Ships moving through a minefield risk running on a mine unless the minefield owner offers a mine-level alliance to the ship owner. For every light year inside the minefield, a dice is rolled whether the ship hits a mine. Cloaked ships have a lower risk of hitting normal mines than uncloaked ships. For web mines, it doesn't matter whether the ship cloaks. The mine hit odds may depend on the ship's speed and experience. See MineHitOdds, MineHitOddsWhenCloakedX10, WebMineHitOdds, EModMineHitOddsBonus, and MineOddsWarpBonusX100 and friends.
Ships moving slower than a particular speed are safe from mine hits. By default, only ships which do not move are safe. Ships which do not move normally (hyperdrive, gravity wells, chunnel, being towed) are safe, too. See MineTravelSafeWarp etc.
Ships which hit a mine (normal or web) take damage and must possibly slow down. See HullTechNotSlowedByMines, MineHitDamageFor100KT, WebHitDamageFor100KT.
Ships which hit a web mine must stop their movement and burn fuel. See WebHitFuelLoss.
Ships which are in a web mine before movement lose fuel, for just being inside the web. See WebDrainFuelLoss, WebDraining stage.
Ships can sweep mines using their beam weapons. Ships can also scoop up mines owned by the same race and build torpedoes. See MineScanRange, MineSweepRange, WebMineSweepRange, MineSweepRate, WebMineSweepRate.
Some races (Colonies, usually) can use their fighters to sweep mines, too. See FighterSweepRate, FighterSweepRange, AllowColoniesSweepWebs.