FILE - In this April 24, 2015, file photo, pumpjacks work in a field in the Permian Basin near Lovington, N.M. Top officials with the largest Native American tribe in the United States are renewing a request for congressional leaders to hold a field hearing before deciding on federal legislation aimed at limiting oil and gas development around Chaco Culture National Historical Park. The Navajo Nation has struggled for years with high poverty rates and joblessness, and the tribe’s legislative leaders say individual Navajo allottees stand to lose an important source of income if a 10-mile buffer is created around the park. (AP Photo/Charlie Riedel, File)