Four junior mining companies are pushing forward gold, silver and tungsten projects across Nevada and Arizona, spanning the spectrum from early-stage drilling to a prefeasibility-stage development backed by the U.S. government.

A2 Gold (TSXV: AUAU; US-OTC: AUXXF) is expanding work at two Nevada projects, Arizona Gold & Silver (TSXV: AZS; US-OTC: AZASF) is preparing a maiden resource estimate, Aztec Minerals (TSXV: AZT; US-OTC: AZZTF) is drilling around the historic Tombstone district, and Guardian Metal Resources (NYSE-A: GMTL; LSE-A: GMET; US-OTC: GMTLF) is advancing one of the largest undeveloped tungsten projects in the United States.

The activity comes as the U.S. government works to shore up domestic supply of minerals it designates as critical, including tungsten and antimony, both of which appear among the projects described below. Nevada and Arizona, historically among the most productive mining states in the American West, have seen renewed exploration interest as companies revisit districts first worked in the late 1800s and early 1900s with modern exploration methods.

A2 Gold

A2 Gold nearly doubled its reverse-circulation drill program to 30,000 metres in January and launched a further 2,500 metres of diamond drilling in April at its Eastside silver-gold project in Nevada.

The company has delineated inferred resources at two deposits within the 92-sq.-km project, located about 243 km southeast of Reno, with another five or six targets under evaluation.

The McIntosh deposit hosts 61.7 million inferred tonnes grading 0.55 gram gold per tonne and 4.4 grams silver, containing 1.1 million oz. gold and 8.7 million oz. silver. The Castle deposit contains about 20 million inferred tonnes averaging 0.49 gram gold for 314,000 ounces.

A2 has also expanded its Nevada holdings by acquiring the 117-sq.-km Taylor silver-gold-antimony project from private explorer White Pine Precious Metals. A 5,000-metre reverse-circulation program began there in July, targeting the historical silver resource as well as gold and antimony. Antimony is on the U.S. critical minerals list and is used in ammunition, flame retardants and solar glass, and new U.S. supply is scarce after China, the dominant producer, imposed export controls on the metal.

Exploration at Taylor has returned oxide gold mineralization, including 18.3 metres grading 1.2 grams gold from surface in hole SPT-66.

A historical 2018 resource at Taylor outlines 3.44 million measured and indicated tonnes grading 99.1 grams silver per tonne for 11 million contained oz. silver, plus about 163,000 inferred tonnes grading 114.9 grams silver for 603,000 ounces. A2 does not treat the estimate as a current resource.

Kinross Gold (TSX: K; NYSE: KGC) owns 9.9% of A2, which has a market capitalization of $82.7 million (US$59.3 million).

Arizona Gold & Silver

Arizona Gold & Silver is preparing an initial resource estimate for its Philadelphia gold-silver project in northwestern Arizona.

Philadelphia was discovered in the 1890s and produced about 40,000 oz. gold before mining ended in 1934. The company began exploring the property in 2019 and discovered the high-grade Perry vein and a broad stockwork zone two years later.

Recent drilling includes hole PC25-158, which cut 60.4 metres grading 4.36 grams gold and 6.38 grams silver from 279 metres downhole, including a higher-grade interval of 24.2 metres grading 6.28 grams gold and 7.18 grams silver.

Hole PC25-156 returned 20.4 metres grading 9.04 grams gold and 34 grams silver from 320.7 metres depth. Metallurgical testing reported in June delivered gold recoveries of 91% to 99% using agitation-leach cyanidation and 84% from heap-leach processing.

The company is also drilling its Silverton antimony-gold project in Nevada, where a 27-hole reverse-circulation program began in June.

Arizona Gold & Silver has a market value of $96.1 million.

Aztec Minerals

Aztec Minerals is advancing its 85%-owned Tombstone gold-silver project in southeastern Arizona, about 100 km southeast of Tucson.

The 8.3-sq.-km property includes the former Contention heap-leach mine and several historic silver-gold workings. Aztec is targeting shallow bulk-tonnage oxide-sulphide mineralization below and around the Contention pit.

Hole TR25-17 returned 57.8 metres grading 5.16 grams gold and 39.12 grams silver from 9.1 metres depth, including 4.6 metres averaging 58.5 grams gold and 173.1 grams silver.

In July, hole TR26-30 cut 155.4 metres grading 1.08 grams gold and 30.23 grams silver from 61 metres depth.

Aztec increased its reverse-circulation campaign by 3,500 metres in May, bringing the program that began in June 2025 to 22,200 metres.

The company is also probing deeper for carbonate-replacement deposits. Tombstone lies about 65 km north of South32's (ASX, LSE: S32) Taylor zinc-lead-copper-silver discovery at Hermosa, one of the most significant U.S. critical-mineral developments in recent years, which helped draw renewed exploration attention to southeastern Arizona's historic mining districts.

Aztec Minerals has a market capitalization of $55.8 million.

Guardian Metal Resources

Guardian Metal Resources completed a new prefeasibility study in June on its Pilot Mountain tungsten project in Nevada, about 270 km southeast of Carson City.

The work was funded in part by a $6.2-million (C$8.65-million) U.S. Defense Production Act award as Washington seeks to rebuild domestic supplies of metals used in defence, aerospace and technology. Tungsten, used in armor-piercing munitions, cutting tools and electronics, is on the U.S. critical minerals list, and the United States has had no domestic tungsten mine production in recent years, relying on imports and scrap recycling.

The study estimates a post-tax net present value of $660.3 million at an 8% discount rate and an internal rate of return of 60%. Initial capital is estimated at $388.7 million with a one-year payback.

Pilot Mountain is designed as an eight-year open-pit operation processing 4,000 tonnes per day. Probable reserves total 11.8 million tonnes grading 0.171% tungsten trioxide, 9.28 grams silver per tonne and 0.28% zinc, for contained metal of 20,275 tonnes tungsten trioxide, 3.5 million oz. silver and 33,396 tonnes zinc.

Guardian also holds the past-producing Tempiute tungsten project north of Las Vegas, which it is evaluating as a potential nearer-term source of tungsten.

Guardian Metal Resources has a market capitalization of $371 million in New York.