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By E. McCullough, D. Preece, M. Ortel

Geophysical explosive charges are used in mineral resource exploration. They are detonated subsurface and radiate sonic waves into ground monitors, which detect the vibration waves and their interaction with underlying geologic strata. Geophysicists perform computer analyses of the waves reflected from the strata to determine their depth and thickness (Strobel, Berger & Schaefer, 2012). The purpose of this research is to determine how the detonating explosive charge interacts with the adjacent ground and how the induced waves propagate through the surrounding medium. Furthermore, it is necessary to optimize the location of the initiation point within the charge. Establishing both the direction and intensity of the waves will allow geoscientists to refine and optimize geophysical studies that employ explosive charges.

Jan 1, 2013

By Hemingway P, Boag J

Major operating aspects of the Mary Kathleen Uranium Ltd. treatment plant are discussed with partkular reference to those which are peculiar to this operation.Problems associated with the production of a penalty free uranium oxide product are examined and the methods developed to overcome them are described in detail.INTRODUCTIONMary K,athleen Uranium Ltd. is the largest of the Australian uranium producers. The flow-sheet is based on fine grinding, standard sulphuric acid leach, ion exchange concentration, and magnesia precipitation of the final product, with certain modifications introduced as the result of pilot plant investigations at the South Australian Department of Mines Research Laboratories in Adelaide.The plant commenced operations in June, 1958, attained design tonnlige of 1,120 tons per day in September of that year and has since operated continuously with a throughput in excess of 1,000 tons per day. Pilot plant recommendations generally have been followed, and predicted results have been attained. The only exception has been the silica and rare earth content of the product produced during the early months of operation. Considerable modification of the early resin regeneration techniques resulted in the reduction of the silica content of the product to within specification limits. Research work in the ion exchange section has also resulted in the reduction of the rare earth content of the product to below specification levels. All product now being produced is completely within the agreed specification limits of impurities.

Jan 1, 1961

By Gorr W. W., Wyche E. H, R. Smith

The combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W‡ and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. Development of the New Steel For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, 0.58; Ni, 7.28; Cr, 17.60; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1947

By J. N. Van der Merwe, M. Mathey

"The South African squat coal pillar strength formula, developed by researchers from the Chamber of Mines Research Organization in the 1980s, predicts an exponential increase in coal pillar strength once a critical width-to-height ratio of 5 is exceeded. The arguments that have been proposed in favour of this formula are discussed critically in this paper.Field experience with squat pillars in the USA and evidence from published physical, analytical, and numerical model pillar studies corroborate the fact that a squat effect is unlikely to occur in coal pillars at width-to-height ratios less than 10. Furthermore, an exponential increase in peak strength of coal pillars does not exist. An alternative design criterion for squat pillars in South Africa is therefore suggested. IntroductionFive decades of coal pillar research in South Africa have produced a wealth of information on the mechanisms contributing to the strength and failure of in-situ coal pillars and accompanying phenomena. The relevant knowledge was sourced from, and for, a South African coal mining environment that remained largely unchanged in the second half of the 20th century. The depth of mining seldom exceeded 250 m, with mined seam thicknesses averaging 3 m and typical pillar width-to-height ratios (w/h) of 3–4.It is therefore not surprising that comparatively little research has been directed at the prediction of coal pillar performance in deeper deposits, where squat pillars of larger width-to-height ratios will be required to support the overlying strata. However, a thorough understanding of squat pillar performance will be necessary should the remaining deep coal deposits of the country be extracted in future, for instance in the Waterberg or Ermelo coalfields.A squat coal pillar strength formula has already been proposed in South Africa. The origin of this formula will be discussed in some detail in the following sections and its appropriateness will be critically reviewed against a great amount of evidence from relevant squat coal pillar research conducted internationally."

Jan 1, 2016

By D. J. Goodings, R. J. Bonenberger, H. U. Leiste, W. L. Foumey

This paper describes a series of two-dimensional tests conducted and filmed with a high-speed (500 frames per second) video camera. The purpose of these tests was to provide a better understanding of the processes involved in creating craters and channels in water covered soils with explosives.

Jan 1, 2000

By Ádria Rocha Corrêa

Durante a solidificação de ligas metálicas, o produto fundido se contrai, o qual provoca o surgimento de espaçamentos vazios na interface metal/molde chamados de “gaps”. Estes gaps causam o aumento da resistência térmica influenciando em toda a cinética da solidificação. A transferência de calor durante a solidificação depende do conhecido parâmetro chamado de coeficiente global de transferência de calor ( hg). Este parâmetro é representado pela equação do tipo: hg =C.t-n, a qual indica que a eficiência térmica na interface metal/molde decai com o tempo. Muitos parâmetros podem influenciar o coeficiente global de transferência de calor (hg), neste estudo, os percentuais de Sn em ligas do sistema Al-Sn são analisados (10,20,30 e 40%Sn). Portanto, o principal objetivo deste estudo é propor uma relação matemática que descreva, para o sistema Al-Sn, a evolução hg em função do teor de Sn. A relação matemática foi obtida através do método dos mínimos quadrados

Aug 17, 2017

By Christian Wawrzyniak

An analysis method for modeling compensation grouting based on the finite element method is presented. By this method the design parameters of compensation grouting, grouting pressure and grouting volume, can be evaluated. Also the subsidence of a building due to tunnel driving as well as the lifting of the building by compensation grouting can be simulated. The stress changes in the tunnel lining and in the foundation of the building are computed as well. The application of the analysis method is demonstrated on two examples for compensation grouting in combination with construction of tunnels.

The distribution of tin and iron between slag and metal phases at about 1150°C was studied in pot scale experiments. The distribution coefficient k = (Sn/Fe) In metal X (Fe/Sn) in slag was found to vary from about 300 for metal corresponding to nearly pure tin, to about 100 for metal of about miscibility gap composition (17' 4 per cent Fe). Results conformed reasonably well to a straight line relationship between log k and (l-2NFe), as expected on theoretical grounds, and are consistent with thermodynamic data for the Fe-Sn phase diagram and the reaction Fe + SnO = FeO + Sn.Calculations are presented indicating the feasibility of smelting low-grade tin concentrates in a two-stage counter-current reduction process.

Jan 1, 1966

By J. R. Kyte, L. A. Rapoport

The material balance equation for partiai or complete 1:trter-drivc reser1,oir.s been re-arranged to include a pressure irrferferencr ternr. This pressure interfernce term was ohtained from the theory established hy Morinda. A .successful progranl deissed to solve the resrclritlg c,qrration in a few hours on a nleelitr .sizeti, digital compuier. No prior knowdelge of the properties of the eqrrifer is required in the solution. 7' ri~rl calculations areatle using various assumed con!binuiions of value of the constant expretsing the qquifer properties correspoinds to the best fit ohtained between observed and calculated field history. Details of the method of calculaion are illus trated by an example. INTKCDUCTICN A method 01' calculating the material balance equation for a partial water-drive reservoir completed in an aquifer has been described in the literature." Pressure interference i'rc,m other pools iocated in the same nquiucr is not taken into account in this solution. When present, the pres- sure interference effect must be included in order to make a complete performance analysis. A correction for this effect has been developed using the theory cstahlished by Mor-tada.' Manual calculation of the material balance for water-drive reservoirs is a formidable task. Such manual ca1culation when interference eflects are includcd would be impossible to completc in any reasonable time period. However, a medium-sized stored program, digltal conlputer can he used satisfactorily. The method is described in the following sections. THECKETICAL CONSIDEKATIOhS The material balance equation for a reservoir producing by partial or total water drive, as proposed by Van Everdingen, This relationship is linear for Z/a from which thc slopc, Z, and the intercept, N, can be obtained by the least-squares method from the data points. It is not necessary lo know the aquifer properties to uktain oplimum values tor 2nd IV. Various assumptions are made tor At,,: where 11 is production time, seconds (oilfield between the equal successive time intervals into which the history is divided. t,, h It, times the number of equal time periods from i.e.. the total dimen-sionless time interval from It is noted that the dinlensionless time interval, At,,, involves all the relevant aquifer properties. Accordingly, any assunlption of is an assumption of the combined aquifer properties which pertain to the solution of the equation. Deviations of the data points from a straight line arc calculated for each assumption of and the value of A, correspond ing to the minimunl deviation is chosen as the optimum solution. This method is described in Ref. 1 and 2. Thc material balance solution is usually made with an initial assumption that the reservoir being studied is located in an infinite aquifer from which there are no other withdrawals. Deviation of the points by amounts greater than can be attributed to inaccuracies in field data may be the result of: (1) boundary effects of a limited aquifer, (2) pressure interference from othcr pools completed in the .sarne aquifer, and (3) a combination of these effects. Differentiation of these effects can be made only on the basis of geologic data. Pressure interference from other fields will result in a pressure drop at the original oil-water boundary having an interference component, The measured instantaneous pressure drops at the oil-water

By Benoît Demers

Dans ses opérations de traitement de concentré de zinc, l?usine de Zinc Électrolytique du Canada à Valleyfield génère un résidu minier appelé « jarosite ». Jusqu?en 1998, le jarosite était transporté hydrauliquement dans des bassins construits en argile. Le jarosite sédimenté possède une consistance très molle (impossible de circuler à pied sur le résidu consolidé) avec une eau interstitielle acide contenant des teneurs élevées en métaux. Ces caractéristiques particulières au jarosite rendaient très coûteuses la construction et la fermeture des bassins de résidus. En 1998, Zinc Électrolytique du Canada a implanté un nouveau procédé, développé chez Noranda, dont le principal objectif était de stabiliser chimiquement et physiquement le jarosite. Un nouveau concept de déposition a été élaboré pour le nouveau résidu minier appelé « jarofix ». Les grandes caractéristiques du nouveau procédé et du concept de déposition sont : ? Le jarosite est lavé et déshydraté à l?usine avec un système de filtre; ? De la chaux, du ciment et de l?eau sont ajoutés pour former le jarofix; ? Le jarofix est transporté par camions jusqu?à l?aire d?accumulation; ? À l?aire d?accumulation, le résidu est géré selon un concept d?empilement. L?élaboration du concept d?empilement et de l?aire d?accumulation devait tenir compte des caractéristiques de déposition du jarofix, de sa résistance à l?érosion hydrique et éolienne, de la gestion de l?eau de ruissellement, de la faisabilité de construire les digues de ceinture en utilisant du jarofix durci et de la nécessité de restaurer progressivement l?aire d?accumulation. Le déchargement du jarofix se fait à partir d?une rampe qui progresse avec une pente ascendante pour développer un front de déversement de plus en plus haut. La hauteur du tas de jarofix atteindra 30 m au centre du site. L?aménagement initial de 1998 a inclut une digue d?amorce de 3 m de hauteur, une rampe de déversement de 8 m de hauteur et un bassin pour la gestion de l?eau de ruissellement. Les propriétés du jarofix consolidé dans l?aire d?accumulation sont déterminées annuellement. Le jarofix durci possède la consistance et la résistance d?une argile très raide. Sa conductivité hydraulique est similaire à celle d?un silt et il résiste bien à l?érosion éolienne. Après trois années de déposition, la température du jarofix au milieu du dépôt demeure élevée. Le jarofix durci est facile à excaver et à compacter, ce qui en fait un excellent matériau pour la construction des digues de ceinture en périphérie du site.

Nov 1, 2002

By John G. Payne

The Pebble deposit contains three contiguous zones. In the Pebble West zone, granodiorite stocks intrude gently warped volcanosedimentary rocks that had been intruded by diorite sills and two felsic intrusion breccias. In the Central zone, volcanosedimentary rocks are cut by diorite and granodiorite sills; the latter are genetically associated with the granodiorite stocks. In these zones, widespread potassic alteration consists of brown biotite and K-feldspar, with abundant quartz-carbonate-sulphide vein stockworks. Chalcopyrite/pyrite ratios range from 2/1 to 1/20. Diorite hosts the highest-grade mineralization, with much of it being disseminated. Patchy, later phyllic alteration is moderate and commonly depleted in copper. The Pebble East zone occupies a granodiorite stock and intruded host rocks below an eastwardly thickening wedge of barren Tertiary volcanic and sedimentary rocks up to 600 m thick. Brown biotite alteration and copper mineralization are strong, with chalcopyrite/pyrite ratios commonly over 1/1. The zone extends to a depth of at least 1200 m below surface; some drill holes bottomed in strong mineralization. Later, weak to moderate sericitic alteration removed some chalcopyrite and locally remobilized gold. The Pebble deposit has a Measured/Indicated resource of 3 billion tonnes grading 0.28% Cu, 0.32 g/t Au and 0.015% Mo (= 0.5% copper-equivalent) and an Inferred resource of 1.13 billion tonnes grading 0.30 g/t Au, 0.27% Cu and 0.015% Mo (0.55% copper-equivalent). The Pebble East zone has an Inferred resource of 2.13 billion tonnes grading 0.55% Cu, 0.34 g/t Au, and 0.037% Mo (0.97% copper-equivalent). The Pebble East zone is open to the east and to a lesser extent to the north, south, and to depth.

May 1, 2006

By P. Sanchez-Mejorada

GEOLOGISTS who are acquainted with the mines of northeastern Mexico realize that the most important lead-silver replacement deposits of the province are confined to a single formation. But since the formation is several hundred meters thick, the author has determined the relative position of the lead mantos in the belief that this information will prove useful in the search for new mines. This article describes the stratigraphic location of lead-silver replacement deposits known in several mines situated in a region comprising part of the states of Coahuila and Nuevo Leon. The area studied extends for 200 km* (125 miles) from east to west and 70 km (45 miles) north to south. Metallogenic Province: The most important metallic deposits of the region have the following common characteristics: 1) The orebodies occur as manto replacements of calcareous sediments. 2) The horizons that have contributed large tonnages of ore are in similar positions in the corresponding stratigraphic columns (as it will be shown later on). 3) Lead is the most important metal in the ores. Silver is commonly present in small amounts. Occurrence of zinc is dependent on the degree of oxidation of the primary sulfides. 4) A large proportion of the total production has been in the form of oxidized ores. 5) The deposits are located on anticlines. Rocks of Cretaceous age crop out over large areas of the states of Nuevo Leon and Coahuila. forming part of a belt that extends to the south along the eastern Sierra Madre. The sediments are cut by a small number of intrusive stocks ranging in characteristics from rhyolite to diorite. The most prominent structural feature of the region is a series of folds trending northwest-southeast. Faulting is not conspicuous in the region, although a major fault zone is found farther East.' The physiography closely reflects structural features, with mountains formed by anticlines and valleys conforming with intermediate synclines. Narrow valleys have also been developed along the axes of many anticlines, where solution of limy sedi- ments and erosion have proceeded along axial tension fractures. Stratigraphy: Rocks of the Upper Cretaceous are exposed in only a small percentage of the total area. Generally they have been eroded away from the mountains and are covered by recent talus and alluvium in the valleys. Humphrey' has published an excellent paper describing the Cretaceous formations of the Sierra de los Muertos, a short distance west of Monterrey. A brief summary of these formations is given below to convey an overall picture of the stratigraphic sequence that prevails just south of the area under consideration. Upper Cretaceous Indidura: Essentially thin shaly sediments. Cuesta del Cura: Limestone in thin wavy beds

Jan 1, 1959

Bahrain's oil revenue increased from $337 million2 in 1916 to $378 million in 1977. Despite the increase in value, petroleum receipts made up only 584 of all Government income in 1877, compared with 74% in 1976 and 83% in 1975. Bahrain became an oil producer in 1932 with the discovery of the Awali oilfield, and since that time, the Awali oilfield has produced over 600 million barrels of crude oil. Awali production in 1977 was 21.2 million barrels. Bahrain shares the revenue from the Abu Safah oilfield, located in the Persian Gulf north of Bahrain, equally with Saudi Arabia. Revenue from the Abu Safah oilfield was approximately $179 million or 47% of oil revenues in 1977. Output from the Abu Safah oilfield was 48 million barrels, an increase of nearly 30% over 1976 output. The Bahrain Petroleum Company (BAPCO). the nation's only oil-producing company, was owned 40% by California Texas Oil Corp. (CALTEX and 60% by the Govern¬ment. The Government established Bahrain National Oil Co. (BANOCO) in 1976 to administer the Government's share of BAPCO, oversee exploration concessions, and manage domestic marketing of petroleum products. The Government announced its intention to acquire 100% control of crude oil and natural gas production. CALTEX was to retain complete control of the 250,000-barrel-per-day oil refinery near Sitrah.

Jan 1, 1981

About MAC ? The national organization of the Canadian mining industry ? Mining, smelting and refining of base and precious metals ? Mining of iron ore, diamonds, uranium, oil sands, coal and industrial minerals ? Many associate members ? www.mining.ca

Aug 1, 2013

By Peter Jackson

The dewatering of the large construction pits required for major infrastructure projects often has a significant impact on the environment. This is particularly so in urban areas and where groundwater resources are of interest. These environmental impacts are inter alia, groundwater lowering and the consequent effects such as settlement and deterioration of timber foundations, together with the impact of the dewatering on the groundwater quality. In order to minimise the environmental impact of the dewatering, the quantity of water to be abstracted and the amount of groundwater lowering in the surrounding area must be minimised. This paper describes the measures that have been taken on the Copenhagen metro project to achieve the objective of minimal environmental impact whilst still carrying out a major dewatering scheme.

Jan 1, 2000

By R Ratlou

Increased contamination due to sand in spiral feed has had a negative effect on the efficiency of spiral concentrators at Navigation Plant. The no. 1 seam at Kromdraai opencast, which was previously mined by underground bord and pillar methods, is now susceptible to spontaneous combustion because of air ingress into the old workings which are exposed in the opencast high wall. This posed a risk in the loss of reserves to burnt coal. As solutions, buffer blasting of the preceding cut to collapse bords and soft overburden dressing of un-collapsed bords were implemented to prevent air entering the workings. The latter remedy resulted in increased contamination due to addition of sand in Run of Mine. After evaluating alternatives, a low capital option was selected. The 110t/hr Teetered Bed Separator (TBS) has been installed, primarily to desand and upgrade the feed to the spiral concentrators. The unit indicated an upgrade with a yield increase of 0.4% during test work and is currently showing an overall plant yield increase of 0.97%.

Jan 1, 2006

Protect mine rescuers from heat-induced stress that drastically cuts their endurance and saps their strength. Approach To prevent exhaustion caused by thermal stress, a rescuer can wear a liquid-cooled hood and vest which absorbs heat, thereby reducing the heat-induced strain on the rescuer's heart and circulatory system. How It Works Liquid coolant is continuously circulated through a self-contained system in which the coolant is chilled by a heat sink on the wearer's belt. The coolant, which is a mixture of alcohol and water, is pumped from the heat sink to bladders inside the hood and vest where it absorbs body heat. After absorbing heat In the hood and vest areas, the coolant returns to the heat sink where it is rechilled by passing through a tube coiled around a steel can containing a block of ice. To adjust the temperature of coolant leaving the heat sink unit, a valve can be operated by the wearer, causing part of the flow to bypass the coil. A small pump and a rechargeable battery are also part of the assembly.

Jan 1, 1979

By Cocquio D. S, Bauchau C

In the course of an integrated airborne survey in 1975, a uranium-molybdenum deposit was discovered by Minatome Australia Pty Limited in North Queensland, Australia, approximately 70 km by road west of Townsville.The mineralization occurs in a welded tuff unit within the Carboniferous St James Vokanics. It is structurally controlled by a complex of subvertical east-west fractures and is exposed over a strike length of 350 m. Drilling has traced a further 150 m extension underneath a barren capping consisting of a thick pile of vokano-sediments. The maximum width of the orebody is 150 m, and its vertical thickness is approximately 100 m.The primary ore minerals are coffinite, pitchblende and molybdenite, accompanied by various alteration products (particularly uranium molybdates).The vein-type mineralization is considered epigenetic.A comprehensive program of surface drilling and underground exploration is in progress to establish the uranium and molybdenum reserves.

Jan 1, 1980

It is no longer satisfactory to assess the value of a coking coal on its intrinsic properties alone; its value depends upon its behaviour as a component in a blend. No single test can be used to make this assessment, it can only be made by carrying out a suite of tests. The quality parameters which are considered desirable, and which have widespread acceptance, have been discussed and their application to the blending of coals from New South Wales and New Zealand has been reported and discussed. Blending can be utilised to offset deficiencies, or capitalise on advantages, of the individual coals making up a blend. Coals can be blended, which alone are poorly, Coking, but which have compensating features. Blending also allows better exploitation of coking coal reserves. Several applications of blending have been reviewed with regard to coal producers and exporters, as well as coal users. The possibility of extracting a coking coal fraction from fuel coals is discussed. Blending systems and the coking of coal are also briefly reviewed.

Jan 1, 1971

By Natasha A. Essar

Nevsun Resources Ltd. Bisha Mine Project is a gold and base metal development project in the Gash Barka region of west-central Eritrea. The project has the potential to be one of the largest industrial developments in the country, and Eritreans have no experience in modern mining. Nevsun recognized early that the success of the Bisha Project would require meaningful consultation and engagement with all levels of Eritrean society. Meaningful engagement required not only full disclosure, but also capacity building from government officials at all levels to other stakeholders who live in the nearby communities. This paper describes the approach used to develop capacity and to help introduce a modern mining culture in a country without previous experience in mining.

May 1, 2007