coaledsweat wrote:You need to pull that piece of wood or what ever it is out and remove those two slabs lying on the grates, the grates should rock side to side once they are freed up. You should be able to burn nut or stove (big chunks) of anthracite in that puppy with no problem.
Coaledsweat is right. Move those pieces of wood ("slabs") then use the channel locks again on the square shaft, the grates should then rotate.
Be careful moving the slabs because they appear to be supporting the brace that runs up the flue to that metal plate which could fall down as was discussed before.
Edit: You may want to leave the brace supporting the plate up in the chimney in place until you get the chimney top repaired. It will keep bricks etc. from falling down through the chimney and hitting the grates/fireplace cast iron. When you remove the brace, put something, like old blankets, whatever you can think of to protect the grates/cast iron in the fireplace from falling debris.
I'm pretty confident that the grates are ok after looking at the new photo(second photo with metal plate taken off).