Remove excess fat from chops. In a large skillet cook chops in hot oil over medium heat until brown on both sides. Drain off fat. Place onion in a 3 1/2 or 4 quart slow cooker. Add chops. Crush tapioca with a mortar and pestle.
Combine in a large bowl tapioca, mushroom soup, apple juice, mushrooms, Worcestershire sauce, thyme, and garlic powder. Pour over chops in cooker.
Cover and cook on low-heat setting for 8 to 9 hours or on high-heat setting for 4 to 4 1/2 hours. Servie with hot cooked rice (optional).