OD6 Metals Limited (ASX: OD6) has released results from its CPC Engineering Optioneering Study, confirming that heap leaching is the lower-cost and preferred primary leach option for the Splinter Rock Rare Earth Project (Figure 1). This is a significant step in de-risking the project and optimising development economics, with the study showing heap leach delivers superior recovery, lower capital intensity, and simplified operations when compared to conventional agitated tank