Despite their significance in numerous applications, many critical minerals and metals are still considered minor. Since most of them are not found alone in mineral deposits, their co- or by-production depends on the production of base metals and other major commodities. In many cases, the concentration of the minor metals is low enough not to be considered part of the production. Hence, their supply is not always secured, their availability decreases, and their criticality increases. Many researchers have addressed this issue, but no one has set actual impact factors other than economic ones that should determine the production of these minor commodities. This study identified several parameters, the number and diversity of which gave birth to developing a computational tool using a multi-criteria-decision analysis model based on the Analytical Hierarchical Process (AHP) and Python. This unprecedented methodology was applied to evaluate the production status of different commodities in a polymetallic deposit located in Chovdar, Azerbaijan. The evaluation outcomes indicated in quantifiable terms the production potentials for several commodities in the deposit and justified the great perspectives of this tool to evaluate all kinds of polymetallic deposits concerning the co- and by-production of several minor critical raw materials.

Disposing of coal gangue and fly-ash on the surface is a risky method with tremendous potential catastrophic consequences for the environment. Backfill mining is a promising practice for turning those hazardous wastes into functional backfill materials. Unfortunately, how to efficiently deliver the slurry to the desired places remains under-researched. To address this issue, the computational fluid dynamics software Fluent was used in the current study in addition to a laboratory rheological test to simulate the impact of various parameters on the evolution of pressure at a particular section of the pipeline. Furthermore, the response surface method was employed to investigate how the various components and their corresponding influencing weights interact to affect the pressure drop. This study demonstrates that the pressure drop of the slurry is highly influenced by slurry concentration, speed, and pipe diameter. While conveying speed is the main component in the bend section, pipe diameter takes over in the horizontal and vertical pipe sections.

Pore Characteristics Analysis of Shale from Sichuan Basin, China

As resource extraction moves deeper underground, backfill mining has received a lot of attention from the industry as a very promising mining method that can provide a safe workplace for workers. However, the safe and efficient transport of fill slurry through pipelines still needs more exploration, especially in the bend section. In order to investigate the flow characteristics and velocity evolution of the slurry in the bend section of the pipe, a three-dimensional (3D) pipe model was developed using the computational fluid dynamics software Fluent, and nine sets of two-factor, three-level simulations were performed. Furthermore, a single-factor analysis was presented to investigate the effects of the two main influencing factors on the shifting of the maximum velocity of the slurry towards the distal side in the bend section, respectively. Then, the response surface analysis method was applied to the two-factor analysis of the maximum velocity shift and the weights of the two influencing factors were specified.

Fly ash, as a kind of hazardous by-product at coal-fired power stations, has been produced on a tremendous scale worldwide. Still, the utilization of fly ash is far from 100% despite some industrial sectors consuming a considerable amount. The top three industries that have successfully applied fly ash on a large scale are cement production, backfill mining, and civil engineering construction. However, compared to the other two fly ash disposal methods, the use of fly ash in backfill mining is still being extensively researched. Not only is fly ash a perfect substitute for cement due to its cementitious properties bringing the cost of backfill mining down to an affordable level for enterprises, the carbon sequestration capacity it possesses is generating new research enthusiasm. This chapter provides a comparative analysis of the current status of the use of fly ash in different mining methods and the role it plays in the corresponding mining method, with an emphasis on the mechanisms by which fly ash content affects the rheological properties of the paste and the strength of the fill. Therefore, this chapter can contribute to understanding the potential of fly ash in mining applications and exploring innovative applications of fly ash.