Improvements to the Zone 1 Mining Method at the Doyon Mine
CIM MEMO 2008
François Girard, Francis Brunet,
The Doyon Mine’s Zone 1 (Altered Zone) is found along the southern boundary of the mine and consists of a series of steeply dipping narrow veins, which are contained in an extremely weak host rock: a sericitic schist with RQD values ranging from 0 to 20. The ore zone RQD values range from 20 to 40. The ore zone is approximately 300 m in length and 900 m in depth with widths of 2 to 15 m. Longhole mining methods are used, with either longitudinal or transverse approaches depending on the width of the ore zone. Mining of the Zone 1 began in 1993; over 1.5 million tonnes have been extracted to date.
Many different development and mining techniques have been tested in an attempt to increase worker safety, reduce stope dilution and improve ore recovery. As a result, modifications have been made to drift dimensions and orientations, drill patterns, blasting techniques, ground support patterns, stope sequencing, and backfilling methods. The following paper discusses several of the different approaches used over time in this challenging mining environment.