Those are a grind sometimes to build, 4 queen cores and chunk loads of ore needed. And now they have been surpassed by the Avalon torpedo launcher which can do plenty more damage. Those Avalons can be found simply by killing some arklans. But the TU mines must be manufactured and takes about x5 longer than to just kill some bots.

Reasons why:
1. With such an explosion as it is, it can't kill some rags, moths, proms
2. It just sits there, it is easily visible on radar and can be avoided easily
3. Time needed to build one
4. Avalons can pretty much take over the job

Dad1, dear, TU and Avalons are completely different weapons, but +1 for less grind in manufacturing TU, Cent superlight and Widowmaker.

The Tellar-Ulam mine is significantly more resource intensive to manufacture than either the Superlight or the Widowmaker according to the mission specs; I suspect that this is partly due to the fact that it is an outlier weapon with radically different stats from its kin. I don't think the TU mine will be outmoded by Avalons because it holds the advantages of dropping out into space as a mine, instantly stationary, and it has the duration of a mine, whereas Avalons last around 30 seconds.

Avalons last a whopping 120 seconds, actually. Which is nothing compared to a mine's potential lifespan, of course.

If the tus lasted untill detonated then they would be worth while

I know that. It's impossible really to use TU as proper mines given that their lifespan is only about 20 minutes. Makes it kind of hard to lay down serious minefields.

A TU mine won't even kill a valk X-1 or wtd.
They need a damage boost.

aye - I was just looking at the specs and the damage does need to be doubled or tripled and they need to be made persistant as well to make it a decent mine

It is suppose to be a nuke after all

Not just a nuke. Teller-Ulam designs can have yields well in to the tens of megatons. Even if this a "miniature."

+1