Rem-Revista Escola De Minas最新文献_第3页

Quality management system implementation for fracture toughness testing 断裂韧性测试质量管理体系的实施

Rem-Revista Escola De Minas Pub Date : 2016-03-01 DOI: 10.1590/0370-44672015690120

D. A. K. Fabricio, C. Rocha, C. S. Caten

引用次数: 4

Feasibility project for implementation of conveyor belts in an iron ore mine. Study case : Fabrica Mine in Minas Gerais State, Brazil. 某铁矿实施输送带的可行性方案。研究案例:巴西米纳斯吉拉斯州的Fabrica矿山。

Rem-Revista Escola De Minas Pub Date : 2016-03-01 DOI: 10.1590/0370-44672013690021

Breno Gonçalves Cardozo Ribeiro, W. D. Sousa, José Aurélio Medeiros da Luz

引用次数: 9

Electron microprobe Th-U-Pb monazite dating and metamorphic evolution of the Acaiaca Granulite Complex, Minas Gerais, Brazil 巴西米纳斯吉拉斯州Acaiaca麻粒岩杂岩Th-U-Pb单独居石定年及变质演化

Rem-Revista Escola De Minas Pub Date : 2016-03-01 DOI: 10.1590/0370-44672015690139

E. B. M. Júnior, H. Jordt-Evangelista, G. Queiroga, B. Schulz, R. Marques

{"title":"Electron microprobe Th-U-Pb monazite dating and metamorphic evolution of the Acaiaca Granulite Complex, Minas Gerais, Brazil","authors":"E. B. M. Júnior, H. Jordt-Evangelista, G. Queiroga, B. Schulz, R. Marques","doi":"10.1590/0370-44672015690139","DOIUrl":"https://doi.org/10.1590/0370-44672015690139","url":null,"abstract":"The Acaiaca Complex (AC) is located in southeastern Minas Gerais state, and comprises felsic, mafic, ultramafic, and aluminous granulites as well as lower grade gneisses and mylonites. The complex is distributed over an area ofca. 36 km by 6 km, surrounded by amphibolite facies gneisses of the Mantiqueira Complex (MC). The discrepancy in the metamorphic grade between both complexes led to the present study aiming to understand the metamorphic history of the AC by means of geothermobarometric calculations and electron microprobe Th-U-Pb monazite dating. Estimates of the metamorphic conditions of the granulites based on conventional geothermobarometry and THERMOCALC resulted in temperatures around 800 oC and pressures between of 5.0 and 9.9 kbar and a retrometamorphic path characterized by near-isobaric cooling. Part of the granulites was affected by anatexis. The melting of felsic granulites resulted in the generation of pegmatites and two aluminous lithotypes. These are: i) garnet-sillimanite granulite with euhedral plagioclase and cordierite that show straight faces against quartz, and is the crystallization product of an anatectic melt, and ii) garnet-kyanite-cordierite granulite, which is probably the restite of anatexis, as indicated by textures and high magnesium contents. Th-U-Pb monazite geochronology of two granulite samples resulted in a metamorphic age around 2060 Ma, which is similar to the age of the MC registered in the literature. The similar Paleoproterozoic metamorphic ages of both complexes lead to the conclusion that the Acaiaca Complex may be the high grade metamorphic unit geochronologically related to the lower grade Mantiqueira Complex.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"121 5 1","pages":"21-32"},"PeriodicalIF":0.0,"publicationDate":"2016-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83063607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Interconnecting financial performance and internationalization: a case of a rare metal producer 财务绩效与国际化的关联:以一家稀有金属生产商为例

Rem-Revista Escola De Minas Pub Date : 2016-03-01 DOI: 10.1590/0370-44672014690102

O. Lukason, Tiia Vissak

引用次数: 4

Thermobarometry and electron-microprobe Th-U-Pb monazite dating in garnet metapelites from the Capelinha Formation, Araçuaí Orogen, Brazil 巴西Araçuaí造山带Capelinha组石榴石变长岩的热压测定和电子探针Th-U-Pb独居石定年

Rem-Revista Escola De Minas Pub Date : 2016-01-03 DOI: 10.1590/0370-44672015690066

G. Queiroga, B. Schulz, Maximiliano D. Martins, M. P. Castro, A. Pedrosa-Soares, H. Jordt-Evangelista, Ana Lúcia da Silva

{"title":"Thermobarometry and electron-microprobe Th-U-Pb monazite dating in garnet metapelites from the Capelinha Formation, Araçuaí Orogen, Brazil","authors":"G. Queiroga, B. Schulz, Maximiliano D. Martins, M. P. Castro, A. Pedrosa-Soares, H. Jordt-Evangelista, Ana Lúcia da Silva","doi":"10.1590/0370-44672015690066","DOIUrl":"https://doi.org/10.1590/0370-44672015690066","url":null,"abstract":"The Capelinha Formation (Macaubas Group) consists of a lower quartzitic unit with metamafic intercalations and an upper metapelitic sequence. It occurs in a complex tectono-metamorphic sector of the Aracuai orogen, where post-collisional collapse-related structures superimposed collisional structures. The garnet-bearing assemblages started crystallization in the collisional deformation stage that formed the main regional foliation around 570 Ma. Garnet porphyroblasts display a well-developed growth zonation of Fe-Mg-Ca-Mn and show, from core to rim, increasing almandine and pyrope contents in contrast with decreasing grossular and spessartine contents. Mineral relations and microstructures provide criteria for local equilibria and a structurally controlled application of geothermobarometers based on cation exchange and net transfer reactions. The P-T values calculated from cores to rims of garnets, aligned along clockwise trends, resulted in increasing temperatures (from 500 oC up to 620 oC) under decompression conditions (from 8.0 kbar to 4.5 kbar). The Th-U-Pb dating of homogeneous monazites by electron microprobe revealed a recrystallization period at around 490 - 480 Ma. These ages can be related to the tectono-thermal event associated with the gravitational collapse, constraining the youngest time limit for metamorphic processes in the Aracuai orogen.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"26 1","pages":"33-44"},"PeriodicalIF":0.0,"publicationDate":"2016-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87123574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Influence of magnesia in the infiltration of magnesia-spinel refractory bricks by different clinkers 不同熟料对镁尖晶石耐火砖渗镁的影响

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672014680117

G. Gonçalves, G. Pacheco, M. A. Brito, Sergio Melo da Silva, V. Lins

引用次数: 8

Deformation induced precipitation in an industrial Ti microalloyed dual phase steel 工业Ti微合金双相钢的变形诱导析出

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672014680140

James Albert dos Santos Soares Mohallem, J. Martins, Charles de Abreu Martins, M. Machado

{"title":"Deformation induced precipitation in an industrial Ti microalloyed dual phase steel","authors":"James Albert dos Santos Soares Mohallem, J. Martins, Charles de Abreu Martins, M. Machado","doi":"10.1590/0370-44672014680140","DOIUrl":"https://doi.org/10.1590/0370-44672014680140","url":null,"abstract":"This study evaluated the influence of plastic deformation during hot strip rolling in the size of TiN precipitates in an industrial Ti microalloyed dual phase steel. TiN is usually used for pinning austenitic grain boundaries during recrystallization and its efficiency depends on factors such as size of the precipitates and Ti precipitated fraction. During the slab reheating process, there occurs a partial dissolution of TiN precipitates that subsequently reprecipitates during the hot rolling process. However, this reprecipitation preferentially takes place at crystalline defects which act as nucleation sites. These sites increase with the amount of applied plastic deformation, resulting in smaller precipitates, due to the partial dissolution of larger particles or due to reprecipitation in the nucleation sites. Results indicate a reduction of about 28 % in the average size of the precipitates for samples extracted from hot bands (with deformation) and, therefore, a significant reduction in austenitic grain size, when compared with samples extracted from slabs (with no deformation).","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"5 1","pages":"435-439"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78594448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Estimating extent and properties of blast-damaged zone around underground excavations 地下开挖爆破破坏区范围及性质估算

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672015680062

Slavko Torbica, Veljko Lapčević

引用次数: 18

Waste disposal using a spreader and conveyor belt method 废物处理采用撒布机和传送带的方法

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672014680125

Diego dos Ramos Nunes, Waldyr Lopes de Oliveira Filho, José Margarida da Silva

引用次数: 0

How the use of stratigraphic coordinates improves grade estimation 地层坐标的使用如何改善品位估计

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672015680057

R. Rubio, V. Koppe, J. Costa, Pablo Koury Cherchenevski

{"title":"How the use of stratigraphic coordinates improves grade estimation","authors":"R. Rubio, V. Koppe, J. Costa, Pablo Koury Cherchenevski","doi":"10.1590/0370-44672015680057","DOIUrl":"https://doi.org/10.1590/0370-44672015680057","url":null,"abstract":"Some mineral deposits show mineralization along layers. These layers may pass through several subsequent geological events such as folding and/or severe erosional processes. Grades within these deposits tend to be correlated along orientations where the mineralization was originally deposited or along the same geological period (stratigraphic level). Consequently, some locations close to each other in terms of geographical coordinates can show uncorrelated grades. Spatial continuity analysis can also be affected by error inflicted by combining samples from different stratigraphic levels. This article uses the coordinate transformation (unfolding) to align the grades measured along the same stratigraphic level. The modification in coordinates improved the spatial continuity modeling and the grade estimates at non-sampled locations. The results showed that the mean of the relative error between the estimated value and the real value of the samples using unfolding is -0.10%. However, when using the original coordinates, the mean of the relative error is -0.65%. Furthermore, the correlation between the real and estimated value using crossvalidation is greater using stratigraphic coordinates. A complete case study in a manganese deposit illustrates the methodology.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"11 1","pages":"471-477"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88395015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2