How has contract law been interpreted in the context of tenders in construction contracts?

In argument before us and in the trial judgment, there was considerable reference to The Queen v. Ron Engineering (1981) 1981 CanLII 17 (SCC), 119 D.L.R. (3d) 267 (S.C.C.) where Estey J. dealt with contract law in relation to tenders in construction contracts. In particular he spoke in terms of contract A and contract B, as follows: There is no question when one reviews the terms and conditions under which the tender was made that a contract arose upon the submission of a tender between the contractor and the owner whereby the tenderer could not withdraw the tender for a period of 60 days after the date of the opening of the tenders. Later in these reasons this initial contract is referred to as contract 'A' to distinguish it from the construction contract itself which would arise on the acceptance of a tender, and which I refer to as contract 'B'."