Aztec chases silver-zinc deposits at Tombstone

Aztec Minerals (TSXV: AZT; US-OTC: AZZTF) has launched the first phase of surface work at its newly-optioned Tombstone silver-zinc district, 104 km southeast of Tuscon, Arizona. The company is chasing multiple types of mineralization, but primarily carbonate replacement deposits (CRDs) similar to South32's (ASX: S32) recently acquired Taylor zinc project, located 65 km southwest of Tombstone in southern Arizona.

Tombstone is the second project for the relatively new company. It controls nearly all the historic, patented land in the district.

In an interview with The Northern Miner, Aztec Chairman Brad Cooke says there are dozens of old mines on Aztec's ground.

"Even though we're just starting," Cooke continues, "Tombstone has a tremendous amount of history and some real obvious targets."

The company aims to refine targets for drilling with its first phase of exploration at Tombstone. The first phase includes $139,000-worth of mapping, soil and rock sampling, trenching and airborne geophysical surveying.

It says it's primarily interested in two styles of mineralization.

The first style is an epithermal mineralization found at the district's past-producing, open pit, heap leach Contention gold-silver mine. Cooke says the company believes the old mine still has "quite significant upside."

It discovered some historic drill data sets that may support this belief. In the early 1990s, USMX drilled 6,108 metres in 63 holes and MPV Capital drilled 1,867 metres in 14 holes in areas that were never mined. Aztec intends to release those results in mid-September, after it's had them verified.

The company also has a 1993 historic resource completed by USMX that outlines 1.15 million near surface tonnes grading 1.79 grams gold per tonne.

The Tombstone project near Tuscon, Arizona. Credit: Aztec Minerals.

"But by far the bigger opportunity is what we call carbonate replacement deposits below the historic mines and below the Contention pit," Cooke says. "We are looking at what we would call a Taylor deposit look-a-like."

South32 recently acquired Taylor when it bought out Arizona Mining for US$1.3 billion. Taylor is a CRD massive sulfide deposit that contains 91.5 million measured and indicated tonnes grading 4.3% lead, 4.1% zinc and 59.5 grams silver, or 10.4% zinc equivalent.

Previously called Wildcat Mining, Arizona Mining had been focused on a historic silver mining camp called, Hermosa. When it ran into metallurgy issues, it shifted its focus from silver to zinc, chasing a historic hole on the property. The hole led to Taylor, lying below the silver district.

"Tombstone looks remarkably similar," Cooke explains. "We have a historic district up in a particular rock formation. The rock formation is only 200 metres thick and then there's an unconformity and you're down into the same host Paleozoic limestone at Tombstone that hosts the Taylor deposit."

Cooke notes that none of the historic mines at Tombstone were able to process any significant amount of mineralization. At Contention, for example, the operators hit sulfides in the late 1800s and early 1900s but didn't have the technology to extract metals from them.

Although its mineral prosperity is an open question, the Tombstone district is rich in American lore.

In the mid-1800s the American army sent groups of scouts to the area looking for Native Americans. One scout, Ed Schieffelin, joined so he could prospect the area part-time.

When his army friends found out what he was doing they told Ed: "The only rock you'll find out there will be your own tombstone."

So the story goes, at least.

Apaches attacked Ed and his party, forcing them into hiding. Ed used the time to prospect and eventually decided to leave the army. He found a silver vein and staked a claim - right next to the grave of a scout killed in the Apache attack.

Ed brought samples of his claim across the state to the McCracken Mine in Signal City, Arizona, where his brother Al worked. He got them assayed by a man named Richard Gird. The two brothers and Gird later formed a business partnership when the samples graded high in silver.

From 1878 to 1939, the Tombstone district produced an estimated 32 million oz. silver.

Aztec expects to finish its phase one program by mid-September and release results in October. It will soon begin trenching that will last two weeks. Because the property is patented land, the company does not need permits to begin trenching.

The Cervantes project in Sonora, Mexico, is currently under option by Aztec. Credit: Aztec Minerals.

Aztec optioned the Tombstone properties from Baroyeca Gold and Silver (TSXV: BGS) in late 2017. The properties total 1.6 sq. km of patented claims and an additional 0.09 sq. km of unpatented claims.

Aztec can acquire a 75% interest in the district by spending $1 million on exploration, issuing Baroyeca 1 million shares and paying Baroyeca $100,000 over a three year period.

The company went public last May with just its Cervantes gold-copper project in Sonora, Mexico, under option from Kootenay Silver (TSXV: KTN; US-OTC: KOOYF).

"We used a chunk of the IPO money last year and this year to do the phase 1 drilling at Cervantes," Cooke says. "And we had some pretty nice results."

The company defined porphyry-type copper-gold mineralization at Cervantes over 800 metres. Highlights include 160 metres from surface grading 0.77 gram gold, 0.13% copper and 3.4 grams silver, as well as 98.5 metres from surface at 0.41 gram gold, 0.13% copper and 2.2 grams silver.

In March, the company expanded its land package at Cervantes six-fold when it won two new concessions totaling 31.5 sq. km in a Mexican government land lottery. It's wrapping up a phase two surface exploration program at Cervantes now.

The company is doing some leaching metallurgy on the Cervantes phase one core and aims to announce the results by November. It's also pursuing a new acquisition.

Next year, it will look to do more drilling, including a phase three drill program at Cervantes.

Shares of Aztec are currently trading at 22 ? with a 52-week range of 14 ? to 38 ?. The company has a $6 million market capitalization.

"We're very excited by the opportunity to identify and ultimately drill Taylor look-a-like targets at Tombstone," Cooke says.