Potential Effect of Porosity Evolution of Cemented Paste Backfill on Selective Solidification of Heavy Metal Ions

Yixuan Yang, Tongqian Zhao, Huazhe Jiao, Yunfei Wang and Haiyan Li
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Yixuan Yang: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000, China
Tongqian Zhao: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000, China
Huazhe Jiao: International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Yunfei Wang: International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Haiyan Li: School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China

IJERPH, 2020, vol. 17, issue 3, 1-12

Abstract: Cemented paste backfill (CPB) is a common environmentally friendly mining approach. However, it remains undetermined whether CPB pollutes underground mine water. Tank leaching analysis of a CPB mass in distilled water was performed for 120 d, and water quality was tested in situ for a long-term pollution assessment. Computerized tomography was also used to determine the CPB micro-pore structure and ion-leaching mechanism. The dissolved Zn 2+ , Pb 2+ and As 5+ concentrations in the leachate peaked at 0.56, 0.11 and 0.066 mg/L, respectively, whereas the Co 2+ and Cd 2+ concentrations were lower than the detection limit. The CPB porosity decreased from 46.07% to 40.88% by soaking, and 80% of the pore diameters were less than 13.81 μm. The permeability decreased from 0.8 to 0.5 cm/s, and the quantity, length, and diameter of the permeate channels decreased with soaking. An in-situ survey showed novel selective solidification. The Zn 2+ concentration in the mine water was 10–20 times that of the background water, and the Pb 2+ concentration was 2–4 times the regulated value. Although the Pb 2+ content decreased significantly with mining depth, there remains a serious environmental risk. Mine water pollution can be reduced by adding a solidifying agent for Pb 2+ and Zn 2+, during CPB preparation.

Keywords: cemented paste backfill; tailings management; underground water pollution; heavy metal ions; selective solidification (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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