The purchase of the 8.1 hectares (20 acres) site at Springfield brought to fruition the dream of finding a healthier environment for the girls' boarding school until that time part of Saint Aloysius College in Angas Street, Adelaide.

[2] After twenty-one years the boarding school was phased out when rising costs and a decline in the rural economy made it financially beyond the means of the very families it was created to serve.

The Duncans eventually bequeathed the property to the Presbyterian Church and it became St Andrew's Residential College attached the University of Adelaide.

Some were the original Irish sisters but many were South American girls who left behind their families and homes.

Mercedes College uses the Adelaide Metro bus service to transport nearby students.