Ann: Response to Marmota Limited (ASX.MEU) Announcement, page-14

Thats a good question.
After a quick look back through wpg announcements, its not excactly clear when ore from the new ML would have been included in the production figures.
in 2018 they produced 53,000 ounces of gold, which includes ore from challenger and Tarcoola. i havent had time to look back any further but i guess we can assume production of at least 50,000 ounces per year for the previous year or so.
As mentioned, at a quick glance its not clear when ore form the new ML started being mined, but if we assume 2-2.5 years of mining based on at least 50,000 ounces per year production, thats at least 100,000-150,000 ounces of gold. Take of 20% wpg/barton JV share and that still a lot of gold in dispute.

if anyone has a better memory or more time to look into the timing of mining and accurate production figures, it would be interesting to find out.

Either way, it seems there has been ongoing disputes over this JV well before Barton and Marmota come along, and its going to be interesting to see how this pans out.