Know your data sources.

Alaska Division of Geological & Geophysical Surveys — state geological survey. Mineral occurrences, geologic-map publication index, mining districts, volcanoes, radon observations. - searchMineralOccurrences ⭐ ~335 — DDS-18 MIL1, filter commodity / group / deposit type / status - searchGeologicMaps ⭐ ~4.16K USGS+DGGS publication index, filter agency / scale / keyword - searchMineralDistricts ⭐ 75 polygons across 14 regions - searchVolcanoes (~53 AVO inventory), getServiceInfo §0 spec drift: geology/statemap_projects + geophysics/Geophysical_Surveys services 500 ("No Layer or Table"). DROPPED. Volcanoes service rejects outFields=* with gateway error — handler enumerates explicit fields. Native CRS varies; outSR=4326 on every call.

Michigan DNR mineral leases, state-managed parcels, ownership, current rights, and conservation easements via the DNRLOTSParcelsOPENDATA FS on services3.arcgis.com. 6 curated layers from MI DNR LOTS Open Data. - searchMineralLeases ⭐ 5.5K leases (5097 O&G / 231 Metallic / 53 Nonmetallic / 66 Gas Storage / 61 Surface Use) - searchManagedLands ⭐ 135.9K parcels by division (Forest Resources / Parks & Rec / Wildlife) - searchDnrParcels 132.7K DNR-tracked parcels - searchConservationEasements ⭐ 1.3K development-rights easements - searchLeaseNominations 25 pending §0: research DEQ/Mineral_Lease/MapServer dead — live data via Hub discovery. Leases have empty geometry. Status A/E codes; LeaseType has trailing whitespace.

USGS MRDS + USMIN — global mineral deposits + US mine-feature points (no auth). Upstream (MapServer WFS 2.0.0): - /services/wfs/mrds — ms:mrds (~304K worldwide deposits) - /services/wfs/usmin — ms:points + ms:polygons (US only) Rich per-record JSON: /mrds/json/{dep_id} returns 26+ subtables (commodities, materials, ages, ore body, production, references, rocks). Filters: commodity (CU/AU/AG/FE/LI/U/REE/PGE…), country (FIPS), US state, dev_stat (Past Producer/Producer/Occurrence/Prospect/Plant/Raw Prospect), bbox. §0 quirks: CQL_FILTER silently ignored by MapServer — handler emits OGC FILTER= XML (fes:Filter). fips_code stored with literal "f" prefix (fCI / f06065). code_list space-separated with leading space.