Pub Date : 2020-11-02DOI: 10.36487/acg_repo/2052_13
F. Braga, R. Guang, J. Pereira, J. Davo, F. Ferrari, T. Nicoli, L. Boxill, J. Russo
Given the current scenario experienced by Brazilian mining industry, the study and development of technologies that enable a more secure and controlled disposal of tailings has gained significant relevance. Among the various alternatives and disposal methodologies, Anglo American has been developing tests on different study fronts. Using dewatering polymers to improve tailings store potentials at tailings dam is one of the methods that has been studied extensively. The tested polymers can enhance de-watering performance and immobilization of mineral slurries during hydraulic deposition, therefore achieving optimization of tailings storage at the existing facility. The studies were divided into laboratory and industrial field-testing phases aiming to evaluate the applicability of this technology for eventual implementation at industrial scale. During the laboratory testing phase, more than two hundred tests were performed to determine the best polymer type, dilution and dosage. The parameters evaluated were based on yield stress measurements by a rheometer, slump tests performance and water released volume after 10 minutes and 24 hours after polymer addition. The results from laboratory testing phase have provided sufficient information for industrial scale trial. The second phase of the study consisted of an industrial field trial with polymer application in the tailings dam for five days. During the trial, topographic measurements were taken in order to evaluate the increase of settled material during the first kilometer after tailings discharge. The results demonstrated a significant increase of settled material and beach slope angle in the measured area. This showed a good potential for improved utilization of the storage in the tailings storage facility in the coming years.
{"title":"Dewatering polymer application in an iron ore tailings dam","authors":"F. Braga, R. Guang, J. Pereira, J. Davo, F. Ferrari, T. Nicoli, L. Boxill, J. Russo","doi":"10.36487/acg_repo/2052_13","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_13","url":null,"abstract":"Given the current scenario experienced by Brazilian mining industry, the study and development of technologies that enable a more secure and controlled disposal of tailings has gained significant relevance. Among the various alternatives and disposal methodologies, Anglo American has been developing tests on different study fronts. Using dewatering polymers to improve tailings store potentials at tailings dam is one of the methods that has been studied extensively. The tested polymers can enhance de-watering performance and immobilization of mineral slurries during hydraulic deposition, therefore achieving optimization of tailings storage at the existing facility. The studies were divided into laboratory and industrial field-testing phases aiming to evaluate the applicability of this technology for eventual implementation at industrial scale. \u0000During the laboratory testing phase, more than two hundred tests were performed to determine the best polymer type, dilution and dosage. The parameters evaluated were based on yield stress measurements by a rheometer, slump tests performance and water released volume after 10 minutes and 24 hours after polymer addition. The results from laboratory testing phase have provided sufficient information for industrial scale trial. The second phase of the study consisted of an industrial field trial with polymer application in the tailings dam for five days. During the trial, topographic measurements were taken in order to evaluate the increase of settled material during the first kilometer after tailings discharge. The results demonstrated a significant increase of settled material and beach slope angle in the measured area. This showed a good potential for improved utilization of the storage in the tailings storage facility in the coming years.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125097709","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_92
A. Ran, N. Pérez, O. Dahan
Mining facilities store process water or paste slurry. Lateral and vertical water percolation may create major problems concerning dam safety and environmental impact. Means for monitoring the saturated zone is widely used, but none concerning the unsaturated zone (vadose zone). A novel Vadose Zone Monitoring System (VMS) was developed at Ben Gurion University in Israel. VMS units include a set of advanced water and pressure sensors along with sampling ports. The units are mounted on a flexible sleeve which is installed through dedicated uncased small diameter boreholes. Through a control panel on the surface, data is transmitted via a cloud-based server directly to the client’s dedicated application. Over the past decade, the VMS was successfully installed in a variety of scientific and commercial projects on water infiltration and contaminant transport from land surface to the groundwater in a variety of geological and hydrological setups. Recently, fertilizers’ producer in Israel (ICL), installed several VMS stations under phosphogypsum waste lagoons for monitoring the potential leaks from the bottom of lagoons to the subsurface, and one system in in an earthen dam for monitoring its safety status. The case study deals with contamination that was discovered in the aquifer. Continuous monitoring of water percolation beneath the ponds indicated that the levels of water percolation and pollution potential from these ponds are relatively low and therefore environmentally safe. These findings were accepted by the environmental authorities and the client wrote: "The VMS already had an important use, in proving the authorities that the contamination is from another source and not from our cell. We couldn't have done it any other way". Implementing of the VMS systems at the above case and other cases produced real time information which has proved to be critical for maintaining long term safe operation of tailing sites.
{"title":"Real Time Monitoring of Infiltration and contamination from Paste Tailing Site","authors":"A. Ran, N. Pérez, O. Dahan","doi":"10.36487/acg_repo/2052_92","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_92","url":null,"abstract":"Mining facilities store process water or paste slurry. Lateral and vertical water percolation may create major problems concerning dam safety and environmental impact. Means for monitoring the saturated zone is widely used, but none concerning the unsaturated zone (vadose zone). A novel Vadose Zone Monitoring System (VMS) was developed at Ben Gurion University in Israel. VMS units include a set of advanced water and pressure sensors along with sampling ports. The units are mounted on a flexible sleeve which is installed through dedicated uncased small diameter boreholes. Through a control panel on the surface, data is transmitted via a cloud-based server directly to the client’s dedicated application. \u0000Over the past decade, the VMS was successfully installed in a variety of scientific and commercial projects on water infiltration and contaminant transport from land surface to the groundwater in a variety of geological and hydrological setups. Recently, fertilizers’ producer in Israel (ICL), installed several VMS stations under phosphogypsum waste lagoons for monitoring the potential leaks from the bottom of lagoons to the subsurface, and one system in in an earthen dam for monitoring its safety status. The case study deals with contamination that was discovered in the aquifer. Continuous monitoring of water percolation beneath the ponds indicated that the levels of water percolation and pollution potential from these ponds are relatively low and therefore environmentally safe. These findings were accepted by the environmental authorities and the client wrote: \"The VMS already had an important use, in proving the authorities that the contamination is from another source and not from our cell. We couldn't have done it any other way\". \u0000Implementing of the VMS systems at the above case and other cases produced real time information which has proved to be critical for maintaining long term safe operation of tailing sites.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126639344","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}
Turmalina Mine has been unsuccessful on mining a high-grade thick zone of its orebody using a sublevel stoping bottom-up sequence with rock fill by having high dilution and ore losses. Being one of few mines in Brazil with a paste fill plant, Turmalina Mine – that used to paste fill only open stopes in old areas – saw as an alternative using paste fill on a primary and secondary stoping sequence to reduce probability of ground falls and successfully extract ore from the high-grade thick zone without leaving rib pillars, increasing recovery Empirical formulas and Map3D – boundary element numerical method - were used to define needed plug and mass fill strengths to reduce risk of liquefaction, to use paste filled areas as working platforms and for vertical exposure after secondary mining with low dilution. A binder created for Turmalina tailings considering its rheological characteristics to achieve good flowability and sufficient compressive strength made possible to reach an optimal cycle, combining low binder utilization and sufficient compressive strength for each step of the cycle confirmed by uniaxial compression tests done in specimens with different binder content and ages. Filling consists of a 5% plug fill and then a 3% mass fill after a two days wait for the plug fill to reach 100kPa. Filled stope is ready to serve as a working platform after 3 days, when it reaches 170kPa. Secondary stoping is sequenced after 28 days when mass fill finishes, as it is ready to have a vertical exposure with a strength of over 500kPa. Paste fill specimens collected are tested to confirm the strengths needed before each step. By implementing paste fill in the sublevel stoping sequence, the mine is planning to control operational dilution at a maximum of 15% and increase ore recovery to 95% in the high-grade thick zone.
{"title":"Use of paste Fill on cycle at Turmalina Mine","authors":"Jéssica Ribeiro Santana, Elías Andrade, Luiz Henrique Milagres, Vitor Balbys","doi":"10.36487/acg_repo/2052_60","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_60","url":null,"abstract":"Turmalina Mine has been unsuccessful on mining a high-grade thick zone of its orebody using a sublevel stoping bottom-up sequence with rock fill by having high dilution and ore losses. Being one of few mines in Brazil with a paste fill plant, Turmalina Mine – that used to paste fill only open stopes in old areas – saw as an alternative using paste fill on a primary and secondary stoping sequence to reduce probability of ground falls and successfully extract ore from the high-grade thick zone without leaving rib pillars, increasing recovery \u0000Empirical formulas and Map3D – boundary element numerical method - were used to define needed plug and mass fill strengths to reduce risk of liquefaction, to use paste filled areas as working platforms and for vertical exposure after secondary mining with low dilution. \u0000A binder created for Turmalina tailings considering its rheological characteristics to achieve good flowability and sufficient compressive strength made possible to reach an optimal cycle, combining low binder utilization and sufficient compressive strength for each step of the cycle confirmed by uniaxial compression tests done in specimens with different binder content and ages. \u0000Filling consists of a 5% plug fill and then a 3% mass fill after a two days wait for the plug fill to reach 100kPa. Filled stope is ready to serve as a working platform after 3 days, when it reaches 170kPa. Secondary stoping is sequenced after 28 days when mass fill finishes, as it is ready to have a vertical exposure with a strength of over 500kPa. Paste fill specimens collected are tested to confirm the strengths needed before each step. \u0000By implementing paste fill in the sublevel stoping sequence, the mine is planning to control operational dilution at a maximum of 15% and increase ore recovery to 95% in the high-grade thick zone.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125618329","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_06
Li Jie Guo, Xinzheng Chen, Xiaocong Yang, Xiaopeng Peng
To explore the spatial strength distribution of backfill in the stope, a group of experiments in a large similar stope model was designed for simulating the consolidation of cemented tailings backfill (CTB) in a stope. The height of CTB in similar stope model was measured to analyse the flow and sedimentation characteristics. The unconfined compressive strength (UCS) test on specimens cored in the different position of CTB sample in similar stope model was conducted. Moreover, the particle size and cement content of CTB sample were tested to help to explain the mechanism. The results show that during the flow and sedimentation of filling slurry in the model, inconsistency of the particle size and cement content leads to the inconsistency of strength. In the flow direction (horizontal direction), the median particle size of CTB first increases and then decreases, the cement content of CTB decreases slowly and then increases sharply, and the strength of CTB first decreases and then rises. In the sedimentation direction (vertical direction), the cement content of CTB decreases with the increase of depth, while the strength of CTB increases with the increase of depth. The strength is affected by the interaction between particle size and cement content, and the higher cement content of CTB does not translate into higher strength. The results provide a theoretical basis for improving the quality of CTB and optimizing the design.
{"title":"An experimental study on the strength distribution of cemented tailings backfill","authors":"Li Jie Guo, Xinzheng Chen, Xiaocong Yang, Xiaopeng Peng","doi":"10.36487/acg_repo/2052_06","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_06","url":null,"abstract":"To explore the spatial strength distribution of backfill in the stope, a group of experiments in a large similar stope model was designed for simulating the consolidation of cemented tailings backfill (CTB) in a stope. The height of CTB in similar stope model was measured to analyse the flow and sedimentation characteristics. The unconfined compressive strength (UCS) test on specimens cored in the different position of CTB sample in similar stope model was conducted. Moreover, the particle size and cement content of CTB sample were tested to help to explain the mechanism. The results show that during the flow and sedimentation of filling slurry in the model, inconsistency of the particle size and cement content leads to the inconsistency of strength. In the flow direction (horizontal direction), the median particle size of CTB first increases and then decreases, the cement content of CTB decreases slowly and then increases sharply, and the strength of CTB first decreases and then rises. In the sedimentation direction (vertical direction), the cement content of CTB decreases with the increase of depth, while the strength of CTB increases with the increase of depth. The strength is affected by the interaction between particle size and cement content, and the higher cement content of CTB does not translate into higher strength. The results provide a theoretical basis for improving the quality of CTB and optimizing the design.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129975723","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_26
R. Klug, N. Schwarz
There are several technologies available for thickening and dewatering of mining process slurries. The most commonly used are thickeners and filters, but technological developments have made centrifuges a viable option and their use, as a modern and alternative technology, is being considered more and more. In terms of tailings, the main goal for all mine operation is to minimize operating costs and the environmental impact on the disposed material. The high potential risk of wet tailing storage in tailing dams is causing this technology to become unpopular, and there is a strong drive in many parts of the world, by governments, communities and environmental agencies to limit any further construction and use of such facilities. For the alternative disposal method of dry disposal of tailings, two aspects of the process have to be evaluated, namely the maximum dryness of the separated solids and the maximum liquid recovery. For most mining operation, dry disposal is a new concept. Presenting these companies with examples of operations where this processing option has been successfully applied and proven, will help them to adapt to the changing requirements in the future. Focus has been placed on adapting decanter centrifuges to the mining environment. Modern decanters stand out in terms of their small footprint, low water demand, high availability and their high degree of automation, combined with the excellent cost / performance ratio. Decanter centrifuges have started to play a key role in applications such as tailing dewatering, drilling and tunneling muds processing, hydrometallurgical processes of gold, nickel or zinc and separating SX crud in copper refineries. This paper will present advantages of decanter centrifuges compared to the traditional technology and corroborate these advantages by case studies, especially from South America.
{"title":"Centrifuges: The Alternative Technology","authors":"R. Klug, N. Schwarz","doi":"10.36487/acg_repo/2052_26","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_26","url":null,"abstract":"There are several technologies available for thickening and dewatering of mining process slurries. The most commonly used are thickeners and filters, but technological developments have made centrifuges a viable option and their use, as a modern and alternative technology, is being considered more and more. In terms of tailings, the main goal for all mine operation is to minimize operating costs and the environmental impact on the disposed material. The high potential risk of wet tailing storage in tailing dams is causing this technology to become unpopular, and there is a strong drive in many parts of the world, by governments, communities and environmental agencies to limit any further construction and use of such facilities. For the alternative disposal method of dry disposal of tailings, two aspects of the process have to be evaluated, namely the maximum dryness of the separated solids and the maximum liquid recovery. For most mining operation, dry disposal is a new concept. Presenting these companies with examples of operations where this processing option has been successfully applied and proven, will help them to adapt to the changing requirements in the future. Focus has been placed on adapting decanter centrifuges to the mining environment. Modern decanters stand out in terms of their small footprint, low water demand, high availability and their high degree of automation, combined with the excellent cost / performance ratio. Decanter centrifuges have started to play a key role in applications such as tailing dewatering, drilling and tunneling muds processing, hydrometallurgical processes of gold, nickel or zinc and separating SX crud in copper refineries. This paper will present advantages of decanter centrifuges compared to the traditional technology and corroborate these advantages by case studies, especially from South America.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131367067","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_99
A. Arriagada, J. Riquelme, Tiaren García-Pérez
Chile is a country with high vulnerability associated with Climate Change, given among other factors, due to the need for development and growing social and environmental conflicts. This motivates the implementation of adaptation, transformation and mitigation measures at all aspects, to deal with climatological phenomena, which despite its future uncertainty, its development is a proven fact by robust and bulky scientific evidence. Motivated by the call from COP25 and the IPCC to assess adaptation and mitigation of effects and consequences of Climate Change, SRK Chile proposed to analyze the response of infrastructure associated with mining in northern Chile, considering General Circulation Models (GCM) downscaled for Atacama region at different elevations, based on the models considered by Chilean Water Directorate (DGA) in its Update of the National Water Balance of Chile (NWBC). This study considers Representative Concentration Pathways RCP 8.5 (most pessimistic scenario) as scenarios to evaluate, same as DGA – NWBC. To observe the effects of these scenarios we applied the GCM as boundary conditions in 1D numerical infiltration models using the software Hydrus. In the simulations water fluxes in a column of thickened tailing above natural soil is analyzed for different precipitation regimes from GCMs. Standard values according to our experience for the hydraulic and geometry properties of the materials forming the columns are used. The results of this study shed light upon the future precipitation’s scenarios affect the available water in the infrastructures at different elevations, providing a quantitative comparison of the infiltration fluxes within the tailing for the GCMs in the Atacama region.
{"title":"Evaluation of the Effects of Climate Change on Water Infiltration on Thickened Tailings in the Atacama Region","authors":"A. Arriagada, J. Riquelme, Tiaren García-Pérez","doi":"10.36487/acg_repo/2052_99","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_99","url":null,"abstract":"Chile is a country with high vulnerability associated with Climate Change, given among other factors, due to the need for development and growing social and environmental conflicts. This motivates the implementation of adaptation, transformation and mitigation measures at all aspects, to deal with climatological phenomena, which despite its future uncertainty, its development is a proven fact by robust and bulky scientific evidence. \u0000Motivated by the call from COP25 and the IPCC to assess adaptation and mitigation of effects and consequences of Climate Change, SRK Chile proposed to analyze the response of infrastructure associated with mining in northern Chile, considering General Circulation Models (GCM) downscaled for Atacama region at different elevations, based on the models considered by Chilean Water Directorate (DGA) in its Update of the National Water Balance of Chile (NWBC). This study considers Representative Concentration Pathways RCP 8.5 (most pessimistic scenario) as scenarios to evaluate, same as DGA – NWBC. \u0000To observe the effects of these scenarios we applied the GCM as boundary conditions in 1D numerical infiltration models using the software Hydrus. In the simulations water fluxes in a column of thickened tailing above natural soil is analyzed for different precipitation regimes from GCMs. Standard values according to our experience for the hydraulic and geometry properties of the materials forming the columns are used. \u0000The results of this study shed light upon the future precipitation’s scenarios affect the available water in the infrastructures at different elevations, providing a quantitative comparison of the infiltration fluxes within the tailing for the GCMs in the Atacama region.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121110548","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_24
R. Jeldres, T. Yang, A. Costine, P. Fawell, J. Bellwood
The use of seawater, hypersaline or other low-quality water supplies in mineral processing operations has strong benefits in places like Chile and Australia, not just economically but in ensuring social license to operate. Despite this commercial application, the effect of dissolved salts on tailings flocculation is not yet fully understood. This partly stems from the operator-dependence that plagues normal cylinder testing and the tendency in some previous literature studies to make flocculant activity comparisons under a narrow range of conditions (single dosage, solids concentration and/or fixed mixing). Six acrylamide/acrylate copolymers with the same anionicity (30%) but different molecular weights, were evaluated in the flocculation of standard kaolin slurries prepared in seawater or solutions containing selected cations at various concentrations. Settling rate-dosage response curves were collected for these polymers, combining continuous Couette flocculation with real-time aggregate sizing and off-line determination of individual aggregate settling rate vs. size, from which their densities could be derived. Shifts in the dosage response curves under different conditions reflected changes in both the aggregate size and density. From the large body of flocculation data produced under tightly controlled conditions, new insights were gained on how salinity alters mixing requirements for aggregation, responses to molecular weight and aggregate structure. Some salt addition was beneficial in producing an initial low level of aggregation of fines that reduced the effective surface area of the suspension and subsequent flocculant dosage requirements. At high ionic strength, a reduction in flocculant bridging capacity due to chain coiling resulted in open, low density aggregate structures, which substantially increased the flocculant demand to achieve a target settling rate. The potential impact should be a much more robust basis for flocculant selection, which is currently very much trial-and-error.
{"title":"The impact of high salinity and seawater on aggregate structures in clay tailings flocculation","authors":"R. Jeldres, T. Yang, A. Costine, P. Fawell, J. Bellwood","doi":"10.36487/acg_repo/2052_24","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_24","url":null,"abstract":"The use of seawater, hypersaline or other low-quality water supplies in mineral processing operations has strong benefits in places like Chile and Australia, not just economically but in ensuring social license to operate. Despite this commercial application, the effect of dissolved salts on tailings flocculation is not yet fully understood. This partly stems from the operator-dependence that plagues normal cylinder testing and the tendency in some previous literature studies to make flocculant activity comparisons under a narrow range of conditions (single dosage, solids concentration and/or fixed mixing). \u0000Six acrylamide/acrylate copolymers with the same anionicity (30%) but different molecular weights, were evaluated in the flocculation of standard kaolin slurries prepared in seawater or solutions containing selected cations at various concentrations. Settling rate-dosage response curves were collected for these polymers, combining continuous Couette flocculation with real-time aggregate sizing and off-line determination of individual aggregate settling rate vs. size, from which their densities could be derived. Shifts in the dosage response curves under different conditions reflected changes in both the aggregate size and density. \u0000From the large body of flocculation data produced under tightly controlled conditions, new insights were gained on how salinity alters mixing requirements for aggregation, responses to molecular weight and aggregate structure. Some salt addition was beneficial in producing an initial low level of aggregation of fines that reduced the effective surface area of the suspension and subsequent flocculant dosage requirements. At high ionic strength, a reduction in flocculant bridging capacity due to chain coiling resulted in open, low density aggregate structures, which substantially increased the flocculant demand to achieve a target settling rate. The potential impact should be a much more robust basis for flocculant selection, which is currently very much trial-and-error.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"87 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134035139","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_58
A. Wu, R. Zhuen, S. Yin, Y. Wang, S. Wang, B. Yan
Inspired by the success of cemented paste backfill in the west orebody of Chambishi Copper Mine, integrated disposal of paste backfill and surface high-concentration tailings stacking was applied in the southeast orebody. This paper presents the integrated disposal system, including two deep cone thickeners, double-shaft horizontal mixer, two plunger pumps for underground backfill and three diaphragm pumps for surface stacking. The challenges of the integrated disposal system were deep backfilling (0.98 km) and long-distance discharging (15 km), so a combination of gravity flow and pumping was used in paste backfill and three diaphragm pumps with a preset pressure of 7 MPa were applied for surface stacking. The annual ore production in the southeast orebody is 3.3 Mt, which is 3.3 times larger than that of the west orebody. Therefore, the capacity of the integrated disposal system also needs to be expanded. The capacity of the paste backfill system and surface stacking system were 160 m3/h with paste concentration of 75 wt.% and 265 m3/h with slurry concentration of 55 wt.%, respectively. In the first phase, the cement to tailings ratios for primary and second stopes are 1/8 and 1/24 respectively. To meet the backfill strength and reduce the cost, waste rock will be added in paste backfill in the second phase, the waste rock to tailings ratio is 1/3, the cement to tailings and waste rock ratio for primary stopes are 1:12, and 1:30 for secondary stopes. As a result, the UCS after 28 days for primary and second stopes were 1.2 MPa and 0.5 MPa, respectively.
{"title":"Integrated Disposal of Paste Backfill and Surface High-concentration Tailings Stacking at Chambishi Copper Mine","authors":"A. Wu, R. Zhuen, S. Yin, Y. Wang, S. Wang, B. Yan","doi":"10.36487/acg_repo/2052_58","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_58","url":null,"abstract":"Inspired by the success of cemented paste backfill in the west orebody of Chambishi Copper Mine, integrated disposal of paste backfill and surface high-concentration tailings stacking was applied in the southeast orebody. This paper presents the integrated disposal system, including two deep cone thickeners, double-shaft horizontal mixer, two plunger pumps for underground backfill and three diaphragm pumps for surface stacking. The challenges of the integrated disposal system were deep backfilling (0.98 km) and long-distance discharging (15 km), so a combination of gravity flow and pumping was used in paste backfill and three diaphragm pumps with a preset pressure of 7 MPa were applied for surface stacking. The annual ore production in the southeast orebody is 3.3 Mt, which is 3.3 times larger than that of the west orebody. Therefore, the capacity of the integrated disposal system also needs to be expanded. The capacity of the paste backfill system and surface stacking system were 160 m3/h with paste concentration of 75 wt.% and 265 m3/h with slurry concentration of 55 wt.%, respectively. In the first phase, the cement to tailings ratios for primary and second stopes are 1/8 and 1/24 respectively. To meet the backfill strength and reduce the cost, waste rock will be added in paste backfill in the second phase, the waste rock to tailings ratio is 1/3, the cement to tailings and waste rock ratio for primary stopes are 1:12, and 1:30 for secondary stopes. As a result, the UCS after 28 days for primary and second stopes were 1.2 MPa and 0.5 MPa, respectively.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122684000","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_19
C. Zamorano, F. Vera, I. Sanchez, Sergio Silva Ramirez, C. Garrido
Several large copper mines are evaluating improvements in the tailings dewatering circuits. Most prevalent alternatives being considered optimize their thickening technologies or the implementation of tailings filtration and stacking. This requirement to optimize water recovery is due to a variety of factors; the deficit and high cost of the water make-up, environmental restrictions, and community relationships. The recent failures in conventional tailing deposit structures and the potential change to reduce the footprint of tailings impounds may also drive the desire to consider alternate technologies. This paper presents technical and economic review of alternate technologies, considering capital investment and operational costs. The five (5) selected alternatives include thickening technologies, pressure filters and a combination with cyclones for classification and filtration of the coarser fraction and thickening of the finer fraction. The selected alternatives are developed and evaluated at trade off study level.
{"title":"Technical and Economic Evaluation of Tailings Dewatering Circuits in the Largest Copper Mines","authors":"C. Zamorano, F. Vera, I. Sanchez, Sergio Silva Ramirez, C. Garrido","doi":"10.36487/acg_repo/2052_19","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_19","url":null,"abstract":"Several large copper mines are evaluating improvements in the tailings dewatering circuits. Most prevalent alternatives being considered optimize their thickening technologies or the implementation of tailings filtration and stacking. This requirement to optimize water recovery is due to a variety of factors; the deficit and high cost of the water make-up, environmental restrictions, and community relationships. The recent failures in conventional tailing deposit structures and the potential change to reduce the footprint of tailings impounds may also drive the desire to consider alternate technologies. \u0000This paper presents technical and economic review of alternate technologies, considering capital investment and operational costs. The five (5) selected alternatives include thickening technologies, pressure filters and a combination with cyclones for classification and filtration of the coarser fraction and thickening of the finer fraction. The selected alternatives are developed and evaluated at trade off study level.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115305783","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 : 2020-11-02DOI: 10.36487/acg_repo/2052_84
Maycon Alves, A. Marques
A new trend in Brazilian iron ore beneficiation processes is the concentration of ultrafine minerals. Such minerals are currently disposed in dams or similar structures despite having a high iron content. With the development of new reagents and new concentration methods, it was possible to concentrate this type of material, however, the tailings from the concentration of these materials must still be disposed. Another upward technique in iron mining in Brazil is the disposal of filtered tailings in the tailings pile (PDR). In order to be able to dispose of ultra-thin materials in the aforementioned manner, it is necessary to perform the filtration using the press filter technology, which is the most suitable to process this type of material. In press-type filters the dewatering is somehow accomplished through the pressurization offered by the pumping system responsible for feeding the filters. The present work aims to present a case study of filtering of ultrafine tailings essentially addressing the various ways studied for feeding and pressurizing filter presses through variations between available technologies. To evaluate the best feeding method, pilot scale tests were performed to determine the specific filtering conditions of ultrafine material. Parameters such as pumping time, filtering time and total cycle time were determined from which scale-up factors were applied to enable the sizing of pumping capacity on an industrial scale. Finally, data from similar systems were used to calibrate the resistance curve of the cake and the AFT Fathom software based on Wilson's theory for mineral slurry handling was used to evaluate possible feed forms. Items such as energy consumption, pumping pressure stability, dewatering efficiency and acquisition cost will be compared.
{"title":"Pressure Filter Feeding Methods - Case Study","authors":"Maycon Alves, A. Marques","doi":"10.36487/acg_repo/2052_84","DOIUrl":"https://doi.org/10.36487/acg_repo/2052_84","url":null,"abstract":"A new trend in Brazilian iron ore beneficiation processes is the concentration of ultrafine minerals. Such minerals are currently disposed in dams or similar structures despite having a high iron content. With the development of new reagents and new concentration methods, it was possible to concentrate this type of material, however, the tailings from the concentration of these materials must still be disposed. \u0000Another upward technique in iron mining in Brazil is the disposal of filtered tailings in the tailings pile (PDR). In order to be able to dispose of ultra-thin materials in the aforementioned manner, it is necessary to perform the filtration using the press filter technology, which is the most suitable to process this type of material. \u0000In press-type filters the dewatering is somehow accomplished through the pressurization offered by the pumping system responsible for feeding the filters. The present work aims to present a case study of filtering of ultrafine tailings essentially addressing the various ways studied for feeding and pressurizing filter presses through variations between available technologies. \u0000To evaluate the best feeding method, pilot scale tests were performed to determine the specific filtering conditions of ultrafine material. Parameters such as pumping time, filtering time and total cycle time were determined from which scale-up factors were applied to enable the sizing of pumping capacity on an industrial scale. \u0000Finally, data from similar systems were used to calibrate the resistance curve of the cake and the AFT Fathom software based on Wilson's theory for mineral slurry handling was used to evaluate possible feed forms. Items such as energy consumption, pumping pressure stability, dewatering efficiency and acquisition cost will be compared.","PeriodicalId":164781,"journal":{"name":"23rd International Conference on Paste, Thickened and Filtered Tailings - PASTE 2020","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123662345","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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