2 tactical options

  (Edited: )

1) U want to position ur units to get a surround on his army while it is still moving. this will make it so that he will need time to get them burrowed and as his army will be clamped up it will maximize the friendly fire from the detonations.

2) U want to bait his units into ur creep and decide well how to engage. the movement speed buff u get for fighting over the creep is critical (stimmed marines can micro vs speed banes unless u fight on creep). 

*If his marines r behind his mines he can easily micro them back as u attack to ensure that all his mines get to do dmg. in this case using a set of lings to detonate the mines is actually effective.

*If his marines are closer to ur units they will be able to snipe ur lings easier. in this case u will most likely be able to force mine-shots over the marines (last patch made friendly fire from mines more dangerous for terran units too). 


Keep in mind that while finding better tactical solutions for this issue might improve ur game in specific situations, there are other things u can focus on to improve in every game such as Macro and map awareness. Zerg needs to have a better economy to overwhelm an oponent with ling bane muta. gettings any amount of innecesary units early on or slowing ur macro for whatever reason might be enough to put u in an unwinnable situation.  That beign said i would advise u to try and use the first solution i wrote: attacking his units while he isn't prepared will give u the best enagement u could get. u will need to know in advance when he will push and the composition he chose. it will take more skill than simply a-moving or spreading a bit, but it will also give better results if successful.

GL in ur future games.