August 30, 2017 Arizona Geological Survey aired its 40th Episode of the Arizona Mining Review – Developing a Pozzolan Mine in Central Arizona. Pozzolan is a geologic material – a volcanic tuff or ash – that when admixed with water, lime, sand and gravel makes a superior and long-lived concrete. Pozzolan is named for the town of Pozzuoli in Italy. Two thousand years ago, the Romans mined pozzolan near Pozzuoli to enhance concrete of new buildings and pillars, some of which still stand today.