The performance of 460 stope surfaces at WMC Resources' Olympic Dam Operation (ODO) has been used to investigate the confidence that can be placed in the Stability Graph Method for design of stope dimensions. A detailed database of stope performance and ground condition information was established for each stope. The database contains all the required stability graph information as well as other factors thought to influence stability, such as discrete major structures, poor shape and exposure time. The performance of each stope surface was quantified by calculating Equivalent Linear Overbreak/Slough (ELOS)._x000D_
The performance of stope walls and crowns was plotted on the supported and unsupported case history stability graphs. Based on this information an ODO design limit of HR = 3.3 x N'0.33 has been suggested for stope walls. Walls that plotted above this line were 80 per cent stable, 20 per cent unstable and zero per cent failed. Below the line 60 per cent were stable, 30 per cent unstable and ten per cent failed._x000D_
Supported crowns that are flat or arched in shape and are not within the influence of major structures can be designed in the stability graph's stable zone' with a strong likelihood of stability. The Stability Graph Method did not reliably predict the performance of unsupported crowns at ODO._x000D_
FORMAL CITATION:Oddie, M E and Pascoe, M J, 2005. Stope performance at Olympic Dam Mine, in Proceedings Ninth Underground Operators' Conference 2005, pp 265-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).