Star Mine — Ruling

Effetto 0

The text that states you can only Special Summon Star Mine once per turn is not an effect.
You can Special Summon 2 or more of these monsters at the same time.

The first effect that inflicts 2000 damage to each player is a Trigger Effect that activates if this card is destroyed. (This effect must be activated if this card is destroyed by an opponent's attacking monster or opponent's card effect. It will also activate during the Damage Step.)
When resolving this effect, you take 2000 damage, then inflict 2000 damage to your opponent. (These actions do not occur simultaneously.)

The second effect that destroys this card and inflicts 2000 damage to each player is a Trigger Effect that activates on the field. (This effect must be activated if a monster in the Main Monster Zones adjacent to this card is destroyed by an opponent's attacking monster or opponent's card effect, while this card is in a Main Monster Zone. It will also activate during the Damage Step.)
When resolving this effect, destroy this card and take 2000 damage. Then, inflict 2000 damage to your opponent. (Destroying this card and taking 2000 damage happen simultaneously. These actions are not simultaneous with inflicting 2000 damage to your opponent.)