b'1957Leichhardt DamLeichhardt Dam,Mount Isa,late 1950s. The rock-fill dam and diversion tunnel for Mount Isa Mines is another example of the companys growing prowess.1958Thiess goes publicIn preparation for the capitalLeichhardt Damconstruction,required for the upcoming Snowy Mount Isa, c. 1957. Mountains Scheme projects, the Thiess brothers collect all fourteen of their businesses into the holding company and go public. The initial public offering of 450,000 shares (at 0.88 cents) in Thiess Holdings sells on the Sydney and Brisbane stock exchanges and sets the company up for bold expansion during the 60s and 70s.29'