Interior Secretary Bruce Babbitt has buckled to the demands of ranchers and other land users along the upper Missouri River and declared that he will not put new restrictions on the area. He had sought to freeze new mining claims and other land uses along a stretch of the river and a surrounding 90,000-acre area in preparation for the upcoming Lewis and Clark bicentennial, but on Friday he changed his mind. Ranchers were worried that the move would threaten their grazing rights, and other opponents feared the designation would be a precursor to making the area a national park.