Green Low-Carbon Technology for Metalliferous Minerals

1. Introduction and Scope

Metalliferous minerals play a central role in the global economy. They will continue to provide the raw materials we need for industrial processes. Significant challenges will likely emerge if the climate-driven green and low-carbon development transition of metalliferous minerals exploitation is not managed responsibly and sustainably. Green low-carbon technology is vital to promote the development of metalliferous mineral resources shifting from extensive destructive mining to clean and energy-saving mining in future decades. Global mining scientists and engineers have conducted a lot of research in related fields such as green mining, ecological mining, energy-saving mining, and mining solid waste recycling, and have achieved a great deal of innovative progress and achievements.

This Special Issue intends to collect the latest developments in the green low-carbon mining field, written by well-known researchers who have contributed to the innovation of new technologies, process optimization methods, or energy-saving techniques in metalliferous minerals development.

Various research topics are available to address this issue related to the role of green low-carbon technology for metalliferous minerals, including: green low-carbon technologies and systems; green low-carbon mining optimization methods; frontiers in mining with backfill; mine waste and heat management; the geo-mechanical behavior of mine backfill; energy-saving techniques in mining; alternative byproduct materials for green mining; green low-carbon development criteria of mining; and case studies of green low-carbon mining.

2. Contributions

In the present Special Issue, ‘Green Low-Carbon Technology for Metalliferous Minerals’, of Metals, 17 manuscripts were published.

The first paper, by Gao et al. [1], provides an experimental study for the disposal of arsenic-containing tailings with low carbon and high efficiency. In their research, sodium sulphate (Na₂SO₄), sodium hydroxide (NaOH), calcium nitrate Ca(NO₃)_2, and calcium hydroxide Ca(OH)₂ were independently added to metallurgical slag-based binder (MSB) solidification/stabilisation (S/S)-treated tailings (MSTs) to enhance the MST arsenic S/S performance. The microstructure analyses showed that the high specific surface area and amorphous properties of calcium–sodium aluminosilicate hydrate facilitated the adsorption or solid-solution formation of As(V) and As(III). As(V) formed an inner-sphere complex in ettringite, whereas As(III) formed an outer-sphere complex, and the relatively larger size and charge of As(V) compared with SO₄²⁻ restrict substitution inside channels without affecting the ettringite structure under high loading of As(V). The added Ca(OH)₂ promoted the hydration reaction of MSBs and facilitated the formation of a Ca–As(V) precipitate with low solubility. This work is beneficial for the application of cement-free MSB in the S/S process. The study carried out by Cui et al. [2] explores efficient methods for enhancing leaching efficiency, which is critical for bioleaching technology to deal with sulfide concentrate. In their study, a novel artificial microbial community was established to augment the bioleaching efficiency and recovery of copper (Cu) and zinc (Zn). This method of Cu and Zn recovery using a new-type artificial microbial community is expected to be an environmentally-friendly and efficient bioleaching technology solution, which has the potential of large-field engineering application in the future.

Regarding energy-saving techniques in mining, Tan et al. [3] provide a case study of structural parameter optimization for large-spacing sublevel caving in Chengchao Iron Mine. The findings of this study can further the goal of green and efficient mining and provide a theoretical reference for the popularization and application of pillarless sublevel caving with large structural parameters at home and abroad. The case study of the dispatch optimization model for haulage equipment between stopes based on mine short-term resource planning carried out by Li et al. [4] constructed an optimization model for short-term resource planning to maximize the total revenue during the planning period. Results show that, based on the improved optimization algorithm, using short-term production planning schemes to guide mine production operations can increase the haulage equipment utilization rate, thereby increasing mine production revenue.

Tailings ponds are one of the three major production facilities in metal mines. Through statistical analysis, Lin et al. [5] reveal the causes and regional distribution patterns of 342 tailings dam failures globally from 1915 to 2021. Causes of tailings pond failures differed among regions. Most tailings pond failures in Asia and Europe were related to hydroclimate, while earthquakes mainly triggered those in South America. Their study provides theoretical data for the pre-design and the safe and stable operation of global tailings ponds, which will help prevent global tailings pond failures. Furthermore, using complex network theory, Zhen et al. [6] studied the propagation laws of reclamation risk in tailings ponds.

Wang & Gan [7] studied the influence degree of particle settlement factors in pipe transportation of backfill slurry. In their study, a particle tracking module of the software was used to simulate the transport process, and the influences on the sedimentation rate were analyzed considering the slurry concentration, particle size, and flow velocity. Li et al. [8] established a mathematical model for the particle-size distribution of mine tailings using twelve tailing materials sourced from metal mines around China. Wang et al. [9] studied the characteristics of spiral pipes that increased resistance and reduced pressure, and the amendment equation of the stowing gradient. In their study, an equation for calculating the effective stowing gradient is obtained, which provides a convenient method for engineering applications and industrial design. Xie et al. [10] established an identification model of tailing settlement velocity to reasonably and accurately acquire the settlement interface and velocity of tailings. Their results show that the model has high recognition accuracy, has a rapid and efficient recognition process, and the relative error can be controlled within 3%. It can be used as a new technology for measuring the settling velocity of tailings. Zhu et al. [11] studied the response of floc networks in cemented paste backfill to a pumping agent, which provides insights into the effects of floc and liquid networks on the performance of paste, and it is of engineering significance in terms of realizing safe and efficient CPB operations.

Regarding the geomechanical behavior of mine backfill, Zhang et al. [12] studied the strength development and engineering performance of coal-based solid waste paste filling material. Peng et al. [13] examined the factors influencing the strength distribution of in situ cemented tailings backfill. In their study, it was found that solid materials settle and become redistributed during the flow of backfill slurries in stopes. With respect to tailings, coarse particles have a larger flowing resistance and are deposited near the feeding point, leading to the median sizes of particles increasing first and then decreasing thereafter. Le et al. [14] established a numerical model for the compressive behavior of backfill. The effects of the particle size of the granular backfill and the height and buried depth of mined-out stopes on surface subsidence have been clarified. The research results are of great significance for guiding backfill mining and evaluating surface subsidence and movement.

In the paper by Liu et al. [15], systematic research was conducted on the dynamic mechanical properties of limestone under confining pressure after high-temperature treatment. A corresponding constitutive model was established, which provides technical support for the green and low-carbon mining of these resources. In the paper by Wang et al. [16], a three-dimensional numerical model using PLAXIS 3D was established to monitor and analyze the dynamic response for an open-pit mine with inside inclined shafts under train loading. In the paper by Shi et al. [17], the blasting dust concentration and particle size distribution during tunnel construction by drilling and blasting were studied to guide the dust reduction technology in tunnel blasting to quickly remove the dust generated during the blasting process and improve the engineering construction efficiency.

3. Conclusions and Outlook

As the guest editor, I sincerely thank all the experts and scholars for submitting excellent papers to this Special Issue, and the reviewers for providing many constructive comments for the Special Issue.

I also want to thank the editor Zach Ma for his great help and contribution to preparing this Special Issue.

Overall, we hope the contribution of this collection builds up the understanding and interest of all researchers and practitioners who are focused on the recent developments and advancements in studying green low-carbon technology for metalliferous minerals. It is hoped that the results of this issue can provide a reference for future research and contribute to promoting the development of green low-carbon technology for metalliferous minerals.