The Governments Mint was never intended to be selling their own gold at consumer price levels.
$50 and $100 precious metal coins are to be sold at these values from the government and incrementally rise within their note value, Notes are likely to only be exchanged amongst business and foreign investors. National Gold and Platinum as well as silver mints can be seen as quite domestic to their nation in most instances. Allowing for minted coins to be exchanged at their metal value allows for an untrustworthy price fluctuation in both the dollar and the domestic coin. While this can easily be manipulated on the market I still suggest placing these on the market at face value as business exchange investments. This will restore some trust in the market. This is undoubtedly a complex topic, that can be resolved. We are certain Gold and Platinum mints must be placed into circulation among the people as well as business and be seen as primarily investments with external markets attached to them.
Gold may legitimately have need to be magnetic impress with bar-code exchanges to limit the amount of exchanges a single piece of gold can be exchanged at a time. This will need a national registry and algorithmic as well as personally practical needs; as to the concern that some may have legitimate reason not to sell. These buyers will have to wait incrementally , appropriately, to a length of time, which will re-enable them their ability to place their gold on the exchange market.