11. Commitments and Contingencies Tetlin Lease . Pursuant to the terms of the Tetlin Lease, the Company is required to spend $350,000 per year until July 15, 2018 in exploration costs. However, the Company's exploration expenditures through the 2011 exploration program have satisfied this requirement because exploration funds spent in any year in excess of $350,000 are credited toward future years' exploration cost requirements. As of March 31, 2012, the total amount spent on exploration expenditures on the Tetlin Lease was approximately $4.7 million. Additionally, should we derive revenues from the properties covered under the Tetlin Lease, the Company is required to pay the Tetlin Village Council a production royalty ranging from 2.0% to 5.0%, depending on the type of metal produced and the year of production. As of March 31, 2012, the Company has paid the Tetlin Village Council $225,000 in exchange for reducing the production royalty payable to them by 0.75%. These payments lowered the production royalty to a range of 1.25% to 4.25%. On or before July 15, 2020, the Tetlin Village Council has the option to increase their production royalty by (i) 0.25% by payment to CORE of $150,000, (ii) 0.50% by payment to CORE of $300,000, or (iii) 0.75% by payment to CORE of $450,000. Until such time as production royalties begin, the Company pays the Tetlin Village Council an advance minimum royalty each year. On July 15, 2012, the advance minimum royalty increases from $50,000 to $75,000 per year, and in subsequent years the advance minimum royalty is escalated by an inflation adjustment. Gold Properties. The Company's Triple Z and TOK/Tetlin claims are both located on State of Alaska lands. The annual delay rentals on these two projects total $12,140 per year, and are due and payable in full by November 30 of each year. The Company has met the annual labor requirements for the Triple Z and TOK/Tetlin claims for the next four years, which is the maximum time frame allowable by Alaska law. REE Properties . The Company's St