My (admittedly limited) understand is as follows:
Rather than subjecting the value of currency to human oversight, you're subjecting its value to the happenstance of gold mining.
I also am no economist and do enter this conversation with limited understanding..but none the less I would like to bounce some thoughts around.
So basically your concerns about a gold standard are based on a belief of gold being volatile and the negative effects of over or under supply of gold could be similar to the same problems presented by our current fiat system.
You are saying that our problem is the corruption of our system not our system in it self. You think the answer to the problem is an educated people to engage in the system cleansing it of the problems instead of relying on a gold system that can be affected by some what random events
The discovery of a new vein of gold would be similar to the Fed printing more money. All currency would devalue, and prices would inflate.
While it is obviously true that the discovery of a gold mine would increase the supply of gold and I am neither a gold miner or a money printer/zero adder(a.k.a. central banker)...but something tells me that a central banker can expand a paper or digital money supply a lot faster than a miner could expand the above ground supply of gold.
By the same token, if we completely mined every ounce of gold on the planet, that would suggest that all production has leveled off. At that point, no value could be added to the economy; value could be only traded. That would not accurately reflect the growth and loss of production.
Value is something that one person cant put a figure on... today there is about 160,000 tons of gold above ground, if that amount was to decrease to 1 ounce over night..it would be logical to assume that the value of that 1 ounce of gold would be a lot higher that it was the night before.
I think the same concept applies in your hypothetical situation where there is no more physical gold to account for an increase in population, goods, services, production and so on . In my opinion the less there is of something desired the more valuable it is...as it becomes more valuable "prices" of other goods go down in terms of gold..so basically less gold is doing the same service ..the money supply is adjusted naturally as it should be.
A nation that increases production two-fold while gaining no gold would still value its currency at the same rate. Prices would be forced to drop, and the amount of capital gained would not outweigh the capital invested. Money would devalue by the act of production, and prices would deflate.
The way I look at it and somebody please do correct me if I am wrong..if production were to increase two-fold there would be twice the amount of products...wouldn't it be natural for the price of that product to decrease based the supply and demand fundamental??? Wouldn't prices going down be a sign that the goal of being productive enough to supply the goods or services needed were met and now since that goal was met certain people would have to find new innovative things to do using their extra sir plus of resources to fund the solving of problems that have not been addressed. Isn't this where economic growth comes from??