10.Asset Retirement and Reclamation Obligations

Asset retirement obligations ("ARO") relate to the Lost Creek mine and Pathfinder projects and are equal to the present value of all estimated future costs required to remediate any environmental disturbances that exist as of the end of the period discounted at a risk-free rate. Included in this liability are the costs of closure, reclamation, demolition and stabilization of the mines, processing plants, infrastructure, aquifer restoration, waste dumps and ongoing post-closure environmental monitoring and maintenance costs.

At March 31, 2018, the total undiscounted amount of the future cash needs was estimated to be $26.9 million. The schedule of payments required to settle the ARO liability extends through 2033.

The restricted cash as discussed in note 5 is related to the surety bonds which provide security to the governmental agencies on these obligations.