Pub Date : 2023-04-03DOI: 10.1080/25726838.2023.2218686
Yannick Saturnin Evina Aboula, Joseph Mvondo Ondoa, P. Ndjigui
ABSTRACT Regional geophysical data are important for detecting the presence of mineral deposits under cover. This study used geophysical data coupled with field geology of the Toko-Nlokeng area, Cameroon, to locate and map structures and lithologies as part of an exploration campaign for mineral deposits. The airborne geophysical survey in the Toko-Nlokeng area located in the Nyong complex revealed a predominantly EW striking highly folded series result of polyphase deformation of iron formations and host rocks divided into domains based on magnetic and radiometric character. The geophysical data indicate that major faults and shear zones strike NE-SW, with N–S striking units on the western margin and mainly E–W striking units in the rest of the area. These data suggest a major N–S thrust fault similar to the Borborema Province (NE Brazil) terrane marked by accretionary processes during the assembly of Western Gondwana. Several significant NE–SW striking shear zones are present. The data revealed many moderate to highly magnetic bodies that are interpreted as magnetite-bearing iron formation, mafic–ultramafic intrusions and flows, skarns, carbonatites and kimberlites. The magnetic and radiometric trends reveal the internal regional rock fabric and strike, and iron ore targets with magnetic anomaly up to 27,000 nT related to iron formations and other significant targets for gold, potassium (alteration) and uranium. The Toko-Nlokeng iron deposit is comprised of magnetite-bearing quartzite beds and is concordant with the surrounding host rocks and stands as one of a broad group of magnetite-dominated iron formations that occur throughout West and Central Africa. A new geological map was produced from mapped lithologies and microstructure characteristics of the iron formations, interpretations of the aeromagnetic data and structural features. The study results have important implications for regional exploration programs.
{"title":"Mapping geological configuration using geophysics data: an investigative approach in targeting iron ore, gold mineralization and other commodities, a case study of Toko-Nlokeng area (Nyong Greenstone Belt, SW Cameroon)","authors":"Yannick Saturnin Evina Aboula, Joseph Mvondo Ondoa, P. Ndjigui","doi":"10.1080/25726838.2023.2218686","DOIUrl":"https://doi.org/10.1080/25726838.2023.2218686","url":null,"abstract":"ABSTRACT Regional geophysical data are important for detecting the presence of mineral deposits under cover. This study used geophysical data coupled with field geology of the Toko-Nlokeng area, Cameroon, to locate and map structures and lithologies as part of an exploration campaign for mineral deposits. The airborne geophysical survey in the Toko-Nlokeng area located in the Nyong complex revealed a predominantly EW striking highly folded series result of polyphase deformation of iron formations and host rocks divided into domains based on magnetic and radiometric character. The geophysical data indicate that major faults and shear zones strike NE-SW, with N–S striking units on the western margin and mainly E–W striking units in the rest of the area. These data suggest a major N–S thrust fault similar to the Borborema Province (NE Brazil) terrane marked by accretionary processes during the assembly of Western Gondwana. Several significant NE–SW striking shear zones are present. The data revealed many moderate to highly magnetic bodies that are interpreted as magnetite-bearing iron formation, mafic–ultramafic intrusions and flows, skarns, carbonatites and kimberlites. The magnetic and radiometric trends reveal the internal regional rock fabric and strike, and iron ore targets with magnetic anomaly up to 27,000 nT related to iron formations and other significant targets for gold, potassium (alteration) and uranium. The Toko-Nlokeng iron deposit is comprised of magnetite-bearing quartzite beds and is concordant with the surrounding host rocks and stands as one of a broad group of magnetite-dominated iron formations that occur throughout West and Central Africa. A new geological map was produced from mapped lithologies and microstructure characteristics of the iron formations, interpretations of the aeromagnetic data and structural features. The study results have important implications for regional exploration programs.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"98 - 129"},"PeriodicalIF":1.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48664444","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}
Pub Date : 2023-04-03DOI: 10.1080/25726838.2023.2223942
M. AL-Bidry, J. Al-Najar, Asawer Al-Wassity
ABSTRACT The utilization of porcellanite rocks as a natural inorganic sorbent for crude oil sorption was investigated in this study. The experiments were achieved in batch operation, the efficiency of porcellanite was studied with different quantities of sorbent weight, grain size, mixing times and temperature. The effect of oil–water mixture pH on the sorption effectiveness of porcellanite at various pH value was tested. Porcellanite was chemically treated with HCl and NaOH to enhance the effectiveness of oil removal. The results show that porcellanite had good sorption effectiveness for crude oil at various pH and temperature. The maximum crude oil removal (82.2%) was obtained at a mixing duration of 20 min at room temperature and 3 g raw porcellanite with grain size 250 µm. Under optimized conditions, the raw porcellanite was found to adsorb about 82.2% of oil in the prepared sample. The study demonstrated that porcellanite has significant potential as a low-cost sorbent for oil spill cleanup.
{"title":"Study the characteristics of porcellanite rocks and applied as a sorbent for removing crude oil","authors":"M. AL-Bidry, J. Al-Najar, Asawer Al-Wassity","doi":"10.1080/25726838.2023.2223942","DOIUrl":"https://doi.org/10.1080/25726838.2023.2223942","url":null,"abstract":"ABSTRACT The utilization of porcellanite rocks as a natural inorganic sorbent for crude oil sorption was investigated in this study. The experiments were achieved in batch operation, the efficiency of porcellanite was studied with different quantities of sorbent weight, grain size, mixing times and temperature. The effect of oil–water mixture pH on the sorption effectiveness of porcellanite at various pH value was tested. Porcellanite was chemically treated with HCl and NaOH to enhance the effectiveness of oil removal. The results show that porcellanite had good sorption effectiveness for crude oil at various pH and temperature. The maximum crude oil removal (82.2%) was obtained at a mixing duration of 20 min at room temperature and 3 g raw porcellanite with grain size 250 µm. Under optimized conditions, the raw porcellanite was found to adsorb about 82.2% of oil in the prepared sample. The study demonstrated that porcellanite has significant potential as a low-cost sorbent for oil spill cleanup.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"142 - 157"},"PeriodicalIF":1.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43165281","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}
Pub Date : 2023-04-03DOI: 10.1080/25726838.2023.2219116
S. Lohmeier, R. Gainov, A. Hodgkin
ABSTRACT Auriferous vein samples of the Angolan M’Popo deposit were characterized by a combination of 2D microscopy and 3D computed tomography (CT) in order to visualize and assess the gold distribution and gold morphology in in situ high-grade gold ore. The 0.1–2.4 m wide hydrothermal quartz veins in the Mesoproterozoic M’Popo granitic complex are composed mainly of quartz and pyrite, minor other sulfides and (visible) gold. The favourable X-ray attenuation/density contrast within this mineral assemblage allows delineation of the gold particle fraction so that gold particles of <0.01–19.95 mm³ in volume have been identified. Statistical analysis reveals that the bulk (∼99.98%) of all gold particles belong to the smallest volume classes (≤0.02 mm²) while large particles (>0.5 mm³) are few. The contrast between rounded, compact smaller particles and branched larger ones is clearly expressed in the CT reconstructions while transitions between these reflect a likely continuum in gold mineralization.
{"title":"Morphological characterization of lode gold in the auriferous quartz veins at M’Popo mine, Angola, by computed tomography and optical microscopy","authors":"S. Lohmeier, R. Gainov, A. Hodgkin","doi":"10.1080/25726838.2023.2219116","DOIUrl":"https://doi.org/10.1080/25726838.2023.2219116","url":null,"abstract":"ABSTRACT Auriferous vein samples of the Angolan M’Popo deposit were characterized by a combination of 2D microscopy and 3D computed tomography (CT) in order to visualize and assess the gold distribution and gold morphology in in situ high-grade gold ore. The 0.1–2.4 m wide hydrothermal quartz veins in the Mesoproterozoic M’Popo granitic complex are composed mainly of quartz and pyrite, minor other sulfides and (visible) gold. The favourable X-ray attenuation/density contrast within this mineral assemblage allows delineation of the gold particle fraction so that gold particles of <0.01–19.95 mm³ in volume have been identified. Statistical analysis reveals that the bulk (∼99.98%) of all gold particles belong to the smallest volume classes (≤0.02 mm²) while large particles (>0.5 mm³) are few. The contrast between rounded, compact smaller particles and branched larger ones is clearly expressed in the CT reconstructions while transitions between these reflect a likely continuum in gold mineralization.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"65 - 89"},"PeriodicalIF":1.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45104923","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}
Pub Date : 2023-02-24DOI: 10.1080/25726838.2023.2178803
Ricardo Hundelshaussen Rubio, J. F. Coimbra Leite Costa, Diego Machado Marques, Marcel Antônio Arcari Bassani
ABSTRACT Estimates of natural phenomena with spatial correlation, i.e. stationary domains, are more precise and accurate when performed using geostatistical techniques (e.g. kriging). The kriging estimates require the definition of the spatial continuity model and a search strategy. Many techniques, such as unfolding and dynamic anisotropy, try to give some improvement in the estimates, considering the variations of the distributions in the geological bodies, however, the definition of the search strategy in the other parameters is unique. This study presents an alternative to this, called Localized Kriging Parameters optimization (LKPO). LKPO considers the best local kriging parameters settings (block by block) through the local uncertainly (simulations). To illustrate this methodology, a synthetic dataset is presented, and the results are compared with the methodologies currently available in the geostatistical literature. Validation checks show a significant improvement in precision and accuracy on the estimates when using local kriging parameters.
{"title":"Localized kriging parameters optimization using local uncertainty","authors":"Ricardo Hundelshaussen Rubio, J. F. Coimbra Leite Costa, Diego Machado Marques, Marcel Antônio Arcari Bassani","doi":"10.1080/25726838.2023.2178803","DOIUrl":"https://doi.org/10.1080/25726838.2023.2178803","url":null,"abstract":"ABSTRACT Estimates of natural phenomena with spatial correlation, i.e. stationary domains, are more precise and accurate when performed using geostatistical techniques (e.g. kriging). The kriging estimates require the definition of the spatial continuity model and a search strategy. Many techniques, such as unfolding and dynamic anisotropy, try to give some improvement in the estimates, considering the variations of the distributions in the geological bodies, however, the definition of the search strategy in the other parameters is unique. This study presents an alternative to this, called Localized Kriging Parameters optimization (LKPO). LKPO considers the best local kriging parameters settings (block by block) through the local uncertainly (simulations). To illustrate this methodology, a synthetic dataset is presented, and the results are compared with the methodologies currently available in the geostatistical literature. Validation checks show a significant improvement in precision and accuracy on the estimates when using local kriging parameters.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"130 - 141"},"PeriodicalIF":1.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47106505","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}
Pub Date : 2023-02-01DOI: 10.1080/25726838.2023.2166282
A. Cabral, L. P. T. Nazareth, L. C. da Silva, L. E. D. Amorim, A. F. Amorim, I. L. F. Ferreira, M. H. S. Franco, M. C. Gomes, P. R. L. Ferreira, M. M. Marques, N. S. Martins, I. Mendes de Oliveira, S. D. Veiga, G. V. Terenzi, F. Rios
ABSTRACT The historical Encardideira gold mine, currently known as Chico Rei, represents a rare case of gold mine owned by a freed slave in Brazil’s colonial times. The term ‘encardideira’ alludes to the property of ingraining dirt on the surface of something. Here, we provide chemical and mineralogical evidence that the Encardideira mine likely had its name from the begriming character of its ore shoots. Gold-mineralised samples are enriched in graphite C, identified as tourmaline-enclosed euhedral graphite, and Mn-oxide minerals, mostly pyrolusite and cryptomelane-like material. Measurements for Au by atomic absorption spectrometry returned Au values above 1 ppm only after cupellation, suggesting the existence of graphite-bound gold in pervasively oxidised rocks. It is hypothesised that graphite-rich ore shoots, with superposition of Mn-oxide minerals, could account for enough gold and softness for manual removal by enslaved miners and their characteristic begriming.
{"title":"Oxidised gold lode stains black: the historical Encardideira (Chico Rei) deposit, Ouro Preto, Brazil","authors":"A. Cabral, L. P. T. Nazareth, L. C. da Silva, L. E. D. Amorim, A. F. Amorim, I. L. F. Ferreira, M. H. S. Franco, M. C. Gomes, P. R. L. Ferreira, M. M. Marques, N. S. Martins, I. Mendes de Oliveira, S. D. Veiga, G. V. Terenzi, F. Rios","doi":"10.1080/25726838.2023.2166282","DOIUrl":"https://doi.org/10.1080/25726838.2023.2166282","url":null,"abstract":"ABSTRACT The historical Encardideira gold mine, currently known as Chico Rei, represents a rare case of gold mine owned by a freed slave in Brazil’s colonial times. The term ‘encardideira’ alludes to the property of ingraining dirt on the surface of something. Here, we provide chemical and mineralogical evidence that the Encardideira mine likely had its name from the begriming character of its ore shoots. Gold-mineralised samples are enriched in graphite C, identified as tourmaline-enclosed euhedral graphite, and Mn-oxide minerals, mostly pyrolusite and cryptomelane-like material. Measurements for Au by atomic absorption spectrometry returned Au values above 1 ppm only after cupellation, suggesting the existence of graphite-bound gold in pervasively oxidised rocks. It is hypothesised that graphite-rich ore shoots, with superposition of Mn-oxide minerals, could account for enough gold and softness for manual removal by enslaved miners and their characteristic begriming.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"90 - 97"},"PeriodicalIF":1.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45594704","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}
Pub Date : 2023-01-02DOI: 10.1080/25726838.2023.2166725
R. Kazapoe, O. Okunlola, E. Arhin, O. Olisa, D. Kwayisi, E. Dzikunoo, E. Amuah
ABSTRACT Gold-bearing granitoid deposits have recently been discovered in the Birimian of Ghana but their mode of formation and ore genesis remain enigmatic. This study presents petrographic, and geochemical characteristics of mineralised and unmineralised (gold grade >0.05 and <0.05 g/t respectively) granitoids (now gneisses) and schists (metasedimentary) to evaluate their petrogenesis/provenance, and relationship to gold mineralisation in the Abansuoso area. The unmineralised rocks comprise biotite- and hornblende-biotite gneisses, sericite-quartz, carbonate-sericite, and biotite-quartz schist. The mineralised varieties are biotite-, muscovite gneiss, iron-carbonate-sericite, carbonate-sericite-quartz, chlorite-carbonate, and biotite-carbonate schist. The mineralised and unmineralised gneisses are both metaluminous and peraluminous. Both mineralised and unmineraised gneiss and schist show Nb-Ta trough, depleted LILE and enriched HFSE although widespread overall trace element concentrations for the mineralised rocks on UCC-normalised multi-element diagram, suggestive of their formation in an arc setting. This suggests coeval granitic plutonism and sedimentation with subduction-accretion during the Eburnean orogeny, hence, mineralisation may be orogenic-type.
{"title":"Compositional characteristics of mineralised and unmineralised gneisses and schist around the Abansuoso area, southwestern Ghana","authors":"R. Kazapoe, O. Okunlola, E. Arhin, O. Olisa, D. Kwayisi, E. Dzikunoo, E. Amuah","doi":"10.1080/25726838.2023.2166725","DOIUrl":"https://doi.org/10.1080/25726838.2023.2166725","url":null,"abstract":"ABSTRACT Gold-bearing granitoid deposits have recently been discovered in the Birimian of Ghana but their mode of formation and ore genesis remain enigmatic. This study presents petrographic, and geochemical characteristics of mineralised and unmineralised (gold grade >0.05 and <0.05 g/t respectively) granitoids (now gneisses) and schists (metasedimentary) to evaluate their petrogenesis/provenance, and relationship to gold mineralisation in the Abansuoso area. The unmineralised rocks comprise biotite- and hornblende-biotite gneisses, sericite-quartz, carbonate-sericite, and biotite-quartz schist. The mineralised varieties are biotite-, muscovite gneiss, iron-carbonate-sericite, carbonate-sericite-quartz, chlorite-carbonate, and biotite-carbonate schist. The mineralised and unmineralised gneisses are both metaluminous and peraluminous. Both mineralised and unmineraised gneiss and schist show Nb-Ta trough, depleted LILE and enriched HFSE although widespread overall trace element concentrations for the mineralised rocks on UCC-normalised multi-element diagram, suggestive of their formation in an arc setting. This suggests coeval granitic plutonism and sedimentation with subduction-accretion during the Eburnean orogeny, hence, mineralisation may be orogenic-type.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"36 - 51"},"PeriodicalIF":1.0,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46685687","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}
Pub Date : 2022-12-10DOI: 10.1080/25726838.2022.2153980
W. Pohl
This book is designed for readers with an interest in gold, science, the mineral industry, and natural curiosity. It is based on the author’s career researching and teaching about the formation of gold deposits; and is written particularly for geoscience graduates, postgraduates, and professional geologists from the mineral industry. The book will be relevant to company leaders, stockbrokers, curious prospectors, and retired scientists.
{"title":"Formation of gold deposits","authors":"W. Pohl","doi":"10.1080/25726838.2022.2153980","DOIUrl":"https://doi.org/10.1080/25726838.2022.2153980","url":null,"abstract":"This book is designed for readers with an interest in gold, science, the mineral industry, and natural curiosity. It is based on the author’s career researching and teaching about the formation of gold deposits; and is written particularly for geoscience graduates, postgraduates, and professional geologists from the mineral industry. The book will be relevant to company leaders, stockbrokers, curious prospectors, and retired scientists.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"62 - 63"},"PeriodicalIF":1.0,"publicationDate":"2022-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48642878","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}
Pub Date : 2022-12-10DOI: 10.1080/25726838.2022.2153000
A. Kalashnikov, Nataly G. Konopleva, K. Danilin
ABSTRACT There are rich deposits of rare earth elements (REE) in the Murmansk region, Russia (approximately 14 194 kt of REE2O3). At the moment only one of REE deposits are being extracted and processed, the Lovozero Loparite deposit. The main purpose of this article is to estimate the expected value of existing REE resources in the Murmansk region and to make an overview on actual technologies for the extraction and processing of REE from ore minerals. Based on these data, the authors propose a direction for the development of REE industry in the region, namely extraction of REE from minerals already mined (apatite of the Khibiny deposits and baddeleyite of the Kovdor deposit); optimisation or development of mineral processing technologies of eudialyte (the Lovozero Eudialyte deposit) and perovskite (the Afrikanda deposit); carrying out exploration works at the Keivy Zr-REE ore occurrences and developing processing and technologies for these ores.
{"title":"Rare earths of the Murmansk Region, NW Russia: minerals, extraction technologies and value","authors":"A. Kalashnikov, Nataly G. Konopleva, K. Danilin","doi":"10.1080/25726838.2022.2153000","DOIUrl":"https://doi.org/10.1080/25726838.2022.2153000","url":null,"abstract":"ABSTRACT There are rich deposits of rare earth elements (REE) in the Murmansk region, Russia (approximately 14 194 kt of REE2O3). At the moment only one of REE deposits are being extracted and processed, the Lovozero Loparite deposit. The main purpose of this article is to estimate the expected value of existing REE resources in the Murmansk region and to make an overview on actual technologies for the extraction and processing of REE from ore minerals. Based on these data, the authors propose a direction for the development of REE industry in the region, namely extraction of REE from minerals already mined (apatite of the Khibiny deposits and baddeleyite of the Kovdor deposit); optimisation or development of mineral processing technologies of eudialyte (the Lovozero Eudialyte deposit) and perovskite (the Afrikanda deposit); carrying out exploration works at the Keivy Zr-REE ore occurrences and developing processing and technologies for these ores.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"52 - 61"},"PeriodicalIF":1.0,"publicationDate":"2022-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44423272","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}
Pub Date : 2022-11-25DOI: 10.1080/25726838.2022.2147682
T. Stark, Jiale Lin, E. Gimenes
ABSTRACT This paper focuses on pore-water pressure accumulation in loose sandy tailings during three (3) earthquakes within four minutes and the accompanying decrease in effective stress to assess the dynamic stability of the Fundão Tailings Dam, which failed on 5 November 2015. Results of laboratory cyclic direct simple shear tests are used to illustrate the accumulation of pore-water pressures with closely spaced low-level cyclic events. The seismically-induced pore-water pressures in the loose sands below the left abutment downstream slope and setback area are used to estimate the decrease in factor of safety with time until failure occurred within 20–30 minutes of the earthquakes. Field cone penetration and standard penetration test conducted prior to the failure are used to calculate the factor of safety against liquefaction to estimate pore-water pressures generated during the fore, main, and aftershocks in the sandy tailings. The effective stress stability analyses utilise a liquefied shear strength ratio for the sand tailings below the left abutment downstream slope and toe of the plateau because the sand tailings reached the critical state condition due to a reduction in the effective stress. SITE LOCATION: 20.206500°S, 43.467111°W
{"title":"Pore-water pressure accumulation during closely spaced earthquakes: Fundão Tailings Dam","authors":"T. Stark, Jiale Lin, E. Gimenes","doi":"10.1080/25726838.2022.2147682","DOIUrl":"https://doi.org/10.1080/25726838.2022.2147682","url":null,"abstract":"ABSTRACT This paper focuses on pore-water pressure accumulation in loose sandy tailings during three (3) earthquakes within four minutes and the accompanying decrease in effective stress to assess the dynamic stability of the Fundão Tailings Dam, which failed on 5 November 2015. Results of laboratory cyclic direct simple shear tests are used to illustrate the accumulation of pore-water pressures with closely spaced low-level cyclic events. The seismically-induced pore-water pressures in the loose sands below the left abutment downstream slope and setback area are used to estimate the decrease in factor of safety with time until failure occurred within 20–30 minutes of the earthquakes. Field cone penetration and standard penetration test conducted prior to the failure are used to calculate the factor of safety against liquefaction to estimate pore-water pressures generated during the fore, main, and aftershocks in the sandy tailings. The effective stress stability analyses utilise a liquefied shear strength ratio for the sand tailings below the left abutment downstream slope and toe of the plateau because the sand tailings reached the critical state condition due to a reduction in the effective stress. SITE LOCATION: 20.206500°S, 43.467111°W","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"16 - 35"},"PeriodicalIF":1.0,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42444625","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}
Pub Date : 2022-11-21DOI: 10.1080/25726838.2022.2147300
K. Khoshnoodi, S. Ziapour, M. Yazdi, M. Cuney
ABSTRACT The Bafq district, well-known in the world, is the most important iron province in Central Iran. The Early Cambrian volcano-sedimentary sequence in this district, hosts a lot of mineral deposits such as Kiruna-type iron oxide-apatite (IOA), Fe-Mn exhalative and Pb-Zn SEDEX types. Th-U-REE mineralisation in the Bafq IOA deposits occurs in a variety of element associations, (i) REE-P mineralisation as apatite hosting REE-mineral inclusions, (ii) Th-REE mineralisation as Th-REE minerals (e.g. REE-bearing thorite and titanite), (iii) thorium mineralisation as thorium minerals (e.g. thorite and huttonite), (iv) U-REE mineralisation as U-REE minerals (e.g. uraninite and cleveite) and (v) REE-U-Th mineralisation as REE-U-Th minerals (e.g. davidite and allanite). Two main types of apatite are recognised: apatite with inclusions (dominantly monazite, xenotime and allanite) and inclusion poor/free apatite. The presence of calcite paragenesis with Th-REE, Th and U-Th-REE mineralisation indicates transportation of Th and REEs by carbonate complexes in post-magmatic alkaline fluids.
{"title":"Mineralogy of various types of Th-U-REE mineralisation in the iron oxide – apatite deposits of the Bafq district, Central Iran","authors":"K. Khoshnoodi, S. Ziapour, M. Yazdi, M. Cuney","doi":"10.1080/25726838.2022.2147300","DOIUrl":"https://doi.org/10.1080/25726838.2022.2147300","url":null,"abstract":"ABSTRACT The Bafq district, well-known in the world, is the most important iron province in Central Iran. The Early Cambrian volcano-sedimentary sequence in this district, hosts a lot of mineral deposits such as Kiruna-type iron oxide-apatite (IOA), Fe-Mn exhalative and Pb-Zn SEDEX types. Th-U-REE mineralisation in the Bafq IOA deposits occurs in a variety of element associations, (i) REE-P mineralisation as apatite hosting REE-mineral inclusions, (ii) Th-REE mineralisation as Th-REE minerals (e.g. REE-bearing thorite and titanite), (iii) thorium mineralisation as thorium minerals (e.g. thorite and huttonite), (iv) U-REE mineralisation as U-REE minerals (e.g. uraninite and cleveite) and (v) REE-U-Th mineralisation as REE-U-Th minerals (e.g. davidite and allanite). Two main types of apatite are recognised: apatite with inclusions (dominantly monazite, xenotime and allanite) and inclusion poor/free apatite. The presence of calcite paragenesis with Th-REE, Th and U-Th-REE mineralisation indicates transportation of Th and REEs by carbonate complexes in post-magmatic alkaline fluids.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"132 1","pages":"1 - 15"},"PeriodicalIF":1.0,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46821172","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}
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