Yes, they can be booked into COGS on the condition that the amount is immaterial. But from what I see, the TA production seems quite high to be considered immaterial. This can fluctuate the gross margins by a lot if the sell their stockpiles in a quarter and none in another quarter, which makes the quarterly reports not comparable.
A40 Price at posting:
18.0¢ Sentiment: Buy Disclosure: Held