After 18 tireless months of acting on the failed BHP Billiton and Rio Tinto merger, Allens Arthur Robinson partner Ewen Crouch is still optimistic.

"It was a terrific effort...our team has been working incredibly hard for the past 12 months and will enjoy the break over Christmas and the New Year. We are optimistic about M&A and capital markets work in 2009 that should get underway from around February," he said.

The two mining giants decided to call off the deal most recently valued at US$66bn, after the fall in metal prices and global financial crisis was feared to have created too much risk for the deal to proceed.

Crouch believes the BHP-Rio takeover bid was unique partly due to the number of jurisdictions involved and nature of the proposal. "This was a unique deal. There are few dual-listed companies and this was the first proposal to acquire a dual-listed company by way of takeover," he said.

There were numerous complexities such as Rio's repeated rejection of BHP's bid and reportedly little interaction between parties. The European Union's antitrust authorities also demanded that BHP divest some assets, while both Japan and China were against the deal due to their reliance on both party's iron ore and raw materials.

On a brighter note some firms are likely to benefit from the cancelled merger, since Chinalco has recently shown interest in increasing its stake in Rio by at least 9% (US$14bn). This could mean more work for Mallesons Stephen Jaques, Simpson Thatcher, Clifford Chance and Sullivan & Cromwell, which formerly acted on Chinalco's initial 12% (US$14bn) stake acquisition in Rio.

Other firms that worked on the BHP-Rio merger include Linklaters, Blake Dawson, Slaughter & May, and Skadden, Arps, Slate, Meagher & Flom.