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By E. Koufetzis

Rock mass classification systems are core elements of tunneling and empirical mine design worldwide. The Bauxite division of S&B Industrial Minerals S.A. decided to implement a rock mass classification system in order to provide mining engineers and supervisors of the underground mines, with guidelines of stability performance and with a complementary tool for the selection of the appropriate tunnel support. The back analysis system employed is based on visual observation of especially selected underground mine sites, representative of all rock types. This fact combined with the failure or success of the already existing support system, constitute the fundamental part of the work undertaken. The paper is divided into three main parts. In the first part the classification methods of Q, RMR89 and GSI are presented and the advantages and disadvantages of each method in connection with underground mining are indicated. RMR89 and GSI are conclusively selected for use, the main criteria for the selection being, the simplicity in use and the competency of the support system suggested for each rock mass category. The second part points out the methodology for measurements, the practical difficulties encountered during this process and the guiding principles followed, in order to avoid these problems. In the third part, the final conclusion of this project is demonstrated and the different rock mass categories are presented with their relative support recommendations, as they were applied and tested in all phases of the bauxite mines? exploitation. The generated methodology is being implemented by the site mining engineers, for validation and potential improvement.

Jan 1, 2008

The rnunber of Cenozoic volcanoes which has already been found in China surpasses 600. An ancient Chinese tourist, Xu Xiake (1587-1641 in the Ming Dynasty), mentioned in his travel notes the volcanoes and hot 'springs in Tengchong, a country of the Yunnan Province, 400 years ago. In 1927, the geologist, Yun Zhanli, expounded generally on the recent volcano distribution in China. In the '70's, China not only accomplished aerial photography and produced topographic and geological naps covering the whole country, but also obtained a new understanding of the geographic distribution and process of development of the Cenozoic volcanoes through Landsat imagery; interpretation and ground verification, together with C14 isotope dating and analysis of volcanic rocks.

Jan 1, 1987

By N. M. Steven, J. M. Moore, J. L. Kuyper

Mineral exploration and research has led to the identification of four types of tungsten mineralization in the NE-trending, Iargelyensialic, inland branch of the late Proterozoic/early Paleozoic Pan-African Damara Orogen. The mineralization (mainly scheelite) occurs in a terrane (the Central Zone) that is characterized by multiple deformation, greenschist/amphibolite-facies metamorphism and numerous peraluminous S-type granitic and pegrnatitic intrusions. The four major types of scheelite mineralization are (in ascending stratigraphic order of host rock): (1) thin (5 cm to 2 meter) quartz+plagioclase+diopside ± scapolite calc-silicate granofels with fmely disseminated scheelite (scheelite-bearing granofels; SBG) developed as discontinuous intercalations within the calc-silicate rocks of the Khan, Spes Bona, Oberwasser and Kuiseb Formations (Nosib and Swakop Groups); (2) gamet+pyroxene± vesuvianite+scheelite ± fluorite replacement skarns hosted by Okawayo, Karibib and lower Kuiseb Formation marbles in the aureoles of late tectonic, unrnineralized leucogranites; (3) metaturbidite-hosted scheelite- (and possibly wolframite-) bearing tourmalinites, both stratiform and crosscutting, in the Kuiseb Formation located in the 'cleavage fronts' of late tectonic granitoids; (4) scheelite-bearing vesuvianite+quartz+garnet skarnoid rocks (several hundred meters in length) in the calcareous metaturbidites of the upper Kuiseb Formation. These scheelite occurrences were discovered by the follow-up of a large number of tungsten anomalies located during a regional stream sediment sampling program. Detailed mapping, ultra-violet surveys and rock sampling proved to be the most effective surface exploration techniques for locating mineralization; soil sampling and geophysics were of almost no use. The largest, continuous scheelite-bearing skarn of economic interest, Otjua, has a drill-indicated reserve of 250 000 tonnes at 0.53 wt5 WO3 and 8 wt% CaF2•

Jan 1, 1994

By R. V. Ramani, K. V. K. Prasad

Forecasting mined grade variability from exploration information is a challenging task in mine planning. For effective planning of activities, such as workplace scheduling, ore grade quality control, etc., development of realistic numerical simulation models of in situ variability from exploration information is an essential first step. Geostatistical conditional simulation (GCS) is one of the well known methods to develop such simulations. Recently, stochastic fractal models based on the assumptions of scale-invariance and self-similarity have been used for developing simulations of several natural phenomena. It has been suggested that these models might permit the generation of short-scale variability information from exploration data with greater fidelity when the data satisfies the attendant assumptions. In this paper, stochastic fractal models are reviewed, and their relationship to geostatistical variogram models is examined. A comparison of the two simulation techniques has been performed using coal sulfur data from a mined-out coal property. The results of this comparative analysis are also presented in the paper.

Jan 1, 1993

By Bill Paparis

The thirty year old wharf structures at the Port Authority of New York & New Jersey?s Port Elizabeth Marine Terminal are being modernized for the next generation of Post-Panamax container ships, which require deeper water and larger container cranes. The terminal operator is upgrading the wharf in order to remain competitive, now and into the future. The upgrade coincides with the Army Corps of Engineers? $733 million project to deepen the main shipping channel in New York Harbor. This paper focuses on the structural modifications to accommodate berth deepening and to support the heavier loads of the new cranes. An overview is provided of the design and actual construction, including typical problems encountered when combining new and existing structures. The wharf improvements included: ? Installation of a steel king pile/sheet pile cutoff wall along the face of the wharf to permit increasing the depth from ?12.2 m + 0.61 m to ?15.2 m + 0.61 m ( ?40 ft + 2 ft to ?50 ft + 2 ft) ? Removal of the existing crane rail support beams and installation of new piles and beams to support the increased crane loads ? Replacement of the existing timber fender system with a new system capable of resisting the berthing energy of a 152,000 MT displacement vessel, and having dedicated sections for berthing barges ? Replacing the existing overhead, landside crane electric feeder system with a waterside, cable reel trench system. The work included upgrading the transformer capacity at the terminal for increased crane power demands This paper provides a case history for port administrators, terminal operators, engineers, and shipping lines challenged with upgrading aging terminals.

Jan 1, 2013

By K. J. Murphy, A. R. Smith, A. P. Odorski

"The need for large quantities of oxygen for use in metallurgical processes was a major driving force in the commercialization of tonnage air separation plants. Oxygen, nitrogen and argon impact the quality, energy efficiency and environmental aspects of metals production. Cryogenic air separation processes have been used to supply most industrial requirements, however, newer technologies are available or under development to meet the needs of today's and tomorrow's metallurgical processes. This paper reviews the technical features and state of development of adsorption, chemical, cryogenic and membrane technologies. The technologies are compared in terms of plant size, oxygen purity and pressure, nitrogen and argon co-production, product use pattern and back-up requirements. Computer control systems are described that optimize operation over varying load patterns and ambient conditions; substantially lowering energy consumption. IntroductionOxygen production totalled 390 billion cubic feet in 1987. Although current production is lower than the peak of 455 billion cubic feet reached in 1979, oxygen remains the fifth leading chemical product manufactured in the u.s. (1) Metals manufacturing and fabrication accounts for sixty percent of the oxygen consumed in the u.s. Oxygen use in the steel industry consists of air enrichment for conversion of iron ore, purification of the iron in basic oxygen or other furnaces, and for cutting and welding the finished steel product. Nonferrous ores are smelted in oxygen enriched atmospheres to reduce energy consumption and increase capture of sulfur compounds to meet environmental requirements. In the future oxygen usage is expected to become even more important in metals production as energy costs increase, environmental standards become more stringent, and as new coal based processes become commercialized. Oxygen usage per ton of metal in the new direct reduction processes can be up to ten times higher than traditional steel making."

Jan 1, 1988

By L. Adler

The valuable Maximum Utilization Factor (MUF) concept has been extended to other rotating excavators beyond stripping shovels and draglines. In this concept the boom reach and bucket capacity are multiplied to get an MUF, then normalized by dividing by the equipment weight. Statistical analyses were applied to the remaining shovels (hydraulic and cable), draglines, and backhoes. Positive correlations were found. Stripping shovels and draglines were also re-examined. The results provide an estimate of equipment diggability and encourage versatility by the interchange of the boom and the bucket. The concept further clarifies the existing equipment classification by delineating general excavating, loading, and stripping kinds. The results also forecast trends, and noted innovative advances and possible retrogression. Extension to other boom excavators, such as front-end loaders is recommended. The MUF concept provides one of the few indices of gross external characteristics available to the engineer-user of equipment.

Jan 1, 1990

By E. A. Lawrence

The experiences of Canex Placer Ltd. in establishing vegetation on a lead-zinc tailing pond are presented, hoping others with similar challenges will be benefited. History The tailing ponds are the result of 23 years of mining and milling operations, which ceased in August 1970. Roughly 7.9 million tons of lead-zinc ore were removed in that time. The ponds are located between Salmo River and B.C. Highway 3, about 8 miles north of Nelway near the Canada-U.S. border.

Jan 1, 1975

By Tarrant GC

Cement and resin encapsulated tendons are widely used in the stabilisation of mine roadways. One of the main factors in controlling the efficiency of the reinforcement is the ability of the tendon to generate load in response to rock deformation. The analysis of field data from instrumented reinforcing tendons complimented with extensive laboratory investigations have more accurately defined the mechanisms by which load generation occurs. The role of reinforcing tendon profiles, hole geometry and encapsulation medium properties in controlling the reinforcement stiffness and capacity are discussed. The results of the investigation have implications in both the design of rock reinforcing systems and the optimisation of encapsulation mediums and tendons.

Jan 1, 1992

By Karl J. Benecke

Though the first patent on a bucket wheel excavator (BWE) was granted in 1881 in the US, this technology was developed in Germany to the high standards of today. However, this development was only possible in parallel with development of shiftable belt conveyors and boom stackers. The combination of these three types of equipment in the open pits of the Federal Republic of Germany has made lignite the cheapest energy source for power generation, despite the low heating value of German lignite on the order of 8500 kJ/kg (3600 Btu/lb) only. Comparing the costs for fuels used in power generating on the basis of their heating value, the relation between lignite, high quality black coal, and imported crude oil is on the order of 1 to 1.5 to 2.5, hence highly in favour of lignite.

Jan 8, 1979

By S. G. Hardcastle, K. C. Butler, M. G. Grenier

The most common method of determining airflow employed by mine ventilation engineers is the product of i) the average air velocity as measured by a vane anemometer and stopwatch through a continuous traversing technique, with ii) the cross-sectional area of the roadway. This method requires the vane anemometer to accumulate the total flow over the duration of the traverse. Historically, this has been facilitated by a mechanical analog instrument that has either a counter or set of dials that display the flow. Common instruments of this type are Airflow Development's AM5000, Davis's, or Taylor's Biram type anemometer. The AM5000 is widely used in the Canadian mining industry but is no longer available. Therefore, regulatory authorities have seen fit to evaluate presently available commercial instruments to replace the AM5000. This paper describes an instrument evaluation contracted by the Atomic Energy Control Board of Canada which regulates the uranium industry. Over the last two decades there have been numerous advances in the development of electronic air velocity meters. Currently available units have the following features: a) battery operation; b) are compact and can be hand-held; c) employ LCD's, and microelectronic circuitry; and d) provide a time integration for the duration of a traverse. These features make such instruments a possible replacement to the analog units and stopwatch determinations. This paper details five of the new generation of vane anemometers plus a vortex air meter, and it explores their limitations in comparison to analog units. Specific consideration is given to linear response, the effects of yaw, traversing speeds and ergonomics relating to both handling and use. The paper concludes with some features that are attractive and should be considered when purchasing a new anemometer.

Jan 1, 1991

By Raphael Mourad, Colin R. Phillips

Investigation of the traps in LiF:Mg, a multi-peak phosphor, was carried out using simple phosphorescence decay analysis. Half lives at room temperature of the trapping centres (peaks -lb, -la, -1, 0, 1, 2, 3a and 3) in the phosphor after irradiation with [a] radiation were found to be 3 s, 5 s, 28 s, 4 min, 15 min, 1 h, 6 h and 2 d respectively. Justification for the method of analysis is pro- vided and the results of measurements compared with published data. The effects of pre-annealing at 400°C for 1 h and 80°C for 24 h on the trapping configuration and on the trapping efficiencies were also studied.

Jan 1, 1981

By Robert J. Timko

The objective of this Bureau of Mines research work was (1) to determine how well the E. I. Du Pont de Nemours and Company P-2500 personal dust sampling pump controls the flow rate at 2 L/min and (2) to compare respirable dust mea-surements made using the P-2500 with those made using a nonpulsating sampling flow system, both using the Dorr-Oliver 10-mm nylon cyclone dust size classifier. The calibrator and the operation manual for the P-2500, supplied by the manufacturer, were also evaluated. Flow tests consisted of long-term (6-to 8-hour) flow stability tests at various backpressures, a low-flow indicator examination, flow controller response time tests and pulsation tests. Dust tests were performed using coal, silica, and Arizona road dust. No tests were performed to examine effects of temperature, barometric pressure, vibration, or mechanical shock. These pumps performed well within manufacturer specifications in all tests.

Jan 1, 1982

By Kathleen S. Smith, Katherine Walton-Day, James F. Ranville

Four different scales of observation were used to evaluate the potential effects of a fluvial tailings deposit on water quality along the flood plain of the upper Arkansas River south of Leadville, Colorado. First, we collected surficial material and subjected it to batch water-leaching test. Second, we excavated and leached an intact eight-inch diameter core. Third, we examined the water quality of the shallow ground water beneath the fluvial tailings deposit, and fourth, we monitored water quality along a 5-km reach of the adjacent Arkansas River. Leaching of surficial samples indicates that there is a reservoir of readily water-soluble material yielding elevated metal concentrations and high acidity. However, there are minimal measurable water quality effects of the fluvial tailings deposit on the adjacent reach of the Arkansas River.

Jan 1, 2000

By H. M. Howe

It is a grave objection to the present system (or rather lack of system) of mineralogical nomenclature that, in the very great majority of cases, the name of a mineral gives no hint of its chemical composition, one might almost say no suggestion, however faint, of anything connected with it or characteristic of it, chemical, physical, historical, geographical, geological, or lithological. In becoming acquainted with a mineral, in addition to learning its composition and important characteristics, one must also learn a name wholly unconnected with any of them. It has occurred to me that a system might be devised in which the name of each mineral should express at least an approximation to its ultimate composition. It is far easier to learn the names of most minerals than their compositions. Most of us are familiar with the names and appearance of many minerals, especially among the silicates, of whose compositions we have but a rough notion. It would be the aim of such a system to enable us, in making the one slight effort of learning the name of a mineral, by that same effort and involuntarily to learn its composition, which now requires an additional and a much greater effort. I have worked out a system designed to meet this requirement, and its description occupies the remainder of this article. Doubtless there are many devices on which could be based other systems fulfilling the requirement above set forth better than that about to be described does, and at the same time furnishing names

Jan 1, 1884

The following briefing is intended to provide an overview of the present and future challenges associated with our access to a secure and adequate supply of electrical energy necessary to support safe, productive and sustainable mining initiatives at Musselwhite. Contents ??Site power demand vs. current available supply ??Supply technical deficiencies ?adequacy and security of present supply ??Present internal generation ??Anticipated future internal generation requirements ??Increased requirements necessary for planned expansion ?demand/security ??Goldcorp?s strategy to achieve required supply ?transmission line initiative ??Subsequent benefits to others from the Goldcorp initiative. ??Economic impact of MusselwhiteMine on the northwest region ??Anticipated economic impact of planned expansion ??Expected life cycle of MusselwhiteMine ??Comparative energy costs for similar operations in other jurisdictions ??Conclusions ??Anticipated action plan ??Energy Management Initiatives ??Site Orientation

May 1, 2009

By Douglas W. Fuerstenau

Technological innovation is needed to meet the challenges that face the mineral industry because ores steadily become lower in grade, more complex in mineralogy, and must be processed in the face of ever- increasing environmental constraints and increased costs. How periodic innovation in mineral processing helped overcome the challenges that faced the mineral industry is briefly traced from antiquity up to the present time.

Jan 1, 1989

By Heyes GW, Orrock GI

The fine grained complex orebody at Elura contains galena, silver and sphalerite in a matrix which is mostly pyrite; sulphides account for about 90% of the orebody. A differential flotation circuit is operated to con- centrate lead and silver in the first section and zinc in the second. The metallurgical performance to date indicates the need for improvement. The lead section has been sampled in detail to comprehensively assess its overall performance and to define problems associated with lead and silver flotation. The substantial amount of pyrite in the feed dominated the perfor- mance of each stage of the separation. It was responsible for extensive dilution of all concentrates and, as a consequence, for very large circulating loads. The rougher concentrate contained 68% pyrite some of which was rejected through the three stages of cleaning to 39% in the final concen- trate. However, this was still sufficient to hold the assay of this product below 45% Pb. Size by size behaviour shows that flotation rates of the valuable minerals, as characterised by their rate coefficients, were low through- out the circuit. There was a significant deterioration in these rates between rougher and cleaner I stages which resulted in large circulating loads between these stages. There was practically no recovery of coarse valu- able minerals to the final concentrate. The dilution of the final concen- trate by non-sulphide gangue was not a major problem. If the recovery of the galena and silver in the +38¦m size range could be raised to that of the - 381Lm size range, galena recovery would rise from 78% to 86% and silver recovery would improve from 46% to 59%. The Pb grade of the final concentrate would remain the same.

Jan 1, 1988

By He De-wen

The influence of wastewater containing benzene from chemical industry by technology combined blow-off with Fenton reagent oxidation was experimentally studied. The present results suggest that the technology combined blow-off with Fenton reagent oxidation can effectively remove benzene pollutant in wastewater. The main factors that influence the removal benzene such as temperature and blowing time and volume, pH and reagent dosage of H2O2 and Fe2+ are studied and the optimal experimental conditions are as follows: time 20min, temperature 40i, air-blowing volume 0.4L/min, pH value 5, and H2O2 and Fe2+ dosage 2mL/L and 200mg/L respectively. Under the above conditions, benzene pollutant can be removed up to 97%. Compared to other removal ways of wastewater containing benzene, the technology combined blow-off with Fenton reagent oxidation is more effective and has the advantage of high speed.

Jan 1, 2009

By S. R. Hutchins

Several refractory sulfide and carbonaceous gold ores were examined to determine whether microbial pretreatment could be used to enhance gold recovery. Test samples were biologically leached using unique, thermophilic microorganisms to solubilize iron sulfide minerals. Gold recovery from sulfide ores and concentrates was enhanced following pretreatment with the thermophiles; responses varied widely for the individual materials. Although bioleaching had little effect on the preg robbing characteristics of the carbonaceous gold ores, cyanidation of the bioleached residues yielded higher gold recoveries than cyanidation of the native ore. By combining bioleaching with abiotic processes designed to inhibit preg robbing, gold recoveries of 83-98% were obtained from carbonaceous ores yielding 10-50% gold recovery by direct cyanidation.

Jan 1, 1987