By the way, I'm a bit skeptical of the provenance of this creature, from what I can find out a Chinese "Celestial Stag" is either a Kirin or Dragon, or a creature very similar to one, rather than resembling the creature described.
Since Borges The Book of Imaginary Beings included many purely fictional creatures (like the Cheshire Cat), many obscure creatures and at least one (the Peryton) which I can't find any mention of from an earlier source, the mine-dwelling version of the Celestial Stag may well be a "made up from scratch" or a local talltale, rather than a true mythical beast.
That doesn't mean we can't convert it though, it does make a cool monster.