The following hasn't been implimented yet and will be released as a patch.

Sector Mines will attack based upon the ship class plus the hull size.  Each ship class has it's own base hull size that will be added to the hull size you purchase or that comes default with the ship.

When your ship enters a sector with mines the combined size of your ship class basehull and hull tech size will determine the percentage of mines it attracts.

When the mines are attracted to the ship your ship will automatically send out any mine deflectors you have.  All of your mine deflectors are sent out and they all attack the incoming mines.  If any mine deflectors are left over after the attack your ship automatically retrieves them.

If the mines that were attracted by your ship are not all destroyed by the mine deflectors they will start impacting upon your ships armor.  There is ALWAYS a chance mines will hit your armor no matter how many mine deflectors you are carrying.  Mine deflectors nolonger take out one mine per one deflector.  Mine deflectors can damage a mine upto 1.5 times the amount of damage a mine can absorb before being destroyed.  So it is possible to destroy more mines than you have mine deflectors.

Mines are also cloaked by the highest planet cloak tech level.  This makes it possible for your mine deflectors to completely miss incoming mines.  So you need to have higher sensors to reduce the possibility of this happening.