Ann: Quarterly Activities Report, page-105

"...the current stage of exploration focusses on drilling holes designed to obtain information on alteration and other pathfinders in order to build a geological model (picture) that enables us to vector our holes towards the porphyry core. At this early stage, the vectoring information sought is not based on copper grades."

Just as mode had already pointed out. Drilling is about finding the porphyry core, not the grades - as low grade will still be viable on a large porphyry deposit.

Thanks for sharing their reply @huflungdung, top work.