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By Noan Tonini SImonassi

Fibras de rami (Boehmeria nivea) estão entre as lignocelulósicas naturais com potencial para utilização em compósitos poliméricos. O presente trabalho avalia a resistência ao impacto deste tipo de compósito. Corpos de prova normalizados foram confeccionados com percentuais de até 30% em volume de tecido de rami alinhadas ao longo de todo o comprimento. As fibras foram embutidas sob pressão em matriz de resina poliéster do tipo ortoftálica curada à temperatura ambiente por 24 horas. Os corpos de prova foram ensaiados em pêndulo de impacto Izod e as superfícies de fratura analisadas por microscopia eletrônica de varredura, MEV. A resistência ao impacto aumentou exponencialmente com a quantidade relativa de tecido de rami reforçando o compósito. Este desempenho foi associado à dificuldade de ruptura imposta pelas fibras bem como ao tipo de trincas resultantes da interação tecido de rami/matriz de poliéster que ajuda a absorver a energia do impacto.

Aug 17, 2017

By Paul D. Merica

This year of 1926 marks the 40th. anniversary of nickel mining in Canada. Although the first nickel mine of the Sudbury basin was discovered in 1883, it was not until 1886 that the Canadian Copper Company was organized and actually began to mine copper-nickel ore from the Lady McDonald, Stobie and Evans mines. The intervening years have witnessed some exceedingly interesting nickel history, particularly interesting and gratifying as well to Canadians. Forty years ago, at the inception of Canadian nickel mining, the world's consumption of that metal was about 1000 tons per annum and this was supplied largely from New Caledonia ores refined in France. This nickel was used principally for the production of nickel-silver, coinage alloys, and for nickel-plating. No processes were then known for refining the Sudbury ores nor for the separation of copper from nickel. Consequently, the pioneers in Canadian nickel mining faced the double problem of finding a method of treating their ores, and of finding a market for the nickel when and if they could extract it.

Jan 1, 1926

By K Ehrig, V Liebezeit, E Macmillan

The results from metallurgical test programs are used in feasibility studies for design of new plants and brownfield expansions, in long term mine plans, and to make decisions in an operating plant. There are many elements which contribute to a well-constructed test work program. Ultimately, understanding the accuracy and precision of the test work results is critical to ensuring good decision-making at various phases of a project.Every resource drilling and associated assaying program will have a quality assurance / quality control (QA/QC) component, however this often seems to be overlooked in metallurgical testing programs. The principles of “international standard” or “certified reference material” samples and replicate/duplicate testing can be applied to metallurgical programs, although there are metallurgical-specific considerations in both generating and analysing the data.This paper will describe the QA/QC program carried out within the Olympic Dam geometallurgy program. It will present results in the form of case studies from ten years of testing of replicates and bulk reference samples for industry-standard comminution tests as well as laboratory flotation and leaching tests. The Olympic Dam geometallurgy quality control program has enabled quantification of the precision of metallurgical testing and improved our understanding of the best possible modelling results given the underlying dataCITATION:Ehrig, K, Liebezeit, V and Macmillan, E, 2017. Metallurgical QA/QC – who needs it? The Olympic Dam experience, in Proceedings MetPlant 2017, pp 31–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By M. R. Geer

The Bureau of Mines surveyed the solid wastes that have accumulated from coal mining in Washington, Oregon, and Montana. Location, amount, character, and condition were determined, and both economic and environmental factors were considered. Areas covered by waste comprise 800 acres in Washington, 5 acres in Oregon, and 1,200 acres in Montana. In a few cases waste is being utilized, particularly cinder from burned refuse dumps, as fill in road construction and as a ceramic raw material. It is estimated that wastes deriving from coal mined for electric power generation by 1974 may amount to 3 million tons of washery refuse, 2.7 million tons of fly ash, and 1,000 acres of spoil banks.

Jan 1, 1969

By Thomas Lardner

Excavation for The Bow, EnCana, in downtown Calgary, occurred between May 2007 and September 2008. A monitoring programme was used to determine the behaviour of the shoring wall, soil and bedrock during the excavation for the 21 metre (69 ft) deep excavation with a footprint of approximately 17,000 m2 (183,000 sq ft). Results from the inclinometer readings indicated that significant horizontal movement due to a weak rock layer and shear band effect. These modes of movement account for up to 100 mm (4.0 in) and 45 mm (1.8 in) of lateral deflection, respectively. Based upon the results of the monitoring programme, rock samples were collected from the weak mudstone bedrock, with great difficulty, to determine the strength and deformation parameters. Results from the uniaxial compression tests indicate a UCS around 830 kPa (120 psi) and elastic modulus between 80 and 180 MPa (11 and 26 ksi). Mohr-Columb parameters were determined to be c' = 340 kPa (49 psi) and f' = 24°. Residual strengths were determined to be c'r = 0 and f'r = 15°. Using the results of the laboratory tests and field investigation records, an initial finite element analysis was conducted. Results of the analysis show good correlation when compared with the observed monitoring deformation, indicating accurate portrayal of rock parameters. Additional analysis and investigation is required to determine the principal horizontal stresses in magnitude and direction.

Jan 1, 2010

By Flaviani Marculano Marchesi, Silas Gambarine Soares, Elton Volkers do Espírito Santo, Felipe Fardin Grillo, Heitor Cristo Clem de Oliveira

O objetivo deste trabalho é utilizar a termodinâmica computacional para estudar as propriedades de escórias iniciais dessulfurantes utilizando misturas com diferentes fluxantes: fluorita, sodalita, borra de alumínio, B2O3 e ilmenita. A princípio, as misturas foram definidas e em seguida foram realizadas simulações para o aquecimento dessas misturas a 1350 ºC por meio do software FactSage 7.2. Assim, foi calculado o fator de dessulfuração (FDeS) para cada mistura com base nas condições de equilíbrio. As misturas contendo 5 e 10% de fluorita e 5% de sodalita foram as que apresentaram maior FDeS. Em contrapartida, as misturas com 10,15 e 20% de B2O3 tiveram os piores resultados nessa análise. Misturas da literatura também foram simuladas a fim de se obter o FDeS e relacioná-lo com a eficiência.

Oct 1, 2019

By Thomas J. Peters

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 7,000 acres of the 9,240-acre Little Blitzen Gorge Wilderness Study Area in Harney County, OR, to evaluate its mineral resources. The study area is dominated by a 1,500-ft-deep canyon that was carved by Pleistocene glaciers in gently westward-dipping homoclinal flows of Miocene Steens Basalt. The Bureau reviewed pertinent literature and county mining records During the field investigations, 18 rock samples were collected from basalt dikes, breccia, fractured or porphyritic flows, and 20 alluvial samples from gravel accumulations. Mercury anomalies from sampling by the Oregon Department of Geology and Mineral Industries could not be verified. The mercury might have originated -From the Pike Creek Formation, a known mercury-producing unit that may extend into the study area beneath the Steens Basalt. Any epithermal deposit at depth would be expensive to explore and develop.

Jan 1, 1986

By J. Harrison Daniel

Were the legislators and politicians responsible for the closing of the U.S. Department of the Interior?s Bureau of Mines (Bureau) in March 1996 fully aware of what they were doing? Throughout the United States? history, the domestic mining and minerals industry has been largely responsible for the nation?s growth and prosperity that had made it a world leader. The mining and minerals industry made it possible for the young nation to catch up with Europe during the Industrial Revolution, played an essential role leading to victories in World Wars I and II and was a core ingredient for continued economic growth. For a number of decades, America?s import dependency on non-fuel mineral materials has continued to increase. (USGS Mineral Commodity Summaries). Developing domestic resources to meet current and future demands ? particularly those resources considered to be of strategic and critical value to national security ? is necessary. Federal involvement is required since many of these resources are located on public lands. Another reason for federal involvement is that the success of the industry depends on long-range research programs and advances that may take up to 25 years to become commercially available. This situation requires federal partnership to coordinate the programs necessary to collectively involve the industry, individual mining companies and colleges and universities. So, how was it possible to close a federal agency that had contributed so much to the nation?s welfare in a mandated 90-day period, with more than 1,200 employees losing their jobs?

Jan 4, 2010

Once every three years the eyes of the construction and mining industry?s turn to Munich, Germany for the bauma trade fair and exhibition. From April 19-25, Messe München International (MMI) will host the 29th edition of this massive show that, despite the recent recession and global financial struggles, has grown yet again. The show, which is completely booked, will take place on a record 555,000 m2 (5.9 million sq ft) of indoor and outdoor exhibition space at the New Munich Trade Fair Centre. More than 3,000 exhibitors are expected to make use of this event. To prepare for the show that highlights some of the largest and most impressive construction and mining equipment in the world, Messe München began working months in advance on getting the infrastructure on the open-air site ready, in time for the arrival of the gigantic machinery exhibits, which started to arrive in March. Part of the preparations include a new entrance at the northwest corner of the exhibition center that was built to regulate visitor flow better. This should help with bauma considering that in 2007 more than 500,000 visitors passed through the gates. ?Although in 2010 the construction machinery sector in many markets worldwide will be recovering only slowly from the recession, we are pleased to report that we are seeing strong demand for exhibition space. This shows that exhibitors regard participation in the world?s leading trade fair bauma as a must, although many are at present having to make cuts in their advertising and trade-fair budgets. We have been particularly surprised by the strong demand for space from exhibitors from markets like China, India and Turkey. The fair is fully booked and many more companies are on the waiting list,? said Eugen Egetenmeir, managing director of Messe München. More than 50 percent of the exhibitors at bauma 2010 come from countries outside of Germany. While the show?s primary focus is on the construction section, it is not as if the mining sector will be difficult to find. With some of the largest equipment in world on display in section C2 (Fig. 1), the mining industry is sure to be well-represented.

Jan 4, 2010

By Hyung-woo Kim, Sup Hong, Sung-Soo Kim, Chang-Ho Lee

A deep-seabed integrated mining system, which consists of four subsystems such as riser pipe, buffer, flexible riser, and tracked vehicles, is presented in Figure 1. In order to collect more manganese nodules, multiple tracked vehicle systems should be used in a deep-seabed integrated mining system.

Sep 1, 2014

The Río Agrio of northern Patagonia, Argentina, is highly acidic due to inputs of volcanic gases (SO2, HCl, HF) in its headwaters. The watershed includes a hyper-acidic (pH <0.5) volcanic crater lake, a larger glacially carved lake that is also strongly acidic (pH 2.6 to 2.7) and an acidic river that flows for more than 40 km (25 miles) before its pH is completely neutralized. This unique watershed has many geochemical and biological similarities to acid waters caused by mining. This paper describes the Río Agrio watershed and draws a comparison with some famous acid mine waters. Learning more about naturally acidic lakes and river systems could have important applications to the bioleaching of ores or biological treatment of mine waters. Therefore, it should be of interest to the general community of mining and metallurgical engineers.

Jan 1, 2008

By V. Rajagopal

Corrosion and abrasion properties of a series of chromium-containing cast iron balls with Cr contents ranging from 0 to 29% was evaluated and compared with austenitic stainless steel and mild steel balls. Marked ball wear tests were performed on artificial ore samples consisting of 95% quartzite with either 5% pyrrhotite or 5% chalcopyrite under a nitrogen or oxygen atmosphere. The electrochemical mechanism was investigated by correlating the corrosive wear with the corrosion currents obtained from potentiodynamic polarization curves under abrasion. An offset in their electrochemical activities was observed somewhere between 16 and 26% Cr. In fact, 26 and 29% Cr cast irons showed an excellent corrosion resistance approaching that of austenitic stainless steel. Flotation recoveries were estimated on a 95% quartzite + 5% pyrrhotite sample ground with various cast iron ball materials under an oxygen or nitrogen atmosphere. Electrochemical results are found to be in good agreement with corrosive wear obtained from marked ball wear test and with flotation results.

Jan 1, 1991

During the period 1979 thru 1982. Multi Mineral Corporation conducted a mining research program at the United StAtes Department of the Interior&apos;s Bureau vi Mines Oil Shale Mining Environmental Research Facility in the Central Piceance Creek Basin, Rio Blanco County, Colorado. The program consisted of mining, environmental and geotechnical research data and. the results are described in this report.

Jan 1, 1983

By Dianne C. Marozas

The U.S. Bureau of Mines is conducting research to evaluate the potential for developing an in situ leach mining process that will selectively extract manganese from oxide ores, leaving gangue relatively undisturbed. To accomplish this, a geochemical approach, based on deposit-specific information such as mineralogy and geology, is used to constrain the operating parameters of the system. Among the studies being conducted are (1) leaching experiments to define reaction mechanisms and kinetics, (2) detailed petrologic characterization at the microscopic scale to assess Mn distribution and leaching efficiencies, (3) deposit characterization and evaluation, and (4) development of potential Mn recovery schemes. Data from these studies are being used to develop engineering design information for an in situ mining process. Specific details of the Bureau&apos;s research project are discussed, including results obtained to date.

Jan 1, 1991

By R. Adsero

"A high altitude review of the state of the mining industry provided by a study of multifactor productivity shows a continuation of lower output year on year for the capital and labor inputs applied. The story is sadly similar for both U.S. mining and the Australian mining sector. In fact, according to PwC analysts, the world’s mining equipment productivity has declined 20 percent during the past seven years (Lumley, 2014). Although the reasons for the continuing decline in mining productivity are varied, the need for improvement is clear.The world’s mining industry fleet of more than 400 large draglines moves billions of tons of overburden and ore (phosphate, limestone, etc.) annually. This discussion will review a few of the tools available for improved productivity in dragline operations.Benchmarking equipment performance exposes the possibilitiesIn the September 2013 Mining Engineering cover story Graham Lumley and R. Adsero suggested that analyzing best practice equipment performance from an industrywide database for specific equipment performance improvement goals would be beneficial (Adsero, 2013). Benchmarking equipment performance by normalizing differences and then comparing specific measures of performance will provide a road map to improvement for those following the leaders. For those already performing at best practice levels, a benchmark confirms and bolsters what has already been achieved. As described in the SME February 2014 paper by this author, best practice is the average of the top 10 percent in annual output. Filling performance gaps identified by a comparison to best practice by investigating the details of the why and taking action to change, makes all the difference. This is true for all major mining equipment. Given the large gap between average performance and best practice performance most mining operations can benefit. Best practice performance provides a view of what is possible to the 90 percent majority of mining operations that are performing below the top 10 percent.For dragline mining operations, identifying specific characteristics and practices of leading dragline performance will provide a reference for comparison."

Nov 1, 2016

By Donald F. Hammer, Donald W. Peterson

The Magma mine at Superior, Arizona, has produced over 13 million tons of ore yielding 1.5 billion pounds of copper. It is a mesathermal deposit, and, although the bulk of the ore has come from the Magma vein, most of the recent production has come from replacement deposits in limestone. The mine lies in a Precambrian and Paleozoic sequence of rocks that includes schist, diabase, quartzite, shale, and limestone; nearby, these rocks are intruded by igneous bodies of Mesozoic age that were probably the source of the ore-bearing fluids. Locally, these rocks are overlain by Cenozoic volcanic rocks and conglomerate. Layered rocks at the mine dip eastward about 30°. The area is extensively faulted, and surface faults are grouped into an earlier east-trending set and a later northtrending set. An additional set of diagonal faults that trends northwest and northeast is recognized underground. The east-trending Magma vein-fault, with its splits and branches, is the principal mineralized structure of the district. The bulk of the ore occurs in large ore shoots that plunge steeply westward and are sporadically connected by irregular ore shoots dipping gently eastward. The main ore controls apparently are selective zones of permeability related to the transverse faults. A bed of crystalline limestone near the base of the Martin Limestone (Devonian) is the host for the replacement ore bodies-discontinuous tabular pods dipping eastward parallel to the bedding. Selective permeability is again the apparent ore control, caused both by local hydrothermal solution of limestone and by deformation along faults. The principal copper minerals in the vein are chalcopyrite, bornite, enargite, tennantite, chalcocite, and digenite; these minerals vary in abundance according to a distinct zoning pattern. The upper part of the mine yielded considerable zinc as sphalerite, and the oxidized zone was rich in silver. The chief gangue minerals are pyrite, quartz, and hematite. In the limestone replacement bodies, chalcopyrite and bornite are the chief ore minerals.

Jan 1, 1968

TABAKOTO / SEGALA ? Annual gold production approximately 100,000 oz ? Debt free ? Unhedged ? Combined surface reserves 949,000 oz ? Combined 9 year life Tabakoto open pit reserve 568,000 oz (3.4m tonnes @ 5.26 g/t Au) Segala open pit reserve 381,000 oz (3.98m tonnes @ 2.98 g/t Au)

May 1, 2006

By Thomas H. Sheldon

IN the zeal for opening up new ore-bodies, or for. extracting the ore from attractive bodies gal ready opened up, we very often lose sight of the fact, that, after all, the operation of a mine is a business proposition, pure and simple; and for the best working-results should be treated upon a strict business basis. Of course, in every mine of consequence a record is kept of expenditures and receipts, and such glittering generalities as "gross receipts," " net receipts," " mining expenses," .and " per cent. profit," can be told to the cent; but does this . record show economy of management, either as compared with the same record of other months, or as compared to the record of other mines of the&apos; same class ? Moreover, if such a record shows that the cost of mining is high, does it in any way en¬able the manager to put his finger on the leakage? Does it necessarily follow that a mine which makes a profit of, say, 40 per cent on 25-dollar ore, is doing less economical mining than one which saves 60 per cent on 80-dollar ore ? Of course the figures in the latter case look the more attractive, but when it comes to a point of saving everything which can be saved, and of cutting down expenses to the lowest possible cost of operation, the former mine is doubtless on the most firm and economical financial basis. But as the relative merits of the system of mining in the two cases, nothing could be decided without a basis of detailed comparison ; if one system is more economical than the other, why is it so, and wherein does the advantage lie ? This can be shown only by keeping accurately the cost of each mining operation. And no matter how dissimilar two mines may be in character and operation, yet there are a few general heads common to all mining operations. In the first place, it is necessary to break the ore from the solid ground ;

Nov 1, 1905

By Eva K. Fernandez, Paul Y. Louie, Derek S. Adams, Renée L. Fippin

The Folsom Area Stormwater Improvement Project is part of SFPUC’s flood resilience efforts under the Sewer System Improvement Program. This 4,000-foot-long, 12-footinside- diameter tunnel will help reduce the risk of flooding in San Francisco’s low-lying Inner Mission neighborhood. The project is in a high seismic hazard zone and extends through a complex geologic corridor that includes full-face soft, compressible Bay Mud, Colma Sands, and full-face rock with several stretches of mixed-face conditions. Additional challenges include removal of 99 piles beneath an existing box sewer, tunneling under commuter rail tracks, and an underground tie-in. This paper examines these challenges and how they are being addressed.

Jun 13, 2023

By J. Coffin, R. Multani, C. Deredin

Glencore’s Strathcona Mill has recently evaluated a pyrrhotite depressant combination of diethylenetriamine (DETA) and sodium metabisulfite (SMBS) to improve its overall plant pyrrhotite- pentlandite (Po-Pn) selectivity, with the aim of producing a higher quality nickel concentrate. In a previous paper, key findings from a comprehensive lab-scale program (completed at the XPS Centre) were summarized where, of the depressants tested, DETA/SMBS combination was found to be the most effective in improving the Po-Pn selectivity. The present paper describes the metallurgical program recently completed at Strathcona Mill; DETA/SMBS evaluation on select plant “grab” samples as well as the major results of three DETA/SMBS plant trials conducted on several plant ore feeds (long-term testing). Interestingly, it was found that there was variable success in using DETA/SMBS depressants on the different plant ore feeds; DETA/SMBS (dosage: 25/50 g/t milled feed) on lower Cu feeds demonstrated a ~2% Ni recovery increase at the same Ni grade. On the other hand, higher Cu feeds demonstrated virtually no benefit from DETA/SMBS at the same plant dosage, suggesting that higher DETA/SMBS dosage (at specific locations) than that tested is required to overcome the increased Cu-DETA complexation for these particular feeds. Glencore Nickel – Sudbury Integrated Nickel Operations owns and operates Strathcona Mill which has been processing Ni-Cu ores from the Sudbury Basin since 1968. The valuable sulfides are pentlandite (Pn) – (Ni,Fe)9S8 and chalcopyrite (Cp) – CuFeS2, majority of the sulfide gangue is pyrrhotite (Po) – Fe(1-x)S [0 < x ≤ 0.125] which is present in two forms: hexagonal Po (Fe9S10) and monoclinic Po (Fe7S8) (Multani & Waters, 2017; Lawson et al., 2014). Currently Strathcona Mill processes ore mined from two primary sources from the Sudbury area and produces two concentrate streams: (1) nickel-copper concentrate that is sent to the Sudbury Smelter; and (2) copper concentrate that is shipped to the Fonderie Horne (Glencore Copper, Rouyn-Noranda).

Jan 1, 2019