Grant will help develop ancient quarry as historical site Minnesota Historical Society grant will help develop with the development of the 11,000-year-old chert mine as an interpretive site. 7:49 am, Dec. 11, 2020 × AUSTIN — A $59,000 grant from the Minnesota Historical Society will help the Mower County Historical Society develop a millennium-old quarry as an educational and interpretive history site. The Grand Meadow Chert Quarry, located on a 15-acre plot of woods and owned by the Archaeological Conservancy, is a series of sites where prehistoric people mined the stone – chert is microcrystalline quartz – to be used as tools such as arrowheads, points, spears and scrapers dating back as far as 9,000 BCE.