I guess I already know this answer; the Hunters, Harvesters and Tanks seem to stop or totally avoid the land mines I put down—perhaps that’s just another drawback of playing single player.
They don’t detect them.
The big bots do however change path or travel more or less randomly, so setting up an ambush with landmines+large fuelcells can be quite annoying.
And hunters always try to flank you if they’ve seen you, so better put them on your sides, or around the house you will probably run into if being swarmed by angry hunters. 
They work well and aren’t detected in any way I managed to notice, but the bots travel paths are as said the biggest problem to get them to step on the mines.
Try to put landmines over a wider area, or around corners, when Hunters are chasing you. You can also put them out, then shoot them when enemies are near
Sometimes i think they do detect them, at least big robots do.
Several times have done trap funnel, or tank walking around building when in combat. And they just start to avoid that area where mines are. And i mean i have tried these mines dozens of times.
First time i manged to bring tank down with 2 mines + 30+ gas tanks was last week. FNIX tank died on huge explosion. I shot it 4-5 times with PVG90 with AP ,to lure it in.
Other feature that mines should have, is that they would NOT trigger from other explosions, only when walked over. They are pretty much as any explosive canister now, and those we have plenty. Little bonus is that you mines stack 2 per inventory slot.
I use mines when running away down roads - the machines tend to follow the road after you if you go fast enough. Never seen a Hunter spot a mine, but I was fighting three rocket dogs, going backwards as you do, and when the first one went over a mine and died, the others instantly stopped following and only fired from a distance, from cover. Took me a long time to bring them down. Dogs seem to be the only machine with a sense of survival (not all, but some, unquestionably - I’ve had them run away and never come back).