During World War two minefields were not placed solely to destroy enemy units like they are used in modern warfare. They were well marked, documented and strategically placed to force enemy formations to go around them, slowing their movements or pushing them into a disadvantageous position.

One of my favourite tactics is the Random Mine. Marines simply place mines in high traffic corridors and vents all over the map to kill skulks who aren't paying attention (which is common since skulks, if they're anything like me, take their getting around-ness for granted and focus on getting to the destination if they don't hear marines around). This can have some aggravating consequences, especially when there's one mine in a vent somewhere and it is not worth bringing in a fade or a gorge to clear it. The skulk can either risk blowing themselves up if they want to proceed, or turn around and find another route. This in turn can slow down skulks that are running around to eat res nodes where marines don't patrol much, and disrupt their movements. Even if the mine doesn't kill them, they may very well waste more time finding an alternate path. If that means a res node survives more ticks, then the mine pays for itself.

I'm not really a fan of complicated placement or coordination tactics, since in pick-up games it's pretty unrealistic to expect your players to be that well coordinated (People blocking their teammates line of sight is a more serious and simpler thing to fix, yet so many still do it.) I'm not a clan quality player and I tend to choose tactics that don't rely on having a skilled, well coordinated marine team.

A nifty mine placement strategy isn't as important in my mind as choosing siege locations that are easy to defend and placing structures so they obstruct alien movements. I've been in a few games where a siege and phase gate is placed around a corner where it makes it easy for aliens to approach to melee range without being shot at. Structure placement has pros and cons, although I think I would prefer having obstacles in the alien's path so there is no clear run at a bunch of marines for a fade, skulk or Onos and they always risk getting caught on something, allowing marines more time to shoot them.

As a standalone defence I don't think the mine thing would work. For one, it is based on the assumption that skulks will choose to charge through and attack the marine, or that they would attack one at a time. Skulks are always more mobile than marines, and it's pretty easy in most cases to use a vent and go around to the rear or avoid such a trap entirely. It will only work if the enemy actually goes through it, and that you can affort to have marines sitting there camping it. Unless of course, the skulks HAVE to go through it, which makes this tactic more useful as a response to a concerted attack. If the marine(s) guarding the trap go, then it becomes useless no matter what. So really you need to put it where skulks have to go through and will continue to go through. If the marines have time to place it I can see its usefulness during sieges or in holding important rooms such as double node rooms, since aliens are forced to try and run a gauntlet to attack. I see its best use as a cheap way to fortify a location that needs to be held and will be constantly guarded.

At least, that's how I see it.