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By João Alberto Fioresi Altoé

Nas indústrias petroquímicas, nucleares e farmacêuticas o avanço tecnológico tem como objetivo a segurança e confiabilidade dos equipamentos com relação à resistência mecânica e à corrosão. Atualmente, o uso dos aços inoxidáveis superausteniticos é uma solução interessante, para uma maior vida útil dos componentes industriais submetidos a ambientes agressivos, como em meios salinos. Esse trabalho tem como objetivo investigar o aparecimento de pites em um aço comercial superaustenitico de composição química aproximada 25Cr28Ni4Mo em solução salina de cloreto de sódio. O aço foi fundido e tratado termicamente por solubilização a 1050ºC por 1h com o objetivo de eliminar os precipitados. As análises microestruturais antes e após os ensaios de corrosão foram feitas por microscopia óptica e eletrônica de varredura. Observou-se com os ensaios eletroquímicos de Polarização linear e impedância, que o aço inoxidável superaustenítico apresenta excelente resistência à corrosão em meio salino, caracterizado também pelas imagens que não revelaram a formação de pites, mesmo quando submetidos a elevados potenciais.

Aug 16, 2017

By Alan Stanley

The MacIntyre Development of the National Lead Co. is located at Tahawus, N. Y. The operations involve the mining and concentrating of a titaniferous iron ore to produce an ilmenite concentrate and a magnetite concentrate. Construction of the MacIntyre plant was commenced during the summer of 1941, when world conditions threatened to cut off the supply of Indian ilmenite. An open pit mining operation was developed and the crushing and milling equipment put in operation in July 1942. A general description of the operation was given in the Adirondack Issue of Mining and Metallurgy for November 1943. The metallurgy of the mill operation was described by Mr. Frank R. Milliken,* Plant Manager, National Lead Company, MacIntyre Development, and presented at the AIME New York Meeting, February 1948.

Jan 1, 1949

By C. Kim

The integration of three-dimensional (3D) data with infrared thermography has received much attention for its potential use as input data for building energy simulations. Therefore, researchers have proposed methods to integrate 3D data with infrared thermography obtained by different sensors. These studies show the potential of the integration of 3D data and infrared thermography using various systems. However, these studies have ignored property aspects of infrared thermography, such as the low resolution of infrared thermography and external environmental influences. Thus, their proposed methods to integrate 3D data and infrared thermography are inadequate because these problems can affect the resulting building energy simulation. This research proposes a framework that integrates infrared thermography and 3D data while accounting for the resolution and shadow effect of infrared thermography. The proposed framework consists of three steps. In the resolution enhancement step, bi-cubic interpolation is proposed. In thermal data correction from the shadow effect, the shadow area is detected from the visible image, and then the shadow effect is removed from the registered infrared thermography. Finally, enhanced infrared thermography is mapped to the 3D data obtained by a laser scanner. The performance of the proposed framework was evaluated using test images obtained from a building in operation. The experimental results show that the proposed framework provides a 3D thermal model that is useful and accurate in simulating building energy. It is expected that the 3D thermal model can be used for accurate energy simulation of existing buildings. In addition, the proposed framework can be applied in defect detection for buildings. Furthermore, this novel approach enhances infrared thermography using visible images.

Aug 1, 2013

By R. Minnitt, C. Morgan, D. Fourie

The problems associated with outliers and their adverse effects on resource estimation in deep level South African gold mines are presented, and solutions suggested in available literature are reviewed. Traditional Witwatersrand type outlier capping uses the 99th percentile grade as the upper limit, a somewhat blunt approach. The occurrence of high and low grade areas in mining operations and the estimation of resources using geostatistical techniques require that the assumption of stationarity be upheld. Honouring the stationarity of data requires that mining areas be subdivided into appropriately sized and spaced domains. In order to overcome high-grade conditionally biased block estimates, the overly strong influence of extreme grades is mitigated by using naturally occurring grade sub-domains, by identifying outliers within the grade sub-domains, allocating relevant capping limits, and weighting them in a post-estimation process to. Rather than applying a capping value across a domain it applies a maximum cap based on the extreme value and its range of influence; the method also ensures that relevant capping occurs even in lower grade sub-domains. The proposed method for capping outliers recognises that metal contained in high grade chip samples should not be over-capped, and based on the grade of surrounding samples. The post-processing method of capping outliers does not interfere with the kriging equations. The method is simple, elegant, and can be easily applied. An advantage is that the output from the kriging process is not overwritten, allowing for comparison between original kriging results and post-processing results.

Sep 1, 2021

By Bernd Friedrich, Elif Emil‑Kaya, Merve Papakci

In the production of SmCo permanent magnets with excellent temperature stability, corrosion resistance, and oxidation resistance, samarium (Sm), one of the rare earth elements (REEs), and cobalt (Co) are employed. Cobalt (Co) is a crucial component in tool materials, nickel-based alloys, tablet and smartphone batteries, and electric car batteries. REEs and Co have been listed as critical raw materials by the European Union Commission for many years. Due to the ever-growing demand for Co and REEs in technological applications, the recovery of these elements from secondary sources has garnered significant interest. There are two types of SmCo magnets, one of which contains a high amount of iron, approximately 15.2%. This paper focuses on the recycling of Fe-bearing SmCo. In this study, an oxidative leaching process with nitric acid was developed to eliminate iron through in situ hydrolysis and to dissolve REEs and Co. The influence of experimental conditions on the formation of an amorphous iron compound through the hydrolysis of Fe3+ in a nitric acid environment was thoroughly examined based on a Taguchi orthogonal array. The optimal parameters for oxidative leaching were determined to be an acid concentration of 3 mol/L, a solid-to-liquid ratio of 1/10, and a process temperature of 60 °C.

Feb 15, 2024

This Bureau of Mines report is devoted to descriptions of investigations pertaining to underground mine trailing cables, their handling, splicing, and the use of couplers.

Jan 1, 1979

By Travis Q. Lyday

During 1983, Ecuador's gross domestic product (GDP) decreased by a reported 3.3% in real terms, the second consecutive decline in the economy after more than a decade of growth generated mainly by petroleum export revenues. The slowdown was due, in part, to the effects of the world recession, lower foreign demand for oil, depressed world oil prices, and reduced demand and prices for Ecuador's traditional agricultural exports. Inflation accelerated to an estimated 55% annual rate. The sucre was devalued in March, for the second time in less than a 12-month period, by 27% after remaining unchanged during the previous decade. In addition, continuous adjustments were made every weekday, effectively devaluing the sucre another 30% by yearend. Ecuador's production of crude petroleum increased almost 12% in 1983 compared with that of 1982. Average daily production was 237,100 barrels per day (bbl/d), up from 211,300 bbl/d in 1982.

Jan 1, 1985

By Yoshikazu Hirosaki

How big or small is the Japanese explosive market? Who are the major explosive customers? Is there any big construction project in which a large amount of explosives is expected? What is the future of the explosives industry in Japan? Is it true that there are no ANFO trucks? What is the licensing system for blasters? Is there any education system for blasters?

Jan 1, 2001

Geologists in some underground gold mines collect grab samples from broken ore piles or trucks as a method of grade control. It is often known as muck sampling. Generally, the goal of grab sampling is to try and reconcile the mined grade at the ore source to the predicted grade and/or predict the mill feed grade. The mass of the sample collected is limited by health and safety issues, as well as by the capacity of the laboratory to process the samples within a given time frame. In general terms, grab sampling is known to be problematic because samplers tend to oversample the fines, and/or pick out high-grade fragments; surface sampling of piles does not test material within the pile; muck piles in development drives/faces are likely to be zoned due to the blasting sequence; high or low-grade material may preferentially segregate in the pile during mucking; the five per cent mass reject size of the material in muck piles is very large from underground blasting; some correlation usually exists whereby the larger fragments are enriched or depleted in the critical component of value; and the average error made in estimating the true stockpile grade is likely to be high. The method is prone to chronic fundamental sampling, grouping and segregation, delimitation, and extraction errors. Substantial warnings must be given about the use of grab sampling for grade control in gold mines. The method may appear to work sometimes, which can be attributed to a fine gold particle sizing and more disseminated distribution. As with all sampling methods, its appropriateness must be determined by ore characterization and heterogeneity testing to ensure the method suits the ore type.

Jan 1, 2010

By S McKinley

"The White Mountain sediment-hosted gold deposit is located in north-eastern China. Mineralisation is associated with silica–hematite–altered polymict breccias that occur within dolomite at or near the contact with overlying sandstone. Economic gold grades are controlled by the distribution of the polymict breccias and can transition rapidly to low or zero grade over short distances. This results in sharp and highly irregular ore contacts on whose accuracy proper stope design and ore control is reliant at this blasthole underground mine.Short-term planning and ore control utilise a grade control model created from infill drilling and grade control sampling (ie face and wall sampling). Typically, the grade control model was maintained by time-consuming manual editing of earlier made contacts to incorporate any new data. This approach also was quite error-prone due to: the complexity of the breccia and ore grade contacts irregularly oriented and/or insufficiently dense drill holes inconsistent incorporation of grade control sampling. These errors resulted in unplanned dilution and ore loss due to inaccurate interpretation of the ore contacts.The primary advantage to implicit geological models over conventional, manually-built wireframe models is that they can be updated very quickly and frequently. In a mine setting, the power and efficiency of using an implicit model is greatest where the use of manual inputs or editing can be minimised. Recently a workflow was set-up for the mine geology team to create an implicitly-modelled ore shape for short-term planning needs by using all data, especially all grade control samples. The resultant 3D shapes provided metre-scale accuracy and consistently reconciled complex ore geometries much faster and to a higher degree of quality relative to the wireframe model. The mine stakeholders can now obtain an accurate ore model that will always be in sync with available data.CITATION:McKinley, S, 2017. Application of implicit geological modelling to improve the grade control process at White Mountain gold mine, Jilin Province, China, in Proceedings Tenth International Mining Geology Conference 2017, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By Filippos Patsiogiannis

Laboratory size (5 kg) aluminum killed low carbon steel melts were desulfurized with synthetic fluxes in zirconia crucibles. The sulfur, oxygen, aluminum, silicon, and manganese contents in the melt were determined as a function of refining time and temperature. With a good argon shield and synthetic flux cover, melt reoxidation was not observed. Sulfur removal followed first order reaction kinetics. The effectiveness of calcia saturated calcium-aluminate (12CaO.7Al2O3) based fluxes in desulfurizing the steel melts was evaluated. The effects of initial sulfur level of the melt, weight of the flux (slag), and additions of tellurium, fluorspar, and barium oxide to the melt on the kinetics of desulfurization were also studied.

Jan 1, 1993

The recent installation of top gas temperature probes in blast furnaces at Australian Iron & Steel Pty. Ltd. - Port Kembla, has provided the means for studying radial gas flow distribution in blast furnace shafts. This paper describes the top gas temperature probes and outlines their development and results of initial studies aimed at obtaining a suitable relationships between temperature profiles and furnace parameters. The effects of various combinations of burden materials have been outlined by the results reported. The use of probes has also helped to clarify the effect of casting cycles on furnace operation leading to increased emphasis on the reduction of the interval between gun-up and drill-out. Areas for future studies are also broadly Outlined.

Jan 1, 1975

By M. du Plessis, J. P. Gouvea

Mesh based areal support is commonly applied in South-African deep-level gold mines. It forms part of an integrated support system that can cater for both rockfall and rockburst incidents. The application has been successfully applied over many years. Operations have different geotechnical conditions and practical considerations, which has led to the development of various types of mesh and integrated mesh-based support systems (i.e. meshing and lacing versus welded or chain-link mesh sheets). Typically rolls or sheets of mesh is pinned with rockbolts to the surface of an exposed excavation. Applications vary from hangingwall coverage in a conventional stope gully to complete excavation coverage in footwall drives of conventional mines or on-reef drives in massive mechanised mines. It is however critical to understand the behaviour of the rockmass and apply suitable support systems.

Apr 26, 2022

By Janet Torma-Krajewski

Job tasks that involve exposure to work-related musculoskeletal disorder (WMSD) risk factors may impact both the risk of injury and production downtime. Common WMSD risks factors associated with mining tasks include forceful exertions, awkward postures, repetitive motion, jolting and jarring, forceful gripping, contact stress, and whole body and segmental vibration. Mining environments that expose workers to temperature/humidity extremes, windy conditions, and slippery and uneven walking surfaces also contribute to injury risk. National Institute for Occupational Safety and Health (NIOSH) researchers worked with powder crew members from the Bridger Coal Company to identify and rank routine work tasks based on perceived exposure to WMSD risk factors. This article presents the process followed to identify tasks that workers believed involved the greatest exposure to risk factors and discusses risk reduction strategies. Specifically, the proposed prill truck design changes addressed cab ingress/egress, loading blast holes, and access to the upper deck of the prill truck.

Jan 1, 2009

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.   There is a great need to improve science, natural science, education at all levels. All people must know how our planet works and that fluctuations, some inevitable, some controllable, are inevitable and that we must prepare for them. And it is clear that protecting the environment, eliminating pollution, preserving bio diversity is good economics. Ecology Economy cannot be separated.  

Jan 1, 1995

By Bruce D. Hansen

For many years, Newmont has focused on improving its operations. After the merger between Newmont and Santa Fe Pacific Gold, Newmont created synergies of more than $50 million a year in Nevada. This was done primarily through optimal ore movements and consolidation of various functions. During the current period of low gold and copper prices, Newmont has refocused its efforts on efficient operations worldwide. At its mine facilities in Nevada, Newmont has used a combination of several strategies to decrease the costs of operations and to increase profitability. These include computer technology, optimal use of infrastructures, procurement strategies, functional consolidation, enhanced mine planning and several available metallurgical processing options.

Jan 1, 1999

By R. Kealey, D. Huo, Q. Zhang, Y. A. Sari

Greenhouse gas (GHG) emissions from primary mineral and metal production account for ~10% of global GHG emissions. One of the main sources of GHG emissions in mining operations is fuel consumption by haul trucks. Given their size and carrying capacity, the fuel consumption of haul trucks can approach 250 liters per hour. An average of 30% of the idle time of the trucks is spent while waiting in the queue. Inefficient truck dispatch planning can waste resources, cause dilution and elevate GHG emissions. In this research, a machine learning based truck dispatch approach was developed to dynamically route the haul trucks based on the loaded material, the road traffic, the estimated wait time, and the maintenance needs of the trucks. The GHG reduction potential of this smart fleet management approach was estimated by calculating and comparing the related carbon emissions versus scenarios using traditional fleet allocation approaches. Results suggest that this dynamic fleet allocation approach can significantly reduce GHG emissions at mineral production sites by optimizing waiting times and the overall distance travelled while achieving the same production levels.

Mar 2, 2022

By H. R. Manouchehri

Sustainable development requires the optimal use of natural resources and recycling of the wastes. In fact recycling is the final productive use of obsoletes. ELVs, obsolete appliances and industrial wastes have become important resources for production of iron and steels, non-ferrous metals, and composites. Within shredding plants, these obsoletes are firstly shredded to the pieces and then processed to recycle different materials, especially ferrous and non-ferrous metals for metallurgy. Traditional and new developed mineral processing technologies are nowadays used for recycling different materials from waste effluents. Shredding and separating plants are currently recycle the wastes by make use of different technologies to mainly produce raw material for metallurgical application. However, other non-ferrous components are also treated for energy conservation and protecting environment. Currently, recovery in shredding and recycling plants maximises to 75% and about 25% of the feed is land-filled. However, recycling rate must be increased in due to the economical, environ-mental and social concerns. A comprehensive study for recycling, with especial focus on ferrous metal recovery, was sup-ported by Swedish Environmental Agency (MISTRA) to look at possibilities to increase the recycling rate and to reduce the amount of disposal. Part of this study was dedicated to study the shred-ding plant facilities and to look for possibilities to improve the quality and quantity of the shredding product streams. The aims were to improve the quality of ferrous scrap (apparent density > 0.9 and Cu<0.25%) for iron and steel production as well as having better quality for non-ferrous metals through the recycling schema, and finally to treat the shredder residue (SR) to recover metals and plastics to reduce the disposals. This paper summarises the results of sampling and conducting separation tests for improving the recovery of the ferrous and non-ferrous metals. The results indicated to be possible to obtain high quality ferrous scrap at recovery of 88%. However, the total recovery for metal scrap has reached 93%. Furthermore, test results on fine, P< 8mm, shredding residue (SR) showed promising prospect in recovery of metals and protecting environment by physical separation, i.e. electrical separation technique.

Jan 1, 2014

By Bhawani Singh, A. K. Dube, B. Singh

At least three hydroelectric tunnels constructed during the last decade through the lower Himalayan region in India have met with serious problems of supporting in squeezing ground conditions. Steel ribs under went intolerable deformations requiring rectification to provide space for concrete lining which delayed the projects inordinately. In an attempt to choose a rational method of predicting rock load, the authors have compared rock loads estimated from various classification systems and elasto-plastic theory with observed values. The deficiencies of the classification systems have been highlighted to show that the combination of elastoplastic theory and tunnel instrumentation programme provides better guidelines for the design of tunnel supports in squeezing ground conditions.

Jan 1, 1981

By A. Moharana

A massive slide at Bingham Canyon wiped out a side of the pit and covered the main haul road in and out of the pit. All pre-slide mine designs and schedules were no longer valid. New designs and schedules needed to be developed quickly to provide management with information regarding the immediate post-slide production potential and the time needed to ramp back up to full production. At the time of the slide, an effort was already underway to convert Bingham?s in-house Medium Term Scheduling Process to MineSight®?s Schedule Optimizer (MSSO). One of the main reasons for doing this was to reduce the time needed to produce Medium Term Schedules at Bingham, which involves a complex shovel-based scheduling approach with shovel productivities based on shovel type and the types of mining cuts to which the shovel is assigned over each planning period. The objective of the schedule was to maximize shovel usage, satisfy mill feed requirements of four SAG mills with variable milling rates, and have flexibility in setting truck constraints. This paper will describe how the new MSSO-based mine scheduling process met the challenge of producing new schedules for Bingham in a minimal amount of time.

Feb 23, 2014