Utilizing concrete pillars as an environmental mining practice in underground mines

Cao, Shuai; Xue, Gaili; Yilmaz, Erol; Yin, Zhen‐Yu; Yang, FuDou

doi:10.1016/j.jclepro.2020.123433

Cited by 69 publications

(15 citation statements)

References 73 publications

(63 reference statements)

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“…Tailings are called solid waste or hazardous waste after ore processing [23,24]. They can also be prepared concrete additives, backfilling, and construction materials [25,26]. However, tailings containing toxic elements or heavy metal ions cannot be used for filling underground voids according to the related environmental protection standards [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Strength and Microstructural Characteristics of Mine Backfills Containing Fly Ash and Desulfurized Gypsum

2021

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The utilization of solid wastes (SWs) as a potential resource for backfilling is not only conducive to environmental protection but also reduces the surface storage of waste. Two types of SWs, including fly ash (FA) and desulfurized gypsum (DG), were used to prepare cementitious backfilling materials for underground mined-out areas. Ordinary Portland cement (OPC) was used as cement in mine backfill. To better investigate the feasibility of preparing backfill materials, some laboratory tests, such as uniaxial compressive strength (UCS), scanning electron microscopy (SEM), and energy dissipation theory, were conducted to explore both strength and microstructural properties of backfilling. Results have demonstrated that the main components of FA and DG in this study are oxides, with few toxic and heavy metal components. The ideal ratio of OPC:FA:DG is 1:6:2 and the corresponding UCS values are 2.5 and 4.2 MPa when the curing time are 7 days and 14 days, respectively. Moreover, the average UCS value of backfilling samples gradually decreased when the proportion of DG in the mixture increased. The main failure modes of various backfilling materials are tensile and shearing cracks. In addition, the corresponding relations among total input energy, dissipated energy and strain energy, and stress–strain curve were investigated. The spatial distribution of oxygen, aluminum, silicon, calcium, iron and magnesium elements, and hydration product are explored from the microstructure’s perspective. The findings of this study provide both invaluable information and industrial applications for the efficient management of solid waste, based on sustainable development and circular economy.

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Section: Introductionmentioning

confidence: 99%

Analysis of Strength and Microstructural Characteristics of Mine Backfills Containing Fly Ash and Desulfurized Gypsum

2021

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“…Among them, the environmental pollution caused by solid waste (SW) storage is severe. Moreover, solid waste includes many types, including tailings and waste rock from mines, fly ash (FA) from power plants, gypsum, steel slag (SS) or water quenched slag from smelters [4][5][6][7][8][9]. Statistically, the estimated accumulation of FA in China will reach more than 3 billion tons in 2020 [10].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Cao

Yılmaz

2021

Minerals

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Using solid wastes (SWs) as backfilling material to fill underground mined-out areas (UMOAs) solved the environmental problems caused by SWs and reduced the backfilling cost. In this study, fly ash (FA), gypsum and steel slag (SS) were used to prepare cement-based composites (CBC). The uniaxial compression, computed tomography (CT) and scanning electron microscope (SEM) laboratory experiments were conducted to explore the macro and micromechanical properties of CBC. The findings showed that the uniaxial compressive strength (UCS) of CBC with a curing time of 7 d could reach 6.54 MPa. The increase of SS content reduced the UCS of CBC, while the gypsum and FA content could increase the UCS of CBC. Microscopic studies have shown that the SS particles in CBC have noticeable sedimentation, and the increase of SS content causes the failure mode of CBC from tensile to tensile-shear. These research results can provide a scientific reference for the preparation of backfilling materials.

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“…Being an innovative tailings disposal system, CPB allows mine operators to send 65-80% of pyritic tailings back to underground stopes as backfill (it helps to build for ground support) or disposal purposes [23,24]. Unlike concrete materials, CPB has unique properties such as finer (at least 15% under 20 μm) grain size, higher (typically more than 5) water/cement ratio, and lower (typically less than 10%) cement content [25,26]. As a result of these characteristics, CPB increases the neutralization potential of pyritic tailings and ensures secure storage in an alkaline environment with low permeability [27].…”

Section: Introductionmentioning

confidence: 99%

Recycling Dam Tailings as Cemented Mine Backfill: Mechanical and Geotechnical Properties

Kasap

Yilmaz

Guner

et al. 2022

Advances in Materials Science and Engineering

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As a result of developing technology and scientific studies, employing dam tailings as critical raw material and vital economic reserve has become widespread recently. Employing dam tailings as a main ingredient of CPB (cemented paste backfill) can offer benefits to mining operations. This study deals with the use of dam tailings in CPB, considering the mechanical and geotechnical aspects. CPB was prepared at fixed solid and cement contents (72%, and 5%, respectively) and tested for different cure ages varying from 3 to 56 days. The results disclosed that the strength of filling increased over time, with the exception of 56-day cured CPB having high sulfur minerals where strength decreased sharply. The reasons behind these strength surges could be clarified by CPB’s basicity, which quickens the hydration of cement. Voids between tailings grains are also occupied by hydration products, resulting in the high strengths. Due to the fact that higher sulfate contents can cause lower pH values within CPB, this is one of the factors that should be considered for the backfill’s strength performance. The cement tends to increase the backfill’s pH in short term, but pH of long-term cured backfills decreases because of dam tailings which is inclined to acid formations and erosions. This is a sign that the deformation properties of CPB are deteriorated. Depending on curing time, CPB’s water content and void ratio decrease, but their surface areas increase. The resulting data will endow to better apprehend the effects of dam tailings on CPB quality integrating cost and quality.

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Utilizing concrete pillars as an environmental mining practice in underground mines

Cited by 69 publications

References 73 publications

Analysis of Strength and Microstructural Characteristics of Mine Backfills Containing Fly Ash and Desulfurized Gypsum

Analysis of Strength and Microstructural Characteristics of Mine Backfills Containing Fly Ash and Desulfurized Gypsum

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Recycling Dam Tailings as Cemented Mine Backfill: Mechanical and Geotechnical Properties

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