Investigation on Mechanical Characteristics and Microstructure of Cemented Whole Tailings Backfill

Tana, Armelle Estelle Belibi; Yin, Shenghua; Wang, Leiming

doi:10.3390/min11060592

Cited by 20 publications

(6 citation statements)

References 35 publications

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“…The above studies mainly focused on the complete filling body, and with the consumption of external mineral resources, deep mining has gradually become the mainstream mining trend [22,23]. The development of deep mining technology is accompanied by the rapid increase in the number and size of goaf [24][25][26][27][28][29]. Limited by the current domestic filling technology, it is almost impossible to fill large-scale mined-out areas once, which leads to the stratification of the filling body due to layer-by-layer filling [30][31][32][33].…”

Section: Methodsmentioning

confidence: 99%

“…Mining is one of the essential conditions to ensure the rapid development of China’s economy, but mining also brings problems such as goaf collapse and mining waste pollution [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The filling mining method can effectively control stope ground pressure and stope deformation while making full use of mine solid waste tailings, which not only ensures the safety of mining but also solves the problem of environmental pollution to a certain extent [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], so it is extensive use of various metal and non-metal mines.…”

Section: Introductionmentioning

confidence: 99%

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Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

Chen

Zhang

et al. 2022

Materials

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Layering of filling body is common in large-scale filling areas. In this paper, the cement–sand ratio of 1:8 is based on the configuration of 68%, 70%, 72% and 74%; four concentrations; and filling layers of one-, two-, three- and four-layered cemented filling samples. Combined with a uniaxial compression test and two-dimensional particle flow software (PFC2D), the mechanical properties and failure modes were explored. The results show that the concentration can strengthen the uniaxial compressive strength of the filling body while increasing the filling times weakens its power; therefore, the constitutive damage model was constructed. It was found that the initial layered damage existed in the layered filling, and the total damage showed an upward trend of first fast and then slow; the main failure modes of one-layer and two-layer backfills showed prominent shear failure characteristics, and the three-layer and four-layer fillings were closer to tensile failure. From the crack generation to the specimen failure, there is a mutual conversion between different energies.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

Chen

Zhang

et al. 2022

Materials

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“…Indeed, the high molecular polymer PAM molecules connected and interacted with TS and OPC particles by the formation of floc and the bridging effect in CPB mixtures [17]. These floc formed between particles not only enhance the viscosity of fresh CPB mixtures but also increase the mechanical strength of hardened CPB specimens [13]. As shown in Figure 6, the morphologies of hydrates including C-S-H, ettringite, and CH are more relevant to W/S ratios rather than the chemical additives.…”

Section: Microstructurementioning

confidence: 99%

“…Li et al [12] used response surface methodology to systematically investigate and illustrate that fly ash, silica fume, sand to binder ratio and water to binder ratio and their partial interactions have remarkable effects on the rheological and mechanical performances of self-compacting mortars, especially the silica fume and sand to binder ratio. In addition, Belibi Tana et al [13] have shown the yield stress and slump value of uncemented whole tailings backfill paste slurries were positively correlated, and that increasing the solids content would affect their porosity and enhances their strength resistance. Libre et al [14] investigated the effect of chemical and mineral admixtures on the fluidity, viscosity, and stability of self-compacting mortars at different water/cement ratios, and proposed suitable workability zones for formulating mixtures.…”

Section: Introductionmentioning

confidence: 99%

The Role of Rheological Additives on Fresh and Hardened Properties of Cemented Paste Backfill

et al. 2022

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Cemented paste backfill (CPB) has become a significant structural material in most mines across the world. In this study, the effects of chemical rheological additives including viscosity modifying agent (i.e., polyacrylamide) and polycarboxylate superplasticizer (PCE) on fresh and hardened properties of CPB with different water-to-solid (W/S) ratios and water-to-cement (W/C) ratios were investigated. The microstructure of CPB specimens was also characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and backscattered electron image (SEM-BSE). The obtained results indicate that PAM (polyacrylamide) dosage and W/S are the most significant parameters influencing the workability of fresh CPB mixtures. For the hardened CPB specimens, the decreasing W/S ratio leads to higher flexural and compressive strength values and lower dry shrinkage strains. The interfacial transition zone (ITZ) between the cement matrix and the tailings sand was also observed to be narrower, with fewer micro cracks and capillary pores. Meanwhile, the existence of PAM decreased the number of hydration products and retarded the hydration reaction. Overall, the CPBs with high W/C ratios (i.e., 1.0 and 1.2), low W/S ratios (i.e., 0.3), and moderate amounts of rheological additives (i.e., 0.05% PAM and 1.0% PCE) have excellent fresh and hardened properties. The findings of this study contribute to better optimization of CPB mixtures in backfill construction, bringing benefits of low costs and low environmental impacts.

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“…These mine tailings usually contain hazardous chemical compounds and would otherwise be impounded on the land posing a grave threat to the environment as well as human lives. In addition, the CPB technology is economically advantageous because it improves the productivity of ore retrieval during mining [1][2][3][4][5][6]. Moreover, binder inclusion ensures that the backfill becomes self-supporting after a short period, making the excavation of adjacent ore body possible.…”

Section: Introductionmentioning

confidence: 99%

Insight into Saturated Hydraulic Conductivity of Cemented Paste Backfill Containing Polycarboxylate Ether-Based Superplasticizer

Haruna

Fall

2022

Minerals

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Recycling of tailings in the form of cemented paste backfill (CPB) is a widely adopted practice in the mining industry. Environmental performance is an important design criterion of CPB structures. This environmental performance of CPB is strongly influenced by its saturated hydraulic conductivity (permeability). Superplasticizers are usually added to improve flowability, but there is a limited understanding of their influence on the hydraulic properties of the CPB. This paper presents new experimental results on the variations of the hydraulic conductivity of CPB containing polycarboxylate-based superplasticizer with different compositions and curing conditions. It is found that the hydraulic conductivity of the CPB decreases with the addition of superplasticizer, which is beneficial to its environmental performance. The reduction is largely attributable to the influence of the ether-based superplasticizer on particles mobility and cement hydration. Moreover, both curing temperature and time have correlations with the hydraulic conductivity of CPB containing superplasticizer. In addition, the presence of sulfate and partial replacement of PCI with blast furnace slag reduces the hydraulic conductivity. The variations are mainly due to the changes in the pore structure of the CPB. The new results discussed in this manuscript will contribute to the design of more environmental-friendly CPBs, which is essential for sustainable mining.

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Investigation on Mechanical Characteristics and Microstructure of Cemented Whole Tailings Backfill

Cited by 20 publications

References 35 publications

Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

The Role of Rheological Additives on Fresh and Hardened Properties of Cemented Paste Backfill

Insight into Saturated Hydraulic Conductivity of Cemented Paste Backfill Containing Polycarboxylate Ether-Based Superplasticizer

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