Mystery brass object

[SG500]

Can anyone identify this please.
Its a heavy brass and alloy object about 17cm by 10cm by 7cm in size. The key fits in the end and turns.
I'm guessing its some sort of remote demolition device.
Would it be for mining or issued to the military?
Any idea of age?
Dave.

 

[Yodamaster]

On first view, it let me think on an old electric induction exploder.
Here under, different model of exploder.





Yoda

 

[tomsk]

Its a little demon single shot battery used in shot firing underground

 

[tomsk]

We used them at Orgreave colliery in the 60s and 70s not sure before that