In 1966, 7-year old Ruth Ann Miller was playing around the abandoned No. 4 shaft of the Tamarack Mine in Houghton County, Michigan. Due to erosion around the cap, she inadvertently slipped under its cap and fell down a 4000 foot deep hole. When rescuers attempted to remove the shaft's concrete cap to mount a rescue the cap broke free and fell down the shaft, making any rescue attempt impossible. Ruth Ann's body was never recovered. __Almost nothing remains of this shaft’s old surface plant except a few scattered rock piles. Sitting over the shaft today is a new concrete cap surrounded by a six-foot fence to keep people out. Inside is pair of memorial stones to Ruth Ann Miller and her mother – who was later laid to rest at the site of her daughter's death. A historical marker sits outside the fence detailing the fateful event. (excerpted from http://keweenawfreeguide.com/tamarack-no-4/).