I've been trying out mining for quite some time; and I understand it's bare-bones, but I see a few issues.
- Resources are infinite, allowing one to harvest planets and then drag them off to a market on a nearby moon. A task with very little danger can generate tens of thousands with an unoptimized fleet and millions with a specialized fleet.
- There is little reason to mine dangerous planets, such as toxic/volcanic.
- The viability of mining is heavily dependent on random chance, for both average market price and price of supplies.
If I could make the following suggestions:
Give planets a two new attributes to increase diversity: Overharvesting and Renewability.
As you obtain more resources from planets, its overharvesting level increases. As overharvesting level increases, further mining efforts will yield fewer resources (Capped at a certain percentage). Overharvesting will decrease over time, but the higher it is, the slower it decreases.
Overharvesting depends on the amount of resources gained, so it won't affect smaller mining fleets than it does with planet-stripping fleets.
The second, renewability, is unique to the planet type, it represents a planet's ability to recover from overharvesting. For example, volcanic planets will recover from overharvesting much faster than a barren planet due to the increased volcanic activity bringing up resources from the mantle, which is beyond the range of conventional mining weapons.
The combination of these two should encourage miners to move onto the next planet as profit margins will become increasingly smaller due to the relatively static cost of supplies versus the decreasing number of resources. It also gives miners a reason to go to more risky planets, as they recover faster.
About gas planets: when it comes right down to it, they're the most profitable mining option due to the relatively low danger level, high resource output, and the higher prices volatiles fetch over basic ore.
To counter this, I would suggest that mining gas planets does not the fleet's traditional mining rating. Instead, mining gas planets should use "Scoop Tonnage", an innate statistic assigned to certain ships; think opening up your cargo hold and flying through the gas cloud like a whale and you're not far off. Possibly increasing the usefulness of ships like the Phaeton and Prometheus, albiet slightly; while also getting rid of the mental image of mining by shooting high-power energy weapons into volatiles - which are by nature... volatile.
Asteroids are exempt from overharvesting, it'd be too annoying to track every single asteroid, but they can compensate by having much lower yield or higher danger.
As for the third issue, this is a little tricky, and I don't think any amount of economy tweaking is going to be enough - At least in the current version.
The biggest exploit in mining has to be the price fixing found in certain markets, where the value of a commodity won't drop to 1 no matter how much you sell. The difference between selling 50,000 volatives at 1cred vs 50,000 volatiles at a price-fixed 23creds is huge.
The only thing I can think of to fix this is reducing the base price of all resources to 1, but this opens up a whole slew of issues; even without including the game's economy calculations.
Then there's the issue of supply cost, depending on random chance it can range anywhere from 50-300+ creds per supply unit.
However, looking at what Steiner's foundation did, perhaps one could add a "Mining Foundation Representative" to certain ports. Allowing the player to barter resources for supplies/credits at a fixed rate (Which is still rather inflated of course). You could limit it to increments (They don't deal in small change) to reduce script complexity.
Of course, these are just suggestions. I'm enjoying the mod as it already is.