why not bhp or rio

Seems very odd to me why RIO or BHP did not takeover SDL.
Look I am no expert, and there may be a simple answer, but why would RIO or BHP let Hanlong takover SDL and weaken their hold on Iron Ore.

If Hanlong get SDL then surely the Chinese are going to control Iron Ore prices or at least require less Iron Ore off Oz. Wouldnt SDL/Hanlong takeover be very bad for BHP and Rio?

Are Rio and BHP actually short of cash!!!.

And I say again, I may not know what I am talking about, but it is something I have always wondered.

Although this seems like easy money, I just cant bring myself to invest, the whole thing just smells really dicey. It probably isnt, but it just smells off. The SDL folks dont seem very professional and Hanlong doesnt seem very organized.