Due to both the geotechnical factors and the geological features of the mineralized bodies within the deposit, the following mining methods are used at Zun-Holba:
- Shrinkage stoping with short blast holes (up to 6% of production).
- Timbered stoping method (up to 3% of production).
- Cut-and-fill method (up to 42% of production).
- Shrinkage stopping with backfill (up to 50%% of production)
The primary mining methods are shrinkage stoping and conventional cut-and-fill, with up to 92% of the present mining being conducted using these methods. Two different variations of the cut-and fill-method are used at Zun Holba:
- Bottom-up (overhand) cut-and-fill method.
- Top-down (underhand) cut-and-fill method.
All mining methods are labour intensive, with the use of both jacklegs and stopers to drill the blast holes. Extraction of the broken material is accomplished primarily by using slushers to move the material into the ore and waste passes. From the ore and waste passes, the broken material is loaded into rail cars using either a chute (for the cut-and-fill and timbered stoping methods) or a mucking machine (shrinkage stoping).
By the time Buryatzoloto became involved with the Zun-Holba mine, in 1991, the upper portion of the deposit had already been developed with the adits spaced 40 m to 50 m apart vertically. This development included: adits # 1 and #2 (the adit entrances at an elevation of 2,256 metre above sea l ........