It was created for the 1960 Brier Parade.
That is the photographer's son, Brandon, in the second photo.
To give an indication of size and location, here is a picture of it
from across the street:
Canadian Car is now Bombardier (makers of subway cars, snowmobiles, planes, etc.). A.J. Childs Ltd. is a plastering contractor.
The stone rests on wooden boards.
Thunder Bay also features a two moose hunters:

Thunder Bay also used to feature a Giant Milk Carton:
Information Sources: Vickie Charest and Canada's Gigantic! by Henri Robideau
Pictures Sources: Vickie Charest and Steve Robinson