[DeathDealer]

It looks like a British WWII general service respirator. The bag is the MKVII (made famous by Indiana Jones), but I do not know if that is related the the respirator part number.

Welcome to British Red Cross and St John Ambulance

 

[DeathDealer]

The closest modern helmet I have found is the Aluminum cap style Skull Bucket.

 

[DeathDealer]

You could make the pick portion out of cardboard or and paint it to look rusty. Then attach it to a replacement handle.

You could use foam, but I think cardboard would be sturdier.