On the issue of stacking works with hardening mixtures in underground mining workings

The relevance of this study lies in the investigation and analysis of the performance of the bottom aerator, compared to the mainline aerator, as a method to improve the transportability of hardening mixtures in underground mine workings and to ensure uniform placement of the mixture in remote backfill areas.Comparative experiments on the aeration of hardening mixtures were conducted using both the mainline aerator and the bottom aerator.The experimental results were presented in the form of graphs clearly illustrating the hardening kinetics of mixtures aerated by the two methods.Analysis revealed that transportation speed and air content in the mixture significantly influence the uniform distribution of solid particles across the flow cross-section.Numerical experiments confirmed the potential for optimizing water consumption: introducing air into the mixture in a precisely defined ratio relative to the water mass allows saving 20 liters per cubic meter.For the M80 PC mixture, this corresponds to a 4% reduction in water content.The study of backfill mixtures identified Portland cement of grades M300 and M400 as the most effective primary binder for hardening hydraulic mixtures, serving as an activator of the hardening process.Anhydrite, used as a secondary binder, was found to reduce cement consumption and improve the flowability of mixtures, which is particularly critical for high-strength backfill.Metallurgical granulated slag was identified as the optimal inert filler, providing additional benefits.The presented findings hold significant practical importance as they contribute to the optimization of technological processes, cost reduction, and enhanced reliability of backfill structures in underground mining operations.