This is a Wild Area event held by Sword and Shield. It appears to have some kind of mining theme, with all the Pokémon being at least part Steel, Ground or Rock type.
One can find a Gigantamax Copperajah or Gigantamax Coalossal if they are lucky.
The release of this event was fraught with issues, and the servers had to redistribute the Wild Area News multiple times to try to tackle them.
Note that these are to me memory, and do not have them 100% correct. I'll replace them when proof comes along.
Index 27: Initial Release. Has bugged item (0x1604) as part of the rewards. Crashes the game upon receiving it.
Index 28: Bonus_reward still has bugged item. However on normal_encount (rigel and base), reference to the bugged item has been removed, instead referencing a different award.
However it still appears to be bugged, perhaps server side. These raids could not be done online.
Index 29: ??? (I do not have this)
Index 30: Properly Fixed: Armorite Ore reinstated in the bugged slot of bonus_reward, and normal_encount references that slot.
Index 32: Post Sea Pokémon Invasion
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page would contain some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.