The abandoned mine is the same mine that appears in the prequel Tremors 4: The Legend Begins (2004), where it is still in use.
In the scene where an apple has its liquids sucked out is actually practical. With being one of the heaviest edited scenes it was set up so a time lapse camera recorded an apple having its liquids sucked out by a special vaccum that was a clear tube in the dirt post production erased the tube sped up the scene and added the ghost to give the effect.
At 28:55, Cletus says "get out of town". Cletus is played by Christopher Lloyd who was in Back to the Future where this was Marty McFly's catchphrase.