| 2013 | Tony Hunter (New Zealand) |
| 2012 | Murray Discombe (New Zealand) |
| 2011 | Glenn Kiernan (New Zealand) |
| 2010 | |
| 2009 | Darcy Maddern, Greg Slaughter (New Zealand) |
| 2008 | C Pretorius (Southern Africa) |
| 2007 | G. Chan, D. Pallot, D. Hogan (Hong Kong) |
| 2006 | G.W. Bolsover |
| 2005 | Gordon Laing, Alan Happy, Arsini Hanna, Michael Harris, Christina Renhart (New Zealand) |
| 2004 | Brian Bouzaid, (New Zealand) |
| 2003 | AJ von Wielligh, NDL Burger & TL Wilcocks (South Africa) |
| 2002 | R McLellan (Australia) |
| 2001 | A. Cluett (South Africa) |
| 2000 | H. van der Zanden (Netherlands) |
| 1999 | I. Dumitru, M. Formosa, I. Browne, K. Lieber (Australia) |
| 1998 | |
| 1997 | Dr B. Denby |
| 1996 | W. Grayson (USA) |
| 1995 | Dr M. Smith |
| 1994 | C.C. Hollinsworth |
| 1993 | K. Holley (Hong Kong) |
| 1992 | |
| 1991 | C. McKenzie (Australia) |
| 1990 | R. Pemberton |
| 1989 | Bryan A. Bartley (New Zealand) Read paper-“Autogenous Crushing” |
