Looks like the takeout price of $414M is in line with the NPV @5% after tax discount in the PEA. Only having a PEA limits the premium amount versus a more detailed/lower risk evaluation like a BFS.
From Xtorre's PEA (http://sedar.com/GetFile.do?lang=EN&docClass=24&issuerNo=00029616&fileName=/csfsprod/data128/filings/01885505/00000001/m%3A%5CG_drive%5CCDL%5Cv38317%5C31dec2011%5Ccerromorro_PEA3.pdf)
"Table 13 Economical Evaluation Results Summary (1,300 tpd)
Financial Model 1,300 tpd
NPV5 pre-tax US $ 737.4 million
NPV5 Free cash flow (after tax) US $ 463.2 million
NPV10 pre-tax US $ 524.7 million
NPV10 Free cash flow (after tax) US $ 320.1 million
IRR pre-tax 63.1%
IRR Free cash flow (after tax) 46.8%
Years to payback from start of production (at 5% discount) 1.98
Years to payback from start of production (at 10% discount) 2.16