Search Documents

By Érico França

A CBMM aplicou aços microligados ao nióbio de alta resistência mecânica para a fabricação de containers de caminhões que transportam grãos na região do Triângulo Mineiro e Alto Paranaíba, com o objetivo de reduzir o peso desses equipamentos e possibilitar o aumento da carga útil transportada. O novo projeto reduziu em 10% o peso do container e também aumentou seu volume útil de 27 m3 para 29 m3. O investimento teve retorno com apenas 8 dias de operação com o novo projeto transportando arroz. Também foram obtidos ganhos no transporte de milho e soja com o retorno do investimento em 21 e 56 dias de trabalho respectivamente. O trabalho mostra os aços utilizados e as principais alterações nos projetos desses componentes.

Aug 16, 2017

By B Olsson, R Norman, M Volz

Australia has seen unprecedented demand for coal exports in the last ten years and this demand is set to expand further still according to many analysts. This rapid increase in demand has placed pressure on multi-user coal chains to guarantee the capability to meet the required demand, in terms of both current operations and capacity expansion.The projects required to deliver these forecast tonnages take place in an increasingly complex commercial and technical environment. These challenges include brownfield and greenfield projects, multiple rail and terminal service providers as well as a myriad of mine operators, all needing to operate in an increasingly integrated manner to get the most out of expensive shared assets.Increasing complexity and integration drives the need for more holistic and sophisticated analysis tools. The capacity of coal chain subsystems, such as mine, rail and port, can no longer be determined effectively in isolation. Understanding the nature of the interactions between these subsystems and the resultant capacity of the integrated system is the key to maximising value. TSG advocates the use of a total integrated system approach to understand the behaviour and performance of complex coal chains.Recently, TSG has worked in conjunction with the Integrated Logistics Company and a number of stakeholders in the Dalrymple Bay Coal Chain to deliver the first independent system master plan. This master plan has provided a quantitative and rational assessment of coal chain capacity in its current state and a prediction of its capacity once a pipeline of committed capacity improvements is in place. It is underpinned by a highly detailed discrete-event simulation model of the complete coal chain as an integrated system, including mine load-outs, rail, terminal and port operations.This paper provides an overview of the study and describes the differences between subsystem and total integrated system model performance.

Sep 26, 2011

By S. H. Chauvenet

HARRISBURG is situated on the Pennsylvania Railroad, one hundred and five miles from Philadelphia, two hundred and forty-eight miles from Pittsburgh, and ninety miles from Baltimore, and has running through it the Pennsylvania, Northern Central, Philadelphia and Reading, and Cumberland Valley Railroads, and the Pennsylvania Canal. Surrounded by a thickly settled farming country, from which to draw native labor, within easy distance of anthracite and bituminous coal, with ores and limestone near at hand, and with the Susquehanna River as a never-failing water supply, Harrisburg has advantages for manufacturing which warrant the investment of the capital that has already been made, and has a future as a manufacturing city second only to Pittsburgh and Philadelphia. THE PENNSYLVANIA STEEL COMPANY, L. S. BENT, SUPERINTENDENT. The works of this company, the largest in Harrisburg, lie between the Pennsylvania and the Philadelphia and Reading Railroads, on. the Pennsylvania Canal, and are essentially devoted to the manufacture of Bessemer steel rails. Capital stock, $2,000,000; invested in business, $5,000,000; wages per month, $80,000; employs 2000 men; capacity, 100,000 tons of rails per year, which is being increased to 130,000 tons. The plant, as it now stands, comprises five Bessemer converters, two 7-ton and three 8-ton converters, two 15-ton open-hearth furnaces in operation, and two 30-ton open-hearth furnaces in course of construction, one blooming mill, one rail mill, seven steam hammers, two blast furnaces in operation, two blast furnaces in course of construction, foundry, pattern $hop, machine shop, blacksmith shop, and frog shop, and merchant mill in course of construction. Bessemer No. 1 was built in 1865, with two 7-ton converters, 2 spiegel cupolas, 3 feet diameter, and 3 iron cupolas 6' 6" diameter,

Jan 1, 1882

By Nikhil Dhawan, Shrey Agrawal, Ashwini Kumar

The current study investigates sericite clay as an alternative source of potash and alumina. The alumina and potash content in the sericite is approximately 35 and 10%, respectively, compared with 50–55% in bauxite ore. Muscovite and illite phases are stable, and direct leaching is found to be ineffective. Here, planetary ball milling was performed, which provided dissociation of stable phases to relatively reactive phases. The milling led to a five-fold increase in the surface area, resulting in enhanced leaching kinetics even at low acid concentration. The statistical design obtained optimal conditions of 8 h of milling followed by leaching in 1.73 M HCl at 75 °C, yielding 82% alumina extraction in precipitate with 85% purity in γ-alumina form and 63% potassium dissolution in sylvinite phase. The yield of the precipitate was ~65–68%, and the acid leach residue contained primarily silica.

By J. E. Miller

Primary standard gas mixtures were developed for more accurate calibration of analytical instruments at the Bureau of Mines Helium Research Center and for calibration of analytical instruments used in the helium conservation program. A 10-kg-capacity balance is used to weigh a 4-kg metal cylinder filled to high pressure (1,800 psi maximum) with the component gases of the desired mixture. At 1,800 psi, a cylinder contains about 60 g of helium, or 420 g of nitrogen. An accuracy of ±0.05 mole-percent or better is claimed for each component in the mixtures.

Jan 1, 1965

By L C. Taylor

Both the U. S. Navy and the U. S. Army are interested in knowing more about the loading applied to vehicles which are unfortunate enough to encounter a detonation of a buried mine in the course of performing their normal duties. The Dynamic Effects Laboratory at the University of Maryland has been involved in small scale testing for ten years to assist the Navy and the Army in understanding the loads that are applied to personnel carriers when a buried explosive detonates beneath them. This paper describes results from small scale tests conducted to determine the loading mechanisms on target plates when subjected to loading due to the detonation of a buried mine in saturated sand, dry sand, and water. Transparent target plates were utilized in order to determine the loading process beneath a floor board on armored vehicles. Various charge sizes were scaled in the laboratory accordingly to a standardized full size threat encountered in the battlefield. Tests were conducted in saturated sand, dry sand, and water keeping the stand-off distance of the target and the depth of burial of the charge constant. In the case of water impacting a transparent PMMA plate the crack propagation was recorded and the crack velocity is determined. Additional tests were performed in saturated sand by varying the stand-off distance of the target but keeping the depth of burial of the charge constant. The small-scale test results could be scaled to full scale by using verified scaling laws.

Jan 1, 2016

By J. Clark

Erosion control during the mining cycle can be more effectively planned using Erosion and Sedimentation Control Plans (ESCPs). This raises the issue of who should develop an Erosion and Sedimentation Control Plan Guidance document (ESCPG) to standardize the content of ESCPs. A search for ESCPG documents in Canada revealed no examples for mine sites. In the U.S. there are a number of regulatory authorities who developed such documents for mine sites, including EPA. An ESCPG is expected to result in: (a) plans will be more standardized (b) more clarity and efficiency for those generating ESCPs; (c) assisting regulators tasked with reviewing/approving ESCPs; (d) providing guidance for the mine effluent permitting process relative to sediment control; (e) providing a basis for developing and including ESCPs in the Environmental Assessment (EA) phase and the mine economic assessment; (f) applying and optimizing ESCPs above the ?watersheds? of sediment ponds; (g) utilizing the ESCPG document for ?exploration? sites; (h) lowering the risk of adversely impacting water quality downstream of mining activities; (i) providing a methodology for determining the need for sedimentation pond(s) during the construction and production phases; and (j) providing a clear environmental sustainability message relative to sediment control if the mining industry takes the lead in developing an ESCPG. ESCPs will proactively create increased administrative (regulatory) efficiency in the EA and sub-EA reviews relative to erosion control and sediment release from mine sites. This also assists the new initiative in BC, One Project, One Process (OPOP) and synchronous permitting (a variation of concurrent permitting): as an example, enhanced erosion control planning at the EA phase then allows the synchronous permitting initiative to proceed efficiently, particularly for the mine permit (Ministry of Energy, Mines and Natural Gas) and effluent permit (Ministry of Environment). Approximately twenty more management plans (e.g. ARD/ML, explosive management, emergency response, hazardous waste, sediment pond operation, environmental effects, environmental sampling, etc.) may also be entered into the EA process to create increased efficiency, and then feed into the synchronous permitting effort. The BC OPOP initiative also adds support to the Canadian Federal ?One Project, One Review Process? approach. The ESCP and a sediment pond management plan will also address the Canadian Metal Mining Effluent Regulations requirement for all discharges from mine sites to meet a grab sample of 30 mg/L Total Suspended Solids.

Aug 1, 2013

By Luzheng Chen

The study aimed to evaluate the separation performance of a full-scale continuous centrifugal concentrator in the reconcentration of fine hematite from high-gradient magnetic separation (HGMS) concentrate in a tailings recovery plant, and to investigate the usefulness of the technology in industrial applications. The effect of changing the operating variables on concentrate grade and recovery was studied. The results indicate that among the variables considered in the study (water spray pressure, centrifugal acceleration, feed volume flow rate, feed percent solids and the reciprocation and spacing of water sprays), the change in centrifugal acceleration affects the recovery the most and continuous concentration can be achieved only when the water spray has a sufficient pressure. In addition, the reciprocation and spacing of the water sprays have a significant influence on the concentrate grade. Although performance of the full-scale concentrator is slightly inferior to pilot-scale trials, due to limitations in the scale-up design and the fluctuations of feed material characteristics, this concentrator provides a potential way to achieve continuous concentration and obtain a high-grade concentrate from tailings.

Jan 1, 2010

By Stephen Kann

El presente texto describe la actividad minera desarrolla en Sudáfrica, la cual posee los mayores yacimientos mundiales de oro, cromo, platino, vanadio, amianto y vermiculita. La riqueza de sus campos diamantíferos es legendaria. Los yacimientos de hierro, espato fluor, antimonio, níquel y titanio son los mayores hasta ahora descubiertos en el continente africano. Los depósitos de uranio y carbón ocupan respectivamente segundo y cuarto lugar por su importancia mundial.

Jul 1, 1968

By J. K. Shaw

The science of low temperature engineering is well entrenched in mining. Uses for common cryogens, including liquid oxygen (LOX), liquid nitrogen (LN2), and liquefied natural gas (LNG) in the gas and minerals industries are reviewed. Potential future applications are discussed within the scope of mining, particularly in refrigeration and ventilation. The second part of this paper focuses on the Linde cycle, which is at the heart of most liquefaction plants. Steady state equations describing the mass and energy flows are presented. The paper concludes by explaining the concept of a wind powered Linde- Hampson cryogenic cycle and assessing, with scoping calculations, the technological feasibility of producing cryogens with an intermittent source of (renewable) energy.

Aug 1, 2013

By Andrew Chegwidden, Tara Wilk

Shaft 18B-1 is the second shaft to be constructed as a part of contract C547A along the New York City water supply system Tunnel No. 3. More complex than Shaft 17B-1, this site has an additional 30 m (100 ft) of overburden for a total excavation depth of approximately 78 m (256 ft) through water-bearing overburden soil and 145 m (475 feet) of gneiss bedrock to connect to the underlying Water Tunnel No. 3. round freeing was specied as the method to provide temporary earth support and ground water control for the overburden material. An extensive supplemental geotechnical investigation (SGI) and frozen soil testing program was performed to develop the design of a temporary ground freezing system, consisting of over 7,315 m (24,000 ft or 4.5 miles) of drilling for the installation of 95 freeze pipes. At the start of shaft excavation, the upper sandy silts strata was found to have an unprecedented low thermal conductivity, leaving the frozen soil face approximately 0.6 to 1 m (2–3 ft) behind the cutline. The ground freezing earth support needed to be augmented with ring beams and liner plates to support this soil face and allow for the excavation to proceed and be completed safely.

Jun 23, 2024

By Peng Cao, Jimin Su, Yang Li

"Abutment pressure distribution is different when a longwall panel is passing through the abandoned gateroads in a damaged coal seam. According to the geological conditon of panel E13103 in Cuijiazhai Coal Mine in China theoretical analysis and finite element numerical simulation were used to determine the front pressure distribution characteristics when the longwall face is 70 m, 50 m, 30 m, 20 m, 10 m, and 5 m from the abandoned gateroads. The research results show that the influence range of abutment pressure is 40 m to 45 m outby the face, and the peak value of front abutment pressure is related to the distance between the face and abandoned gateroads. When the distance between the longwall face and abandoned gateroads is reduced from 50 m to 10 m, the front abutment pressure peak value kept increasing.When the distance is 10 m, it has reached the maximum. The peak value is located in 5 to 6 m outby the faceline. When the distance between the longwall face and abandoned gateroads is reduced from10 m to 5 m, the front abutment pressure sharply decreases, the intact coal yields and is even in plastic state. The peak value transfers to the other side of the abandoned gateroads. The research results provide a theoretical basis for determining the advance support distance of two gateroads in the panel and the reinforcement for face stability when the longwall face is passing through the abandoned gateroads.INTRODUCTIONFront abutment pressure is the result of rearrangement of in situ rock stress caused by the mining (removal) of the coal seam. Research on the distribution character of face abutment pressure have significant importance in confirming the width of the coal pillar and the distance of advance support in roadways (Liu et al., 2011; Liu, Jiang, and Zhu, 2015). Currently, there is a lot of research on abutment pressure characteristics of traditional longwall coal faces, thick coal seam longwall faces, isolated faces, and extra wide face abutment pressure distribution (Xie et al., 2006). However, theoretical analysis and research on the distribution law of the fully mechanized coal face to abandoned gateroads are relatively less. Abandoned roadways are often from less mechanized or room and pillar mines. Due to the existence of these roadways pre-longwall mining, the in situ stress has already been redistributed around the roadway (Liu et al., 2007). Thus, when the longwall approaches and mines through the roadway, the abutment pressure distribution behaviour has different characteristics than those of traditional solid undisturbed coal. Especially when the face approaches the abandoned roadway, the understanding of face abutment pressure distribution has significant importance to the timing of support installation (Ren and Ning, 2014). This prevents the occurrence of a roof and rib failure ahead of and on the longwall and highly efficient advance of the longwall safely and productivity. This paper analyses the E13103 face of the Cuijiazhai Mine of Wenzhou Mining Co., Ltd of Kailuan Group, as the engineering case study, and uses FLAC3D numerical simulation software to conduct numerical simulated analysis on the abutment pressure distribution mechanism of longwall coal mining face."

Jan 1, 2018

By Arthur Notman

THE raw material men in all industries, and copper is no exception, are accustomed to think of them- selves as the whole show, and not without justice, for if there were no copper mines the world would have no copper. Nevertheless, many different things costing money and resulting in profits must be done to their product before it is ready for the world's use. In other words, they are making the frequent mistake of Chinking in terms of partial costs. Nobody really uses electrolytic copper. Possibly that is why nobody seems willing to pay anything for it. The manufacturers, being canny, do not buy any more electrolytic than they feel that they can work up and sell profitably, although they like to make the raw material men Chink that they will take all that can be produced. This is a state of affairs that has aroused my sympathy and curiosity, and has induced me to study the financial history of the copper wire and brass industry of the country or such portion of it as publishes any records readily available to the curious minded. About 60 per cent of the electrolytic copper used in this country is drawn into wire and consumed by the electrical industries. The remaining 40 per cent is

Jan 1, 1926

By Smortchevskyk N. J.

THIS paper describes the electrical features of the locomotive now (August, 1962) under construction for Craigmont Mines. Intended for non-specialists, it avoids details of design and calculations interesting to electricians only. The paper is divided into three sections. The first deals very briefly with the mine layout and with operating conditions -existing and expected. Reference is made to economic considerations leading to the selection of the type and size of locomotive, as well as to traction diagrams and the calculations. This material is not included in the paper because of its length and because it does not represent anything new. The second section deals with engineering and economic considerations and shows, in some detail, why the A.C. system was chosen. The third section describes the basic components of the locomotive, including the voltage regulator, the rectifiers, the control arrangement and the filter, and deals with considerations affecting the selection of their rating and design. A concluding sub-section describes, very briefly, the track and trolley details and the power distribution switchgear.

Jan 1, 1963

By L Abrahamsson

The aim with this paper is to discuss experiences from the ongoing research project ‘Attract: A roadmap to attractive, inclusive, and safe mining workplaces’. The project’s aim is to analyse possibilities, effects, and consequences of the green and digital transformation in the Swedish mining industry from workplace, socio-technical and gender equality perspectives. The research project (2022–2025) at Human Work Science at Luleå University of Technology is financed by the strategic innovation program Swedish Mining Innovation (a joint venture by the national research funds Vinnova, Formas and the Swedish Energy Agency). The project includes a multidisciplinary research group of five senior researchers and five PhDstudents and a broad repertoire of methods, eg literature reviews, qualitative interviews with both managers and workers, workplace observations, workshops, surveys, and project seminars where the researchers and the company representatives together analyse the results. One important part of the project is the applied approach where the researchers work together with two mining companies and one subcontractor company. The project has two parallel main subprojects.

Sep 1, 2024

By F. M. Isik

Due to not to being our own sources, some energy sources such as oil and natural gas which are used frequently, are not reliable energy sources for our country. Coal is an important energy source that Turkey also has a certain reserve as many countries have. To be able to use for many years the reserves of this source that comes from fossils, there is a great need to make more investigation and development activities on it. On behalf of using more productively the current sources, briquetting facility is represented that commenced production in The Aegean Lignite Establishment in 2005 which is in Manisa, Soma. This facility is a part of General Directorate of Turkish Coal. This facility is run by Soma Coal Establishment that works in return for royalty in a licensed field that belongs to TKI. As the demand of market for 0.5 mm dust coal diminishes, we had to accumulate and stock unmerchantable dust coal. Besides, we have intermixed 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal obtained as a result of washing in coal washer with thermic coal with low price as we could not find a client in the market. In this study, the production stages of briquette coal with high quality produced as a result of pressing by mixing 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal with molasse and lime, quality control, and data?s obtained about calories and solidity of products were presented. By briquetting of 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal washed in coal washer, it became possible to sell these coals on a high unit price and by providing the demand of coal of the market, we contributed to productivity of our firm. Keywords: briquette coal, briquetting, producing stage

Sep 1, 2012

By F. J. Palumbo

An electronic color-sorting machine was tested for recovering colorless glass concentrates from mixed glass products. The tests were made using glass recovered from unincinerated (raw) urban refuse and residues resulting from the incineration of refuse. The results of the study revealed that concentrates analyzing about 86 percent colorless glass could be recovered from mixed unincinerated glass containing 54 percent colorless glass material. Recovery of the colorless glass was about 62 percent. Color sorting the incinerated glass was somewhat more difficult. Multiple-stage processing was required to recover 59 percent of the colorless glass material in a product analyzing 89 percent colorless glass. The feed material analyzed 41 percent colorless glass.

Jan 1, 1971

By J. F. Papp

The microstructures of a CF2Br2-inhibited methane flame and its uninhibited analog have been determined using molecular beam-mass spectrometry. The slightly lean flames were stabilized on a cooled porous plug burner at reduced pressure. Composition profiles of stable, intermediate, and radical species and temperature profiles were obtained. Comparisons of the uninhibited and inhibited flame profiles revealed the following inhibition effects; a shift of the primary reaction zone to higher temperatures, a higher maximum flame temperature, an increase in the CH3 concentration, and a reduction in the H2CO, H, 0, and OH concentrations. Kinetic analyses of the data yielded rate coefficients at flame temperatures for the reactions H + CH4 ? CH3 + H2, H + O2 ? OH + O, CO + OH ? CO2 + H, and CH3 + O ? H2CO + H. CF2Br2 is judged to decay by thermal decomposition and abstraction reactions.

Jan 1, 1981

By H. D. Jacobs

The Federal Bureau of Mines, as part of a program to insure future raw material needs for the iron and steel industry, undertook research to beneficiate the oxidized taconites from the western Mesabi range in Minnesota. The data presented were obtained by applying the Bureau-developed selective-flocculation/cationic-flotation process to the second of three oxidized taconite samples. These three samples are representative of an estimated 10 billion tons of ore analyzing 30 to 40 pct iron. The experimental work was performed in a 900-lb/hr pilot plant. Treating the ore sample (36.1 pct Fe) with the Bureau's process produced commercially acceptable concentrates averaging 63.5 pct Fe and 4.3 pct SiO2, with an average iron recovery of 84.6 pct.

Jan 1, 1980

By S. -Y. Hwang

An ongoing problem for industry in Korea is effective removal of heavy metals from and safe disposal of spent power plant fly ash. This research endeavor attempts to develop selective separation of Ni from leach liquor using a selective chemical precipitation method. The research was conducted by changing two variables, the pH and the concentration of ions in solution. The effect of other ions present in the system on the separation efficiency of Ni species was also investigated by adjusting OH and NH3 concentrations. In the pH range of 7-9, the chemical precipitation method produced a high yield of Ni by precipitation from the fly ash leach liquor.

Jan 1, 2010