Experimental Testing Of Geomechanical Behavior Of Fiber Reinforced Cemented Paste Backfill Fr Cpb Under Warmer Curing Temperature
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Experimental Testing Of Geomechanical Behavior Of Fiber Reinforced Cemented Paste Backfill Fr Cpb Under Warmer Curing Temperature
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Author : Iarley Loan Sampaio Libos
language : en
Publisher:
Release Date : 2020
Experimental Testing Of Geomechanical Behavior Of Fiber Reinforced Cemented Paste Backfill Fr Cpb Under Warmer Curing Temperature written by Iarley Loan Sampaio Libos and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Backfilling techniques enable improved ore recovery and structural stability to underground mines employing a material to fill the voids after the excavation. Fiber-reinforced cemented paste backfill (FR-CPB) is this material and it consists of mine tailings, cement, mixing, and fibers. After placed into the underground space (called stope), FR-CPB provides sufficient ground support, enables the exploration of larger amounts of ore since no orebody pillars are required to sustain the excavations, and thus enhances mining production. The reinforcement technique has been considered as a promising approach for the backfilling design. However, regarding that mining activities may take place at a depth of more than 1000 meters, the geothermal gradient can not only change the temperature of FR-CPB but also affect its geomechanical behaviors due to its temperature-dependent characteristics. Therefore, the objective of this research is to experimentally investigate compression, tension, shear, triaxial, and fracture behaviors of FR-CPB subjected to different warmer curing temperatures (20°C, 35°C, and 45°C). Moreover, to identify the mechanisms responsible for the evolution of geomechanical behavior, a series of mold-based monitoring programs have been designed and performed to measure changes related to matric suction, electrical conductivity, and temperature in FR-CPB. Additionally, to determine the progress of binder hydration and associated microstructure change, extensive X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) observation have been conducted at the microscale. The obtained results evidenced that warmer curing temperature can significantly affect the fiber-CPB matrix interfacial interaction. Correspondingly, the geomechanical (including tensile, compressive, shear, and fracture) behavior show strong temperature sensitivity from early to advanced ages. Therefore, the obtained results from the present study can not only improve the understanding of the geomechanical behavior of FR-CPB but also contribute to the safe design of backfill structures in underground mines.
Testing And Multiphysics Modelling Of The Shear Behaviour Of Rock Cemented Paste Backfill Interface
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Author : Kun Fang
language : en
Publisher:
Release Date : 2021
Testing And Multiphysics Modelling Of The Shear Behaviour Of Rock Cemented Paste Backfill Interface written by Kun Fang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Cemented paste backfill (CPB) is an innovative technology developed in the mining industry during the last few decades. It has been adopted worldwide by many underground mines for its tremendous advantages: (1) mining space is stabilized by pumping cemented paste backfill into the underground cavities created by mining activity, which is critical to the safety of mine workers; (2) the consumption of tailings (which is stored at the ground surface and is a major source of acid mine drainage (AMD)) is beneficial for environmental protection and community safety; (3) due to the supporting effect of the CPB structure on underground cavities, the recovery ratio is significantly increased; and (4) CPB structures can also carry heavy equipment when mining the adjacent orebody, facilitating mining operations. How to design a safe and cost-effective CPB structure is a key task or challenge for mining engineers and researchers. Mechanical stability is one of the most important design criteria. This stability is mainly a function of the uniaxial compressive strength (UCS) of CPB body and the shear strength/behaviour of the CPB-rock interface. Given the lower friction angle and adhesion of the CPB-rock interface (in comparison with the friction angle and cohesion of CPB body), a thorough understanding of the shear strength/behaviour of the interface is critical for a cost-effective geotechnical design of underground CPB structures. However, only limited studies have been conducted to date on the shear performance of the CPB-rock interface, and no studies have taken into consideration the effects of different factors (e.g., temperature, sulphate ions, self-weight or surface morphology) on the shear behaviour of the CPB-rock interface. Moreover, no multiphysics interface model is currently available that incorporates the aforementioned factors to describe and predict the CPB-rock interface shear behaviour. This research gap was therefore addressed in this PhD study. In this PhD research, a series of laboratory tests were conducted assessing the effects of sulphate content, temperature, curing stress, drainage condition and interface roughness on the shear strength/behaviour of the interface between CPB and rock. The results obtained so far indicated that sulphate and temperature can either positively or negatively affect the shear strength of the CPB-rock interface, depending on the initial sulphate contents and curing time. In terms of the effect of temperature, the shear strength and shear strength properties generally increased with temperature. However, high temperature (≥ 35°C) resulted in an adverse effect on the shear strength because of the crossover effect. In addition, higher curing stress benefitted to the shear strength acquisition of the interface and, due to the increased effective stress and matrix suction, the drained condition increased shear strength as well. As for the effect of surface morphology, the shear strength of the CPB-rock interface rose with surface roughness. Furthermore, chemo-elastic as well as coupled thermo-chemo-mechanical cohesive zone models (CZMs), which take the sulphate attack and temperature-induced acceleration in the cement hydration into consideration, are also developed to simulate the shear strength and behaviour of the CPB-rock interface. The proposed models can well capture the shear behaviour of the interface under different loading conditions. Besides, they also numerically attest to the importance of the shear resistance of the CPB-rock interface in controlling stress distribution in CPB structures. The results obtained from experimental tests, numerical modelling and simulations concerning the shear behaviour of the CPB-rock interface under different multiphysics conditions provided useful information for understanding and more effectively assessing the shear strength and behaviour of the interface between a CPB structure and rock mass, which is critical for the design of safer and more cost-effective CPB structures.
An Experimental Study Of Cementing Paste Backfill
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Author : Megan Walske
language : en
Publisher:
Release Date : 2014
An Experimental Study Of Cementing Paste Backfill written by Megan Walske and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
[Truncated abstract] This thesis focuses on experimental element testing of cementing paste backfill (CPB) to examine and improve on existing laboratory testing techniques. Specifically, the work focuses on developing a framework to account for differences in curing conditions between in situ and laboratory environments, given the recognised improvement in mechanical properties of in situ cured CPB. This has been explored within the effective stress framework by making use of a hydration cell testing apparatus. The existing hydration cell set-up was modified to allow control over the rate of temperature increase and final temperature of specimens during curing, to replicate in situ curing conditions. The combination of elevated curing temperature and effective stress generation was found to significantly increase the mechanical properties of CPB compared with curing at elevated effective stress and ambient temperatures. The current procedure for curing under effective stress can be expensive and time consuming. As such, the standard test method for chemical shrinkage of hydraulic cement paste (ASTM C1608-07) was investigated as a potential index/screening test for use in the design of CPB mixes through comparison of the chemical shrinkage-induced strain generated in both the ASTM and hydration cell tests. The appropriate use of this ASTM standard with CPB was validated despite the high w/c ratio of typical CPB mixes.
Effects Of Dynamic Loading On The Geomechanical Behaviour Of Cemented Paste Backfill
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Author : Gonzalo Hernan Suazo Fuentealba
language : en
Publisher:
Release Date : 2016
Effects Of Dynamic Loading On The Geomechanical Behaviour Of Cemented Paste Backfill written by Gonzalo Hernan Suazo Fuentealba and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
[Truncated] Backfill is any material that is placed underground to fill the voids (stopes) left after the process of extracting minerals from crushed rock. Cemented Paste Backfill (CPB) is one of these materials, which consists of a mixture of full stream tailings, a small percentage of cement and water. Underground space is a dynamic environment that subjects these fills to a series of dynamic loading resulting from blasting and seismic events. Refracted stress waves at the CPB-rock interface can increase the shear and compressive stresses in the fill. As a result, excess pore water pressures may develop and liquefaction can eventually be triggered. Liquefaction might cause the failure of the retaining barricade constructed at the bottom of the stope since total pressure can rise to as high as the full hydrostatic head of the fill. However, the amount of dynamic energy transmitted to the fill as well as the liquefaction risk, greatly diminishes as the fill desaturates and negative water pressures arise in the pore space. In this context, the primarily objective of this thesis is to evaluate the liquefaction susceptibility of CPB at early curing ages due to seismic and blasting stress waves. In addition, the propagation phenomena of compressional waves in CPB, the effects of degree of saturation on stress wave refraction at CPB interfaces and the blast response of a backfilled stopes are explored. Finally, the evolution of unsaturated CPB properties and the mechanism of desaturation of the fill are investigated. This research consisted of in situ and experimental testing, and a numerical modelling component.Direct simple shear (DSS) tests were conducted to study the cyclic undrained shear response of CPB. The effects of confining stress, initial static shear stress and void ratio on the liquefaction resistance of uncemented fine-grained tailings was firstly researched. Then, the cyclic response of cemented tailings prepared at different curing ages, cement contents and initial void ratios, was examined. The material, independently of the degree of cementation, showed a predominantly cyclic mobility type response with large degradation of shear stiffness at advanced numbers of shear cycles. However, no flow type of failure was observed in any of the tests conducted. The overburden stress correction factor was found to decrease with increasing confining stresses in the range 100 to 400 kPa and to gradually increase from 400 kPa onwards, when samples were tested at the same initial void ratio. Similarly, higher cement contents, longer curing periods or higher initial solids contents were found to increase liquefaction resistance. A unconfined compressive strength (UCS) of about 70kPa, which corresponds to a shear wave velocity of 220 m/s, was found to be adequate to resist liquefaction under a large earthquake-induced cyclic stress ratio (CSR).
Temperature Dependency Of The Rheological Properties And Strength Of Cemented Paste Backfill That Contains Sodium Silicate
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Author : Ghada Abdulbaqi Ali
language : en
Publisher:
Release Date : 2021
Temperature Dependency Of The Rheological Properties And Strength Of Cemented Paste Backfill That Contains Sodium Silicate written by Ghada Abdulbaqi Ali and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Over the past decades, cemented paste backfill (CPB) has become a common, environmentally friendly method of managing mine wastes (such as tailings). This technology allows up to 60% of the total amount of tailings to be reused and filled in the mine stopes after converting them into cemented material. Beside reducing the environmental risks associated with the traditional disposal of these materials, turning them into cemented material and placing them in the underground mine stopes can also provide secondary support for these stopes in addition to minimizing the risk of ground subsidence in the mine area. CPB is an engineered mixture of tailings, water, and hydraulic binder (such as cement, blast furnace slag, and fly ash) that is mixed in the paste plant and delivered into the mine stopes through a gravity or pumping based transportation system. During the transportation of CPB through the delivery system pipelines, the flowability of CPB depends on the rheology of the transported CPB, which is affected by different factors, such as the transportation time, temperature variation, binder type, and chemical composition of these mixtures. In addition, the performance of CPB, after placing the CPB mixture into the mine stopes, is mainly dependent on the role of the hydraulic binder, as it increases the mechanical strength of the mixture through the process of cement hydration. The mechanical strength is also influenced by different factors, such as time progress, temperature variation, and presence of chemical additives. It has previously been found that fresh CPB transported and/or placed in the mine stopes can be susceptible to temperature variation of different sources, such as the climatic effects, heat generated from the surrounding rocks, and heat generated during the process of cement hydration. Unsuitable flowability of CPB through the delivery system might lead to significant financial losses due to clogging of pipelines with unexpected hardening of CPB during transportation, which will cause delay in work and possible damages to the pipelines. Also, failure of CPB structure in the mine stopes due to inappropriate mechanical strength may cause casualties to the mine workers as well as significant environmental and economic damages. Many researchers studied the rheological properties and/or strength development of CPB under the individual effect of any of the aforementioned factors. Additionally, many researchers have evaluated the coupled effect of some of these factors on the rheology and mechanical strength of CPB material. Hitherto, there are currently no studies that addressed the combined effect of all these conditions on the rheological properties and strength development of CPB. At the first stage of this M.A.Sc. study, a series of experimental tests was conducted on fresh CPB in order to determine the combined effect of time, temperature, binder content, and chemical additives on the rheological properties of CPB. These experiments include rheological properties test (yield stress and viscosity), microstructural analysis (thermal analysis and XRD), chemical analysis (pH and Zeta potential), and monitoring tests (electrical conductivity), which were conducted on 125 CPB samples that were mixed and prepared at different temperatures (2oC, 20oC, 35oC) and cured for different curing time (0 hrs., 0.25 hrs., 1 hr., 2hrs, and 4 hrs.). These samples were prepared with different blends of hydraulic binders (PCI, PCI/Slag, and PCI/FA) and contained different dosages of sodium silicate (0%, 0.1%, 0.3%, and 0.5%). The results obtained show that rheology of CPB increases with the progress of curing time. It also increases with the increase in the initial (mixing and curing) temperature and content of sodium silicate. It was also found that the partial usage of slag and FA reduces the rheological properties. However, CPBs containing PCI/FA as binder have lower rheological properties, and thus better flowability, than those that contain PCI/Slag as binder. At the second stage of this M.A.Sc. study, in order to understand the combined effect of time, temperature and sodium silicate content on the strength development of slag-CPB, unconfined compression (UCS) test, microstructural analysis (thermal analysis and MIP), and monitoring tests (electrical conductivity, suction, and volumetric water content) were conducted on 72 CPB samples that were prepared with PCI-Slag as a binder, cured for different times (1 day, 3 days, 7 days, and 28 days) under different curing temperatures of (2oC, 20oC, 35oC), and contained different dosages of sodium silicate (0%, 0.3% and 0.5%). The results obtained at this stage showed that the strength development of slag-CPB increases with the progress of curing time and temperature. It also increases with the increase in the sodium silicate content. Also, the combined effect of high temperature, high dosage of sodium silicate and longer curing time showed significant enhancement in the mechanical strength of slag-CPB. The findings of this M.A.Sc. research will contribute to cost effective, efficient, and safer design of CPB structures in the mine areas. It will also help in minimizing financial loss associated with unsuitable flowability of CPB transported in the CPB delivery system besides reducing the risks of human loss, and the environmental and economic damages associated with the failure of CPB structures.
Shaking Table Testing Of Cyclic Behaviour Of Fine Grained Soils Undergoing Cementation
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Author : Imad Hazim Alainachi
language : en
Publisher:
Release Date : 2020
Shaking Table Testing Of Cyclic Behaviour Of Fine Grained Soils Undergoing Cementation written by Imad Hazim Alainachi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Cemented paste backfill (CPB) is a novel technology developed in the past few decades to better manage mining wastes (such as tailings) in environmentally friendly way. It has received prominent interest in the mining industry around the world. In this technology, up to 60% of the total amount of tailings is reused and converted into cemented construction material that can be used for secondary support in underground mine openings (stopes) and to maximize the recovery of ore from pillars. CPB is an engineered mixture of tailings, water, and hydraulic binder (such as cement), that is mixed in the paste plant and delivered into the mine stopes either by gravity or pumping. During and after placing it into the mine stopes, the performance of CPB mainly depends on the role of the hydraulic binder, which increases the mechanical strength of the mixture through the process of cement hydration. Similar to other fine-grained soils undergoing cementations, CPB's behavior is affected by several conditions or factors, such as cement hydration progress (curing time), chemistry of pore water, mixing and curing temperature, and filling strategy. Also, it has been found that fresh CPB placed in the mine stopes can be susceptible to many geotechnical issues, such as liquefaction under ground shaking conditions. Liquefaction-induced failure of CPB structure may cause injuries and fatalities, as well as significant environmental and economic damages. Many researches studied the effect of the aforementioned conditions on the static mechanical behavior of CPB. Other researches have evaluated the liquefaction behavior of natural soils and tailings (without cement) during cyclic loadings using shaking table test technique. Only few studies investigated the CPB liquefaction during dynamic loading events using the triaxial tests. Yet, there are currently no studies that addressed the liquefaction behavior of CPB under the previous conditions by using the shaking table technique. In this Ph.D. study, a series of shaking table tests were conducted on fresh CPB samples (75 cm × 75 cm ×70 cm), which were mixed and poured into a flexible laminar shear box (that was designed and build for the purpose of this research). Some of these shaking table tests were performed at different maturity ages of 2.5 hrs, 4.0 hrs, and 10.0 hrs, to investigate the effect of cement hydration progress on the liquefaction potential of CPB. Another set of tests were conducted to assess the effect of the chemistry (sulphate content) of the pore-water on the cyclic response of fresh CPB by exposing cyclic loads on couple of CPB models that contain different concertation of sulphate ions of 0.0 ppm and 5000 ppm. Moreover, as part of this study, series of shaking table test was conducted on CPB samples that were prepared and cured at different temperatures of 20oC and 35oC, to evaluate the effect of temperature of the cyclic behavior of CPB. Furthermore, the effect of filling strategy on the cyclic behavior of fresh CPB was assessed by conducting set of shaking tables tests on CPB models that were prepared at different filling strategies of continuous filling, and sequential or discontinuous (layered) filling. The results obtained show that CPB has different cyclic behavior and performance under these different conditions. It is observed that the progress of cement hydration (longer curing time) enhances the liquefaction resistance of CPB, while the presence of sulphate ions diminishes it. It is also found that CPB mixed and cured in low temperature is more prone to liquefaction than those prepared at higher temperatures. Moreover, the obtained results show that adopting the discontinuous (layered) filling strategy will improve the liquefaction resistance of CPB. The finding presented in this thesis will contribute to efficient, cost effective and safer design of CPB structures in the mine areas, and will help in minimizing the risks of liquefaction-induced failure of CPB structures.
Prediction Of Mechanical Performance Of Cemented Paste Backfill By The Electrical Resistivity Measurement
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Author : Wenbin Xu
language : en
Publisher:
Release Date : 2018
Prediction Of Mechanical Performance Of Cemented Paste Backfill By The Electrical Resistivity Measurement written by Wenbin Xu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Concrete categories.
Cemented Paste Backfill (CPB) has become a useful practice in many modern operations around the world. This method is an innovative tailings disposal and underground mine backfilling scheme that returns much of this material to the underground stope field. Thus, it is of great interest for financial and security reasons to fully comprehend the mechanical performance of such underground CPB. Uniaxial compressive strength (UCS) is one of the most commonly used parameters for evaluating the mechanical performance of CPB. Electrical resistivity (ER) measurement, which is a method of nondestructive testing, can also be used to determine the mechanical properties of CPB. This study was undertaken to suggest a nondestructive testing method that would permit prediction of the UCS of a CPB within 90 days. Five CPB samples were prepared at different cement-to-tailing ratios (1/4, 1/6, and 1/8 by weight) and solid content (65 and 70 wt. %), and a curing period of 3-90 days was used for ER measurement. Seventy-five CPB samples were prepared with the same cement content as those used in the pastes for UCS tests cured for 3, 7, 28, 56, and 90 days. The results of the ER measurement show that the ER versus curing periods of 3-90 days first drop to a minimum value and then gradually increase with time. The greater ER values of CPB are reached when the greater cement-to-tailing ratio and solid content is used. A logarithmic relationship is established between the UCS and the ER of CPB at 90 days. It is possible that a nondestructive method could be developed to evaluate the strength of underground CPB based on the obtained logarithmic relationship with ER at 90 days.
Cemented Paste Backfill
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Author : Yong Wang
language : en
Publisher: Elsevier
Release Date : 2024-05-19
Cemented Paste Backfill written by Yong Wang and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-05-19 with Science categories.
In view of the demand for the research on the transport resistance characteristics and mechanical properties of CPB under the influence of temperature effect, the book comprehensively describes the studies on rheological and mechanical properties of CPB materials used in underground metal mines. This book covers a wide range of topics, including a new definition of CPB, past participation and flow-induced corrosion of pipeline under the constant temperature condition, multiphysics processes in CPB and the associated consolidation process, the variation of rheological parameters and transport resistance, prediction model for rheological properties, mechanical behavior and properties of CPB and fiber-reinforced CPB, and control technology to reduce the adverse effect of temperature. Therefore, an academic framework for the transport resistance characteristics and mechanical properties under the temperature effect was established in this book. - Investigates rheological properties and multiphysics processes in CPB materials around the world - Looks into systematic studies on pipe transport and mechanical properties of CPB under temperature effects - Focuses mainly on the effect of temperature on paste transport and mechanical properties under the temperature effect, which provides a theoretical basis for safe and efficient filling operation and associated future research in this field - Offer in-depth insights into the evolution of the rheological and mechanical properties of CPB under the effect of temperatures
Reactivity Of Cemented Paste Backfill
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Author : Zaid Aldhafeeri
language : en
Publisher:
Release Date : 2018
Reactivity Of Cemented Paste Backfill written by Zaid Aldhafeeri and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
Mining has been one of the main industries in the course of the development of human civilization and economies of various nations. However, every industry has issues, and one of the problems the mining industry has faced is the management of waste, especially sulphide-bearing tailings, which are considered to be a global environmental problem. This issue puts pressure on the mining industry to seek alternative approaches for tailings management. Among the several different types of methods used, cemented paste backfilling is one of the technologies that offers good management practices for the disposal of tailings in underground mines worldwide. Cemented paste backfill (CPB) is a cementitious composite made from a mixture of mine tailings, water and binder. This technology offers several advantages, such as improving the production and safety conditions of underground mines. Among these advantages, CPB is a promising solution for the management of sulphidic tailings, which are considered to be reactive materials (i.e., not chemically stable in an atmospheric condition) and the main source of acid mine drainage, which constitutes a serious environmental challenge faced by mining companies worldwide. Such tailings, if they come into direct contact with atmospheric elements (mainly oxygen and water), face oxidation of their sulphidic minerals, thus causing the release of acidic drainage (i.e., acid mine drainage) and several types of heavy metals into surrounding water bodies and land. Therefore, the reactivity of sulphidic tailings with and without cement content can be considered as a key indicator of the environmental behavior and durability performance of CPB systems. For a better understanding of the reactivity, it is important to investigate the influencing factors. In this research, several influencing factors are experimentally studied by conducting oxygen consumption tests on different sulphidic CPB mixtures as well as their tailings under different operational and environmental conditions. These factors include time, curing temperature, initial sulphate content, curing stress, mechanical damage, binder type and content, and the addition of mineral admixtures. In addition, several microstructural techniques (e.g., x-ray diffraction and scanning electron microscopy) are applied in order to understand the changes in the CPB matrices and identify newly formed products. The results reveal that the reactivity of CPB is affected by several factors (e.g., curing time, initial sulphate content, ageing, curing and atmospheric temperature, binder type and content, vertical curing stress, filling strategy, hydration and drainage, etc.), either alone or in combination. These factors can affect reactivity either positively or negatively. It is observed that CPB reactivity decreases with increasing curing time, temperature (i.e., curing and atmospheric temperatures), curing stress, binder content, the addition of mineral admixtures, degree of saturation, and the binder hydration process, whereas reactivity increases with increases in sulphide minerals (e.g., pyrite), initial sulphate content, mechanical damage, and with decreased degrees of saturation and binder content. The effect of sulphate on the reactivity of CPB is based on the initial sulphate content as well as curing time and temperature. It is concluded that the reactivity of CPB systems is time- and temperature-dependent with respect to other factors. Also, binders play a significant role in lowering CPB reactivity due to their respective hydration processes.
Geotechnical Characterization Of Cemented Paste Backfill
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Author : Erol Yilmaz
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2015-02-10
Geotechnical Characterization Of Cemented Paste Backfill written by Erol Yilmaz and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-02-10 with categories.
Cemented paste backfill (CPB) technology is now widely utilized by most modern underground hard rock mines in Canada, Australia, the United States, South Africa and Turkey. CPB is a cementitious material produced with three ingredients: filtered wet tailings, hydraulic binders, and mixing water to ensure the paste's flowability in pipeline for final deposition. This book investigates CPB technology using a recently designed lab apparatus called CUAPS (curing under applied pressure system) that estimates in situ CPB conditions. The CUAPS apparatus has been demonstrated as a practical and cost-effective tool that effectively replaces the traditional approach using non-perforated plastic moulds. The results obtained with the CUAPS apparatus will contribute to improve the safety of mines and miners and provide a better understanding of paste backfill. Each section of this book represents an original contribution to the science and engineering of paste backfill. This book provides some theoretical and experimental bases for designing paste backfill mixtures in terms of cost savings and safety and for incorporating in situ backfill behaviour and properties.