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

Tuesday, August 29, 2017

M3.3 Earthquake & aftershocks in northwestern-most Arizona

M3.3 Earthquake & 7 aftershocks (8/28/2017)

At 7:03 a.m. on 28 August, a magnitude 3.3 earthquake occurred in the northwest corner of Arizona about 20 miles SSE of Mesquite, Nevada. Seven smaller aftershocks followed on the heels of the initial event (Table 1, Figure 1). 

According to AZGS geologist Jeri Young, the earthquakes occurred just west of the Grand Wash Fault.  The range of depths, from 0 to 13 km is not uncommon ‘due to the westward stepping off the Colorado Plateau here.’

Table 1*. Earthquake events of NW Arizona of 8/28/2017 

MAGNITUDE (ML)            DATE               LAT        LONG       DEPTH (km)
0.8                        8/28/2017           36.593   -113.848              9.7
1.1                        8/28/2017           36.584   -113.866              13.3
1                            8/28/2017           36.609   -113.813              13.2
0.3                        8/28/2017           36.638   -113.832              12.1
0.2                        8/28/2017           36.611   -113.854              0
1.3                        8/28/2017           36.627   -113.823              12.3
1.2                        8/28/2017           36.622   -113.826              6.1
3.3                        8/28/2017           36.572   -113.887              3.8

*Data derived from the Arizona Broadband Seismic Network by Jeri Young (AZGS).

Wednesday, August 16, 2017

Remembering M. Lee Allison: one year later

Lee Allison examining a diversion ditch, Flagstaff, AZ. 

A year ago today Lee Allison, Director of the Arizona Geological Survey and State Geologist, passed away 3 days after suffering a tragic accident at his home. We cannot adequately express the scope of this tremendous loss to the AZGS and staff members. Lee was unique and irreplaceable, a dynamo who was primarily responsible for the survival and growth of the AZGS during the 10+ years when he was Director. For Lee, challenges were opportunities to do more, and obstacles never stopped him from going forward. The AZGS became involved in areas of research and outreach that we never would have imagined before his arrival, and the profile of the AZGS was raised within Arizona, nationally, and internationally.

Fortunately for us who have had to carry on without him, the legacy of Lee’s dynamic tenure as Director was incredibly influential as the state legislature considered re-establishing a state appropriation for the AZGS this past spring. It was much easier to explain the critical value the AZGS provides to the State of Arizona because of the work we completed under Lee’s leadership, addressing many different aspects of geology and its impact on society and commerce. Lee truly viewed geology as underpinning modern society, and he never passed up an opportunity to make that argument in public forums. (Photo by A. Youberg, 8/25/2010)

Phil Pearthree
AZGS Director & State Geologist