The difference in grade between resource (~6g/t - Say $240) and...

The difference in grade between resource (~6g/t - Say $240) and reserve (~4g/t - Say $160) seems very significant. I would like to get a handle on how they are getting the ore out because with a payload of only ~$160 per tonne, it would have to be a very efficient extraction method to leave enough surplus to pay for the processing, admin and further development.

I know this is the lazy way to get information so apologies in advance but can anyone point me to an announcement or a section in WPG's reports that talks about the mining methods they are using to extract the ore? I've looked at the company presentations but they seem to be light on mining techniques and rich on geology

I'm not trying to down ramp, i'm just looking for some info to see if there is a hidden gem here