Flint mining

Krzemionki, also Krzemionki Opatowskie (, "Opatów silica-mine"), is a Neolithic and early Bronze Age complex of flint mines for the extraction of Upper Jurassic (Oxfordian) banded flints located about eight kilometers north-east of the Polish city of Ostrowiec Świętokrzyski. It is one of the largest known complexes of prehistoric flint mines in Europe together with Grime's Graves in England and Spiennes in Belgium.

mine

U.S. national monument in Texas

flint mine in Norfolk, England, UK