Selection of the optimal composition and analysis of the detonating characteristics of low-density mixed explosives applied to break thin ore bodies

Abstract

Purpose is to select the optimal composition of the mixed low-density explosive (Es) applied in the form of blasthole charges which provide high efficiency of blasting operations while mining of thin ore deposits. The abovementioned becomes possible while studying features of the foamed polystyrene chemical decomposition and gasification; role of additional water components as well as catalyzator being sodium carboxymethyl cellulose; and analysis of explosive characteristics of the compositions. Methods. The research involved lab-based experiments to define application efficiency of the recommended low-density blasting agents through identification of the basic explosive characteristics of the model mixed Es. Findings. The optimal composition of the mixed low-density Es has been developed. It consists of ammonia nitrate, diesel fuel, granulated foamed polystyrene, water, and sodium carboxymethyl cellulose to be used to break thin ore bodies. Owing to it, the possibility has arisen to control over a wide range both detonation velocity and pressure of blasting fumes during the charge density increasing or decreasing. The main detonative characteristics of the proposed compositions of low-density Es have been determined helping perform explosive rock mass loading in terms of extremely low values of both energy and explosive characteristics. The developed composition of the mixed low-density Es makes it possible to control quantity of Es energy in a volume well unit by means of increase or decrease in the charge energy concentration depending upon the changes in the rock mass resistance; in such a way, efficient breakage of thin ore bodies is provided inclusive of less dilution indicators. Originality. For the first time, dependence of the relative efficiency of the mixed low-density Es upon the foamed polystyrene volume content has been identified as well as dependence of pressure of blasting fumes upon the charging density. Practical implications are the development of procedures for blasting operations while thin ore body mining. The procedures are based upon formulating of the optimal composition of low-density Es differing in its simplicity, safety, and efficiency; and helping reduce prime cost of the extracted mineral at the expense of the decreased degree of the ore dilution. An empiric formula to define specific consumption of the low-density Es has been proposed for Akbakay mine.