I have added a new type of team for v3.1, the Geology Team. This team carries out more detailed survey of planets, trying to find any mineral deposits that might have been missed by the orbital survey. They may find a new deposit of a mineral that has previously been mined out, additional deposits of an existing mineral or even a way to increase the accessibility of an existing mineral.
The team skill is Survey, so you will need five team members with decent survey skills. The mechanics are fairly straightforward. When a team is on a system body during the 5-day increment, it makes a mineral deposit check. This is done using the same base mineral discovery chance as when a new planet is being created with two modifiers, the skills of the team/100 and a the proportion of a year. So over a year, a team with a skill of 100 should have approximately the same chance of generating a mineral as when the original mineral deposit check was made. Depending on how this works in testing, I might drop this chance a little.
If a mineral is generated, the program picks one at random, although Duranium has twice the chance of any other mineral. If this mineral does not exist on the planet, a new deposit is generated using the normal mineral generation process for that type of planet. If it already exists, a new deposit is generated and compared to the existing deposit. If it is larger, then the mineral amount on the planet is set to that of the new deposit but using the existing accessibility. If the new deposit has a higher accessibility then the existing deposit, the existing deposit is changed to the new accessibility, regardless of whether the amount is also changed.
Every time additional minerals are added to the planet, or a deposit is changed to higher accessibility, a check is made to see if the geological survey team decides that further surveys are futile. This check is equal to 150-Team Skill with a minimum of 10, so a team with a skill of 140 or above will minimise the chance that surveys will miss potential deposits.
This was based on a post regarding random events in the suggestion thread by Haegan2005
Steve