If we suddenly have large amounts of previously expensive (rare or difficult to extract) metals available, what will this do to commodity markets? Would prices be driven down?
If the price of $mineral goes down below a certain level, demand has to go up for continued asteroid mining to be viable. What future activities (apart from the obvious, like catalytic converters) might provide this demand?
It's just a question of efficiency, if the cheapest way to get platinum is asteroid mining then once it starts it can out compete traditional platinum mining.(1) Generally speaking as the price for a commodity drops the market for that commodity increases more than the price drop. AKA, if gold costs X, and you can produce gold for 1/2 the price then expect to sell more than 2x as much gold. With Oil being a classic example, it's used to make roads because it's so cheap vs. being a better road surface.
1) Not that anyone directly mines for just platinum it tends to be a byproduct of the refining process for things like nickel, copper or gold. Even 'platinum' mines end up producing platinum, palladium, rhodium, ruthenium, iridium and osmium rather than just platinum. Still, it significantly influence the profitability of such mining operations to the point where if the price drops many mines will slow down production.
Substitution. What materials you use to build something is a function of their property's and their costs. AKA, you can use timber frame or steel to build a house which one you chose depends on their costs not just their inherent property's because either one will meet the same basic needs (strength, durability, toxicity, etc.)
Also, economy's are complex enough that there are a wide range of cost/benefit trade-offs going on. Electrically silver is a better conductor than copper which is better than Aluminum. While silver costs to much to be used for most wiring copper and aluminum tend to trade off based on weight strength issues. So, high tension power wires tend to use aluminum due to it's physical property's outweighing electrical issues after costs are taken into consideration.
Again this is just the size of the market in nominal value. AKA if the price drops to 1/2 and you sell 2.1 times as much the total market increased even if everyone's margins where squeezed.
I'm by no means an expert on the topic, and I don't have any specific examples to cite, but it seems like an almost weekly occurrence to read about some cool new technology that will 'never' be economically viable, due to the cost of the 'unobtanium' required to mass produce it (holy long sentence batman...).
It seems likely that the end result of a massive influx of rare materials would simply make 'never' happen a whole lot sooner. While the price would obviously fall (likely by quite a significant amount, that's kinda the point), I doubt it would fall to the point of being 'worthless.'
So then this is basically a bet on being able to "make 'never' happen a whole lot sooner". Or maybe they have someone in the background saying "sure, we can build the antigravity device / FTL drive but we'll need an mega-ton of platinum to make it work". The other alternative is that they believe all the "future of mankind" stuff...
If the price of $mineral goes down below a certain level, demand has to go up for continued asteroid mining to be viable. What future activities (apart from the obvious, like catalytic converters) might provide this demand?