Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings最新文献

{"title":"A simple test to determine the settling behaviour of slurries in piston diaphragm pumps","authors":"H. Krimpenfort, Daniel Nägel","doi":"10.36487/acg_repo/2115_21","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_21","url":null,"abstract":"One of the most critical issues when designing a slurry system is sedimentation of solid particles in pipelines and pumps. In pipelines, sedimentation will occur when the transportation velocity of a slurry through the pipe is below the deposition velocity. As soon as particles are settled, there is a considerable risk that, in time, a plug will be created which will block the pipeline completely. \u0000Settling of solids can, however, also be detrimental for piston diaphragm pumps; large and heavy solids may settle within the diaphragm housing, on top of the suction valves. This layer of solids will cause diaphragms to rupture. In addition, there is a risk that the settling particles may block the valve, causing pressure surges and further damage to the downstream equipment. \u0000In order to determine the settling behaviour of a slurry, costly and time-consuming loop tests need to be executed in specialised laboratories for which large quantities of solids are required. This test may also be an indication of the settling behaviour of solids within a piston diaphragm pump, but would not be very accurate, leaving risk of damage to diaphragms. \u0000Therefore, a simple, quick and inexpensive test (SE: sedimentation detection system with evaluation algorithm) was developed which indicates if a slurry is prone to settling or not, by determining how fast solids will settle within a diaphragm housing. For this test, just a few kilograms of solids are required, and the result of the test is known within a very short period of time. \u0000In principle, the test is based on the measurement of the speed at which particles settle on a scale; the faster the particles settle, the higher the risk of a settled pipeline and the higher the transportation velocity needs to be. \u0000This paper will describe the methodology of this test, its results and interpretation. Also, a technology will be presented which prevents settling of solids within the diaphragm housing of piston diaphragm pumps.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128317652","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}

{"title":"The effect of changing grinding cycle on the flow-ability of cemented paste backfill: effect of particle size distribution","authors":"A. Safarizadeh, A. Taheri","doi":"10.36487/acg_repo/2115_36","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_36","url":null,"abstract":"Cemented paste backfill (CPB) is an engineered design mixture that is commonly implemented to fill the left behind voids of mining. Depending on the sides of the stope under vertical and horizontal exposure, different mixture designs are needed to provide the minimum required strength to continue mining underfilled mass safely. Various parameters affect the strength of CPB and need to be checked daily as CPB quality control. One of the most important of these parameters is the particle size distribution (PSD). One way to increase the recovery of metal is to increase the milling time, which decreases the PSD of tailings significantly. This particle size reduction can undoubtedly change the properties of CPB. This study investigates the effect of changing PSD on both the strength and flow-ability of CPB binary. In this regard, a range of tailings with variations of PSDs from 90% less than 35 µm to 90% more than 35 µm were prepared. P10 and P80 of samples were meticulously obtained and unconfined compressive strength (UCS), slump, and density tests conducted on 52 mm cylinder-shaped samples with a cylinder shape slump coin and with a Marcy scale. The results show that decreasing PSD can have a negative effect on the flow-ability of CPB, but strength first decreased; and then by a further decrease of PSD, strength increased significantly. Outcomes of this research were applied to CSA Mine’s paste mixture due to the changes in the milling circle. Furthermore, the results of this research can be considered for backfill design if the PSD size has exceeded the limitations.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"418 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130220821","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}

{"title":"Online yield stress measurement for real-time process control","authors":"F. Sofrà, P. Bhattacharjee","doi":"10.36487/acg_repo/2115_11","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_11","url":null,"abstract":"The authors report a robust estimate of the shear yield stress of a slurry from inline measurement of a flowing slurry process stream. At present, slurry density is often used as a proxy in estimating the shear yield stress based on laboratory-scale measurements performed as a function of solids concentration. However, this approach leads to inaccuracies due to poor translation of laboratory data to operational situations and fluctuations in the sensitive yield stress-concentration dependence due to material and process variations. A robust inline measurement that directly relates to the in situ yield stress is therefore both a valuable and significant advance. \u0000In order to provide continual, inline rheology data for process control, the OnLine Rheometer Series 1000 (OLR) was piloted for a high clay, gold process thickener underflow in a pilot pipe loop facility. Benchtop measurements of the vane yield stress, and solids concentration were performed on samples drawn from the line as the circulating liquid was progressively diluted. The measured vane yield stress was compared with the Yield Stress Index (YSI), a native function available in the software of the OLR, over a concentration (c) ranging between 49.4 wt% < c < 64.5 wt%. Over the concentration range studied, the vane yield stress exponentially increased with concentration and ranged between 4 and 65 Pa while the YSI values ranged between 16 and 131 units showing an identical dependence on concentration. Importantly, it was found that the YSI correlated linearly with the yield stress values measured using the vane. It follows that the YSI metric can be used to estimate the yield stress within a small factor in actual operations. This finding supports the use of the YSI as an inline control variable in mineral processing and tailings management operations; in thickening and paste preparation for example.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126468344","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}

{"title":"Mixing requirement for ultra paste tailings","authors":"A. Roshdieh, S. Javadi, M. Williams, E. Karamad","doi":"10.36487/acg_repo/2115_06","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_06","url":null,"abstract":"A controlling variable for a thickened tailings scheme design is the beach slope that will be formed by the tailings as they deposit. The slope will be mainly related to the discharge flow rate and the slurry rheology. The latter will, in turn, be dependent on the solids concentration of the thickener underflow. A higher solids concentration can be achieved by combining thickening and filtration. The objective is to still maintain a slurry that is pumpable and self-distributing at the tailings storage facility (TSF), rather than having to rely on trucks or on conveyors and stacking systems to manage a ‘cake’, but one that will deposit at a steeper beach slope than can be achieved by thickening alone. The use of ultra paste has the potential to broaden the range of topographic conditions that will suit thickened tailings discharge. \u0000The ultra paste thickened option is when a portion of the tailings is separated and dewatered in a more advanced dewatering unit (in this case filter presses). The filtered cake will then be re-mixed with the paste thickener underflow stream. \u0000This paper presents a case study for a large copper mine in which underflow from a series of paste thickeners with a nominal tonnage of 3,660 tph at 59% solids concentration would be mixed with 1,363 tph of filter cake at 80% solids concentration. The combined tailings (ultra paste) would be discharged equally into two open channels (flumes) at the combined solids concentration of 63.5%. \u0000The ultimate goal of adopting an ‘ultra paste’ scheme is to produce homogenous consistency tailings, hence proper mixing of the paste and filter cake has to occur. In this study based on a series of tests, the mixing requirement has been assessed. The study also covers a conceptual investigation of natural turbulent mixing (NTM) of the filtered tailings with paste thickened tailings and issues associated with the deposition of the combined tailings, the ultra paste, into the existing TSF. \u0000In the conclusion, the study indicates that NTM can possibly occur only for the case in which the total tailings are discharged into one channel, which is not practical due to limitations with regards to tailings management. Hence, mechanical mixing has been recommended in this case.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125929311","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}

{"title":"Cake formation: three tailings filtration technologies using pressure","authors":"Steven P. Meiring","doi":"10.36487/acg_repo/2115_09","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_09","url":null,"abstract":"The equipment selection for a fine coal tailings dewatering application is filled with numerous challenges and complications. There are known technologies operating in the Australian coal industry such as belt press filters and, recently, solid bowl centrifuges. This paper looks at three known technologies, namely belt press filters, plate and frame filters, and solid bowl centrifuges to dewater thickened fine coal tailings. A comparison of recovery, moisture, reagent addition, solids and volumetric throughput is presented. Some pros and cons of each application will also be provided. Specialised technical information on each application including the major factors that have the greatest dewatering impact on the technologies will be highlighted. Information from an installation from South Africa is shared. The paper assists with the selection process and explains important information that must be brought to light when considering a change from wet disposal to dry disposal. Elements of this paper were previously published in Meiring (2021).","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127508815","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}

{"title":"Clay-bearing mine tailings analysis and implications in large filter press design","authors":"A. Grosso, F. Kaswalder, A. Hawkey","doi":"10.36487/acg_repo/2115_10","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_10","url":null,"abstract":"Filtered tailings dry stack disposal often requires low cake residual moistures to meet the stacking specifications defined by geotechnical studies. Low residual moisture targets and increasing throughputs require careful definition of filter press process parameters in order to prevent unnecessary extra capital and operating costs. Because of this, alongside the testing phase, a comprehensive characterisation of the material, not limited to standard geotechnical tests, becomes important. Standard physical/chemical characterisation of mining slurries includes both basic (liquor, solid and slurry density, solid concentration, solid specific gravity) and thorough analysis (yield stress, particle size distribution, elements and mineral phase detection). Each of these requires different techniques. Phyllosilicates (i.e. clays) are one of the most common components of mine tailings, together with quartz, feldspar and other aluminosilicates. Clay type and relative content can have a drastic influence on the filtration process and furthermore on filter design. A detailed analysis of clayey phases can give useful information about the filterability of a slurry and, therefore, on the expected filter performance and its variability. A comprehensive study about clay detection and quantification and correlation with dewatering properties is presented here. It involves different analytical techniques (powder X-ray diffraction, Rietveld refinement, qualitative evaluation) and correlation studies based on the lab testing campaign’s database. The results show how the filterability can be strongly affected by the phyllosilicate type and small variations in their content, to yield completely different cake properties, showing that smectite group clays have the greatest influence on filterability. The impact of these characteristics on filter sizing, especially for large equipment (like the GHT5000F filter press) and related ancillaries will be discussed.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132403675","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}

{"title":"Paste backfill continuous pour: Red Lake operations case study","authors":"J. Oke, K. Hawley, T. Belem, A. Hashemi","doi":"10.36487/acg_repo/2115_31","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_31","url":null,"abstract":"Cemented paste backfill (CPB) has become known as a superior secondary ground support technique and mine tailings storage method for stoping. Extensive scientific research has been conducted by the authors on CPB to provide the Red Lake operation (RLO) of Evolution Mining with an optimised backfill placement process. CPB mechanical/viscous behaviour is governed by its plasticity, the tailings particle size distribution, particle shape, mineralogical composition, water content, and the type and dosage of binder used (e.g. cement and/or supplementary cementitious material). For the CPB design, it is necessary to have a thorough understanding of the combined effects of filling rate, self-weight consolidation (volume shrinkage/settlement), and binder hydration rate for each specific paste mixture. Due to these complex factors and interactions, a rational CPB material design process was assessed to demonstrate the safety aspects related to a continuous pour. For this purpose, an extensive field monitoring program was required to quantify the CPB performance and characteristics. There are two different ways of optimising the CPB design to maximise placement rate: (i) optimising the type and amount of binder added to the system, and (ii) optimising the CPB placement process underground. Optimisation of binder type and dosage is relatively easy as the required backfill stand-up strength is based on block dimensions, stope stability, and extraction sequencing. Optimisation of backfill placement is more difficult, as the understanding of the viscous/pseudo-plastic behaviour of the CPB is required throughout the pour. Typically, a three-stage (plug–cure–main) pouring strategy is implemented to mitigate the lack of understanding of the CPB behaviour during placement. The CPB plug (i.e. height of initial pour regime) is designed to mitigate the pressure on the backfill fence. Once this CPB plug has cured and reached the required shear strength, the backfill fence is no longer required, and the remainder of the stope void (main) can be filled. However, if the curing time of the in situ paste is accelerated due to the binder exothermic hydration process (volume shrinkage) and backfill self-weight consolidation (water drainage), it is possible to have a more aggressive pour regime provided that all the required design parameters, site procedures, company protocols, and critical controls are met. RLO implemented instrumentation, and an early-age CPB strength testing program to evaluate whether their CPB can be poured continuously or at least more aggressively. Four stopes were instrumented with total earth pressure cells (TEPCs) and piezometers to capture the pressures acting on the fill fence structures and the strengthening response of the CPB plug within the stopes. This paper summarises the results of each of the tests performed. Based on the results obtained from this study, it was concluded that RLO can safely conduct continuous CPB pours with appropriate s","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133802722","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}

{"title":"Optimising the design stability of cemented paste backfilled stopes","authors":"R. Veenstra, J. Grobler","doi":"10.36487/acg_repo/2115_37","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_37","url":null,"abstract":"This paper presents an optimisation loop that looked to improve how Newmont’s Tanami Operations (NTO) determines its required stable stope strengths. In order to do this, a comparison exercise was completed, in which NTO’s current stability assessment method was compared to other popular assessment methods ranging from analytical to numerical methods. From this comparison, it was decided to proceed with a different stability assessment method that uses shear stress reduction. The paper then presents how the use of this method was implemented and presents three case studies on how the new stability assessment method has benefited NTO.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"258 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114438066","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}

{"title":"The new cemented paste backfill recipes selection method at Newmont Éléonore mine","authors":"Chloé Carlier, R. Veenstra","doi":"10.36487/acg_repo/2115_35","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_35","url":null,"abstract":"Until mid-2020, the Newmont Éléonore mine cemented paste backfill (CPB) recipes were chosen from charts comparing binder contents and strengths at specific curing ages up to 56 days. However, these charts were based on Mitchell’s method using Éléonore’s biggest stope dimensions. They also did not consider any rheology, maximum surface pump pressure capacities or mix density. Using the new system, and its resulting template, backfill personnel can tailor a recipe for each stope to meet the latest sequence and environment conditions. This paper explains how the new paste recipes are selected, as well as the costs savings and productivity increases they enabled. cyanidation. UG voids are backfilled using cemented paste backfill (CPB) and waste rockfill.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114833337","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}

{"title":"Paste backfill thermal contraction: Red Lake operations case study","authors":"J. Oke, K. Hawley, T. Belem, A. Hashemi","doi":"10.36487/acg_repo/2115_34","DOIUrl":"https://doi.org/10.36487/acg_repo/2115_34","url":null,"abstract":"One of the earliest attempts at field measurement within hydraulically placed cemented backfill occurred over 20 years ago. Recently, Thompson et al. (2014a) published their findings on capturing thermal expansion within cemented paste backfill (CPB) and cemented hydraulic backfill (CHB). They discovered that the total earth pressure within the CPB following placement is likely to increase at a rate of 30 kPa/°C (i.e. for an 11°C temperature increase). However, Thompson and his co-authors' research did not elaborate on the subsequent effects of thermal dissipation (or thermal contraction) in backfill. A comprehensive literature study concluded with no clear evidence of thermal dissipation phenomenon and its effects in backfill. It is hypothesised by the authors that if thermal expansion can occur, then thermal dissipation or contraction is also likely to occur. Red Lake operation (RLO) of Evolution Mining conducted a field program to capture the characteristics of the CPB during a transition from a plug–cure–main pour strategy to a more aggressive pour strategy (i.e. continuous pour operation). During this investigation, strong evidence of thermal contraction was observed in three of the four instrumented stopes. This paper presents detailed findings of two of the instrumented stopes.","PeriodicalId":410057,"journal":{"name":"Paste 2021: 24th International Conference on Paste, Thickened and Filtered Tailings","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117207540","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}