All valid points, but why cannot gold miners auction their...

All valid points, but why cannot gold miners auction their monthly gold production, say 100,000 ounces, to be converted into gold bars of choice, such as 100 ounce or 400 ounce, through a refiner such as Perth Mint. (Assuming they can do 400 ounce bars??)

This way, those who need physical gold, and not paper derivatives, pulled out of the rear end of a rocking horse, will be willing to pay for physical ounces, and ensure their market supply.

Further, as the gold is auctioned, to the highest bidder, then the gold miners maximise their production price??

Everyone is happy, except the derivative demons, who no longer extract their traditional, 'vampire cut'????? Anyone want to buy a second hand rocking horse??