rio valuation vs deloitte valuation

where did this RIO valuation come from? never heard of it before and why would it be in the public domain being used against them by FMG?

today's AFR p50

"On Monday, Fortescue's lawyer, Jonathan Beach, QC, argued that the mining giants could snap up tenements cheaply from smaller miners that did not have access to rail lines. He cited the example of BHP buying iron ore junior United Minerals for $204 million - a 76 per cent discount on Rio's valuation of the miner - as evidence of "cherry picking."

there is another article of interest to small IO shareholders on the same page "Time to stop railroading minnows"

it's a pity UMC directors didn't have the ticker to hold out for a better deal or take their chances with CRM