I cannot imagine that Zijin will make a higher offer if they are not forced to do so.
I guess they will come up with an "independent" ( paid by Zijin) valuation with a fair price of 8 cent.
Reasons for this "low level" might be Platinum is in a very depressed environment, sovereign risk South Africa and course the significant premium to the share price (3 cent), when they initiated the offer.