Chloride Flat / Boston Hill / Silver City
Deposit type & geology
Carbonate-hosted Ag(-Pb-Mn) replacement.
Fusselman Dolomite and Montoya Fm. along a north-trending fracture zone.
Age: Likely Laramide-related, based on regional pluton associations.
Structural geology & terrain
Vein/structure orientation: N-trending fracture zone (Chloride Flat); NE-trending faults along the west side of the Silver City stock (Boston Hill)
Named controlling structure: Silver City stock (named intrusive body, not a fault)
Elevation range: ~5,900–6,400 ft
Rolling foothills, now a Silver City town trail system — not rugged.
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. Toggling to a different district turns this off.
Historical production
Silver-dominant: ~3.3M oz Ag (est.), with gold as a minor byproduct — NMBGMR estimates >50,000 oz Au district-wide but a directly reported figure in the same source is only 98 oz, an internal inconsistency the source itself doesn't reconcile. Manganiferous iron ore also mined 1916 and early 1940s.
Sources: USGS MRDS; USGS Bull. 1534; NMBGMR Resource Map 15; Town of Silver City AML Safeguard Project records researched — see sources
Current status
Reclaimed. Most of the Boston Hill portion (1,190 acres) is now Town of Silver City open space; a Phase I abandoned-mine safeguarding project addressed ~510 mine features. No current mining or exploration activity identified.
Dormant — no recent activity
No claim activity since conversion to municipal open space; AML safeguarding of ~510 mine features is complete.
Land ownership & directions
Public land held by a city or similar body, typically as open space or parkland — generally closed to new mineral entry regardless of federal mining law.
Town of Silver City open space, BLM, and private land. ~1 mi NW of downtown Silver City, paved and trail access.
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
Older (1870s–1940s) silver- and manganese-focused processing with gold only a minor byproduct, never the mill's target commodity — but the site is now municipal open space, foreclosing any reprocessing regardless of tailings quality.
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
A useful negative case: prime downtown-adjacent real estate with real historic silver-and-byproduct-gold production, permanently retired from mining via municipal open-space acquisition — land-use conversion, not geological exhaustion, closed this district.