A bill to further amend the Mineral Leasing Act of 1920 (30 U.S.C. 181 Et. Seq.) as amended by Section 2 and 13(B) of the Federal Coal Leasing Amendments Act of 1975 to authorize the Secretary of the Interior to exchange Federal coal leases and modify existing Federal coal leases to include additional lease acreage without changing the other terms and conditions of those leases and to encourage recovery of marginal coal deposits and for other purposes.

Amends the Mineral Leasing Act of 1920 to authorize the Secretary of the Interior to exchange Federal coal leases and to modify existing Federal coal leases to include additional lease acreage of up to ten percent without changing the other terms of such leases. Limits such exchange authority to lands where the development of the relinquished lease would result in damage to the environment or would conflict with public land purposes not considered at the time of the issuance of the lease.

Authorizes the Secretary to provide a royalty of less than 12 1/2 percent on such new leases.