Continuous Monitoring and Improvement of the Blasting Process in Open Pit Mines Using Unmanned Aerial Vehicle Techniques

Kamran Esmaeili,Thomas Bamford,Filip Medinac

doi:10.3390/rs12172801

Abstract

The current techniques used for monitoring the blasting process in open pit mines are manual, intermittent and inefficient and can expose technical manpower to hazardous conditions. This study presents the application of unmanned aerial vehicle (UAV) systems for monitoring and improving the blasting process in open pit mines. Field experiments were conducted in different open pit mines to assess rock fragmentation, blast-induced damage on final pit walls, blast dynamics and the accuracy of blastholes including production and pre-split holes. The UAV-based monitoring was done in three different stages, including pre-blasting, blasting and post-blasting. In the pre-blasting stage, pit walls were mapped to collect structural data to predict in situ block size distribution and to develop as-built pit wall digital elevation models (DEM) to assess blast-induced damage. This was followed by mapping the production blasthole patterns implemented in the mine to investigate drillhole alignment. To monitor the blasting process, a high-speed camera was mounted on the UAV to investigate blast initiation, sequencing, misfired holes and stemming ejection. In the post-blast stage, the blasted rock pile (muck pile) was monitored to estimate fragmentation and assess muck pile configuration, heave and throw. The collected aerial data provide detailed information and high spatial and temporal resolution on the quality of the blasting process and significant opportunities for process improvement. The current challenges with regards to the application of UAVs for blasting process monitoring are discussed, and recommendations for obtaining the most value out of an UAV application are provided.

Highlights

Blasting is a key activity in the mining cycle, commonly used in both open pit and underground mines to fragment the rock mass into rock boulders that can be handled by mine equipment
The valuable feedback described in this study included pre-blast structural mapping of pit walls and in situ block size distribution (IBSD) estimation, assessment of drillhole alignment, identification of problem areas during the blast using high-speed photography, post-blast blasted block size distribution (BBSD) measurement, comparison of the theoretical and actual powder factor, assessment of blasting impact on final pit walls, quality control of pre-split drillholes and an assessment of muck pile configuration
Work stoppages can be avoided because remote sensing techniques are employed to collect data: a shovel does not need to stop working in order to conduct a flyover on a muck pile

Summary

Introduction

Blasting is a key activity in the mining cycle, commonly used in both open pit and underground mines to fragment the rock mass into rock boulders that can be handled by mine equipment. Achieving a desired BBSD requires a comprehensive quality assurance/quality control (QA/QC) procedure to ensure that the blasting parameters are accurately implemented in the field [5,6] This entails monitoring of the blast location and assessing the blasting pattern’s compliance with the designed pattern. With reduced damage to the final pit walls, the mining operation can achieve the desired final wall geometry and can steepen the pit slope angles This has both safety and economic implications: minimizing overbreak improves structural integrity and stability, while reducing waste rock removal [8,9]. The current techniques used for monitoring and assessing the blasting process in open pit mines are manual, discontinuous and intermittent These methods hinder timely and efficient decision-making and limit improvement opportunities. A continuous process control and feedback are required to better manage and improve the blasting process in mining operations

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Discussion

Conclusion