It's this:
"-up" (pronounced with a consonant somewhere between phonetic /p/ and /b/) is a suffix used in many parts of WA and simply means "place".
As in "Porongur-up" (place of spirits) and "Gidgegannup" (place where spears are made).
The "Minj" (plural: "Minjur") is a small marsupial, unrecorded since 1873 and probably now extinct -- also, though more recently, eponymised in the placename "Mingenew".
It is related to the Quoll and resembles the European beaver, being hairy and having rodent-like teeth, but also an inverted pouch and a spotty back.
The only known preserved specimen, held in the WA Museum vaults, has the label: Dasyurus novaehollandiae.
When I'm next up there, I'll try to get a picture or two.
