The effect of geometrical presplit blast parameters on presplit quality at Kuusilampi open pit mine

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Volume Title

Insinööritieteiden korkeakoulu | Master's thesis

Date

2021-10-18

Department

Major/Subject

European mining course

Mcode

ENG3077

Degree programme

European Mining, Minerals and Environmental Programme (EMMEP)

Language

en

Pages

81+7

Series

Abstract

In open pit mines, controlled blasting methods are used to reduce blast damage on the remaining rock mass, which increases the safety and economy of the operation. Presplitting is one of the most common controlled blasting methods used to achieve stable pit walls. The aim of this thesis is to discover suitable presplitting designs for the different areas of the Kuusilampi open pit mine. Furthermore, this thesis studied the connection between a geotechnical block model's rock mass quality estimates and the result of presplit blasting. This study has been conducted to improve the slope stability at the mine by improving the presplit blasting practices. This thesis consists of a historical review of presplitting practice at Kuusilampi open pit and presplitting tests. Presplitting tests were conducted with smaller diameter explosive cartridge than previously used and different borehole diameters, inclinations and spacings. The results were estimated based on visual inspection of the presplit faces and by calculating the half core factor, and over- and underbreak in cubic meters per square meter of presplit face. In this thesis, no major differences were found in the presplit results with the different presplit parameters. Furthermore, it was concluded that the greatest improvements to the slope stability at the Kuusilampi open pit could be achieved with modifications to the buffer row. Additionally, no connection was found between the rock mass quality estimate of the geotechnical block model and presplitting results, because the geotechnical block model was found to lack sufficient accuracy and resolution to represent the rock mass quality accurately.

Description

Supervisor

Rinne, Mikael

Thesis advisor

Torvi, Juho

Keywords

presplitting, presplit blasting, controlled blasting, pit slope stability

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