16 U.S. Code § 410zz–2 - Expansion of boundaries
(a) In general
The boundaries of the park are hereby modified to reflect the addition of approximately 3,460 acres of land and interests therein as generally depicted on the map entitled “Saguaro National Monument Additions” and dated April, 1994.
(b) Land acquisition
(1) Within the lands added to the park pursuant to subsection (a) of this section, the Secretary is authorized to acquire lands and interests therein by donation, purchase with donated or appropriated funds, transfer, or exchange: Provided, That no such lands or interests therein may be acquired without the consent of the owner thereof unless the Secretary determines that the land is being developed, or is proposed to be developed in a manner which is determental  to the integrity of the park.
Subject to valid existing rights, all Federal lands within the park are hereby withdrawn from all forms of entry, appropriation, or disposal under the public land laws, from location, entry, or patent under the United States mining laws, and from disposition under all laws relating to mineral and geothermal leasing, and mineral materials, and all amendments thereto.
 So in original. Probably should be “detrimental”.