Looks to be better than the "replica" lamps on sale in the tourist shops.
It has a gauze bonnet and sealing gaskets.
E.Thomas and Williams did make lamps for colliery work, but are now known for light weight replicas.
On a "real working colliery lamp" I would expect to see some form of lock.
Possibly a lamp sold as a souvenir, or presentation.
I would suspect that it is designed to use paraffin, not Colzaline or petrol type liquids.