R. D. Ardi, A. Aswan, K. Maryunani, E. Yulianto, P. Putra, S. H. Nugroho
Despite its importance, sea surface paleoproductivity of the western Savu Strait is not well studied. Results from previous studies at the nearby Southwest Sumba and Sumba Strait might not be applicable due to the oceanographic difference. Foraminiferal proxies from gravity core ST10 were applied to generate sea surface paleoproductivity and thermocline depth reconstruction. Foraminiferal Accumulation Rate and Benthic Foraminiferal Accumulation Rate were used as paleoproductivity proxies while the thermocline dwellers’ relative abundance was applied as the thermocline depth proxy. This study suggested paleoproductivity increase during the Last Glacial Maximum (LGM)–~16 ka BP and Holocene (after ~11.65 ka BP) in the western Savu Strait. Thermocline depth was relatively shallower during the LGM–Last Deglaciation and became deeper afterwards. Paleoproductivity increase at LGM–~16 ka BP was caused by the Australian-Indonesian winter monsoon (AIWM)-like condition, characterized by intense coastal upwelling while the Holocene paleoproductivity increase was related to the abrupt rainfall increase which enhanced terrestrial/riverine input. Thermocline depth variability in the western Savu Strait is in-phase with thermocline depth variability in the Java upwelling region, characterized by a shallower thermocline during the LGM–Last Deglaciation (before ~11.65 ka BP) and a deeper thermocline during the Holocene (after ~11.65 ka BP). This thermocline depth shifting indicates a strong Australian-Indonesian Monsoon (AIM) influence on the paleoceanography of the western Savu Strait since LGM.
尽管萨武海峡西部的海面古生产力具有重要意义，但目前对其研究还不够深入。先前在附近的西南松巴海峡和松巴海峡进行的研究结果可能由于海洋学的差异而不适用。利用ST10重力岩心有孔虫代用物进行了海表古生产力和温跃层深度重建。以有孔虫积累率和底栖有孔虫积累率作为古生产力指标，以温跃层生物相对丰度作为温跃层深度指标。研究表明，萨武海峡西部的古生产力在末次盛冰期(LGM) - ~16 ka BP和全新世(~11.65 ka BP之后)期间有所增加。在lgm -末次消冰期，温跃层深度相对较浅，之后逐渐变深。LGM - ~16 ka BP古生产力的增加是由澳大利亚-印度尼西亚冬季风(AIWM)样条件引起的，其特征是强烈的海岸上升流，而全新世古生产力的增加与降雨量的突然增加有关，增加了陆地/河流的输入。萨武海峡西部的温跃层深度变化与爪哇上升流区的温跃层深度变化相一致，表现为lmg -末次脱冰期(~11.65 ka BP之前)的温跃层较浅，全新世(~11.65 ka BP之后)的温跃层较深。这种温跃层深度变化表明，自LGM以来，澳大利亚-印度尼西亚季风(AIM)对萨武海峡西部的古海洋学有强烈的影响。
{"title":"EA SURFACE PALEOPRODUCTIVITY RECONSTRUCTION BASED ON FORAMINIFERAL ACCUMULATION RATE IN THE WESTERN SAVU STRAIT SINCE THE LAST GLACIAL MAXIMUM (~23 KA BP)","authors":"R. D. Ardi, A. Aswan, K. Maryunani, E. Yulianto, P. Putra, S. H. Nugroho","doi":"10.17794/rgn.2023.1.14","DOIUrl":"https://doi.org/10.17794/rgn.2023.1.14","url":null,"abstract":"Despite its importance, sea surface paleoproductivity of the western Savu Strait is not well studied. Results from previous studies at the nearby Southwest Sumba and Sumba Strait might not be applicable due to the oceanographic difference. Foraminiferal proxies from gravity core ST10 were applied to generate sea surface paleoproductivity and thermocline depth reconstruction. Foraminiferal Accumulation Rate and Benthic Foraminiferal Accumulation Rate were used as paleoproductivity proxies while the thermocline dwellers’ relative abundance was applied as the thermocline depth proxy. This study suggested paleoproductivity increase during the Last Glacial Maximum (LGM)–~16 ka BP and Holocene (after ~11.65 ka BP) in the western Savu Strait. Thermocline depth was relatively shallower during the LGM–Last Deglaciation and became deeper afterwards. Paleoproductivity increase at LGM–~16 ka BP was caused by the Australian-Indonesian winter monsoon (AIWM)-like condition, characterized by intense coastal upwelling while the Holocene paleoproductivity increase was related to the abrupt rainfall increase which enhanced terrestrial/riverine input. Thermocline depth variability in the western Savu Strait is in-phase with thermocline depth variability in the Java upwelling region, characterized by a shallower thermocline during the LGM–Last Deglaciation (before ~11.65 ka BP) and a deeper thermocline during the Holocene (after ~11.65 ka BP). This thermocline depth shifting indicates a strong Australian-Indonesian Monsoon (AIM) influence on the paleoceanography of the western Savu Strait since LGM.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68156276","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}
Tarek A. Mohamed, Mohamed A. Yousef, Mustafa K. Alemam, Y. Mostafa
Since the establishment of the International GNSS Service (IGS) stations, they have been used as control stations for assigning the Precise point positioning (PPP) positions using one Global Navigation Satellite System (GNSS) receiver, which has increased from day-to-day. There are some factors affecting the accuracy of PPP positioning. This research aims to investigate the relation between the IGS distance and observed field points as well as to attempt to describe that relation mathematically/statically. For the realization of that aim, two field points are fixed inside the Assiut University campus and observed successively for a session of 24 hour observation. The position of each field point is assigned with the help of each one of the available IGS station products. It must be known that these products are found after observations in three files (IGU, IGR, and final IGS), whereas IGU is used directly as real-time data (ultra-rapid), IGR (rapid) is used through (17-41 hours) after observation, and (final IGS) used after 12 – 18 days. Coordinates and point errors of each field points are computed and represented. It has been found that the errors have a positive relation with the available IGS stations distances. The relation between these distances and point positioning errors have been represented and described according to a model. The accuracy of the presented model is (R ≅ .98, x2 ≅ 2.5 × 10-3).
{"title":"EFFECT OF IGS BASELINE LENGTH ON GNSS POSITIONING ACCURACY","authors":"Tarek A. Mohamed, Mohamed A. Yousef, Mustafa K. Alemam, Y. Mostafa","doi":"10.17794/rgn.2023.3.7","DOIUrl":"https://doi.org/10.17794/rgn.2023.3.7","url":null,"abstract":"Since the establishment of the International GNSS Service (IGS) stations, they have been used as control stations for assigning the Precise point positioning (PPP) positions using one Global Navigation Satellite System (GNSS) receiver, which has increased from day-to-day. There are some factors affecting the accuracy of PPP positioning. This research aims to investigate the relation between the IGS distance and observed field points as well as to attempt to describe that relation mathematically/statically. For the realization of that aim, two field points are fixed inside the Assiut University campus and observed successively for a session of 24 hour observation. The position of each field point is assigned with the help of each one of the available IGS station products. It must be known that these products are found after observations in three files (IGU, IGR, and final IGS), whereas IGU is used directly as real-time data (ultra-rapid), IGR (rapid) is used through (17-41 hours) after observation, and (final IGS) used after 12 – 18 days. Coordinates and point errors of each field points are computed and represented. It has been found that the errors have a positive relation with the available IGS stations distances. The relation between these distances and point positioning errors have been represented and described according to a model. The accuracy of the presented model is (R ≅ .98, x2 ≅ 2.5 × 10-3).","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68158675","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}
High quality coke is a key raw material for the metallurgical industry. The characteristics of the coal have a significant influence on the parameters of the coke produced and, consequently, on the valuation of coal deposits and the economic assessment of mining projects. Predicting the quality of coking coal allows for the optimisation of production processes, including the planning and management of operations and the early detection of quality problems. In this study, using the principles of a smart mine, it is proposed to determine the quality of coal based on the combination of mining and geological conditions of mineral deposits and its quality indicators. Possible interrelationships between the quality of the coal in the deposit and the characteristics of the final product have been identified. A neural network is used to determine the priority of individual indicators that have a significant impact on the quality of coking coal. An important part of the research is its practical implementation in the conditions of the Jastrzębska Spółka Węglowa SA. Qualitative and quantitative parameters of coking coals were obtained for each mine of the region by the method of sampling and statistical processing of data such as: degree of metamorphism, thickness, deviation of volatile substances, presence of phosphorus, ash content, etc. For their evaluation, the Group Method of Data Handling was used to compare the factors of quality indicators depending on the priority of influence on the final characteristics of the coking coal. Based on the results obtained, it is shown that not all coal quality indicators have a significant impact on the quality of the final product. The study shows that it is possible to predict the main indicators (CRI – Coke Reactivity Index, CSR – Coke Strength after Reaction) of coke quality using neural networks based on a larger number of coal quality parameters and to eliminate parameters that have virtually no influence on the value of the final product. This method can also be used to improve the results of economic valuation of a deposit and to better plan exploration and mining operations.
{"title":"REAL-TIME FORECASTING OF KEY COKING COAL QUALITY PARAMETERS USING NEURAL NETWORKS AND ARTIFICIAL INTELLIGENCE","authors":"A. Dyczko","doi":"10.17794/rgn.2023.3.9","DOIUrl":"https://doi.org/10.17794/rgn.2023.3.9","url":null,"abstract":"High quality coke is a key raw material for the metallurgical industry. The characteristics of the coal have a significant influence on the parameters of the coke produced and, consequently, on the valuation of coal deposits and the economic assessment of mining projects. Predicting the quality of coking coal allows for the optimisation of production processes, including the planning and management of operations and the early detection of quality problems. In this study, using the principles of a smart mine, it is proposed to determine the quality of coal based on the combination of mining and geological conditions of mineral deposits and its quality indicators. Possible interrelationships between the quality of the coal in the deposit and the characteristics of the final product have been identified. A neural network is used to determine the priority of individual indicators that have a significant impact on the quality of coking coal. An important part of the research is its practical implementation in the conditions of the Jastrzębska Spółka Węglowa SA. Qualitative and quantitative parameters of coking coals were obtained for each mine of the region by the method of sampling and statistical processing of data such as: degree of metamorphism, thickness, deviation of volatile substances, presence of phosphorus, ash content, etc. For their evaluation, the Group Method of Data Handling was used to compare the factors of quality indicators depending on the priority of influence on the final characteristics of the coking coal. Based on the results obtained, it is shown that not all coal quality indicators have a significant impact on the quality of the final product. The study shows that it is possible to predict the main indicators (CRI – Coke Reactivity Index, CSR – Coke Strength after Reaction) of coke quality using neural networks based on a larger number of coal quality parameters and to eliminate parameters that have virtually no influence on the value of the final product. This method can also be used to improve the results of economic valuation of a deposit and to better plan exploration and mining operations.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68158895","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}
Natali Neral, Andreja Kudelić, A. Maričić, Marta Mileusnić
Consideration of multiperiod archaeological sites to understand the mechanisms of large-scale cultural changes is still a very rare research topic in Croatia. Technological traditions are of great importance, especially in the context of considering continuity, innovation, and change. In this paper, we used an archaeometric approach to investigate pottery technology. Therefore, this article presents an analysis of petrography and mineralogy of archaeological ceramics and potential raw materials collected in the vicinity of the multi-period archaeological site (the Neolithic through the Medieval period) Jagodnjak-Krčevine located in eastern Croatia, i.e. the south-western part of the Pannonian Basin. The primary goal is to determine what kind of clay recipe (clay and temper) potters used to make vessels in order to better understand their variability in the context of techno-functional features. The additional objective is to examine the availability and quality of clays for pottery production and to study their distribution in the local landscape. The analytical methods applied in the research are optical microscopy, X-ray diffraction, and grain size analysis. The comparison of archaeological ceramics with clayey materials established that ancient potters used locally available clays, and the selection of temper material added to the clay represents a strong element of techno-tradition, which is more pronounced for prehistoric communities. Furthermore, these results represent the first research in Croatia focused on a discussion about distances that potters travelled to obtain their resources in the different periods of the past, which can contribute to the study of a regional system of production and landscape use.
{"title":"POTTERY TECHNOLOGY THROUGH TIME: ARCHAEOMETRY OF POTTERY AND CLAYEY RAW MATERIAL FROM THE MULTI-PERIOD SITE IN EASTERN CROATIA","authors":"Natali Neral, Andreja Kudelić, A. Maričić, Marta Mileusnić","doi":"10.17794/rgn.2023.2.1","DOIUrl":"https://doi.org/10.17794/rgn.2023.2.1","url":null,"abstract":"Consideration of multiperiod archaeological sites to understand the mechanisms of large-scale cultural changes is still a very rare research topic in Croatia. Technological traditions are of great importance, especially in the context of considering continuity, innovation, and change. In this paper, we used an archaeometric approach to investigate pottery technology. Therefore, this article presents an analysis of petrography and mineralogy of archaeological ceramics and potential raw materials collected in the vicinity of the multi-period archaeological site (the Neolithic through the Medieval period) Jagodnjak-Krčevine located in eastern Croatia, i.e. the south-western part of the Pannonian Basin. The primary goal is to determine what kind of clay recipe (clay and temper) potters used to make vessels in order to better understand their variability in the context of techno-functional features. The additional objective is to examine the availability and quality of clays for pottery production and to study their distribution in the local landscape. The analytical methods applied in the research are optical microscopy, X-ray diffraction, and grain size analysis. The comparison of archaeological ceramics with clayey materials established that ancient potters used locally available clays, and the selection of temper material added to the clay represents a strong element of techno-tradition, which is more pronounced for prehistoric communities. Furthermore, these results represent the first research in Croatia focused on a discussion about distances that potters travelled to obtain their resources in the different periods of the past, which can contribute to the study of a regional system of production and landscape use.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68156498","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}
The process of creating a slope in a rock mass using the excavation and blasting methods consistently leads to stress release in the rock mass, resulting in a certain level of fracture and disturbance. Blast-induced vibrations can also influence the quality of the rock mass remaining after the blasting, as well as the stability and bench damage monitoring (BDM) of mines. A damage factor (D) is included in the Hoek–Brown failure criterion to compute the disturbance of a rock mass in creating a slope. Choosing the value and thickness of the blast zone for the Hoek–Brown criterion is crucial in the safety analysis and BDM of mines. However, the selection is still a crucial technical challenge in this criterion. Employing nonlinear layering, the present study divides the rock mass behind a blast hole into several layers with decreasing D values applied to each layer. The numerical simulation was conducted using the FLAC finite difference software for bench vibration assessment and damage monitoring by checking the peak particle velocity (PPV) in the bench face with different geometries. Behind the blast hole, five different layers of D were considered through which the Hoek–Brown properties of the rock mass declined nonlinearly during the execution of the model. Since the disturbance threshold of PPV was assumed to be 120 mm/s, the toe and middle parts of the small benches were in the disturbance threshold, while for the medium and high benches, only the bench toe was within the disturbance threshold.
{"title":"IMPACT OF THE LAYERING OF BLAST-INDUCED DAMAGE FACTORS IN THE HOEK–BROWN FAILURE CRITERION ON THE BENCH DAMAGE MONITORING OF MINES","authors":"Seyed Ahmad Mousavi, K. Ahangari, K. Goshtasbi","doi":"10.17794/rgn.2023.1.9","DOIUrl":"https://doi.org/10.17794/rgn.2023.1.9","url":null,"abstract":"The process of creating a slope in a rock mass using the excavation and blasting methods consistently leads to stress release in the rock mass, resulting in a certain level of fracture and disturbance. Blast-induced vibrations can also influence the quality of the rock mass remaining after the blasting, as well as the stability and bench damage monitoring (BDM) of mines. A damage factor (D) is included in the Hoek–Brown failure criterion to compute the disturbance of a rock mass in creating a slope. Choosing the value and thickness of the blast zone for the Hoek–Brown criterion is crucial in the safety analysis and BDM of mines. However, the selection is still a crucial technical challenge in this criterion. Employing nonlinear layering, the present study divides the rock mass behind a blast hole into several layers with decreasing D values applied to each layer. The numerical simulation was conducted using the FLAC finite difference software for bench vibration assessment and damage monitoring by checking the peak particle velocity (PPV) in the bench face with different geometries. Behind the blast hole, five different layers of D were considered through which the Hoek–Brown properties of the rock mass declined nonlinearly during the execution of the model. Since the disturbance threshold of PPV was assumed to be 120 mm/s, the toe and middle parts of the small benches were in the disturbance threshold, while for the medium and high benches, only the bench toe was within the disturbance threshold.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68156310","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}
A. Maričić, Z. Briševac, P. Hrženjak, Helena Jezidžić
Natural stone has been used since the dawn of civilization as a construction material for buildings that are historical and cultural buildings and monuments. The Zagreb Cathedral is an example of such a historical and cultural building and data regarding the extraction of stone for its construction and reconstruction is scientifically underestimated. Based on a review of previously published literature and an investigation on the current state of the sites where stone for construction was previously quarried, this paper presents a systematic overview of challenges regarding stone material that will be faced in the restoration of the Cathedral after the 2020 earthquakes. The autochthonous stone varieties used for the Cathedral, namely lithothamnium limestone, litavac, calcareous sandstone, and vinicite were determined. The description of the locations where they were quarried was emphasized, and the suitability of these sites for re-quarrying the stone blocks during reconstruction after the 2020 earthquake was investigated. In addition, the Cathedral was renovated in the meantime with travertine imported from Italy, which, although it is not of domestic origin, represents an integral part of the Cathedral and whose characteristics must be taken into account in the planning of the current reconstruction of the Cathedral. To preserve the cultural memory of quarrying in the Zagreb area, emphasis is given to the importance of preserving and showing old visual representations of the quarries.
{"title":"NATURAL BUILDING STONE IN THE CONSTRUCTION AND RENOVATION OF THE ZAGREB CATHEDRAL","authors":"A. Maričić, Z. Briševac, P. Hrženjak, Helena Jezidžić","doi":"10.17794/rgn.2023.3.3","DOIUrl":"https://doi.org/10.17794/rgn.2023.3.3","url":null,"abstract":"Natural stone has been used since the dawn of civilization as a construction material for buildings that are historical and cultural buildings and monuments. The Zagreb Cathedral is an example of such a historical and cultural building and data regarding the extraction of stone for its construction and reconstruction is scientifically underestimated. Based on a review of previously published literature and an investigation on the current state of the sites where stone for construction was previously quarried, this paper presents a systematic overview of challenges regarding stone material that will be faced in the restoration of the Cathedral after the 2020 earthquakes. The autochthonous stone varieties used for the Cathedral, namely lithothamnium limestone, litavac, calcareous sandstone, and vinicite were determined. The description of the locations where they were quarried was emphasized, and the suitability of these sites for re-quarrying the stone blocks during reconstruction after the 2020 earthquake was investigated. In addition, the Cathedral was renovated in the meantime with travertine imported from Italy, which, although it is not of domestic origin, represents an integral part of the Cathedral and whose characteristics must be taken into account in the planning of the current reconstruction of the Cathedral. To preserve the cultural memory of quarrying in the Zagreb area, emphasis is given to the importance of preserving and showing old visual representations of the quarries.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"41 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68158791","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}
F. Kazemi, A. Bahrami, Y. Ghorbani, Abolfazl Danesh, M. Abdollahi, H. Falah, Mohsen Salehi
The interaction and synergic effect of particle size on flotation efficiency were investigated by a comparison study between laboratories (size-by-size flotation modes) and industrial scale operational data (whole mixed size fraction). For this purpose, sampling was done from the feed, concentrate, and tailing of the flotation rougher cells of the Sungun copper processing complex (located in the northwest of Iran). In the size-by-size flotation mode (lab scale), the sample was first subjected to different size fractions, and then flotation tests were performed for each fraction. On an industrial scale, the particle size distribution of feed, concentrate, and tailing of flotation of the rougher stage have been analyzed. According to the results, in the case of industrial flotation mode (whole mixed size fraction), the particles with d80=84 μm were more likely to reach the tailing of flotation, and the particles within the size range of +63-180 μm constituted the highest amount of concentrate particles. In lab flotation mode (size-by-size), the maximum recovery was in the size fraction of +40-60 μm. By comparing the two flotation modes of industrial (whole mixed size fraction) and lab (size-by-size), for fractions <45 μm, the industrial flotation recovery was approximately 40% greater than the lab flotation recovery. However, for fractions >125 μm, the recovery trend was reversed and the lab flotation recovery was greater than the industrial flotation recovery. Coarse particle flotation has significant economic and technological benefits. By improving the recovery of coarse particles during the flotation process, the amount of grinding requirements will be reduced and consequently, it will considerably decrease the amount of energy consumption.
{"title":"THE INTERACTION AND SYNERGIC EFFECT OF PARTICLE SIZE ON FLOTATION EFFICIENCY: A COMPARISON STUDY OF RECOVERY BY SIZE, AND BY LIBERATION BETWEEN LAB AND INDUSTRIAL SCALE DATA","authors":"F. Kazemi, A. Bahrami, Y. Ghorbani, Abolfazl Danesh, M. Abdollahi, H. Falah, Mohsen Salehi","doi":"10.17794/rgn.2023.1.1","DOIUrl":"https://doi.org/10.17794/rgn.2023.1.1","url":null,"abstract":"The interaction and synergic effect of particle size on flotation efficiency were investigated by a comparison study between laboratories (size-by-size flotation modes) and industrial scale operational data (whole mixed size fraction). For this purpose, sampling was done from the feed, concentrate, and tailing of the flotation rougher cells of the Sungun copper processing complex (located in the northwest of Iran). In the size-by-size flotation mode (lab scale), the sample was first subjected to different size fractions, and then flotation tests were performed for each fraction. On an industrial scale, the particle size distribution of feed, concentrate, and tailing of flotation of the rougher stage have been analyzed. According to the results, in the case of industrial flotation mode (whole mixed size fraction), the particles with d80=84 μm were more likely to reach the tailing of flotation, and the particles within the size range of +63-180 μm constituted the highest amount of concentrate particles. In lab flotation mode (size-by-size), the maximum recovery was in the size fraction of +40-60 μm. By comparing the two flotation modes of industrial (whole mixed size fraction) and lab (size-by-size), for fractions <45 μm, the industrial flotation recovery was approximately 40% greater than the lab flotation recovery. However, for fractions >125 μm, the recovery trend was reversed and the lab flotation recovery was greater than the industrial flotation recovery. Coarse particle flotation has significant economic and technological benefits. By improving the recovery of coarse particles during the flotation process, the amount of grinding requirements will be reduced and consequently, it will considerably decrease the amount of energy consumption.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68155328","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}
Putu Billy Suryanata, S. Bijaksana, M. Abdurrachman, D. Dahrin, Aditya Pratama, N. R. D. W. Ndari, S. J. Fajar
Geochemical and petrographic characterizations were carried out on five episodic effusive eruptions from Batur Volcano on the Island of Bali, Indonesia, and revealed that these lavas are basaltic to andesitic in composition. Various micro-textures were identified, reflecting pre-eruptive magmatic processes, magma mixing, and adiabatic decompression. Apart from XRF analyses, the five lava flows (L849, L926, L963, L968 and L974) were subjected to magnetic analyses in the form of magnetic susceptibility and magnetic hysteresis measurements. The presence of cyclicity in the magmatic process is suggested by the variation of micro-texture types, CaO content, and magnetic susceptibility values. Two possible models of this cyclicity are presented. In the first model, cyclicity is driven by the variation of influx from the lower magma chamber that affects the interaction of magma with the surrounding rocks. In the second model, cyclicity is affected by the appearance of a new magmatic vent, which causes intense interaction with surrounding rocks. This study infers that combined micro-texture, composition, and magnetic susceptibility analyses might provide insight into the cyclicity of lava episodes observed in active volcanos such as Batur.
{"title":"PRELIMINARY PETROMAGNETIC STUDY OF 1849, 1926, 1963, 1968 AND 1974 SURFACE LAVAS FROM BATUR VOLCANO, BALI, INDONESIA: INSIGHT ON THE MAGMATIC PROCESS OF SOURCE AND ROCK MAGNETIC NATURE","authors":"Putu Billy Suryanata, S. Bijaksana, M. Abdurrachman, D. Dahrin, Aditya Pratama, N. R. D. W. Ndari, S. J. Fajar","doi":"10.17794/rgn.2023.1.3","DOIUrl":"https://doi.org/10.17794/rgn.2023.1.3","url":null,"abstract":"Geochemical and petrographic characterizations were carried out on five episodic effusive eruptions from Batur Volcano on the Island of Bali, Indonesia, and revealed that these lavas are basaltic to andesitic in composition. Various micro-textures were identified, reflecting pre-eruptive magmatic processes, magma mixing, and adiabatic decompression. Apart from XRF analyses, the five lava flows (L849, L926, L963, L968 and L974) were subjected to magnetic analyses in the form of magnetic susceptibility and magnetic hysteresis measurements. The presence of cyclicity in the magmatic process is suggested by the variation of micro-texture types, CaO content, and magnetic susceptibility values. Two possible models of this cyclicity are presented. In the first model, cyclicity is driven by the variation of influx from the lower magma chamber that affects the interaction of magma with the surrounding rocks. In the second model, cyclicity is affected by the appearance of a new magmatic vent, which causes intense interaction with surrounding rocks. This study infers that combined micro-texture, composition, and magnetic susceptibility analyses might provide insight into the cyclicity of lava episodes observed in active volcanos such as Batur.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68156005","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}
The stability of a jointed rock mass is generally controlled by its shear strength that significantly depends on surface roughness. So far, different methods have been presented for determining surface roughness using 2D profiles. In this study, a new method based on the unsupervised pattern recognition technique using a combination of statistical, geostatistical, directional, and spectral methods for the quantification of the surface roughness will be proposed. To reach this goal, more than 10,000 profiles gathered from 92 surfaces of natural rock joints were scanned. The samples were collected from limestone cores of the Lar Dam located in the Mazandaran Province, Iran. After introducing a new spectral index, determined from the fast Fourier transform for measuring the unevenness of rough profiles, statistical, geostatistical, directional, and spectral features revealing waviness and unevenness of the 2D profiles were extracted, and a representative vector and profile for each surface were introduced through the weighted mean and median of the profile features. Principal component analysis (PCA) was utilized for finding the direction of the maximum variance of information. Then, clustering of the 92 samples was performed via K-means, and the silhouette measure was used in order to find the optimal number of clusters resulted in the creation of 13 clusters. To verify the procedure, a sample was selected in each cluster, and direct shear tests were performed on the samples. Comparing the experiments and the clustering results shows they are in good agreement. Thus, the method is an efficient tool for the quantitative recognition of surface roughness considering the waviness and unevenness of a surface.
{"title":"SURFACE ROUGHNESS ASSESSMENT OF NATURAL ROCK JOINTS BASED ON AN UNSUPERVISED PATTERN RECOGNITION TECHNIQUE USING 2D PROFILES","authors":"Ali Mohamad Pakdaman, M. Moosavi","doi":"10.17794/rgn.2023.2.14","DOIUrl":"https://doi.org/10.17794/rgn.2023.2.14","url":null,"abstract":"The stability of a jointed rock mass is generally controlled by its shear strength that significantly depends on surface roughness. So far, different methods have been presented for determining surface roughness using 2D profiles. In this study, a new method based on the unsupervised pattern recognition technique using a combination of statistical, geostatistical, directional, and spectral methods for the quantification of the surface roughness will be proposed. To reach this goal, more than 10,000 profiles gathered from 92 surfaces of natural rock joints were scanned. The samples were collected from limestone cores of the Lar Dam located in the Mazandaran Province, Iran. After introducing a new spectral index, determined from the fast Fourier transform for measuring the unevenness of rough profiles, statistical, geostatistical, directional, and spectral features revealing waviness and unevenness of the 2D profiles were extracted, and a representative vector and profile for each surface were introduced through the weighted mean and median of the profile features. Principal component analysis (PCA) was utilized for finding the direction of the maximum variance of information. Then, clustering of the 92 samples was performed via K-means, and the silhouette measure was used in order to find the optimal number of clusters resulted in the creation of 13 clusters. To verify the procedure, a sample was selected in each cluster, and direct shear tests were performed on the samples. Comparing the experiments and the clustering results shows they are in good agreement. Thus, the method is an efficient tool for the quantitative recognition of surface roughness considering the waviness and unevenness of a surface.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68157390","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}
PT.X, a coal mining company in South Kalimantan, Indonesia, plans to use the highwall mining method to excavate marginal reserves on the final slope to maintain production. However, the stability of the slope and determination of the highwall mining dimensions are major concerns due to unfavourable rock mass conditions caused by intensive weathering and tectonics. This paper aims to evaluate the feasibility of highwall mining in the study area using empirical, analytical and numerical methods. The innovation of this research is the integration of these methods, which include rock mass classification, analytical calculation of load and rock support strength, 2D and 3D numerical modelling, and estimation of recovered coal from the highwall design. The initial condition assessment using rock mass classification and analytics calculation of the mining geometry model determined mine openings and pillar dimensions. Numerical modelling re-evaluated the geometry models to obtain an optimal design. The suggested optimal thickness, mine opening, web pillars, and barrier pillars are 3.20, 3.00, 3.50, and 4.00 m, respectively, with four web pillars in one panel at Seam-C and 2.50, 3.00, 3.50, and 4.00 m with four web pillars in one panel at Seam-D. The recovery of coal for Seam-C and Seam-D is estimated to be 40.54%. Deformation was found to have the closest relationship with the dimensions of the mine opening, and the safety factor is most sensitive to changes in the depth of the mine opening. This study provides a reference for future highwall mining in Indonesia and other regions with similar conditions.
{"title":"ASSESSMENT OF ROCK SLOPE STABILITY IN A HUMID TROPICAL REGION: CASE STUDY OF A COAL MINE IN SOUTH KALIMANTAN, INDONESIA","authors":"Z. Zulfahmi, D. Sarah, F. Novico, R. B. Susilo","doi":"10.17794/rgn.2023.2.8","DOIUrl":"https://doi.org/10.17794/rgn.2023.2.8","url":null,"abstract":"PT.X, a coal mining company in South Kalimantan, Indonesia, plans to use the highwall mining method to excavate marginal reserves on the final slope to maintain production. However, the stability of the slope and determination of the highwall mining dimensions are major concerns due to unfavourable rock mass conditions caused by intensive weathering and tectonics. This paper aims to evaluate the feasibility of highwall mining in the study area using empirical, analytical and numerical methods. The innovation of this research is the integration of these methods, which include rock mass classification, analytical calculation of load and rock support strength, 2D and 3D numerical modelling, and estimation of recovered coal from the highwall design. The initial condition assessment using rock mass classification and analytics calculation of the mining geometry model determined mine openings and pillar dimensions. Numerical modelling re-evaluated the geometry models to obtain an optimal design. The suggested optimal thickness, mine opening, web pillars, and barrier pillars are 3.20, 3.00, 3.50, and 4.00 m, respectively, with four web pillars in one panel at Seam-C and 2.50, 3.00, 3.50, and 4.00 m with four web pillars in one panel at Seam-D. The recovery of coal for Seam-C and Seam-D is estimated to be 40.54%. Deformation was found to have the closest relationship with the dimensions of the mine opening, and the safety factor is most sensitive to changes in the depth of the mine opening. This study provides a reference for future highwall mining in Indonesia and other regions with similar conditions.","PeriodicalId":44536,"journal":{"name":"Rudarsko-Geolosko-Naftni Zbornik","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68158058","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：