There are four types of mines: the normal Mine, and the three variants being the Mega Mine, the Ultra Mine, (it being the strongest) and the Ice Mine, that inflicts damage and freezes the shark for a short period of time. The Ice Mine is exclusive to a special area part of the Christmas-themed content released in 2014.
The Mega Mine is more dangerous than standard Mine, and can only be eaten by the Megalodon or better. Its danger level is higher than the smaller variety of mines, yet they cannot be eaten by the Robo Shark, but can be destroyed by his mine blast. It can kill Reef Shark.
Ice MineThe Ice Mine is a mine that is made from ice and has spikes of ice as well. The Ice Mine seems to inflict the same damage of a Mega Mine and freezes the shark, making it slower for a few seconds. Its name is official because it is showed in the Hungry Shark Evolution Christmas land official video made by FGOL, the developers of the game. You can see the trailer here. The Ice Mine appears only in the Christmas Wonderland and the Arctic Land. It can be eaten by Megalodon, Big Daddy, Mr Snappy, and Robo Shark It does not affect the Ice Shark or any shark with the Santa Baby equipped.
Ultra Mines can only be eaten by the Big Daddy or better (in which it can heal a small amount of health), but can be destroyed by the Robo Shark's mine blast. This deadly mine can kill most sharks in one hit, start starvation at a Tiger shark, and smolders down approximately two thirds of the Megalodon's and Great White's health.
It deals the most damage out of any object in Hungry Shark Evolution, except the Enemy Big Daddy, Mr Snappy and Alan destroyer of worlds. When approached, the camera zooms out, possibly to help larger sharks avoid it.
While some Ultra mines spawn at certain places at default, most of them seem to spawn randomly near your shark when you earn a lot of points at one time so big sharks may see (or eat) dozens of them in one session depending on how fast you get a lot of points. They seem to spawn even more the longer you are surviving one session.
However, on the Facebook page for Hungry Shark Evolution, one of the posts by the developers referred to the mine as "Ultra Mine", and in the museum it is also called "Ultra Mine". Therefore, both Ultra Mine and Death Mine names are acceptable. In Hungry Shark World, death mines are black and have a red line in the middle and deal the most damage, often killing the shark instantly and rarely it'll just take a chunk to health critical.
Unlike other mines, when you eat a Death/Ultra Mine it explodes with bubbles rather then being eaten.