Almost never - usually requires the merger to be...

Almost never - usually requires the merger to be anti-competitive/against the concerned markets best interests (say a merger of telstra and optus; they would have major pricing power and would be against consumers best interests as a monopoly would be close to existing)

Although for mining its a formality; for example, Norther Star and Saracen merged earlier this year, $15B merger. That is perfectly fine and in best interest of all partys and the wider economy.

I see this next court hearing as a mere formality, today was the big risk and it passed in flying colours.

Hope that helps.