I'm saying that if the rate of creation of the elements takes enough energy, perhaps the output may not be enough to completely take over the market supply, but merely be a slight addition to output by human miners. If that happens to be the case, then it may even be a good thing; a technology that turns our nuclear waste into objects that have value for others.

Scenario A: Say, if Elon Musk's wish came true and we made it to Mars and found that there's no precious metals on Mars (and we didn't want another fiat-based currency). Ship that machine over for it to generate a fixed amount of gold.
Scenario B: The world has too much radiation. We use the machine in huge numbers to "clean up" the world, for free. The people using the machine keep the metals and distributes them to whoever needs them for technologies, wealth buildup, etc.

So talking about the metal prices, I don't imagine it collapsing them.