LDI Property: Underground Mining

Development of the underground mine began in the second quarter of 2004 in order to access the higher grade portion of the Roby Zone. The underground deposit lies below the ultimate pit bottom of the open pit and extends to a depth of approximately 660 metres below the surface where it is truncated by an offset fault. Commercial production from the underground mine began on April 1, 2006.  For the 2008 fiscal year, the underground mine had a run-of-mine average head grade of 5.71 grams per tonne of palladium compared to 5.79 grams per tonne in 2007.

The chosen mining method for the underground mine is sublevel retreat longitudinal longhole stoping with unconsolidated rock fill. The mining block interval is 95 metres floor to floor with two sublevels in between and twenty metre sill pillars between blocks.  Stopes average 60 metres in length with 7-10 metre wide vertical rib pillars between stopes. Total intake ventilation for the mine is designed to be 205 cubic metres per minute. There is one intake ventilation raise/secondary egress situated outside the ultimate open pit limits and air exhausts up the main ramp.