I'm a great fan of tripmines, to me they're the most entertaining way of getting kills because there is quite a lot of tactics involved in using them. Not only that, but to see the kill sprite pop up makes you feel all fuzzy inside to know that someone fell for your trap. I'm sure there is a lot more of you explosive fiends out there that share my passion.

I'm going to post my ideas based on other games and logic as I expect it to be pretty similar in NS. I can always correct anything that doesn't fit pretty soon anyway. I also invite anyone to add their strategies with tripmines for all to enjoy.

I believe there to be 2 main tripmine strategies. First is trying to conceal them, and strategically place them so that the enemy triggers them when it's too late. Second is spamming them in clear sight serving more as a deterrant than trying to get a kill.

If you want to kill enemies before they get to you, the idea is to place the tripmine in a place where the enemy doesn't spot them until it's too late.

Some of my favourite places are at the top or bottom of ladders (depending which way the enemy should be coming from).
When you climb up a ladder, it's rare that you go slow and look over the top rung before stepping onto the platform. A tripmine or even a proxy mine placed here is almost sure to catch the enemy off guard.

Stairs or ramps obviously change heights which affects the vision of the enemy. For something like a skulk which has a low viewpoint, running along towards the top of some stairs probably means that they cant see down the stairs until they get very close. So try placing a trip mine just down from the top step and hopefully they're running too fast and trigger the mines.

Around corners is another good use, the view is obstructed by the wall and people tend to stick close to the wall when running around. (Pretty much because its the shortest root and humans don't walk angular) Place a tripmine right on a corner so that a running enemy will trigger it as soon as they turn.

Holes or places where the enemy tend to drop from is also a good tactic, just let gravity help you make the kill. If there is a hole where the enemy drops down from like a vent, or something like a cliff, place mines at the bottom so that if they don't spot the mines before jumping, gravity leads them down to their death.

Lifts are really entertaining, the problem is that it depends on the type of lift used in the map. There is usually two types of lifts, open ones where you just stand on a single platform. Then theres enclosed lifts which are like real life ones. they have a roof and walls.
IF the lift is the open type then this tactic applies.
Take the lift to the top of the shaft. Place several tripmines on the walls as close to the floor surrounding the trip platform as possible. Then send the lift back to the lower floor and wait for the enemy to get onboard and use the lift. The reason this tactic works is because lifts cannot be stopped half way up a shaft when the enemy notices the tripmines. So if they fall for it and begin rising, they're almost certainly dead.

NOTE: Remember when you use tripmines to try and conceal the "box" where the laser comes from so that it can't be easily detonated from long range. Also try to vary where you place tripmines so that the enemy doesn't get too cautious and walk around paranoid. If they get to this state you might as well resume normal fragging as they'll fall for the traps less often. The enemy isn't stupid... well not always. They usually don't fall for the same trick twice.

I'll only briefly cover the second "spamming" strategy as I don't find it as fun and it isn't as tactical.

Sometimes there are passageways that you just don't have the men to cover, theres no lockable door but you still want to try to stop the enemy using that passage. Well try placing a few tripmines in that area to put the enemy off. Still try to conceal the "box" but make the lasers in clear view. When doing this though, one trip mine is rarely enough as the enemy can either crawl underneath or just hop over the top. Two or three look nastier to the enemy, and try to cover low on the floor, and high so that the enemy can't just hop over the low mine.

A last use of this tactic is in vents. Half-Life generally makes explosions in small vents more powerful, hopefully this is the same in NS. If an alien has just spent quite a long time crawling through a large vent system and gets to the end to see a couple of mines, most likely he/she is gonna be quite annoyed cos the only optiosn are to either suicide or go back and find another path. If someone is following, the amplified explosion would probably kill them all.

This concludes my tripmine tactics for now, feel free to notify me of any mistakes or add your own to this thread. Someone that is more interested in the floor mines could also add tactics for them. I guess their main attraction is they are more stealthy than trip mines due tot he lack of the big glowing laser.

Also remember that in NS, the enemy isn't always going to be a skulk. If you place one tripmine to take out that low healthed Skulk or Lerk but an Onos appears, he's most likely going to shrug off the shrapnel and keep coming. So don't say I didn't warn you!

Early in the game, the aliens don't have any classes that can shrug off mine damage or detonate them with projectiles. As a result, try using them around resource nodes near the alien hive. This will either force skulks to suicide, clearing a path for the gorges, which takes time or will make the node temporarily unavailable to the aliens. Either outcome is good.  

I like to call this the Mission: Impossible Tripmine Strategy:

Provided the mines are stickymines, place them in corners, the roof, the floor, the walls making it impossible to walk through.

Dark vents are also good. Jetfly to a vent in the roof and place a mine there. Who knows. Perhaps it'll start raining green goo from the the ventilation system.

Drop one pack the moment you finish building your first armory. Place them around your Resource node and you'll be set for defending it until the mid game. Place them on the ground or ceiling to make them Proximity.

I like sticking them in proximity mode to the bases of resource towers.  Then, when the skulks rush in to chew on them, they get a nice surprise.

Does proximity mines go off on teammates?

Nope, you can freely walk over mines and through mines.  HOWEVER, if an alien kills a mine, the splash damage done by them HURT YOU.  It's emabrassing and hilarious when people get killed by mines due to aliens.

Plaguebearer's strategy is very sadly overlooked by most Frontiersmen.  A few easily overlooked prox mines near your infantry portal or CC can finish off an alien assault that's taken some damage from your turrets and marines.

Tripmine usage should definitely be monitored though -- if I'm a Fade, and I see your base is full of tripmines and marines, I'm going to shoot an acid rocket at the tripmines and blow all of your marines to kingdom come.  So just be a bit careful.  

Quote (Plaguebearer @ Oct. 30 2002,11:52)

I like sticking them in proximity mode to the bases of resource towers.  Then, when the skulks rush in to chew on them, they get a nice surprise.

Doesn't the explosion damage the building?

Put mines on door entrances and in airvents.

Quote (Vo0do0-MoNk3h @ Oct. 30 2002,14:16)

Quote (Plaguebearer @ Oct. 30 2002,11:52) I like sticking them in proximity mode to the bases of resource towers.  Then, when the skulks rush in to chew on them, they get a nice surprise. Doesn't the explosion damage the building?

Not nearly as much as a skulk biting it to pieces would.

the only place that is good to put mines is in their base coz not alot of mariens would get there and if you put it any where else you own team will hit them!

I love using tripmines.

A good idea when planting tripmines is to use the enemy's actual real life shortcomings to fool them.  For example, if the tripmine beam is red (I think it's red) plant your tripmines in places with red lighting.  It's really hard to spot a thin red line until it's too late .  

Also, plant them behind func_illusionaries (like piping or ladders) or sprites, and then enemy will have almost no idea that they're there.

Another thing to maximize on is moving brushes like doors.  If a door moves when a tripmine has its laser on it, the mine will blow up.  A good idea (hard to implement though) is to put them on the enemy side of the door behind some obstacle (bulkhead or crate).  Run, and when the enemy opens the door, the mines will blow up near him (hopefully he didn't notice).

I assume placing mines in dark, high places will be able to blast unsuspecting Lerks too

here's mine:

One high
One low
Both opposing
and one that'll kill them both.

PS: this is a riddle.

hmm. tripmines?
one person will kill both tripmines, especially if they're opposing each other (beams intersect)

Here's a few vent ideas...