Wicked Little Things (2006) on Netflix

In 1913, in Carlton Mine, Addytown, Pennsylvania, the cruel owner of a mine uses poor children in the exploration and after an explosion, a group of children is buried alive. On the present days, Karen Tunny has just lost her husband after a long period of terminal disease when the family savings have been spent in the treatment. Without any money, she moves with her daughters Sarah and Emma to an old house in the mountains that belonged to her husband. Karen is advised by her neighbors to stay at home in the night, and Sarah hears that there are zombies in the area. When Emma becomes friend of Mary, he mother believes she is an imaginary friend. However, when Sarah's friends are attacked and eaten alive by zombie children and Emma vanishes, Karen and Sarah chase her nearby the mine.