Spawner Mining Not Working?

[KatnissKill]

On survival, I have tried to mine spawners but it's not working. I am a diamond rank and was using a silktouch pickaxe, is this a bug or was spawner mining removed?

 

[Angry_Squid]

Spawner mining isn't working. I'm not sure if it was removed or is just broken. Also, if you place any spawner they turn into a pig spawner.