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By K. E. Stanfield

[Asphalt and road oil are the principal products manufactured from Wyoming ?clack oils? which, because of their high asphalt an high sulfur content, are difficult and costly to refine into high-grade motor fuels, burning oils, and lubricants by pre sent methods. Accordingly, the remand for these asphaltic residuums for the construction of roads and other uses is a controlling- factor in the quantity of crude oil produced. The increasing utilization of special asphalts as inexpensive bonding, insulating, and waterproofing materials indicates the desirability of obtaining information on the yield and properties, of asphalts from Wyoming black oil to promote a wider and more stable caret for these asphaltic materials.]

Jan 1, 1941

By E. E. De Beer

This paper describes a method for the determination of the settlement of an individual H-bearing pile, based on the results of CPT-tests. As implied by the nature of the problem, no analysis performed on one pile can be regarded as generally valid for a whole piling foundation project because, even on one site, the pile behaviour varies from one pile to another. Consequently, no precise mathematical analysis has been established; the proposed procedure represents a simple model for the determination of the probable settlement behaviour of an H-pile under a compressive load. Prior to the settlement computations, the rupture load and the resistance distribution along the pile have to be determined. Since the method for the determination of the H-pile bearing capacity from the results of CPT tests has been described elsewhere (de Beer, 1971, 72; de Beer et al., 1982; Arbed, 1985), no details will be given in this paper. The proposed method is valid for both uniform and non-uniform H-piles. The computed results have been satisfactorely compared to the static loading tests performed on different types of piles in clayey and sandy soils during an ECSC research program on H-bearing piles (1983-1987).

Jan 1, 1987

By Betty L. Gibbs

Geologically simple deposits can be modeled quickly and easily with inexpensive gridding and mapping software. Hundreds of mines around the world use RockWorks99 and Surfer 7 for generating contour maps, producing log plots and cross sections, and performing other useful geological calculations. These programs are used by many mining operations as their only modeling and graphical software or they are used in conjunction with larger systems. The investment in learning time is low and the programs produce reasonable quality results with standard computing equipment. RockWorks99 and Surfer 7 provide a good level of capability while maintaining high quality technical integrity. Both programs are used for many applications in mining, oil and gas, environmental and other fields that require analysis of spatial data.

Jan 1, 2000

By D. Harrington

A uniform hoisting-signal code for mines hoisting from more than one level, if adopted by all mining States, would be beneficial to employees and owners alike and should largely reduce the number of hoisting accidents. Misunderstood hoisting signals cause many shaft accidents involving injuries to men, damage to equipment, and loss of production from the resultant delay. Many of the metal-mining States have adopted codes for hoisting that are effective within the borders of that State but usually entirely different from the signal code, if any, in use in an adjoining State. For many years safety engineers have recognized this lack of uniformity as a distinct hazard, but a uniform code has never been adopted by the States or by the mining industry in those States that have not incorporated signal codes in their mining laws or mining regulations.

Jan 1, 1944

Resonance re-emission from nickel vapour affords a convenient method for isolating the resonance lines at 3415A, 3515A, and 3524A. The vapour is generated by cathodic sputtering and is illuminated by light from a nickel atomic spectral lamp. The resonance lines thus isolated can be usefully employed for absorption measurements on mineral samples where the nickel concentration is too high for measurements with the more sensitive line at 2320A. A spectrophotometer employing a resonance lamp as monochromator possesses several advantages where a great number of determinations are made under routine conditions. The wavelength setting is stable under even the most rigorous conditions and with the provision for automatic setting of full scale deflection the instrument requires virtually no adjustment. The instrument has been used under routine conditions for the determination of nickel (in the range O· 05-2 per cent) in mineral samples.

Jan 1, 1968

By John E. Leitch

The cost of corrosion as measured by such cost components as the renovation or replacement of coated steel, or the use of expensive coating systems on steel, is considerable. Extrapolating from figures for the USA would place the overall cost of corrosion for South Africa as a figure of the order of magnitude of something over 1% of the GNP. This is a sizeable amount, of which costs associated with atmospheric corrosion would be a significant proportion. The corrosivity of an atmosphere can be defined as the ability of the atmosphere to cause corrosion in a given metal or alloy (International Standards Organization [1]). The ISO Standard 9223 specifies the key factors in the atmospheric corrosion of metals and alloys, and defines categories of corrosivity on the basis of these factors. Prior to the publication of that ISO standard, Callaghan published the results of his twenty-year exposure programme and his excellent corrosivity map of Southern Africa [2]. The present author published updates of the corrosivity map in 1999 [3] and again in 2003 [4]. The summary of the individual areas of corrosivity around Southern Africa was published in the latter paper, and is reproduced here as the following TABLE 1. Of significance in TABLE 1 are the numerous regions of very high corrosivity (C5 or beyond), particularly the rural West Coast shoreline, the North East Coast (KZN) shoreline, and the coastal cities Cape Town, Durban and Richards Bay. The corrosivity map as published is obviously based on much extrapolation as only a small number of points have been measured. During the past three years further measurements have been made, mostly however at the same sites in order to give greater reliability and to monitor long-term trends with changes in pollution. These two aspects are incorporated in this update. There has become available a greater amount of air pollution data for centres in South Africa than was the case some years ago. In this present paper the pollution data are used to extrapolate the corrosivity over areas where little or no direct corrosivity measurement has been made. This methodology is described in ISO 9223.

Jan 1, 2006

By S. Dessureault, J. Porter, M. Woodhall

Information and communication technology (ICT) is seen as a key source of future productivity improvements in mines. The information technology infrastructure (ITI) necessary to achieve these productivity improvements will come in the form of data integrated from multiple source systems throughout the mining value chain. Two pure approaches are available: supplier-controlled or operations controlled data structures; each strategy has its own advantages and disadvantages. Case studies involving the South African mining industry are used to demonstrate the advantages of using hybrid-controlled data structures. Depending on the level of operational control, new skills are also necessary to be learnt by mining professionals including: information engineering; creating consistent and quality data; and process improvement techniques that use the integrated data for improving the operation.

Jan 1, 2004

By Dyson N. F

Mixed cobalt-nickel sulphides precipitated from ammoniacal process liquors derived from nickel sulphide concentrates, mattes, and reduced nickeliferous laterites have been characterized.The mixed sulphides are prone to oxidation on standing and are rapidly leached under relatively mild conditions. The kinetics of the leaching reactions are controlled principally by temperature and oxygen partial pressure. Although the samples have different CO:Ni ratios and have undergone varying degrees of oxidation, there is little difference in their leaching behaviour. The results suggest that a single plant would be able to process mixed sulphides of varying composition. Any copper and zinc present in the mixed sulphides as impurities also go into solution and must be removed prior to recovery of the cobalt and nickel in metallic form.

Jan 1, 1981

The ~2500 km long Kermadec-Tonga arc northeast ofNew Zealand is the longest continuous intraoceanic arc in the world. At least 94 volcanic centres along the arc are submarine, most (87 per cent) within the Kermadec arc (de Ronde et al, 2003a). Volcanic rocks range from basalt to rhyodacite with trace element and isotopic data indicating significant magma source heterogeneity both along and across the arc.   The entire ~1300 km of the Kermadec arc has now been surveyed for hydrothermal emissions (de Ronde et al, 2004). First-stage surveys utilised surface vessels. In February 1996, the first sulfide samples from the southern Kermadec arc were dredged from the Brothers and Rumble II West caldera volcanoes (R/V Tangaroa cruise TAN96/03; Wright et al, 1998; de Ronde et al, 2003b). In September 1998, low-temperature, diffuse venting was discovered at Monowai, Rumble III and Clark volcanoes, and high-temperature, black smoker venting was found within Brothers caldera (R/V Sonne cruise SO-135; Stoffers et al, 1999). The NZAPLUME cruise of March 1999 surveyed 13 volcanic centres (each mainly comprised of single, large volcanoes) of the southern Kermadec arc and documented hydrothermal emissions above seven of them (de Ronde et al, 2001; Baker et al, 2003; Massoth et al, 2003). In July 2001, additional mineralised and hydrothermally altered samples were dredged from Brothers volcano (R/V Tangaroa cruise TAN01/07). The NZAPLUME II cruise of May 2002 confirmed venting was still occurring at all the known hydrothermal sites, and that ten active vent sites occurred along the mid-part of the arc, between Brothers and Raoul Island (de Ronde et al, 2002). In September-October 2004, NZAPLUME III surveyed the northern-most part of the Kermadec arc where another nine volcanic centres are hydrothermally active.   Second-stage exploration of the Kermadec arc hydrothermal systems utilised deep submergence vehicles. In October-November 2004, the Japanese submersible Shinkai 6500 made four dives on Brothers. Samples recovered include vent fluids, chimneys, altered rocks and various animals and microbes. In April-May 2005, a more extensive expedition using the American submersible Pisces V made 23 dives on nine different volcanic centres, eight of them for the first time.   Extensive plume surveys show Brothers volcano is host to the most hydrothermally active sites of all those known along the Kermadec arc. In total, nine dives have been made on Brothers, six on the NW caldera site and three on the cone site. The NW caldera vent site is a long-term hydrothermal system that is today dominated by evolved seawater but has had episodic injections of magmatic fluid. The cone site is a nascent magmatic-hydrothermal system where crack zones localise upwelling acidic waters (de Ronde et al, 2005). A SE caldera site represents the main upflow of a relatively well-established magmatic-hydrothermal system on the seafloor where sulfide-rich chimneys are extant. Each of these different vent sites represent diverse parts of an evolving hydrothermal system, any one of which may be typical of submarine volcanic arcs.

Jan 1, 2005

By K L. Temel, W P. Player

The underlying message of this paper is that investment in prospecting, exploration and mining in New Zealand is welcomed. The Government's policy with respect to Crown owned minerals is for continuing investment in prospecting, exploration and mining which is in accordance with good exploration or mining practice. To encourage continued investment requires a business-friendly environment. Government policies and initiatives to enhance the business environment for the minerals and coal exploration and mining industries are discussed in this paper. As well, new initiatives under consideration, which have the purpose of enhancing the investment environment, are discussed.

Jan 1, 1997

IN the irregularly shaped ore-bodies of the North Mount Lyell mine by overhead stoping, the method of filling the is a special feature.The situation of the mine two miles from the smelter and mill at an devation of 1000 ft. above the latter, precluded the economical use of granulated furnace or the mill tailings, even if these materials were as suitable for the purpose as the rock nowquarried at North Lyell methods at Mount Lyell have already been described in Proceedings of the Institute.*The breaking the ore in large dome-shaped stopes is still the rule, but the slope or "rill" is much flatter now than formerly. Owing the greater fluidity of the filling now in use, it is sometimes necessary to resort to square-sets, both at the ground floor and above, the roofs and walls are generally enough to permit stoping without timber, except for ground and occasional stacks on the rills.Sufficient area of ground floor has been beaten out to start overhead stoping, the dome back is partly formed, with its apex a rise which connects with the mullock-pass reticulation.(Sce 1 showing this reticulation in diagrammatic form.)

Jan 1, 1927

Typically, large volumes of data are collected during geotechnical investigations for mining projects but rarely is this done in a comprehensive manner that enables all aspects of the geotechnical environment to be evaluated. A geotechnical core logging process has been developed to record mechanical and structural properties of the rock mass. The method enables data for a wide range of rock properties and geotechnically significant major structures to be collected including rock strength, joint surface condition, fracture frequency and fracture orientation. The logging method is unique in that sufficient data is collected to enable the independent determination of all the major rock mass classification systems including rock mass rating (RMR), (Bieniawski 1976, 1989; Laubscher, 1990) Norwegian Geotechnical Institute (NGI) tunnelling quality index (Q) (Barton, Lien and Lunde, 1974) and geological strength index (GSI) (Hoek, Kaiser and Bawden, 1995). The logging system has been specifically developed to allow better and more precise appreciation of rock mass and structural conditions across the project area thereby optimising the use and application of the available geotechnical data and improving confidence in the outcomes of geotechnical investigations. This paper describes the core logging process with case examples showing how the logged data can be used for underground and open pit mine design.

Nov 25, 2010

By A. Bascetin

One very important aspect of mining is deciding what material in a deposit is worth mining and processing, versus what material should be considered waste. This decision is summarized by the cut-off grade policy. The cut-off grade strategy for an open pit mine influences the annual cash flows and affects the net present value of a project. The optimization of cut-off grade strategy requires the knowledge of detailed operational costs, mining sequence, mining operation, processing, and product constraints, as well as the grade distribution of a given deposit defined by pit, phase, and different material types. Cut-off grade optimization algorithms have been developed in the past. The most common criteria used in cut-off grade optimization is to maximize the net present value (NPV). This paper describes the determination of a cut-off grade strategy based on Lane?s algorithm adding an optimization factor based on the generalized reduced gradient (GRG) algorithm to maximize the project?s NPV. The introduced algorithm is a windows based program developed at Virginia Tech that is based on a series of Visual Basic routines within a spreadsheet environment (Excel).The benefits of the methodology are demonstrated using a hypothetical case study. Keywords: Cut-off grade optimization, net present value maximization, generalized reduced gradient algorithm method.

Jan 1, 2007

By Tony Mazzo

It has often been said by consulting engineers that foundation contractors are in the business of taking risks. One would agree that the mere fact a foundation project can be budgeted, planned, engineered and executed solely on the reliability of eight test borings made at a proposed site having an area of approximately 19,000 square feet, is a risky proposition, in and of itself. Now imagine that this site is actually one half of a city block located in an urban setting in an old, congested, historical neighborhood, surrounded by narrow city streets and historic landmark buildings. And suppose that the required depth of excavation for the construction of the new building on this site is approximately 35 feet and the natural groundwater table is at a depth below existing grade of only 25 feet. Given the difficult site conditions outlined above, one could certainly add the words "challenging" and "complicated" to the inherent word "risky" when describing the construction techniques involved to undertake a foundation project of this magnitude. This case study will discuss in detail how the excavation, sheeting, dewatering and underpinning work was accomplished as well as the problems overcome along the way.

Jan 1, 2003

By M. A. Raza

Cable shovels are capital-expensive and primary production equipment in many surface mines. The forces acting on the shovel dipper vary as the dipper moves through the muck-pile. The variations in the forces cause stress loading of the components of shovel and dipper resulting in unplanned downtimes, reduced shovel efficiency, and high mining costs. A potential solution to the above problems is the deployment of an intelligent shovel excavation (ISE) technology, with real-time formation identification, recording, and knowledge transmission capabilities. This research advances the ISE technology by developing dynamic model of cable shovel dipper using Newton-Euler techniques. The model includes the dynamic cutting and dynamic weight forces acting on the dipper as it moves through the muck-pile.

Jan 1, 2011

The occurrence of molybdenite in a small shaft in the western margin of the Wuuluman Granite in central western New South Wales is noted. Full petrographic and mineragraphic descriptions are given of a mineralized contact zone between the granite and a basic hornfels.Mineralogical data .indicate a similarity between this mineral occurrence and other occurrences in larger mines remote from the granite.

Jan 1, 1968

By J. D. Noll

Elemental carbon (EC) is used as a surrogate for regulating the exposure to diesel particulate matter (DPM) of underground metal/non-metal miners. EC was chosen as a surrogate because EC is selective to DPM and is a major component of DPM. Using EC as a surrogate also gives one the advantages of no sampling artifacts and being able to sample at all locations in the mine. Currently, EC represents DPM well in underground mines. Some control technologies have been shown to possibly alter the relationship between DPM and EC and characteristics of DPM. Therefore, future work will investigate the relationship between DPM and EC as new control technologies are implemented.

Jan 1, 2002

In the Broken Hill South mine tile practice of issuing to the miner a quantity of fuse and a box of caps from which he made up the "rods" required for a particular blast, has been abandoned. Instead, capping stations have been established, and the miner can now obtain, from the magazines, fuses cut to accurate lengths with the detonators attached.Various types of fuse-cutting machines and crimping devices are available, but only those used by the Broken Hill South Mine Ltd. are described in this paper.The fuse-cutting machine, designed by the engineering staff, is an electrically driven unit fitted with a gear box for the purpose of adjusting the rate at which the fuse is fed to the cutting device, thereby enabling fuses of various lengths to be accurately severed from the main coil of fuse.The machine in question is designed to cut 4, 6, and 8-ft. fuses, but no difficulty should be experienced in designing a machine to cut fuses to any required lengths.

Jan 1, 1932

By M. Hopf, E. Rossouw

Keywords: Pyrometallurgy, furnace, copper coolers, freeze lining, monitoring, Saveway The use of water-cooled copper components as sidewall elements of submerged arc furnaces and other pyrometallurgical applications has become increasingly common. The high cooling efficiency of copper has made it possible to increase the service life of furnace refractories when compared to conventional refractory linings. However even the self-healing effect of ?freezing? worn areas of the lining does not necessarily protect the copper coolers against wear or corrosion completely. In order to avoid furnace explosions, various methods have been used to monitor the wear of coolers. Unfortunately, these have not been able to consistently identify localized wear. Thos Begbie (South African) and SAVEWAY (German) jointly developed technology to embed a line sensor into the copper cooler during the casting process. This system allows an exhaustive monitoring of the copper cooler. A SAVELINE sensor is placed inside the copper-cooling panel between the water-cooling passage and the hot face of the panel. The sensor follows the meandering shape of the cooling water channels. In the first instance, the sensor provides analogue information as the thickness of the copper reduces. Secondly, this wear signal will be confirmed by a signal of interruption if the sensor is washed away. Because of the structure of the sensor, a self-diagnosis is possible and indications can be confirmed (double proofed). Subsequent to the manufacture of some test pieces, coolers for a large submerged arc furnace were manufactured. The sensorized coolers have been installed at the intermittent surface (slag line) where the largest amount of corrosion has been encountered. The system has been operating since December 2005 in what is considered one of the largest submerged arc furnaces in South Africa.

Jan 1, 2006

By Lucien Eaton

THE use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material :st be used. In different parts of the world sand, clay, gravel, culm, nulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, butt to describe some of the methods used for placing sand fill and to make a brief comparison of their merits.

Jan 1, 1932