The only problem I see with your solution of minting high denomination coins is that it is wholly unnecessary. Our economy is entirely fictional, as demonstrated by the Fed creating trillions of dollars out of nothing. They did this not by printing money, but simply by altering balance sheets on a computer. If the federal reserve act is repealed as unconstitutional, control of the national money supply can revert to the federal government, where it belongs. There is already plenty of hard currency in circulation, and no real reason to add to it. "Melted down pot metal" may be cheap, but there is the cost of actually designing and making the mint for them, which is wasted money on such a limited run. Electrons are free. Additionally, once control of the money supply has reverted to the federal government, taxation becomes frivolous, and necessary only to combat inflation and control the total amount of wealth in the system. Spending was limited with a gold and silver backed economy, because there was a fixed amount of both metals available. This is no longer an issue, and with the understanding that we live in a fictional economy, spending becomes simply a way of indicating priorities.
Just read the ENTIRE plan and you will change you mind.
It's about bring wealth back into circulation (creating American jobs, business expansion, etc...) and drop kicking the Fed Res. who own Congress. There is no new cost for minting coins that are already being minted, simply the value placed on such coins with banked precious metals where the coins intrinsic value is represented on a certificate.
If you had read the plans (rather than my brief notes), you would know that the coins are simply a leverage that is Constitutionally sound to control bribery, corruption, etc... In fact, it is THE ONLY VIABLE plan.. because the Fed can be shut down (by law and at the US' option IF Congress and POTUS were not owned by the Fed Res). We need to get rid of the USURY of the FRN.
The melted down pot metal would simply be a snub for the bad guys. ONE TIME USE coins to clear up all debts goes a long way. No rules say these coins need to be fancy.. Technically a slug or washer would suffice provided Congress gave them value (and they would once under a National Security Threat... Or go to Guantanamo for their past bribes and corruption and treason against the USA)