SOUTHERN RIO GRANDE LAND EXCHANGE.

SEC. 501. SOUTHERN RIO GRANDE LAND EXCHANGE. The Secretary of the Interior is authorized to exchange certain lands as identified for disposal in the Southern Rio Grande Plan Amendment for certain mining claims on lands withdrawn for the National Aeronautic and Space Administration and New Mexico A and M College (now New Mexico State University) under P.L.O. 3685 and P.L.O. 2051. Once the United States determines the claims are valid under existing law, the exchange authorized by the preceding sentence shall be made on an equal value basis as determined by an independent appraisal.