Burro Mountains / Tyrone
Deposit type & geology
Laramide porphyry copper with byproduct gold-silver.
Precambrian Burro Mountain granite (~1.46 Ga) intruded by the Laramide Tyrone stock.
Age: Tyrone stock ~53–57 Ma (Laramide).
Structural geology & terrain
Vein/structure orientation: Osmer fault N60°E (2,000 m vein); Sprouse-Copeland fault N87°E/75°SE, one of five major NE faults
Named controlling structure: Sprouse-Copeland fault (major NE corridor); Osmer fault
Elevation range: ~6,152–6,499 ft; peak 8,035 ft
Chihuahuan scrub grading to Madrean woodland; terrain around Tyrone itself heavily disturbed by open-pit mining.
High-resolution terrain
~6 m/pixel lidar-derived hillshade (USGS 3DEP) — fine enough to reveal old mine workings, waste-rock piles, trenches, and roads the statewide terrain layer can’t show.
Historical production
No standalone gold figure found; gold is a documented secondary/tertiary commodity behind copper and molybdenum. County-wide context: Grant Co. produced ~501,000 oz Au through 1959, much of it byproduct of base-metal mining from 1912 onward.
Sources: USGS MRDS; NMBGMR Tyrone Mine tour page; Western Mining History (Grant County); freeportinnewmexico.com; USGS Bull. 1348 (Johnson 1972) researched — see sources
Current status
Actively producing copper (SX/EW cathode only since the concentrator was suspended in 1992). Freeport-McMoRan's own New Mexico operations materials do not currently list gold/silver recovery at Tyrone — flagged as unconfirmed whether byproduct precious metals are presently recovered here.
Active within ~12 months
Continuously operating SX/EW copper production by Freeport-McMoRan; current byproduct gold/silver recovery not confirmed.
Land ownership & directions
Privately held — a mix of patented mining claims, ranch land, and corporate holdings. Mineral and surface rights may be held separately (split estate); accessing or exploring here requires the owner's permission or a lease/purchase agreement, not a BLM claim filing.
Private/patented, Freeport-McMoRan-owned. ~15 mi SW of Silver City.
See specimen photos (mindat.org) → — this app doesn’t host specimen photos itself; this searches mindat.org’s own mineral-specimen database, which isn’t necessarily specific to this exact district.
This pin is a generalized district/historic-site reference point, not a surveyed claim boundary — routes may cross private or patented inholdings where public access isn’t guaranteed even if a road reaches the site. Backcountry mine areas commonly have unmarked shafts, unstable ground, and no cell service; confirm current access and safety conditions (land manager, county, or landowner) before heading out.
Tailings reprocessing potential
The pre-1992 era ran a copper-focused flotation concentrator (real flotation tailings, byproduct gold); the current SX/EW leach-only operation produces a different kind of residue, not traditional tailings.
This is a documentary heuristic, not assay data.The tier above is inferred from historic production era, processing method, and ore character already cited elsewhere on this page — nobody has sampled or assayed this district’s tailings as part of this research. Actual recoverable gold content can only be established by physical sampling.
Reprocessing tailings is regulated mining. Disturbing or reprocessing historic mill waste requires the same NM Mining Act permitting as new mining (see the regulatory companion guide), regardless of who currently holds the claim or surface rights — and ownership of the tailings material itself is a separate legal question from mineral rights on the underlying land.
Legacy tailings can be hazardous. Pre-modern processing commonly used mercury (amalgamation) or cyanide (heap leach), and can carry elevated arsenic and other heavy metals — not a casual sampling target, and disturbing contaminated material can carry real environmental liability.
Geologist’s read
Included as a boundary case: geologically and historically a gold-bearing porphyry system, but current byproduct gold recovery could not be confirmed — don't assume every active Freeport copper operation in this belt is currently crediting gold. USGS Bulletin 1348 (Johnson 1972) separately states the district has "essentially no placer basis" — treat any placer-gold implication here as unsupported.