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By George H. K. Schenck

In this decade of the 1.970's it is forecast that eight billion cubic yards of rock will be excavated from 400, 000 miles of new tunnels, drifts and other underground workings in the western world, according to estimates in a report of the Organization for Economic Cooperation and Development (OECD). It is expected that the cost of this work will be in excess of $54 billion in constant 1970 dollars. Most of this underground excavation will be in mining -- 97% of the tunnel length and 89% of the volume - -the balance in construction. In addition to this huge excavating task, in the 18 developed nations of OECD, will be projects in the Communist Bloc and in the developing nations. Underground excavation requires the successful completion of three principle activities: A. Break -- to free rock from the solid work face. B. Remove-- to clear the work area of broken rock. C. Support -- to assure stability of rock surrounding the underground excavation and to eliminate risk of rock collapse. In today's fully mechanized excavation systems, continuous miners, roadheaders or tunnel borers, (A) break the rock loose from the face, and (B) remove broken rock with their mucking devices and load it onto belt conveyors, mine cars, trucks, or any other appropriate haulage system for disposal. Such operations contrast to the more complex, intermittent systems employed when

Jan 1, 1974

By Anna Carolina Cerqueira Neves

As fibras sintéticas vêm sendo gradualmente substituídas por fibras naturais. Em comparação com a fibra sintética, fibra natural demonstrou vantagens econômicas e ambientais. Visto que apresenta características interfaciais com matrizes poliméricas que favorecem a absorção de energia de alto impacto pela estrutura. No entanto, até agora pouco foi avaliado sobre a fibra de cânhamo incorporada em matrizes poliméricas. Este estudo tem o objetivo de avaliar a resistência ao impacto deste tipo de compósito com matriz de poliéster reforçada com diferentes porcentagens de fibras de cânhamo. A resistência ao impacto aumenta proporcionalmente com a quantidade relativa de fibras incorporadas como reforço na matriz polimérica. Este desempenho foi relacionado com a dificuldade de ruptura imposta pelas fibras, resultante da interação da matriz de fibra de cânhamo / poliéster de forma a ajudar a absorção da energia de impacto.

Aug 17, 2017

By Henry Howe

1. Introduction.-This paper is based in large part on the examination of two rings, shown in section in Fig. 4 to 15, cut from an eroded 14-in. (35.56-cm.) gun, liner, and containing, according to Booth, Garrett, & Blair: Carbon, 0.380 per cent.; manganese, 0.655 per cent.; nickel, 2.810 per cent.; vanadium, 0; chromium, a few hundredths of 1 per cent.; tungsten, 0; molybdenum, 0. These rings were received from Admiral Joseph Strauss, then Chief of Ordnance, U. S. Navy, through the kindness of Mr. Hudson Maxim, Chairman of the Committee on Ordnance and Explosives,, of the U. S. Naval Consulting Board.

Jan 2, 1918

By A. Bamber

Canadian leadership in a global mining context will depend not only on entrepreneurship and best practice but also on technological innovation. This paper argues for more ambition and commitment to R&D for technological innovation in Canadian mining. It focuses on underground hardrock mining, where past R&D initiatives have simply not stood the test of time, and it is important to examine why. Concerns arise because industry’s commitment to R&D has not been sustained over time. Innovation through exploration, processing, and environmental technologies has been more significant. Meanwhile, R&D capacity and synergies in government institutions and universities have not been exploited. There is a need for more commitment, coordination, and collaboration by industry, governments, and universities. This paper examines some corporate models that have achieved sustainable innovation, along with some that have not. A strategy for innovation is discussed that relates to culture, commitment, coordination, and collaboration.

Jan 1, 2005

By Roger Scarr, Richard A. Walker

Interactive video is the combination of computer and laser disc -technologies that allows for the storing of 54,000 single images or 30 minutes of video with the ability to access any segment or single image within a half a second. This capability combined with the use of a graphics overlay on the video and accessed through a keyboard or touchscreen creates a very powerful and versatile marketing or training tool.

Jan 1, 1990

By Zeng Zheng, Liu Chen, Yu Xing-Fu, Tian Su-Gui, Zhang Chao

"Single crystal nickel-base superalloy is prepared by using the various withdrawing rates. By measuring creep properties and microstructure observation, the influence of the element segregation on creep properties of the superalloys is investigated. Results show that the dendrite spacing and the segregation extent of the elements decrease with the enhancing withdrawing rate. The superalloy with smaller dendrite spacing has lower segregation of the elements and better creep resistance. The dislocations climbing over the rafted y’ phase is thought to be the deformation mechanism of the alloy during steady state creep. In the later stage of creep, the fact that some dislocations shear into the rafted y’ phase may twist the rafted y’ phase. As the creep goes on, the initiation and propagation of the cracks occur up to occurring creep fracture, which is thought to be the fracture mechanism of the superalloy during creep.1. IntroductionSingle crystal nickel-based superalloys consist of high volume fraction of ?? strengthening phase and ? matrix, and possess the excellent high-temperature mechanical and creep properties, therefore, they have become the main material to make the blades of the advanced aeroengines[1-3]. Some literatures report that the temperature-bearing and creep-resistance properties of the single crystal nickel-based superalloys can be remarkably improved as the increases content of the refractory elements, such as W and Re[4-6]."

Jan 1, 2012

By M. De Ladurantaye-Noël, M. Laliberte

Selenium is widely present in the environment at usually low concentration. It is mostly present in the environment at higher oxidation states, i.e., as selenites and selenates (+4 and +6 oxidation states respectively). It is rarely present as selenides (-2 oxidation state) and almost never found as the element (0 oxidation state). Selenites and selenates are generally soluble in water, as such they cannot easily be removed from water by precipitation. Selenites can form insoluble surface complexes with metal oxides such as ferric hydrous oxide and manganese hydroxide, and can therefore be removed that way. However, it is not so common to find selenites in natural environments as it will quickly oxidize to selenate in aerobic conditions. Elemental selenium can also be produced from selenites or selenates by using a reduction process; the end product is a colloid that can be destabilized to be removed from water using the right chemistry. Because of their toxicity, selenides need to be handled with care, and if present, it can form insoluble metal salts or, at low pH, be emitted as H2Se, a noxious and highly toxic gas. The most favorable selenium forms for its removal are therefore selenite and elemental selenium. Organo-selenium species play a crucial part in understanding selenium toxicity. There are a great number of these species. Basically, any organic species that contains sulfur has an equivalent that contains selenium. Of particular interest is the substitution of sulfur by selenium in the two sulfur-bearing amino acids, cysteine and methionine, resulting in selenocysteine and selenomethionine. Methylseleninic acid (CH3SeO2H) is another organo-selenium specie which has been detected in water treated by biological processes and which is biologically active.

Feb 1, 2023

By George Chung

"The Iron Ore Company of Canada's Carol Lake Project is Located near the western boundary of Labrador, 960 air kilometers northeast of Montreal (Figure 1).The Concentrator operation was started in 1962 with a capacity to produce 7 million tonnes of concentrate per year. The bulk of the concentrate was pelletized at a 6 million tonnes per year pelletizing plant completed in 1963. The remaining concentrate was sold in the international market. The concentrator was first expanded in 1966 to 10 million tonnes per year capacity with the pellet plant also expanded in 1967 to match the increase in concentrate production. In 1973, the concentrator was further expanded to gear with the increase in concentrate sales. In 1977, more than 40 million tonnes of crude ore was processed to produce in excess of 17.4 million tonnes of concentrate and 10.4 million tonnes of pellets."

Jan 1, 1980

By B Stump

Reliable particle size analysis in minerals processing plants is a critical factor to the economic return of a plant. As recovery of valuable minerals is compromised for particles outside the optimal size range, effective and reliable particle size analysis is more crucial than ever, particularly in the current upswing of the global commodities market. Inefficient particle size analysis can lead to excessive over-grinding, thereby significantly increasing energy consumption and reagent costs, whilst negatively affecting process operation, thickening capacity, water recovery and tailings disposal.Australia’s first installation of a particle size analyser in Iron Ore has been monitored with great interest by the industry. Previously, manual size sampling at Rio Tinto’s Paraburdoo fines processing plant involved off-site sample analysis, with a turnaround measured in days. The Outotec PSI® 500 particle size indicator, commissioned in July 2009, takes approximately three minutes per line at site.The paper will include details on the following:• plant description,• sampling design,• PSI® 500 analyser functionality description, and• key learnings from site.

Jul 11, 2011

By Michael Horn

[An economic trading region made up of 22 eastern Washington, northern Idaho, and western Montana counties, with Spokane, Washington as the central place, was defined for this study. modeling system with the, 1985 county database was to create an Input/Output based model of the regional economy. The leading ice, with respect to income, employment, value of exports, and total industry output are shown for each county and the region. The value of total industry output from natural resource based industries is also shown for each county and the region. Interindustry transactions, final demand, and value added components for the region are shown in the Regional Gross Flows Table. The total gross output for the region is valued at $36.7 billion. Total industry output for the region is $18.1 billion. The region provides $5.4 billion in income to a work force of 286,000. Spokane County, Washington accounts for about 50 percent of the regional total industry output, income, and employment. Both Spokane County and then as a whole produce about 80 percent of the total industry output for final demand with remaining 20 percent going to intermediate inputs for further production. Spokane County exports about 43 percent of its total output while 35 of the regional output is exported. Exports account for more 50 percent of the total in 18 of the 22 counties within the region. About 9 percent of the total industry output from Spokane County and 19 of the total output from resource f: .t *III For counties Spokane a industry ? N from nafural resource based represents 18 percent ?.{1 to 71 s. ?-{ and averages 39 r. ?-11 of total county +' ' 7:. FS.-f.?) If t. Natural resource it us -t for more than 50 coutny 1 s ? sass in seven counties within region.]

Jan 1, 1992

By R. P. Walters, M. J. Lynch, D. R. Flinn

The Bureau of Mines evaluated tthhee feasibility of substituting platinum- coated metals for bulk platinum shapes as a means for conserving platinum . Platinum coatings were prepared using four different methods of electrodeposition , then tested and evaluated . In order for platinum coatings to be useful in process environments , they must be thick , adherent , stress - free , and pore - free . The Bureau evaluated direct - current , current reversal , cathode shielding , and pulsed- current plating techniques for producing a pore-free platinum electrodeposit from a molten cyanide bath . Aqueous corrosion tests of Fe - 10Cr substrates coated with approximately 25 μm of platinum showed that pulse plating yielded the most corrosion- resistant and , hence , the most pore -free coatings . The morphology of coating cross sections was in all cases columnar . The average grain size of pulse -plated deposits was independent of thickness , while all other plating techniques produced grains that increased in size as the coatings became thicker . It is believed that the constant grain size in the pulse - plated deposits resulted from better mass transport during the electrodeposition .

Jan 1, 1965

By Tuncel M. Yegulalp

This article summarizes some of the results of the continuing research activity at the Henry Krumb School of Mines, Columbia University, directed towards a better understanding of the stochastic behavior of slurry flows in underground coal-slurry pipeline systems. The slurry system under consideration here replaces all conventional haulage systems between the coal face and the coal preparation plant on the surface. At the beginning of the pipeline system, flow rate and frequency of coal slurry is very closely related to the activities of production equipment at the coal face. Due to several scheduled and unscheduled interruptions in continuous miner's coal mining activity, resulting slurry flows possess stochastic characteristics. Proper understanding of these characteristics is believed to lead to a more realissic and economic design of slurry handling equipment. Fundamental ideas supported by field observations are presented and a Semi-Markov model of the slurry flows is developed. As a result of this formulation, behavior of combined slurry flows from N independent coal faces can be expressed in analytical form. The contents of a slurry surge tank receiving slurry flows with certain stochastic characteristics is investigated as a function of discharge pump characteristics and time.

Jan 1, 1981

By C. A. Young

The remediation of cyanide (CN-) and nitrate (NO)-) anions in mine and agricultural waters by various photolytic methods has been reviewed and investigated. Photolytic methods such as direct photolysis, homogenous photolysis, and heterogeneous photocatalysis are briefly described and compared. Results and discussions show that each method has certain advantages and disadvantages. For each method, Eh-pH diagrams prove useful for determining reaction mechanisms. Preliminary results obtained for cyanide oxidation and nitrate reduction show that homogeneous photolysis can be superior due to faster kinetics than the other methods. The photolytic methods were individually, not simultaneously, tested and compared. Differences in concentrations of products were obtained and attributed to differences in photoconversion efficiencies and other inherent characteristics of .the photolytic methods. Various reaction mechanisms are proposed in accordance with the literature as well as measurements obtained from solution analysis using ion selective electrodes and ion chromatography .

Jan 1, 1995

Geotechnical conditions in the Lochiel Deposit are somewhat unusual, and thus geotechnical and hydrological investigations have assumed a high priority. The cost of mining the deposit has been shown to be very sensitive to geotechnical design parameters, and it is now seen to be of paramount importance to establish a high level of confidence in the design parameters used for mining cost estimation. Geotechnical investigations in the Lochiel Deposit reached a crossroads in 1985, when there appeared to be several quite different and equally attractive routes to follow to establish a satisfactory level of confidence in geotechnical mine design parameters. Three main options were identified, referred to as the No Further Work Route, the Drill and Trench Route, and the Trial Pit Route. The No Further Work Route was ruled out as being technically unsound and as satisfying none of the Electricity Trust of South Australia's (ETSA's) or the State Government's requirements. The planning process for further geotechnical investigation involved: clearly identifying the current status of work and significant geotechnical and geological factors planning and costing the alternative schemes for improving knowledge assessing the increase in knowledge to be gained from the alternative schemes . choosing the preferred scheme This process resulted in ETSA's

Jan 1, 1986

The Ngakuru zeolites are located about 20 km south of Rotorua and comprise a number of deposits dispersed along several fault lines. Relatively recent volcanic activity (250,000 years ago) resulted in ash depositions that vary in depth and mineralogy. Subsequent variable thermal alteration intensities generated predominantly clinoptilolite and mordenite zeolites with a range of physical characteristics. Typically the zeolites have low density (650 kg/m3), have high liquid (60% of dry weight) and odour absorption characteristics, and a high affinity for soluble cations (CEC =: 100 meq/100 g). Traditional kitty litter and oil absorbency markets are being expanded. New opportunities in waste and potable water treatment, organic and synthetic slow release fertilisers, use as a light weight aggregate for speciality concretes, and pozzalome activity are currently being researched.

Jan 1, 2000

By S Hawker, M Gibbs, A Craven

Current climate change projections suggest both an increase in the intensity of significant rainfall events and an increase in the variability of rainfall in some regions of Australia. It is necessary for mine site owners and operators to understand the effects that this potential shift in climate may have on their operations. The ability to maintain compliance with discharge regulations and operational security for those sites that rely on surface water run-off harvesting may be negatively impacted if some current climate change projections are realised. Although current regulations require the preparation of water management plans, these are generally developed using historical climate records for the site in question and as such do not give any indication of a siteÆs resilience to the influences of climate change.This study compares design and operational considerations for a case study mine site using historical rainfall records and modified records representing climate change projections. The future climate models are invariably broad scale and are limited in their capacity to be downscaled to a reasonable resolution for developing a site water balance. Instead the local historical data set has been modified to concentrate precipitation to peak periods and propagated through the model. The study looks at the siteÆs response to the potential changes in climate.It is shown that if current climate change projections are realised, this will have a significant effect on both the necessary size of designed surface water infrastructure and operational considerations on-site. A discussion is presented on the potential risks that climate change presents to mine sites and the range of options that could be considered to mitigate these risks. Depending on a number of factors, including location and risk profile of the owner/operator, resilience to climate change can be addressed as either a capital or operational expenditure (CAPEX/OPEX).CITATION:Craven, A, Hawker, S and Gibbs, M, 2013. Site water balance response to variable climatic conditions, in Proceedings Water in Mining 2013 , pp 211-216 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

The Wattle Dam gold mine, located near Kambalda in the Goldfi elds region of Western Australia has recently progressed to an underground operation and is now believed to be Australia's highest grade operating gold mine. At end of March 2010, the deposit had reserves of 132 000 t @ 20.8 g/t for 88 000 oz and by the end of June 2010 had produced 110 000 oz from open-pit and underground mining. The Wattle Dam main lode is characterised by very coarse gold mineralisation. Gold occurs as cm to decimetre fracture fi ll veinlets, shear surface coatings and erratic fl akey clusters. The gold has no quartz or silica association and lacks adjacent low-grade mineralisation or alteration assemblage. Geologically it appears atypical of Archaean lode gold deposits and may represent an extreme end member of the type. Definition of the lode is largely dependent on effective geological identification of the host lode zone and an understanding of the erratic distribution and grade behaviour of a high-nugget, coarse gold deposit. Dependence on assay data to defi ne the lode zone would result in the deposit being mined incorrectly and much of the deposit being left unexploited. This paper discusses the geology, coarse gold characteristics and defi nition methods which are used to successfully defi ne and mine the deposit.

Aug 1, 2010

On Feb. 16, 2012, the Polish coal mining company Lubelski Wegiel Bogdanka S.A. set the world record for daily production from a plow-equipped longwall, with an output of 24.4 kt (26,900 st) of coal from a single face. The company commissioned the first Cat longwall system at its Bogdanka Mine, near Lublin in eastern Poland, in March 2010 and within six months had raised the bar to nearly 17 kt/d (18,700 stpd) of cut coal. Since then, Bogdanka has continued to increase its daily output with a plow face that began mining in the new 7/VII/385 panel last October, taking the world record to new levels. In addition to the record output achievement, the plow face advanced more than 27 m (89 ft) at a 1.63-m- (5.3-ft-) cutting height. ?We thought this achievement would be impossible for any shearer in seam heights as low as this,? said Zbigniew Stopa, vice president of Bogdanka.

Jan 1, 2012

By C. Lurie

This final report describes the work performed by Gulton Battery Corporation under USBM Contract No. HO-112033, entitled "Research and Development on Lithium-Nickel Fluoride Batteries For Mint Life Support Equipment". The lithium-nickel fluoride couple was chosen For this investigation because of its high theoretical energy density (626 Wh/lb), its ability to operate at ambient temperatures and the fact that it showed promise as a secondary system. The theoretical energy density of the lithium-nickel fluoride couple is ten times greater than that of the widely used lead-acid battery and three times greater than the silver-zinc battery which has the highest theoretical energy density of the commercially available secondary systems. The experimental program first evaluated the cell components individually. The results of these studies then formed the basis for investigations of cell performance using experimental three-plate cells. These cells consisted of one nickel-fluoride and two lithium electrodes. All work was performed in a glove box under an argon atmosphere which was sufficiently pure to maintain the shiny appearance on freshly prepared lithium surfaces. The major portion of the work effort was concerned with the nickel fluoride electrode. Binder, conductive diluent, fabrication technique, as well as the nickel fluoride active material itself, were considered. Criteria for binder materials were established and six classes of materials encompassing thirteen binders were evaluated. The candidate materials were initially screened for appropriate chemical and physical properties and finally evaluated in three.-plate cells, Two epoxy powders emerged as the most promising binders. Two types of conductive diluent were evaluated. The first is a carbon black of low bulk density and high surface area. This material is a good conductive diluent; however, electrodes fabricated with it lacked good mechanical strength. It was hypothesized that a uni¬form, small particle size, low specific surface area would improve the mechanical properties of the electrodes. Therefore, two samples of graphicic materials, milled to uniform powders in the one-to-ten micron range were evaluated. Electrodes prepared with the graphitic materials had superior mechanical properties, However, their electrical performance was significantly poorer and voltage losses of 0.2 to 0.3 volts were observed. Several electrolyte solutions were evaluated. N-Methyl-2-Pyrrolidone was tested but found to be incompatible in the presence of lithium. Lithium perchlorate, lithium hexafluoroarsenate, and lithium bromide were tested as two-component electrolytes in propylene carbonate solvent and their performance compared with that of the single electrolyte solutions, Lithium perchlorate gave the best performance. Lithium hexafluoroarsenate was also evaluated in methyl formate and appears to give equivalent performance. The lithium perchlorate-propylene carbonate system is preferred as it is easier to handle and less expensive.

Jan 1, 1973

By Andreas Bienz

The safety of persons from accidental explosions and fires during manufacture, storage, transport etc. of explosives, pyrotechnics, propellants, firework and ammunition is most commonly assessed according to prescriptive rule-based approach: Safety is given when all requirements which are listed in numerous regulations and directives (such as e.g. safety distances, limited quantities, protective installations etc.) are complied with. Such a deterministic prescriptive rule-based approach is quite easy to apply but has got disadvantages, however: The actual state of safety in a specific case is not explicitly and quantitatively expressed, and it is not distinguished between the endangered individuals and the whole group. As a result, the effects of the safety measures cannot be measured. This is why uneconomical and in the worst case useless safety precautions cannot be avoided. In addition, waivers are difficult to negotiate, meaningful and sound arguments for pro and con being lacking.

Jan 1, 2007