Thiess constructed the Bayswater Power Station - Units 1 to 4 Plant Civil Works - Stage 1, one of the largest government civil contracts let to one contractor at that time.

Consisting of 13 several portions, each with separate completion dates, a contract condition enabled the client to finalise or change design within a period of eight weeks before the commencement of any particular portion or area of the works. It gave the client flexibility which, under other types of contracts, would not exist.

The value of the portions varied in cost from approximately $2 million to $16 million per portion, including a portion of building works with the approximate value of $6 million.

Including approved extensions of time, each portion was completed within the contracted period for construction. Several of the portions were constructed concurrently, which required operation on several work faces at any one time.