Hovell tree marks the exploration by Hamilton Hume and William Hovell. The original tree is/was in Albury some 500KM away. Not sure of the connection with a coal mining museum.
Plaque reads:
'A clone of the original Hovell Tree
River Red Gum (Eucalyptus Cameldulensis)
Donated to the State Coal Mine by Humphris Nursery and Bass Coast Council 2013'
Submitted with: @IanThorp