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Operating well designed and maintained surface mine haul roads is the key to minimising truck haulage costs - in itself a significant component of the total cost per tonne mined. Existing and proposed mining operations are subject to scrutiny, both from the economic and environmental perspectives. In the long run, this scrutiny returns improved efficiencies and leaner, 'greener' operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations - simply by virtue of their contribution to overall cost of operations and sustainability impacts. Whilst the end result - improved efficiency and contributions to resource sustainability - is not in itself problematic, it is the route, or process followed to achieve these improvements that needs to be carefully managed. We can be guided on this journey by our understanding of how a road is designed, and, critically, the technological solutions that can contribute to a company's sustainability initiatives. This paper examines the current state of mine road design and operation, together with the economic and environmental issues associated with under-performance. The paper serves as a basis for evaluating the economic and environmental contributions that technology in road design and management can deliver to sustainable operations. Utilising innovation is the key to long-term sustainability and as a means of positioning the industry for the imminent structural changes to the economy and environment, changes which are now within the operating life of many mines, haul roads and haul trucks.

Jun 1, 2010

By Marvin P. Barnes, John G. Simos

The Park City District, Utah, is situated in the Wasatch Range at the intersection of the westward extension of the axis of the Uinta Range. Ore has been mined almost continuously from the first discovery in 1869 to the present day, with a total production of over 14 million tons. Sediments of Carboniferous to Triassic age have been folded into the northerly plunging Park City anticline and subsequently modified by thrust faulting, diorite and diorite porphyry intrusions, and strong east-west normal faulting during the Laramide orogeny. Younger andesitic volcanics partially cover the eastern edge of the district. The ore bodies occur as both lode and bedded replacement deposits over widely scattered localities. Near surface, high-grade silver "bonanza" ores were mined in early days from the Ontario and Daly Lodes, which occur along the east-west zone of faulting near the center of the district. Other lode or fissure deposits were found along the Mayflower and Hawkeye faults to the east and southeast. Large bedded replacement silver-lead-zinc ore bodies associated with east-west zones of fissuring, have been mined from favorable horizons in the Park City Formation in the Daly West and Judge mines. A series of long, narrow, high-grade, replacement ore bodies occur in the Silver King mine at a single horizon in the Park City Formation. Ore is currently being mined from strong bedded replacements in the Humbug Formation near the apex of the Park City anticline. Factors controlling ore deposition are: magmatic source, structural feeder systems, and favorable host rocks. Ore deposition along favorable beds is primarily a function of physical conditioning and secondarily of chemical composition.

Jan 1, 1968

By Guo H. Lei

Over the last four decades, barrettes have been ever-increasingly adopted as the foundations for tall buildings and heavy infrastructure projects all over the world. Many findings have been gained from practical applications and theoretical researches. In this article, a collection of literature is reviewed on the installation effects and load-carrying behaviour of barrettes derived from field and laboratory tests and theoretical studies. It covers many aspects, such as the ground deformations and stress changes caused by the installation of barrettes, the shaft resistance mobilisation behaviour, the construction effects on the shaft resistance, and the effects of pile spacing, pile shape and pile group layout on the load-carrying behaviour of barrettes.

Jan 1, 2006

GOOD ventilation is recognized as an essential for the preservation of health, and laws have accordingly been framed in many countries for the provision of adequate ventilation in factories and places of public resort as well as in mines.Apart from the legislative enforcement of hygienic measures as a matter of public 'policy, the ventilation of mines has an important economic aspect, since it affects to a large extent the industrial efficiency of the workmen, and consequently the cost of mineral production. Until recent years the ventilation of metal mines has not generally received much consideration, and the importance of pure air has been sometimes overlooked. To the absence of explosive gases in such mines, and to the cost of the installation and working of mechanical ventilators, may generally be attributed disregard of adequate ventilation. In this paper it is not proposed to furnish statistics on the mortality and morbidity of miners, or a treatise on the medical aspect of the rock-dust problem, to further elaborate which would be superfluous, the deleterious effects of the latter having been...

Jan 1, 1912

By S. D. Cramer

Corrosion research is being conducted by the Federal Bureau of Mines to determine suitable construction materials for geothermal resource recovery plants. As part of this research, the corrosion resistance of 31 iron-nickel-, aluminum-, copper-, titanium-, and molybdenum-base alloys was characterized and evaluated in laboratory corrosion studies in low-and high-salinity geobrines representative of those found in the Imperial Valley, Calif. General, crevice, pitting, weld, and stress corrosion were measured at 105° and 232° C in deaerated brines and brines containing dissolved 02, C02, and CH4 General corrosion rates in deaerated brines at 105° and 232° C were usually below 5 mpy for the alloys tested except carbon steel, the low-alloy steels, Monel 400, 70-30 cupronickel, and the aluminum-base alloys. Dissolving carbon dioxide and methane in the brines at 2320 did not markedly alter these results. However, the introduction of oxygen, which can enter the brine during process operations, seriously degraded the corrosion resistance of many alloys by increasing the incidence of stress corrosion cracking, crevice corrosion and, except for the titanium-base alloys, pitting. In deaerated brine at 2320 C, the general corrosion rates for carbon steel and the low-alloy steels were relatively unaffected by pH in the range of 6.1 to 3.0. However, general corrosion rates increased sharply below pH 3.0. In deaerated brine at 232° C, welds in several iron-, nickel-, and titanium-base alloys corroded at rates comparable to the general corrosion rates of the alloys, but the addition of oxygen to the brine increased corrosion rates for welds in Inconel 625 and E-Brite 26-1. Alloys exhibiting good corrosion resistance in the deaerated Salton Sea KGRA-type brine at 232° C were E-Brite 26-1, Inconel 625, Hastelloy S, Hastelloy G, Hastelloy C-276, TiCode-12, Ti-0.2Pd, Ti-2Ni, Ti-1.7W, and TZM. The alloys most resistant to corrosion in oxygenated Salton Sea KGRA-type brine at 232° C were the titanium-base alloys. These alloys appear the most suitable for use in the construction of geothermal resource recovery plants. Carbon steel and the low-alloy steels are unsatisfactory for high-temperature, high-salinity brines and alternative low-cost materials with improved corrosion resistance should be sought.

Jan 1, 1980

Block caving is an underground mining method for the profitable extraction of massive, low-grade orebodies. Lately, it has become the mining method of choice, for many mining companies, because of depleted high-grade orebodies, and declining metal market prices. Block cave mining, however, still faces several challenges. Lack of access to the cave remains a major issue in understanding the rockmass response to mining for method optimisation. Improving our understanding of the rockmass response to caving will lead to safer and more productive operations. Combining large datasets from multiple sources with virtual reality scientific visualisation (VRSV) is a viable alternative to understanding complex cave behaviour without access to the cave. This is achieved using immersive environments with the ability to view complex multi-dimensional data (beyond 3D) graphically. VRSV offers a unique platform where it becomes possible to immerse the multi-disciplinary experts, and/or management team, in a virtual mine environment for quick decision making and fast resolution to conflicting conclusions. The underground mining system is complex due to multiple interrelating factors such as geology, excavation geometries, stress and time. Block caving is even more complex than most underground mining methods due to the network of tunnels required, and the use of induced stress, among others. As a consequence of the complexity in the block caving environment, it is vital that the mining system is analysed holistically, as a system, rather than optimizing individual factors one at a time. This paper presents a customised software module developed for use in the Advanced Visualisation Interactive Environment (AVIE) at The University of New South Wales (UNSW), Australia, to enable VRSV investigation into block cave mining systems (BCMS). This approach has the potential to provide a better understanding of the effect of time in in rock engineering, which has proven to be an important factor in hard rock mines (Ma & Daemen, 2006; Malan et al., 1997; Suorineni, 2010) but never validated. This work back analyses the early undercutting phase of a case study block caving operation with the view to understanding time/sequence effects. There is evidence that heterogeneous rockmass time-dependent behaviour governs the seismic response of the rockmass following undercut developments.

Jan 1, 2015

By B. M. England, L. C. Mackey

Magnesia minerals are included in most iron ore sinter mixes to provide the MgO requirements of blast furnace slag. The properties of these minerals have an influence on the eventual sintering properties of the mixes. A detailed study was undertaken of serpentine and dolomite and the use of limestone, olivine and magnesite was also investigated. A consideration of particle properties indicated that as these materials calcine a reduction in size can occur together with cracking and changes in surface properties. These changes could affect the permeability of the sintering bed and sintering performance. Studies of sintering reactions showed that magnesium and calcium, formed from the calcination of dolomite, are extremely mobile before the formation of melt. Evidence suggests that the movement of these oxides into surrounding areas is via a solid-state diffusion process. The diffusion of Ca into the surrounding hematite particles is faster than that of Mg, resulting in the formation of dicalcium ferrite and magnetite or magnesioferrite, the last two subsequently being converted to dicalcium ferrite in the presence of Ca with removal of Mg from the structure as ferroan periclase. Studies of pilot-plant sinters indicated that reaction mechanisms formulated from the bench-scale studies were occurring in actual sintering processes. The differences in sintering reactions between dolomite and serpentine were considered to be the major cause of differences in the availability of lime for bonding phase formation. Pilot-scale studies indicated that the sintering properties of a mix containing dolomite could be improved by increasing the basicity of the sinter mix while keeping the MgO level constant

Jun 18, 1905

By Jay S. Gunasekera

Metal parts are traditionally processed by either filly-liquid (e.g., casting) or filly-solid (e.g., forging) state. Semi-solid metal forming incorporates elements of both casting and forging. In 1991, Gunasekera(5) developed a model illustrating the influence of flow stress by the liquid fraction. The result fits Kiuchi's (1979)(7) experimental data quite well. This model assumed the liquid part is surrounded by solid as small pockets inside the material, which is opposite to the real practical situation. Since the melting usually first happens at the grain boundary, it is better to treat the semi-solid material as small metal crystal surrounded by liquid.

Jan 1, 1997

By CHARLES R. KETES

I. INTRODUCTORY. INDUSTRIALLY, the most important service that geological science can now render to mining in the Upper Mississippi leadand zinc-fields is to devise some practical scheme whereby the productive ore-belts may be located with greater certainty than they have been in the past. Up to the present time there has been little service of this kind, and in spite of all that has been worked out concerning the geologic features of the region, and notwithstanding all that has been written about these ore-deposits, this particular phase of the subject has been, for some reason or other, the very one that has received the least consideration. The neglect by geologists in this respect has been all but complete. The following notes are suggestive of some practical solutions to the problems presented. As here suggested, the geologic relationships of the ore-bodies were surmised some years ago, though somewhat vaguely perhaps. No opportunity for securing critical data appeared until recent investigations of a private character were undertaken, which bad in view the extensive prospecting of undeveloped areas. Fresh from rather wide experiences of a decade in the principal mining-regions of four continents, and after a lenstrum's residence among the chief mining-camps of the West and of Mexico, under conditions which measured geologic hypotheses in meters and rigidly tested their values in, terms of dollars, the recent return to the Joplin field and a new survey of its ore-conditions were fraught with somewhat unexpected results. Aspects of the ore-deposition were presented of which previously there was no hint. Ten years' absence from the district had tended greatly to clarify former hazy impressions. It enabled many features, then only dimly outlined, to be considered more nearly in their true perspective and in their real relationships to their surroundings. It permitted a great mass of details collected a dozen years before in connection with the work of the Missouri Geological Survey to be viewed under new light and to

Feb 1, 1909

By Phil Thwaites

"The mining industry uses many types of mineral and metallurgical plants to produce saleable product from ore mined. Plant design history has left current operations with a mixture of manual operation and various forms of automated process controls. Consequently, we typically see high variability in the continuous operations together with a shortfall in the attainment of full capacity, or higher utilization of consumables.At a level of best practice, “Operational Performance Excellence” focuses on process control, using automation and control systems to deliver process optimization. This more sophisticated delivery is a great deal more difficult than the first stage of equipment selection / installation. It includes the appropriate selection of the right instrumentation, control system, key process knowledge, individuals with a solid control engineering background/experience, and the essential backing/ support of the operations management team together leading to higher value delivery. Robust solutions can be realized, considerably minimizing process variation, thus leading to process optimization. This approach results in an easier, efficient and safer process while providing considerable returns for the plant owners.How variable are your processes, and do you maintain optimized process performance with dedicated resources, modern instrumentation, ‘best practice’ control systems and performance monitoring tools? In this lecture, these questions and their possible answers are discussed.357"

Jan 1, 2013

By J. L. Wiley

[NOTE. - P before the number indicates that the ab tract appears in patent section. Abstract numbers without. P appear in literature section. A Abietic acid, hydrogenolysis - 404 Acetone, recovery - P-4024 Acetylacetonate catalyst - P-3352, P-3664, P-6067 Acetylene, production - P-2556, P-3169, P-4064, P-4221, P-4222, P-5002 Acid catalyst - P-4584 Salts - P-4555 See also Specific acid. Acid treatment. See Procedure. Adsorption. See Hydrogen, adsorption. Agitation. See Equipment, agitators; Procedure. Alcohols: Decomposition -1128 Hydrogenation - P-3288, P-4743 In motor fuel - 1486]

Jan 1, 1952

By Günther Staudinger

Danieli Linz Technology has been honored at 4.1.2013 with the first contract for the exchange of a 350 t BOF converter for ArcelorMittal Poland Dabrowa Gornicza on a turnkey basis. This paper describes the new design features of this converter based on the development of a new Danieli converter suspension system. The issue was to install a new converter (incl. trunnion ring, suspension system and bearings) with maximum volume but keeping most of the existing equipment unchanged. So, the big tilting drives on both sides had to be reused and the existing foundation, pedestals as well as the bearing distance had to be maintained. Further on the welded coreequipment (vessel shell, trunnion ring, pedestals, slag shields, etc.) was manufactured in-house within the pressure vessel division of Danieli Thailand. Due to the huge dimensions of these parts the delivery had to take place in parts which had to be welded together on site under full production conditions of the steel plant. But also the erection had to be applied under this condition. Additionally the main support bearings, parts of the screening (doghouse) as well as an upgrade of the existing relining machine had to be delivered.

Jul 29, 2018

By F. H. Samuel, A. M. Samuel, H. R. Ammar

Casting imperfections, such as porosity, in cast aluminum components greatly influence their fatigue properties. The effect of porosity on the fatigue life of 319-F and A356-T6 aluminum alloys was studied, where the porosity characteristics on the fracture surfaces of fatigue-tested samples were examined using SEM and image analysis. The results show that porosity has the most detrimental effect on the fatigue life: 92 % of all tested samples fractured due to porosity acting as the main crack initiation site. In the absence of casting imperfections, other microstructural aspects such as slip bands can be responsible ( 4 % ). The porosity was investigated in terms of the pore size at the sample fracture surface and its location i.e. near the edge or close to the interior. It was found that porosity located far from the sample surface (edge) has less influence on the fatigue crack initiation, and the fatigue life decreases as the size of the pore located at the sample surface increases. Aluminium

Jan 1, 2006

By Robert B. Bittner

"AbstractLarge diameter tubular piles offer significant advantages in terms of design performance and economy for major marine structures. This is particularly true for foundations of major overwater bridges in regions of high seismicity such as the west coast of North America. The use of large diameter piles in the range of 2 to 3 m diameter means that fewer piles are required, and the size and mass of the pile caps can be significantly reduced, thereby greatly reducing lateral load demand during seismic events. Another advantage of using larger diameter piles is increased pile stiffness that allows the pile caps to be located at or near the waterline rather than being positioned at or below the mud line. This elevating of the pile cap offers significant cost savings by eliminating the need for deep cofferdams. However, relocation of the pile cap creates new problems and opportunities in regard to the means and methods used to construct the pile cap. With the pile cap at depth, conventional steel sheet pile cofferdams with thick tremie seals are typically used to isolated the cap location and allow dewatering for construction of the cap. However with pile caps positioned up off the bottom, conventional bottom founded cofferdams are no longer cost efficient. Float-in or lift-in cofferdams have been developed to address the need for a more cost efficient method for cap construction. This paper describes the key features of the concept and provides three case history examples of its successful implementation.Pier Construction Using Conventional Sheet-Pile CofferdamsCofferdams are temporary structures used in the construction of bridge piers and other marine structures. Their primary purpose is to hold out water and unstable soil from the construction area, and thereby, allow in-the-dry construction of the permanent structure below the water line and quite often below the mud line. Typically, cofferdams consist of long interlocking steel sheet piles driven through water into the bottom of the waterway. The sheet piles form temporary exterior walls which are typically braced internally with wales and struts. The bottom of the cofferdam is typically sealed with tremie concrete or an impervious clay layer if one exists. The depth at which this type of cofferdam can be used is typically limited by the length of steel sheet pile that can be transported and handled by conventional marine equipment."

Jan 1, 2014

By David L. Holt

It is well-established that hydrostatic pressure distribution is hardly achieved during uniaxial compaction of powders. All the previous investigations1-4 give consistent results and this variation is attributed to the die-wall friction. The conclusions are based on measurements of the density of very small portions of the compact. Although the analysis of the density or the strain distribution in the compact is very helpful in obtaining information about the stress distribution within a powder compact, it does not describe the problem from a more fundamental point of view. The densification in metal powder compacts takes place chiefly by plastic deformation (ignoring particle rearrangement) at the points of contact of the powder particles. The onset of yielding and subsequent growth of the contact areas (for spherical powders) take place fixed by a constant stress equal to three times the yield stress in tension or compression,5-7 assuming little or no work hardening. Therefore, by deforming spherical powders in the die and measuring the contact areas on each particle, the load at each contact point can be determined. In the present investigation, this was done by hot-pressing uniform spheres of lead, K-Monel, and sapphire. The details of the experiment have been described elsewhere.' The spheres were studied for the size and the number of contact points on each particle using a specially designed goniometer. It was found that the deformed faces that were approximately normal to the direction of pressing were about 2.2 times larger than those parallel to the direction of pressing. Fig. 1 shows the typical deformed sphere. A detailed study showed that the mean value of the contact areas on each sphere was within 5 pct for all the spheres in the die (ignoring those touching the die walls and the top and bottom of the die).' The spheres touching the die walls and the top and bottom of the die were found to have larger contact areas (8 to 10 pct) which indicates higher pressures in these regions of the compact and thus higher compact densities in these regions. These results show that density distribution calculated from such an experiment will give results consistent with the previous investigators. It is concluded, therefore, that the pressure distribution in the die is better understood by studying contact areas on each particle. 'R. Kamm, M. A. Steinberg, and J. Wulff: Trans. TMS-AIME, 1947, vol. 171, p. 439. 'Pol Duwez and Leo Zwell: I. Metals, 1949, vol. 1, p. 137. 'G. C. Kucynski and I. Zaplatynskyj: Trans. TMS-AIIME, 1956, vol. 206, p. 215. 'R. P. Seelig and J. Wulff: Trans. TMS-AIME, 1946, vol. 166, p. 492. 'H. Hencky: Z. Angew. Math. Mech., 1923, vol. 3, p. 241. "J. Ishlinsky: I. Appl. Math. Mech. USSR, 1944, vol. 8, p. 233. 'D. Tabor: Proc. Roy. Soc. (London), Ser. A, 1948, vol. 192, p. 247. 'Ashok K. Kakar and A. C. D. Chaklader: 1. Appl. Phys., 1967, vol. 38, p. 3223. Superplasticity in 60Zn-40Al David L. Holt THE occurrence of superplasticity in Al-Zn alloys is of interest because of its possible industrial exploitation.' The eutectoid composition (78Zn-22A1) has been the most extensively studied;'-= neck resistant flow and high strain rate sensitivity of flow stress (characteristic of superplasticity) are associated with a micron-size grain conferred on the alloy by an homo-genization and quench.5'6 Compositions away from the eutectoid have received comparatively little attention, especially from the viewpoint of relating the structural

Jan 1, 1969

By S. P. Narayan

The hot deformation behavior of Pure Mg and Mg-0.29Ce alloy were studied by isothermal hot compression tests in the temperature range of 250 - 500°C and strain rate range of 10-3 - 102 s-1 in a computer-controlled 50kN servo hydraulic universal testing machine (UTM). The results show that the flow stress of Mg pure and Mg-0.29Ce alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. Process efficiency was increased by nearly 10 to 12% by addition of Ce in Mg. Mg pure exhibits instability zones between 250-275°C at 10 ? 102 s-1 and 400¬500°C at 101 ? 102 s-1 temperatures and strain rates respectively, rest is the safe deformation zone. Wherein, Mg-0.29 Ce exhibits two low efficiency zones from 250 ? 300°C at 10-2? 10° s-1, 400 ? 500°C at 101 ? 102s-1 and high efficiency zone at 450 ? 500°C at 10-3? 10-1s-1. 4D process maps were generated for the above said alloys which illustrate contours of power dissipation and instability in the 3D space of strain rate, temperature and strain.

Jan 1, 2011

The Environmental Excellence in Exploration (E3) project is driven by the recognition that the minerals industry can only maintain its long term viability by ensuring its continued access to lands to explore for, and develop, new mines. Widespread implementation of sound environmental management practices by the exploration community and improved education and understanding of that by stakeholders will help substantially in accomplishing this, and E3 is designed to meet these needs. Exploration crews are now viewed as ambassadors for the global mining community. Their performance in managing the environmental aspects of an exploration program can demonstrate a commitment on the part of the international mining sector to environmentally responsible exploration and mining. We have all observed that failure to behave responsibly can alienate local residents, encourage anti-mining NGOs and jeopardize development. As the saying goes, ?you don?t get a second chance to make a first impression?, and we want to make a favourable first impression. The E3 project is focused on creating an electronic manual, the e-manual, which will provide rapid access to the most up-to-date information on environmental management practices for minerals exploration globally. The e-manual will reflect current thinking and practices in environmental management. It will be richly illustrated with actual examples that reflect the realities of exploration. It will strive to identify the key environmental issues and concerns that apply to most exploration projects, and identify other sources of relevant information useful to field practice. It is our belief that E3, or something very like it, is central to ensuring that the industry survives the current challenges to its viability. E3 will be a cornerstone of the mining industry?s drive to sustainability simply stated, if we are not permitted to explore for mines, there will be none of them at some point in the relatively near future.

May 1, 2002

By H. C. George

This bulletin deals with prime movers, power-transmitting machinery, and the surface equipment and methods used to pump oil wells. It does not discuss geological problems nor the methods and equipment used in drilling or at flowing oil wells. Much of the presentation is by photographs and drawings which are described in the text. Underground equipment and methods for pumping oil wells will be discussed in a later publication of the Bureau of Mines.

Jan 1, 1925

By Raj P. Singh Gaur

Due to high concentration of NaOH in the digested slurry after scheelite digestion, it is diluted to about 4N before filtration to separate sodium tungstate solution from the sludge (residue). However, in practice there may be deviations in the normality of NaOH present in the slurry. There may also be variations in the temperature of the slurry and filtration time. Slight variations in these parameters could cause tungsten losses in the sludge via the back reaction: Ca(OH)2 + Na2WO4? CaWO4 + 2NaOH This paper pertains to the effect of normality, temperature and time on the tungsten losses in the sludge that is separated from ?diluted-scheelite-slurry-in-NaOH? via filtration. Results indicated that tungsten losses in the filtered residue (sludge) were quite significant when the slurry temperature was kept at 70°C or higher. The effect of high temperature was less significant at the slurry normality of 3.6 or higher. Combination of low slurry normality (<3.6) and high temperature (>60°C) resulted into large W-losses in the sludge.

Jan 1, 2006

By Jewel A. G. Gomes

Electrocoagulation (EC) has been performed with Al-Fe electrode system with changing polarity for the removal of arsenic from water. The removal process has been studied using ICP-AES and Anodic Stripping Voltammetry with a wide range of arsenic concentration (1-1000 ppm) at various pH (4-10) and residence times (1-60 min). Electrochemically generated by-products have been analyzed using XRD, FTIR, XPS, SEM/EDS and Mössbauer Spectroscopy. Results revealed expected crystalline iron oxides (magnetite (Fe3O4), lepidocrocite (FeO(OH)), iron oxide (FeO)) and aluminum oxides (bayerite (Al(OH)3), diaspore (AlO(OH)), mansfieldite (AlAsO4?2(H2O)), as well as some interaction between the phases. The amorphous or ultra-fine particular phase was also found in the floc. The substitution of Fe3+ ions by Al3+ ions in the solid surface has been observed, indicating an alternative removal mechanism of arsenic in these metal hydroxides and oxyhydroxides by providing larger surface area for arsenic adsorption via retarding the crystalline formation of iron oxides.

Jan 1, 2006