{
  "schema_version": "1.0.0",
  "last_reviewed": "2026-08-22",
  "scope": "silver",
  "description": "Silver-specific sources plus sources explicitly shared by both metals.",
  "sources": [
    {
      "id": "usgs-mcs-2026-silver",
      "publisher": "U.S. Geological Survey",
      "dataset_name": "Mineral Commodity Summaries 2026 - Silver",
      "label": "USGS Mineral Commodity Summaries 2026 - Silver",
      "href": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf",
      "licence_name": "U.S. public domain",
      "licence_url": "https://www.usgs.gov/faqs/are-usgs-reportspublications-copyrighted",
      "required_attribution": "Credit: U.S. Geological Survey.",
      "allowed_use_notes": "USGS-authored data and information are in the U.S. public domain. Check individually marked third-party elements before reuse.",
      "retrieval_method": "Official PDF snapshot with table transcription and checksum verification",
      "update_frequency": "Annual",
      "expected_reporting_lag": "The 2026 summary reports estimated 2025 production.",
      "last_successful_retrieval": "2026-07-28T23:52:00-04:00",
      "checksum": "sha256:f0dfe407304855a51f7647fc711f6c32081188a86269d011cd45e297aa673855",
      "human_review_notes": "The table names 14 countries. Other countries and World are aggregates and are excluded from per-capita rankings.",
      "role": "Silver mine production and underground reserves",
      "metals": [
        "silver"
      ],
      "access": "open",
      "publication_status": "approved"
    },
    {
      "id": "world-bank-pink-sheet",
      "publisher": "World Bank",
      "dataset_name": "Commodity Price Data (The Pink Sheet)",
      "label": "World Bank Commodity Price Data (The Pink Sheet)",
      "href": "https://www.worldbank.org/en/research/commodity-markets",
      "licence_name": "Creative Commons Attribution 4.0",
      "licence_url": "https://creativecommons.org/licenses/by/4.0/",
      "required_attribution": "World Bank Commodity Price Data (The Pink Sheet).",
      "allowed_use_notes": "Annual and monthly nominal price observations may be shared and adapted with attribution under CC BY 4.0.",
      "retrieval_method": "Official annual and monthly XLSX snapshots with checksums",
      "update_frequency": "Monthly",
      "expected_reporting_lag": "Approximately one month for the monthly workbook",
      "last_successful_retrieval": "2026-08-11",
      "checksum": "sha256:7902a77505ebdc5d202ce65f666c2ee1b04b626f042d7738ed3e6f7d112c8433",
      "human_review_notes": "Gold and silver use the same nominal U.S.-dollar-per-troy-ounce workbook columns. Ratios are derived from matched periods.",
      "role": "Historical gold and silver prices and derived ratio",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "open",
      "publication_status": "approved"
    },
    {
      "id": "usgs-ds140-silver",
      "publisher": "U.S. Geological Survey",
      "dataset_name": "Silver Historical Statistics, Data Series 140",
      "label": "USGS Silver Historical Statistics",
      "href": "https://www.usgs.gov/media/files/silver-historical-statistics-data-series-140",
      "licence_name": "U.S. public domain",
      "licence_url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
      "required_attribution": "Credit: U.S. Geological Survey, Data Series 140.",
      "allowed_use_notes": "USGS-authored data and information are in the U.S. public domain.",
      "retrieval_method": "Official XLSX snapshot with checksum verification",
      "update_frequency": "Periodic",
      "expected_reporting_lag": "The current workbook ends in 2021.",
      "last_successful_retrieval": "2026-08-11",
      "checksum": "sha256:e57b952a5fd469291341bf275fbaa1c20dfd0caa9b40f383a2a19076efa9e997",
      "human_review_notes": "Mine production, world production and U.S. apparent consumption are retained as separate fields; unavailable cells remain null.",
      "role": "Long-run silver production and U.S. consumption history",
      "metals": [
        "silver"
      ],
      "access": "open",
      "publication_status": "approved"
    },
    {
      "id": "usgs-mcs-2026-research-data",
      "publisher": "U.S. Geological Survey",
      "dataset_name": "Mineral Commodity Summaries 2026 Data Release",
      "label": "USGS Mineral Commodity Summaries 2026 data release",
      "href": "https://doi.org/10.5066/P1WKQ63T",
      "licence_name": "U.S. public domain",
      "licence_url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
      "required_attribution": "Credit: U.S. Geological Survey, Mineral Commodity Summaries 2026.",
      "allowed_use_notes": "The USGS data release is labelled U.S. public domain; individually marked third-party media are not used.",
      "retrieval_method": "Official ScienceBase CSV snapshot with checksum verification",
      "update_frequency": "Annual with revisions",
      "expected_reporting_lag": "The 2026 release contains 2021 through estimated 2025 observations.",
      "last_successful_retrieval": "2026-08-11",
      "checksum": "sha256:582a0aa231aea53d8a97dc8d1cd3dfa5f885cf3760353e3d029d7f0ae4fbaaf5",
      "human_review_notes": "Used for current production context, U.S. silver demand context and the narrow U.S. Treasury gold series.",
      "role": "Current gold and silver production, demand and Treasury-gold context",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "open",
      "publication_status": "approved"
    },
    {
      "id": "silver-institute",
      "publisher": "The Silver Institute",
      "dataset_name": "World Silver Survey and market materials",
      "label": "The Silver Institute",
      "href": "https://silverinstitute.org/silver-supply-demand/",
      "licence_name": "Silver Institute copyright terms",
      "licence_url": "https://silverinstitute.org/copyright/",
      "required_attribution": "Written permission may be required for reproduction of tables, graphs or extracts.",
      "allowed_use_notes": "Methodological context only. Do not scrape, copy or redistribute tables without confirmed permission.",
      "retrieval_method": "Human contextual review only",
      "update_frequency": "Annual",
      "expected_reporting_lag": "Varies",
      "last_successful_retrieval": null,
      "checksum": null,
      "human_review_notes": "Not a publication source for measured country rows.",
      "role": "Context for the experimental above-ground model only",
      "metals": [
        "silver"
      ],
      "access": "permission-required",
      "publication_status": "excluded-from-measured-publication-inputs"
    },
    {
      "id": "un-wpp-2024",
      "publisher": "United Nations, Department of Economic and Social Affairs, Population Division",
      "dataset_name": "World Population Prospects 2024",
      "label": "UN World Population Prospects 2024",
      "href": "https://population.un.org/wpp/",
      "licence_name": "United Nations data terms",
      "licence_url": "https://www.un.org/en/about-us/terms-of-use",
      "required_attribution": "United Nations, Department of Economic and Social Affairs, Population Division, World Population Prospects 2024.",
      "allowed_use_notes": "Use the same annual mid-year resident-population series consistently across a release.",
      "retrieval_method": "UN WPP bulk CSV",
      "update_frequency": "Revision cycle with annual values",
      "expected_reporting_lag": "Projection vintage",
      "last_successful_retrieval": "2026-07-28",
      "checksum": null,
      "human_review_notes": "The current universe stores 2025 and 2026 mid-year values from the medium projection.",
      "role": "Population denominator",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "open-with-terms",
      "publication_status": "approved"
    },
    {
      "id": "un-m49",
      "publisher": "United Nations Statistics Division",
      "dataset_name": "Standard country or area codes for statistical use",
      "label": "UN M49 country and area standard",
      "href": "https://unstats.un.org/unsd/methodology/m49/",
      "licence_name": "United Nations website terms",
      "licence_url": "https://www.un.org/en/about-us/terms-of-use",
      "required_attribution": "United Nations Statistics Division.",
      "allowed_use_notes": "Used for stable geography identifiers and aggregate exclusion.",
      "retrieval_method": "Official web table",
      "update_frequency": "As updated",
      "expected_reporting_lag": "Not applicable",
      "last_successful_retrieval": "2026-07-28",
      "checksum": null,
      "human_review_notes": "Sovereign-state universe includes 193 UN member states, Palestine and Vatican City.",
      "role": "Entity identity and classification",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "open-with-terms",
      "publication_status": "approved"
    },
    {
      "id": "world-bank-country-groups",
      "publisher": "World Bank",
      "dataset_name": "Country and lending groups",
      "label": "World Bank country and lending groups",
      "href": "https://datahelpdesk.worldbank.org/knowledgebase/articles/906519",
      "licence_name": "World Bank data terms",
      "licence_url": "https://www.worldbank.org/en/about/legal/terms-of-use-for-datasets",
      "required_attribution": "World Bank.",
      "allowed_use_notes": "Used only as a covariate in the experimental legacy model.",
      "retrieval_method": "Official metadata table",
      "update_frequency": "Annual",
      "expected_reporting_lag": "Annual classification",
      "last_successful_retrieval": "2026-07-28",
      "checksum": null,
      "human_review_notes": "Not used in measured silver production or reserves.",
      "role": "Experimental model grouping",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "open-with-terms",
      "publication_status": "experimental-only"
    },
    {
      "id": "research-model-v2",
      "publisher": "Metal Per Capita",
      "dataset_name": "Legacy global peer model",
      "label": "Metal Per Capita legacy peer model",
      "href": "/experimental",
      "licence_name": "Project-authored research method",
      "licence_url": null,
      "required_attribution": "Metal Per Capita.",
      "allowed_use_notes": "Experimental development output. It must not be presented with the same authority as reported or source-compiled data.",
      "retrieval_method": "Deterministic source-code model",
      "update_frequency": "Frozen pending redesign",
      "expected_reporting_lag": "Not applicable",
      "last_successful_retrieval": "2026-07-28",
      "checksum": null,
      "human_review_notes": "Uses manually encoded anchors and model calibration totals. Retained for research continuity but removed from the primary Silver product.",
      "role": "Experimental above-ground holdings model",
      "metals": [
        "gold",
        "silver"
      ],
      "access": "research-reference",
      "publication_status": "experimental-only"
    }
  ]
}