6.7 vol per cent, stibiopalladinite 4.3 vol per cent, sobolevskite 1.9 vol per cent, kotulskite 0.7 vol per cent, michenerite 0.6 vol per cent, keithconnite 0.3 vol per cent, rustenburgite 0.1 vol per cent, melonite, froodite, laurite together 0.1 vol per cent and only a few grains of sudburyite, irarsite, vysotskite, erlichmanite, hongishiite, Pt-Cu-alloys, three undefined Pd and Pt bismuthinides and antimonides and a Pd-Cu-bearing Pt-Ni-Fe sulfide. Most of the PGM, 62 per cent, are enclosed in silicates, 29 per cent are intergrown with sulfides, nine per cent are within sulfides. A portion of the PGE occurs in solid solution in sulfides and arsenides. Ni flotation yielded smelter-grade concentrates averaging 12.2 per cent nickel. The average sulfide Ni recovery is 78.8 per cent and total Ni recovery is 65.3 per cent. The average Pt is 10 g/t at 55 per cent recovery, Pd 7.7 g/t at 38 per cent recovery and Au 1.6 g/t at ten per cent recovery. Cu concentrates averaged 28.6 per cent Cu with an average recovery of 78 per cent and further 11 per cent in the nickel concentrate. The copper concentrate contains 4 g/t Au at 24 per cent recovery. The average Fe to MgO ratio 17.9 is well above the targeted minimum of 4.5. The pilot results show that the previously used TETA (triethylene tetramine) can be avoided and good quality, smelter-grade concentrates can be produced from the Kevitsa ore at economical levels of recovery by conventional flotation methods.

Jan 1, 2008

By F. Castelli

A simplified non-linear method to predict the behaviour of a single pile and/or pile group under horizontal loads is presented in the paper. The evaluation of the non-linear lateral deflection is based on a procedure taking into account the decrease of the model stiffness with the increasing of the applied load. The solution derived firstly for the single pile, was extended to the case of a pile group introducing the p-multiplier (fm) concept proposed by Brown et al. (1988).

Jan 1, 2006