Walter Duane Simpson, 71, of Great Falls, a retired restaurant owner, died at a local hospital on Friday, March 9, 2012 of natural causes.A graveside service will be held on Wednesday, March 14, 2012 at 2:00 p.m. at Mount Olivet Cemetery. Schnider Funeral Home is handling the arrangements.Walt was born in Livingston, MT on February 14, 1941 to Jim Frederick Simpson and Ruth Simpson.After graduation from Wilsall High School, he married Karen Hereim on September 13, 1959.Walt worked as a meat cutter in White Sulphur Springs for four years before moving to Great Falls in 1964.Walt and Karen purchased Zandys Drive In in 1964 and ran it until their retirement in 2000.Walter is survived by his wife, Karen; his son, Bill Simpson of Great Falls; his daughters, Carrie (Dean) Brown, of Sutton, AK and Valerie Christiaens, of Great Falls; a brother, Ervin (Doris) Simpson of Billings; a sister, Edna (Bill) Terry of Billings; seven grandchildren, Kristie, Jeff, Andrea, Deanna, Jessica, Jesse, and Max; and seven great-grandchildren, Kristopher, Malachi, Jayden, Jessalynn, Lucas, and Maisy.Walter was preceded in death by his parents, Jim and Ruth Simpson; and a daughter, Terrie Richards.Condolences may be left for the family at www.schniderfuneralhome.com.