The Michigan Karst Conservancy’s page on Fiborn Quarry begins:
The unusually pure limestone found in what is now the Fiborn Karst Preserve led to development of Fiborn Quarry, which operated from early 1905 until January 1936. The quarry mined, crushed and shipped limestone for use mostly in steelmaking, but also calcium carbide manufacturing and road building.
A small town grew up next to the quarry, which included an elementary school, a boarding house, a company store and housing for employees and their families.
“You just felt like you were living in a little world all of your own. Just like there was no other place,” recalled one former resident who was 13 years old in 1930. “You had your grocery store. You had your post office. You had your school. You had your minister that came in there and gave services. And it just seemed like it was real private.”
Workers broke up the limestone with dynamite, steam shovels loaded the rock into cars which hauled it to a crusher. Crushed limestone was sorted into different sizes hauled on the railroad spur 3-4 miles north to Fiborn Junction and the main rail line to Sault Ste. Marie.