Timing

[Bio beast]

 {Goblin Kaboomist} does the flip on the coin to determine the goblins fate occur after he creates the mine, or after you detonate it?

[Popper23345]

After you detonate, because it's as if he got hurt a little bit to 😉

[Cender]

The colorless mine occurs first and regardless of whatever fate he falls to. Then the flip occurs to determine whether he lives or dies.

[particle]

The colorless mine occurs first and regardless of whatever fate he falls to. Then the flip occurs to determine whether he lives or dies.

this is correct. during each of your upkeeps, youll first make a landmine token, and then youll flip a coin and determine the goblins fate.
note that the goblin's fate and the landmine arent tied to each other.  if you sac the goblin, the token remains and if you sac the landmine the goblin remains.

[LinkCelestrial]

Also, if you have a way to give {Goblin Kaboomist} +0/+1 he'll survive even if it goes bad. (assuming of course that he doesn't take more damage.)