A review of Stemming Accessories Used to Control Air Blast in Surface Mining Operations

Abstract This paper reviews the stemming accessories commonly used in surface mining operations to control the environmental effects of rock blasting with specific emphasis on air blast. Indeed, air blast is a major byproduct of blasting that poses a serious operational and safety consequence. Uncontrolled air blasts can cause structural damage, endanger workers and nearby communities, and result in legal infractions, especially when pressure levels go beyond established safety limits. Different types of stemming accessories are used in conjunction with stemming materials to improve blast performance by enhancing the confinement of explosive gases. Often, drill cuttings are utilised for stemming over alternative materials since they are cheap and readily available on the site. However, crushed aggregates used for stemming have been found to perform better in terms of enhancing rock fragmentation and explosive energy utilisation. This is ascribed to the interlocking of aggregate fragments in the stemming column. It is therefore evident that adequate stemming of blastholes is key to the successful control of air blast. Considering this, the need for the efficient mitigation of air blast continues to grow as mining activities move closer to populated areas and regulatory scrutiny increases. This review examines the type of stemming accessories available for use, their effectiveness, best practices for stemming design and prospects for future research around air blast control.