?Bottom of fireplace

[The Clot]

I am opening up a fireplace that had been bricked up. It's a 1964 house. Stupid question, but have I excavated the fireplace enough? I'm not sure if I have got to the base, and also it seems very shallow - it is only 13cm deep. Is that possible, or is there more cement to be removed?
Please see pics, thanks for any advice on whether I should keep removing stuff.

 

[The Clot]

 

[The Clot]

Sorry bungled the photo upload earlier...

 

[vinn]

Dont go any deeper for the moment.

What you show in the pics is a two piece fire back - used with a solid fuel fire. The fireback will have been fitted in a fireplace opening thats just the right dimensions for the fireback.
So, if you removed the fireback (they smash out) you will only have an opening a little wider and deeper.
It all depends on what you intend to use the fireplace for: solid fuel fire or some kind of appliance?

If you intend to open up a large opening then post pics of the whole wall or chimney breast.

 

[The Clot]

Vinn, thanks for taking time to reply; I've stopped chiselling. Long term, I'm hoping to burn solid fuel (in an open fire) in the grate. The existing fireplace is flush with the wall (the chimney is built outside the house). I'm getting the chimney swept later this week so will wait until then after getting further advice. Thanks again.