i don't know but i remember that you can access the Magma Cave/Hideout in order to battle Maxie / or even not. I think after you defeat Maxie, it is closed. But i Already Finished Pokemon Emerald..
Chat with our AI personalities
In Emerald, an old lady in Mt. Pyre will give you Magma Emblem. After you got it, go to Judged Pass. If you bring the Magma Emblem, the Magma Hideout will appear in Judged Pass.
Go to the top of Mt. Pyre summit and you will discover Maxie/Archie already took the Orb that was upon the summit. The elderly man will give you the Magma Emblem to open Team Magma's hideout.
go to mount pryre.
Go to Jagged Pass and go in the middle where the Magma guy was. There is an earthquake and a door appears.
To infiltrate the Magma Hideout in Ruby Version, go to Mt. Pyre. At the top, the old woman should give you the Magma Emblem. Then go to Jagged Pass and wander around. when you get to the right place, the Jagged Pass will react with the Magma Emblem. Then the entrance to the Magma Hideout appears. Warning: you have to fight Magma Leader Maxie. Hope this helped! Shinin.