In a medium saucepan, bring beef broth to a boil.  Add rice, cover, and cook for 20 minutes.  Meanwhile, in a large skillet, heat olive oil over medium heat.  Saute white part of green onions and garlic until softened.  Add mushrooms and ground meat.  Cook to brown and crumble meat.  Add diced tomatoes, worcestershire sauce, chili powder, and salt and pepper to taste.  Simmer a few minutes until flavors meld together.  Fold in cooked rice.  Serve topped with green part of the green onions.