To the people who actually set up Mine Fields...
Procs in trip mine work the exact same way they do in any regular damaging AoE power - each of them will make a single roll against each enemy in the AoE when it goes off.
33% worth of damage enhancement in trip mine is worth ~64 points of damage. A regular proc (20% chance for ~72 damage) is worth a bit more than 14 points of damage on average. A purple proc (33% chance for ~107 damage) is worth ~36 damage on average. The blaster PPM proc, it depends on the proc rate, which I don't think anyone has figured out for sure yet (especially in AoEs). If it's (cycle time/(60/ppm))/target cap, that works out to ~7.5 average for the regular proc and ~14 average for the superior. If the dividing factor is aoe factor instead the blaster procs will be worth somewhat more, although I seem to have lost the aoe factor formula. Point is, with the possible exception of the blaster proc, it's not worth using procs until trip mine is already maxed out on damage enhancement.
If you want to try to max out damage and recharge in as few slots as possible to leave room for procs (i.e. the absolute most damage per boom, while still getting as much recharge as possible), I might slot the purple dam/rech, acc/dam/rech, proc, and superior blaster acc/dam, proc, along with a third proc of your choice (possibly store-bought, depending on whether the PPM actually leads to a higher proc rate than the normal proc or not). This sacrifices any ability to get the best set bonuses out of either of those sets, but if you toss a few boosters onto the purples you're sitting at 65+ acc, capped damage, and almost 90% recharge while still fitting in 2 purple and one regular proc (if you're willing to +5 both purples you could even swap the blaster acc/dam for the acc/dam/end and get a bit of endredux while still keeping capped damage, although your acc will dip to just under 60%, which might start to get problematic against +level foes - set bonuses won't transfer to the mines, although I wonder if tactics might).
Overall, though, unless you use mines *really* heavily I do have to wonder whether it'd be worth it. It's a lot of expensive enhancements and boosters to simply pack an extra two procs into the power (relative to using 6 oblits), and you're really sacrificing set bonuses.
@MuonNeutrino
Student, Gamer, Altaholic, and future Astronomer.
This is what it means to be a tank!
I slot 5 oblits (all but the proc) and a Multistrike dam/rech.
I don't set up "mine fields" anymore unless I'm trying to one shot an EB.
Slotted as above each mine will deal ~400 damage. 50% of the time the mine will "crit" and do ~500 instead.
I usually set out 3 mines and 2 caltrop patches if there are bosses in the spawn (2 and 1 if its Lieuts and Minions). I open with an AoE or 2 (depending on Primary) and duck around a corner. 3 Booms later any thing that is left gets a single target attack and is gone.
Self buffs copy to the mines but most of them don't last long enough to be worthwhile. (Targetting drone lasts .75 seconds, Assault and Tactics last 2.25 seconds, Aim lasts 10 seconds). The notable exception to that is red inspirations. They last 60 seconds.
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Outside of playing my AR/Dev with the rest of her team (friends all running their AR/Dev) a true minefield is rare (with 6 AR/Dev minefields can get silly large silly fast 
and really do become "fields"). Pretty much as Miladys_Knight describes, I only really start stacking them up for a larger harder target i.e. Boss and above. Rest of the time it's 2 or 3 to where I plan to pull or fight them (corner/doorway etc.). Usually 1 of the group of mines will be more or less at my feet (as I know anything surviving the rest of the field and my firing will stop there to take a swipe at me). On my trappers (both Defender and Corrupter) it's a bit different depending on the set pairing and a greater tendency to toe bomb plus all the other tools in a trappers kit. But again its usually no more than 2 or 3 mines mixed in with the AM and PGT when I do pull.
As far as slotting usually with Oblits once the build is using sets. 5 or 6 varies depending on the build (needing the +def or not) and looking to max the recharge. And while I haven't gone live this way yet I've also used combo's of Oblits and Erad while playing around in Mids (4 Oblits/2 Erads typically).
I have while moving between commons and sets (and having less slots at that point in leveling) used dam/rech frankenslotting) as well.
Doomguide
How do you slot Trip Mine. I have a build where I'm just using 6 Oblits because every bit of defense helps when you're a squishy as a Blaster. Then I got to wondering exactly how damage procs work in Trip Mine, and if frankenslotting some Armaggedons and damage procs will let you achieve the same killing IN LESS TIME. If I sacrifice too much recharge and it takes me longer between each mine then it becomes counter productive, since mine-fielding is already a painfully slow strategy. So... how do you slot it?
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