Those figures come from the announcement on 2/8/18 when they...

Those figures come from the announcement on 2/8/18 when they were testing the stock piles for copper content and concentrating it.

The feed in was 1-1.2% copper. But this announcement does talk 200kt of copper concentrate. Meaning the stockpiles must be 10-20 times bigger than the 200kt. Is 2000-4000kt a lot of rocks for Cangai stockpiles?

The 22% was the maximum output but the recovery was only 64% at that level. The other technique had 80% recovery at 10% copper concentrate. The other composite showed much lower yield at 10% and 7.5% for 60% and 80% recovery respectively. See page 9 of the announcement

So 22% at 60% would be 26kt that you could expect based on those results?

I'll disclaim that I don't know what I'm talking about here, just trying to interpret the reports.

Also 1-1.2% seems a low head grade for Cangai. If these are stockpiles rather than tailings or waste then wouldn't they be at least the 3.5% average grade for Cangai and possibly much higher given the rich seams were the ones being targeted?

Regardless of whether it's 1.6kt, 26kt or 44kt it's not enough to get the mine open but it is enough to fully fund the company for all its exploration in the foreseeable future.