Model or measure blast movement to maximise ore recovery in open cast mines?
This study compares the economic impact of modelling versus measuring blast movement at a Canadian gold mine.
Movement of ore-waste boundaries to post-blast positions was identified by direct measurement and also by modeled distance in four blasts.
The paper contents includes:
Can blast movement be modelled?
Blast movement variability
Modelling vs measurement examples from a Canadian gold mine
The study monitored four blasts.
BMMs were placed in the blast area for four blasts (five BMMs per blast) and post-blast movement was measured.
The engineering department modelled blast movement magnitude (distance) and bearing (direction), in each location.
Model validation compared calculated model vectors with BMM measurements.
Measured-BMM-translated polygons were compared to predicted-model-translated polygons to calculate the cost (production losses due to ore loss, dilution or misclassification) associated with the differences.
Across these four blasts:
Average error between the model vs measured vector magnitude was 50%.
Average error between the model and measured vector bearing was 9%.
BMM-translated polygons recovered ore valued at over US$490,000 (as a result of less ore loss and dilution) compared with model-translated polygons:
7,782 tonnes of ore would have been lost, resulting in US$306,9241 revenue lost across 4 blasts.
8,784 tonnes of dilution—waste processed as ore—resulting in $186,248 in additional processing costs.
10,555 tonnes of ore would have been misclassified (i.e. HG ore stockpiled as LG).