A father and son from Nevada County were sentenced to jail and ordered to restore land damaged by illegal mining along Keystone Creek near Loganville in Sierra County, prosecutors said. Gregory Arnoldi Jr. of Nevada City and Gregory Arnoldi Sr. of Browns Valley pleaded no contest to felony vandalism of public and private property and misdemeanor charges of water pollution and stream alteration, the Sierra County District Attorney’s Office said. The case involved an illegally built dirt road and mining near the creek. … The men were also charged with felony conspiracy and misdemeanors alleging mining without a reclamation plan or county use permit, grading without a permit and failing to notify the California Department of Fish and Wildlife before altering a stream.