A new procedure for recycling waste tailings as cemented paste backfill to underground stopes and open pits

New paper published on Journal of Cleaner Production

Paper Title: A new procedure for recycling waste tailings as cemented paste backfill to underground stopes and open pits

Authors: Hongjian Lu, Chongchong Qi, Qiusong Chen, Deqing Gan, Zhenlin Xue, Yajun Hu

Abstract: Waste tailings are increasingly being recycled as cemented paste backfill (CPB) for the cleaner production of mineral resources. In most cases, the waste tailings cannot be fully recycled and the stability of underground stopes and open pits cannot be ensured. This research proposed a new procedure for recycling waste tailings as CPB to both underground stopes and open pits. Firstly, the physical, geotechnical and chemical tests required before the application of such procedure were discussed. Then, the new procedure was introduced in detail, including the process parameters determination and the backfill implementation. Finite element method and the three-zone theory were used to determine the process parameters. The application of this new procedure to an engineering instance, the Shirengou Iron Mine (SIM), was expatiated. The process parameters of recycling waste tailings as CPB in SIM were determined as follows. The solids content of CPB was 72%, the cement-tailings ratios were 1:8, 1:10, 1:20, the total height of open pit backfill was 80m (with four backfilling stages), the stratification height was 1.5m, and the cement-tailing ratios for four open-pit backfilling stages were 1:8 (stage 1 and 2), 1:10 (stage 3), and 1:20 (stage 4). It is shown that this new procedure achieved 100% recycling of waste tailings in SIM, which is of great environmental significance during mining operations. This research indicates that harnessing such procedure extends recent efforts to recycle waste tailings as CPB, and can significantly promote the cleaner and safer production of minerals resources worldwide.

Keywords: Waste tailings, cemented paste backfill, recycling, underground stopes and open pits, cleaner production.

Reviewer 1: I have examined the paper entitled "A new procedure for recycling waste tailings as cemented paste backfill to underground stopes and open pits " in detail. The authors may find the following comments helpful to enhance the paper's quality.

Reviewer 2: This paper provides information about the potential application of cemented paste backfill for underground and open pit mines as mine tailings disposal on the surface and mine backfill in underground mine voids. Some laboratory tests are undertaken on samples and the application stages of the technique used are given in detail in this study. This manuscript is well written. When considered attentively the complex structure of cemented paste backfill for its ultimate lucrative design at mines, this work brings a new light to the mining and/or mineral industry. The authors should be commended for that.

The reviewer is proposing the following minor revisions to improve the manuscript. Once the revisions suggested are implemented, this reviewer feels that the revised manuscript should be accepted for publication.

Reviewer 3: This is an interesting paper where the authors evaluate a new procedure for recycling waste tailings as cemented paste backfill to underground stopes and open pits.  However, I have some comments regarding this paper, as the following.

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