Wednesday, August 30, 2017

Return of Arizona Mining Review: Mining Pozzolan in Central Arizona

Volcanic tuff pozzolan exposed at Kirkland Mine
Return of Arizona Mining Review 
Following a 15-month hiatus, the Arizona Mining Review (AMR) filmed and its 40th episode, Pozzolan mining in central Arizona, on 28 Aug 2017. The Arizona Geological Survey’s Geologic Extension Service launched the Review in Jan. 2013. With a few lapses, we released monthly episodes until May of 2016. In May, the Review went on hiatus as we moved from State Agency status to the College of Science at the University of Arizona. Plans to restart the program in Aug. 2016 were put on hold after host Lee Allison’s tragic death.

We are now back in business and ready to explore and broadcast developments in Arizona’s mining and mineral industry. 

Project map for pozzolan at Kirkland Mine.
The small mine in the low hills north of Kirkland encroaching on the southern edge of Skull Valley, Yavapai County, Arizona, has been worked on-and-off for more than 100 years. It’s seen half-a-dozen name changes to reflect changes in use of its mining products. In the 1950s, it was the Arizona Capital Mine, as cutters carved out dimension stone for the Arizona State Capital building. In the 1970s, it was the Kitty Litter Mine, as a more prosaic product was harvested. 

Currently, Kirkland Mining Co. president Areta Zouvas and project manager Al Burch are working with the Bureau of Land Management (BLM) to re-permit the quarry to mine pozzolan. (The Zouvas family has owned the Kirkland Mine claims since 1989.) An environmental assessment of the mine and environs, a requirement of the BLM, is underway and expected to take 12- to 18-months to complete. If approved, the quarry could open shortly thereafter. 

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. 

Kirkland’s pozzolan deposit is hosted in Miocene-age volcanic tuff. The tuff is a white to tan, massive crystal-lithic tuff in excess of 250 feet thick that dips gently to the northeast. Extraction of the tuff requires simple earth-moving equipment to quarry and crush the stone. The mine operators anticipate extracting ~500,000 tons of ore annually at peak production at an astounding 95% rate of yield for as much as 40 years. 
The resulting pozzolan mine will find a market in the western U.S., where it likely will be processed and sold as a Supplementary Cementitous Material (SCM) added to cement and concrete to replace or be blended with Fly Ash to enhance the durability and strength of concrete.

Online Resources

Posted 8/30 
M. Conway

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