Re: 4.6 Bullion fault, 6.8 New Ireland
Posted by Canie on March 12, 2003 at 08:34:10:

This from SCEC on the Hector Mine quake:
FAULTS RUPTURED: the Lavic Lake fault and the central section of the Bullion fault; some slip may have occurred along other nearby fault zones (current studies are working on this issue)
Length of surface rupture: 41 km

I don't have any maps with great resolution to determine an answer to the question - but you suggested the southern end of the Bullion fault - it does look to be the southern end of the rupture zone.
There's a great map of it here:
http://www.scecdc.scec.org/Pics/hector_04.gif