Mindoro has completed 147 reverse circulation (RC) and 26 core drill holes at Kay Tanda. Almost all holes have encountered near-surface, generally flat-lying to gently-dipping blanket-like low-grade stockwork mineralization. This is strongly to partially oxidized to depths of 40 to 160 meters and non-oxide below this. Drilling, especially at deeper levels, has encountered at least five steeply-dipping, much higher-grade zones with bonanza grades to 246 grams per tonne (g/t) gold and over 1,000 g/t silver, which are interpreted as structurally controlled upflow, or "feeder" zones.

The high-grade mineralization appears to occur preferentially at elevations below 250 meters (ASL) interpreted to be a paleo-boiling zone. Few holes have penetrated to this depth to date. Such upflow zones can be associated with bonanza mineralization and constitute some of the world's best epithermal gold-silver deposits.