New theory for the rock mass destruction by blasting

Maksym Kononenko,Oleh Khomenko

doi:10.33271/mining15.02.111

Abstract

Purpose. To develop a new theory for the rocks destruction by blasting using a description of the formation processes of zones with various mass state around the charging cavity. Methods. The new theory for the rock mass destruction by blasting has been developed based on the use of the well-known elasticity theory laws and the main provisions of the quasi-static-wave hypothesis about the mechanism of a solid medium destruction under the blasting action. The models of zones of crumpling, intensive fragmentation and fracturing that arise around the charging cavity in the rock mass during its blasting destruction, depending on the physical and mechanical pro-perties of the rock mass, the energy characteristics of explosives and the rock pressure impact, have been developed using the technique of mathematical modeling. Findings. Based on the mathematical modeling results of the blasting action in a solid medium, the mathematical models have been developed of the zones of crumpling, intensive fragmentation and fracturing, which are formed around the char-ging cavity in a monolithic or fractured rock mass. Originality. The rock mass destruction by blasting is realized according to the stepwise patterns of forming the zones of crumpling, intensive fragmentation and fracturing, which takes into account the physical and mechanical properties of the medium, the energy characteristics of explosives and the rock pressure impact. Practical implications. When using the calculation results in the mathematical modeling the radii of the zones of crumpling, intensive fragmentation and fracturing in the rock mass around the charging cavity, it is possible to determine the rational distance between the blasthole charges in the blasting chart, as well as to calculate the line of least resistance for designing huge blasts.

Highlights

The mining industry is an important industry influencing the economic and technical development of countries around the world
The dependences have been determined for the formed zones of crumpling, intensive fragmentation and fracturing, which arise around the charging cavity in a monolithic and fractured rock mass under its blast loading, taking into account the physical and mechanical properties of the medium, the energy characteristics of explosives and the rock pressure impact
The dependence of the crumpling zone has been obtained, from which it follows that the radius of the crumpling zone created during blasting of an extended explosive charge is directly proportional to the charging cavity radius and the square root of the pressure, developed by the explosive detonation products, and is inversely proportional to the square root of the ultimate compression strength of the rock, compaction coefficient of the rock and coefficient of structural weakening of a mass

Summary

Introduction

The mining industry is an important industry influencing the economic and technical development of countries around the world. Manganese ores are mined using mechanical breaking, and the extraction of iron ores is associated with the destruction of large volumes of hard rocks, the development of which requires preliminary fragmentation using drilling-and-blasting operations. Special attention of scientists and production workers is paid to the improvement and development of new methods for calculating the parameters of drilling-andblasting operations, which will improve the performance of driving and mining operations. Another way to improve the technology of drilling-and-blasting operations is to increase the safety of blasting operations and reduce their impact on the environment by replacing TNT-based explosives with emulsion explosives (EEM) of domestic production.

Methods

Results

Conclusion