they are usually buried underground or thrown in front of tanks.
they come in multiple types anti personnel and anti armour
True land mines; those that are normally factory built and designed for either anti-personnel or anti-vehicle (primarily anti-tank) are shape charges-extremely more powerful than any improvised device (homemade or utilizing found artillery shells).
All land mines are indiscriminate; they will kill friend and foe alike. (until smart mines are developed).
All land mines (until smart ones are developed) will kill long after a conflict is over with; and land mines are often forgotten...and never found again...until they explode.
Older buried land mines can explode when temperatures drop.
Buried land mines can remain undisturbed for decades-- until one explodes.