Abstract
Lalor Mine completed the refurbishment of the New Britannia gold mill in 2021 and began producing a High Gold production stream, along with the already existing Base Metal(Zn/Cu) ore stream. The new production areas presented challenges in fragmentation due to the different geotechnical characteristics of the gold ore, which created a material bottleneck to production due to the size limitations at the rockbreakers. A continuous improvement team was assembled and work started at this time to investigate the issues causing this production issue.
The team started by conducting tests and evaluating fragmentation against several design parameters. Some of the items that were tested were; changes to stemming depths, hole deviation, blast timing, hole gassing, drill pattern and hole diameter. These factors were tested over the span of almost 2 years, with different levels of success before reaching the target.
Through a series of adjustments to the blasting processes, throughput at the rockbreakers was improved by ~15% and total stope fragmentation was improved by >20%. This presentation explores the methodology used to achieve this success, the challenges associated with change management and how the company intends to continue this path of improvement. Thanks to Nathan Rouse, PE, Phd, President of Thoroughbred Drill and Blast Consultants for his contributions to this presentation.