All-up settlement offer for all claims in the proceeding? – Think again

The high-profile case recently decided by the Queensland Court of Appeal ('Court') involved a substantial construction dispute between Civil Mining & Construction ('CMC') (the contractor) and Wiggins Island Coal Export Terminal ('WICET') (the principal). While CMC succeeded on their claim against WICET at trial, WICET also succeeded on their counterclaim against CMC. The key issue arose from the fact that WICET made an "all-up" offer, expressed to be under Chapter 9, Part 5 of the Uniform Civil Procedure Rules 1999 ('UCPR'), to settle "all claims in the proceeding". The offer was also accompanied by a covering letter which bore the heading "without prejudice except as to costs".