PlanetsCentral

The probability that a ship hits a mine depends on the type of the minefield and the ship's speed.

Mine_hit_odds =
   0                 ...if Speed ≤ Safe_warp
   Max(0, Base - (9 - Speed) * Bonus / 100)
   ...with
      (Base, Bonus) =
          WebMineHitOdds, WebMineOddsWarpBonusX100
                     ...if web minefield
          MineHitOdds, MineOddsWarpBonusX100
                     ...if ship is not cloaked, normal minefield
          MineHitOddsWhenCloakedX10/10, CloakMineOddsWarpBonusX100
                     ...if ship is cloaked, normal minefield

If you put the normal integer option values into this formula, you will get out a (possibly fractional) percentage, 0 to 100. This is the probability that the ship hits a mine when moving through 1 ly of the minefield.

All relevant options are arrayized and can therefore be different for each player. PHost consults the ship owner's value when moving a particular ship. It does not matter who owns the minefield.

PHost uses standard probability calculus to determine whether a ship successfully passes a minefield and, if it hits a mine, where that happens. For your convenience, here is the formula that a ship successfully passes a minefield of a given size (which is not in this form used in PHost):

Percentage =
   100 * (((100 - Mine_hit_odds)/100) ^ Distance)