Feasability study does not change what is in the ground.
What they do is DETERMINE what is in the ground, including where and how much. And that leads to determining how and where to mine, and then how and where to process the material to recover the minerals. If ONE of the steps turns out to be negative, then it is not economic to mine. It also prevents throwing money at uneconomic ground, which is why feasibility studies are the norm in the industry. Everyone does them, unless companies feel like wasting shareholder money in futile mining operations.
Or if the purpose of the Company is something else entirely.