Interior Secretary Ken Salazar is scheduled to visit the Grand Canyon on Monday and could announce changes for mining claims near the park.
Salazar temporarily blocked new mining claims on 1 million acres of land around the Grand Canyon in 2009 while his department studied whether to set aside the acreage for a longer period.
The department released four proposals in February and asked the public to weigh in — take no action, set aside the 1 million acres for 20 years or partially withdraw either 300,000 or 650,000 acres from any new claims.
Environmentalists, American Indian tribes and others say a ban would protect the environment and groundwater.
The mining industry says prohibiting new claims in the area with high-grade uranium ore would cost jobs and harm the economy.