Drill Progress, page-28

To get a risked resource you need to multiply the unrisked resource by the COS. It's absolutely fundamental to the oil and gas industry, so if this is news to you, I might respectfully suggest some research into O&G fundamentals.

From the risked resource you can calculate an EMV for the prospect, which determines whether it is worth drilling. At the stated COS and mean recoverable resource, the EMV for TAO-1 quite clearly was worth drilling which is why many think TPT is a good punt.