"therefore, can only (guess) at a few grams per tonne. (average)."

Is the best you can do guess its a few if they don't say even though they say they cant publich due to JORC rules?

"Showing some HIGH GRADE hits, but over what TOTAL depth????"

"with the true width estimated to be0.8m" https://www.austargold.com/wp-content/uploads/2019/01/1888229.pdf

"But how much dirt has to be processed to extract those grades?
Nearly 10 metres @ 67gpt is excellent, but how much waste ore to get at it?"

"Well if the true width is say an average of 0.5m (0.8m is indicated) then stoping with require 4x material dropping the feed grade to 17gpt which is still 4x what is required to be breakeven.

"Don't forget that these grades are over a an approx. 50 mm diameter core,
You can drill a hole, get a results of 100 gpt, but drill
and come up with ZERO gpt."

That would have to be the luckiest drill core in the history of mining if that were the case...