Tierra Group International, Ltd. participated as the geotechnical lead engineering firm for the Copperstone Project Pre-Feasibility Study (PFS) in Arizona, U.S.A. Tierra Group was responsible for tailings and waste rock storage, water management and underground geotechnics design and cost estimates prepared for a NI 43-101 Technical Report prepared by Hard Rock Consulting, LLC. Tierra Group also assisted the mine owner, Kerr Mines Inc., evaluating underground mining methods and developing a ground control plan.