Mining raw materials in Adalia is called “extraction”.
Extraction requires a deposit (the result of a Core Sample) to begin and proceeds at a declining rate as the deposit diminishes. This necessitates a repeat of the core-sampling process once the extraction rate falls below the player’s personal “economic viability” threshold.
First, calculate the time required (Tstart) to mine out the entire remaining deposit based on the maximum possible yield (Ymax):
Tstart = Ystart / Ymax
Then, calculate the time required (Tend) to mine out the entire remaining deposit after extraction of the target yield (Ytarget):
Tend = (Ystart - Ytarget) / Ymax
The total time required (before applying efficiency bonuses) is the difference between the two:
T = Tstart - Tend