{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-07T13:22:16Z",
    "providers": [
      "Codex",
      "Grok"
    ],
    "missingProviders": [],
    "pass": 2,
    "cost": {
      "grok": {
        "usd": 0.01049138,
        "turns": 1,
        "seconds": 158.2,
        "error": null
      },
      "codex": {
        "seconds": 74.3,
        "error": "Reading additional input from stdin...\nOpenAI Codex v0.153.3\n--------\nworkdir: R:\\02_PROJECTS\\02_Meta_Models_Platforms\\Ver.cy\\current\\thing-registry-backlog\nmodel: gpt-6-astra\nprovider: openai\napproval: never\nsandbox: read-only\nreasoning effort: none\nreasoning summaries: none\nsession id: 01a07c05-bde0-7671-a152-818464d0fcad\n--------\nuser\nYou are drafting a Vercy meta-model for one registered thing. Answer as JSON only, no prose around it.\n\nThing: mud\nRegistry id: vr.tr.mud\nPlane / domain: PHY / PHY.MAT\nRegistry definition: (none recorded)\nNames folded into this entry: (none)\n\nA Vercy model say"
      }
    },
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-06T12:00:00Z",
      "ingestedAt": "2026-10-06T08:00:45+00:00",
      "fields": [
        "agent_conduct",
        "ethics",
        "failure_modes_and_hazards",
        "owners",
        "visual_identification"
      ]
    },
    "revisions": [
      {
        "at": "2026-10-07T11:14:07+00:00",
        "engine": "codex",
        "fields": [
          "definition",
          "distinguishing_features",
          "scope_statement",
          "visual_identification"
        ],
        "answering_review": "eb2d23abd05e99153a02171e2ca3a4282a32778d0f3e74a830f40b1df3370b1f"
      }
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    "gate": {
      "passed": true,
      "version": "1.0",
      "at": "2026-10-07T12:16:29+00:00",
      "evidence": [
        "completeness 1.00",
        "sense: Wikidata description",
        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "metaModel": {
    "id": "THING-Q170449",
    "registryId": "vr.tr.mud",
    "name": "mud",
    "version": "0.1.0-research.1",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "PHY.MAT"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q170449/",
  "model": {
    "registry_id": "vr.tr.mud",
    "name": "mud",
    "purpose": "Enable an agent to recognise mud, assess its current material behaviour and determine appropriate handling, use or further investigation.",
    "definition": "Mud is a mixture of water and any combination of soil, silt and clay, generally forming a soft or semi-fluid earth material whose consistency depends on its constituents and water content, without requiring silt or clay to dominate.",
    "scope_statement": "This model owns mud as a particular body or sample of water mixed with soil, silt, clay or any combination of them, including its constituents, water condition, consistency, spatial extent and response to disturbance; boundaries with neighbouring materials remain explicit where identification is uncertain.",
    "in_scope": [
      "Identification of a body or sample as mud, including ambiguous cases",
      "Mineral particles, water and associated organic or introduced constituents",
      "Consistency, water separation and changes during wetting or drying",
      "Thickness, extent and variation within a mud body",
      "Behaviour during loading, stirring, transport, placement and removal"
    ],
    "out_of_scope": [
      "The full soil profile, soil formation and land capability",
      "Sediment transport systems and depositional environments beyond the identified mud body",
      "Landslides, debris flows and other mass movement events",
      "Engineered drilling fluid formulations and drilling system operation",
      "Wastewater treatment processes and sludge management systems",
      "Finished earthen products, structures and their structural performance"
    ],
    "distinguishing_features": [
      "A wet earth mixture that smears or deforms can support identification as mud, while colour or location alone cannot establish it.",
      "Fine particles can influence consistency, but soil-water mixtures need not be dominated by silt or clay to qualify as mud.",
      "Particles forming a bulk material with appreciable consistency help distinguish mud from dilute muddy water, although the boundary can remain unresolved.",
      "Mineral particles, organic matter and process residues inform distinctions from peat, organic muck or sludge without making mineral dominance a requirement for mud.",
      "Origin and intended function help distinguish mud from an engineered slurry or drilling fluid, since the word mud alone does not establish equivalence."
    ],
    "characteristics": [
      {
        "name": "Material identification",
        "kind": "category",
        "unit_or_values": "mud; candidate mud; neighbouring material; unresolved, with evidence",
        "why_it_matters": "Prevents a familiar label from substituting for an assessment of the actual material."
      },
      {
        "name": "Particle size distribution",
        "kind": "measurement",
        "unit_or_values": "Dry mass percentage by declared particle size classes and test method",
        "why_it_matters": "Helps distinguish fine material from wet granular mixtures and interpret consistency."
      },
      {
        "name": "Water content",
        "kind": "measurement",
        "unit_or_values": "Percentage with declared wet mass or dry mass basis, sampling time and method",
        "why_it_matters": "Supports comparisons between samples and interpretation of wetting or drying changes."
      },
      {
        "name": "Constituent composition",
        "kind": "measurement",
        "unit_or_values": "Mineral, organic and introduced constituent fractions or concentrations, with analytical basis",
        "why_it_matters": "Composition can alter identification, behaviour and suitability for a proposed use."
      },
      {
        "name": "Observed consistency",
        "kind": "state",
        "unit_or_values": "Described response to a stated manipulation or test, including flow, smearing, cohesion and shape retention",
        "why_it_matters": "Connects recognition to observable behaviour under known conditions."
      },
      {
        "name": "Resistance to shear",
        "kind": "measurement",
        "unit_or_values": "Pa or kPa, with method, drainage condition and disturbance history",
        "why_it_matters": "Informs whether the material resists deformation under a specified action."
      },
      {
        "name": "Water separation condition",
        "kind": "state",
        "unit_or_values": "No visible separation; surface water; settling interface; drainage observed; unassessed",
        "why_it_matters": "Identifies changes in uniformity and the need to distinguish mud from adjacent water."
      },
      {
        "name": "Mud body geometry",
        "kind": "measurement",
        "unit_or_values": "Area in m², thickness in m and volume in m³, with spatial variation and uncertainty",
        "why_it_matters": "Supports estimates for sampling, handling and removal while exposing hidden thickness variation."
      },
      {
        "name": "Material origin",
        "kind": "relation",
        "unit_or_values": "Links to source soil, sediment, deposition event or mixing process, with confidence",
        "why_it_matters": "Provides context for constituent investigation and possible neighbouring classifications."
      },
      {
        "name": "Relevant contaminant status",
        "kind": "state",
        "unit_or_values": "Untested; suspected; tested, with named analytes, results, detection limits and intended use",
        "why_it_matters": "Prevents appearance from being used to infer suitability for contact, reuse or disposal."
      }
    ],
    "affordances": [
      "Inspect and sample distinct depths or patches to assess identification and variability.",
      "Measure water content, particle sizes and consistency using methods suited to the sample.",
      "Test changes caused by stirring, resting, wetting, drainage or drying.",
      "Assess excavation, pumping, scooping or placement against observed consistency and equipment requirements.",
      "Evaluate a specified reuse or removal route using constituent evidence and destination requirements."
    ],
    "agent_conduct": {
      "may": [
        "Describe and sample mud for soil, geological or environmental study where permitted.",
        "Warn people about mud on roads, paths and sites."
      ],
      "must_not": [
        "Discharge mud into watercourses or drains from sites it controls.",
        "Send people or vehicles across mudflats or soft mud without warning of the danger.",
        "Remove mud from protected wetlands or intertidal habitats without permission.",
        "Present contaminated mud as safe for therapy or cosmetic use without testing."
      ],
      "requires_human": [
        "Clearing mud after floods where contamination or structural damage is possible."
      ]
    },
    "ethics": {
      "considerations": [
        "Mudslides and flood mud destroy homes and livelihoods.",
        "Mudflats and wetlands are habitats for many species."
      ],
      "affected_parties": [
        "Residents of flood and slide areas",
        "Wetland wildlife",
        "Road users"
      ]
    },
    "owners": {
      "steward": "The owner of the land on which it lies; in tidal and public waters, the public authority.",
      "master_systems": []
    },
    "visual_identification": [
      "Mud commonly appears as soft, wet earth that deforms or sticks, with variable grain size and visible organic material.",
      "Some mud develops a glossy surface when wet or polygonal cracks as it dries."
    ],
    "failure_modes_and_hazards": [
      "People and vehicles can become trapped in deep or tidal mud.",
      "Mudflows and slides bury buildings and roads.",
      "Mud on roads causes skidding."
    ],
    "what_it_is_for": [
      "Mud occurs in waterlogged ground, river margins, wetlands and disturbed earth where water mixes with soil particles.",
      "It is encountered during construction, agriculture and environmental investigation, where its consistency affects movement, drainage and ground support."
    ],
    "standards_and_regulation": [
      "ISO 14688-1, issued by the International Organization for Standardization, provides identification and description rules for soil when mud is investigated as a geotechnical material.",
      "ISO 14688-2, issued by the International Organization for Standardization, provides soil classification principles applicable to the soil constituents of mud."
    ]
  },
  "sources": [
    {
      "id": "wentworth-1922",
      "title": "A Scale of Grade and Class Terms for Clastic Sediments - C. K. Wentworth, Journal of Geology (University of Chicago Press), 1922",
      "url": "",
      "what_it_supports": "Grain-size definition of mud as silt plus clay below the sand boundary (1/16 mm / 62.5 µm) and the Wentworth grade terms still used in sedimentology."
    },
    {
      "id": "iso-14688-1",
      "title": "ISO 14688-1:2017, Geotechnical investigation and testing - Identification and classification of soil - Part 1: Identification and description - International Organization for Standardization",
      "url": "",
      "what_it_supports": "Laboratory and field identification of silt and clay fractions, soil description practice, and the 0.063 mm sand-fines boundary used in European geotechnics."
    },
    {
      "id": "astm-d2487",
      "title": "ASTM D2487, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) - ASTM International",
      "url": "",
      "what_it_supports": "Engineering classification of fine-grained soils (CL, CH, ML, MH and organic analogues) that practitioners treat as mud when wet."
    },
    {
      "id": "api-13a",
      "title": "API Specification 13A / ISO 13500, Specification for Drilling Fluids Materials - American Petroleum Institute",
      "url": "",
      "what_it_supports": "Product specification of materials that constitute oilfield drilling mud and the industry sense in which \"mud\" names a circulating fluid rather than a natural sediment."
    },
    {
      "id": "wiki-mud",
      "title": "Mud - Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Mud",
      "what_it_supports": "Common-language and cross-domain overview of geological mud, construction mud, drilling mud and related hazards, used only as a map of senses, not as a primary technical authority.",
      "url_status": "live"
    },
    {
      "id": "wikidata",
      "title": "Wikidata item Q170449: mud",
      "url": "https://www.wikidata.org/wiki/Q170449",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    }
  ],
  "structure": {
    "bundles": [
      {
        "id": "mud-identity-and-constituents",
        "name": "Mud identity and constituents",
        "description": "Establish what material is being called mud and which constituent evidence supports that identification.",
        "rationale": "Mud can be confused with wet sand, muddy water, organic muck and process slurries, each of which may require different interpretation.",
        "layers": [
          {
            "id": "material-boundary",
            "name": "Material boundary",
            "description": "Record the evidence for recognising mud and the nearest competing identification.",
            "findings": [
              {
                "id": "basis-for-mud-identification",
                "name": "Basis for mud identification",
                "description": "Capture observations of the particulate mass, wetness and manipulation response without treating the supplied name as proof.",
                "questions": [
                  {
                    "text": "Which observations of wetness, fine particles, smearing or deformation support identifying this material as mud?",
                    "kind": "definition",
                    "id": "basis-for-mud-identification-q01"
                  },
                  {
                    "text": "What evidence distinguishes this sample from wet sand, muddy water, organic muck or an engineered slurry?",
                    "kind": "boundary",
                    "id": "basis-for-mud-identification-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "solid-and-liquid-constituents",
            "name": "Solid and liquid constituents",
            "description": "Describe the solids and liquid sufficiently to interpret the mixture rather than assuming all mud behaves alike.",
            "findings": [
              {
                "id": "constituent-evidence",
                "name": "Constituent evidence",
                "description": "Record particle size results, mineral and organic constituents, and evidence about the source of the water and solids.",
                "questions": [
                  {
                    "text": "What particle size distribution and mineral or organic fractions have been measured, using which classification and methods?",
                    "kind": "measurement",
                    "id": "constituent-evidence-q01"
                  },
                  {
                    "text": "Where did the solids and water originate, and what introduced substances could that origin require investigating?",
                    "kind": "provenance",
                    "id": "constituent-evidence-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "water-consistency-and-change",
        "name": "Water, consistency and change",
        "description": "Describe the mud's present water condition and how its consistency changes over time or with manipulation.",
        "rationale": "A mud identification alone does not indicate whether the material flows, holds a shape, separates or changes during handling.",
        "layers": [
          {
            "id": "present-water-and-consistency",
            "name": "Present water and consistency",
            "description": "Relate observed consistency to measured water content and the conditions of observation.",
            "findings": [
              {
                "id": "current-mixture-condition",
                "name": "Current mixture condition",
                "description": "Record water content, shape retention and flow response for a particular sample at a stated time.",
                "questions": [
                  {
                    "text": "What is the water content, on what mass basis, and when was the sample collected and measured?",
                    "kind": "measurement",
                    "id": "current-mixture-condition-q01"
                  },
                  {
                    "text": "Under a stated tilt, compression or stirring test, does the mud flow, smear, slump or retain its shape?",
                    "kind": "measurement",
                    "id": "current-mixture-condition-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "wetting-drying-and-rest",
            "name": "Wetting, drying and rest",
            "description": "Track observed changes under water exchange, disturbance and subsequent rest.",
            "findings": [
              {
                "id": "condition-change-response",
                "name": "Condition change response",
                "description": "Distinguish measured changes from assumptions about settling, drying, rewetting or recovery after stirring.",
                "questions": [
                  {
                    "text": "After a stated period of rest or drainage, what water separation, settling or consistency change is observed?",
                    "kind": "measurement",
                    "id": "condition-change-response-q01"
                  },
                  {
                    "text": "How does a controlled addition or removal of water change workability, and is that change reversed by restoring water?",
                    "kind": "action",
                    "id": "condition-change-response-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "mud-body-and-mechanical-response",
        "name": "Mud body and mechanical response",
        "description": "Locate the material, describe its internal variation and assess its response to a defined physical action.",
        "rationale": "A surface impression or isolated sample may conceal deeper, wetter or weaker mud that changes a handling decision.",
        "layers": [
          {
            "id": "extent-depth-and-variation",
            "name": "Extent, depth and variation",
            "description": "Identify the limits of the mud body and where sample observations apply.",
            "findings": [
              {
                "id": "representative-mud-body",
                "name": "Representative mud body",
                "description": "Record thickness, interfaces, inclusions and differences between the surface and interior.",
                "questions": [
                  {
                    "text": "What are the measured extent and thickness of the mud, and where are its interfaces with standing water or firmer material?",
                    "kind": "boundary",
                    "id": "representative-mud-body-q01"
                  },
                  {
                    "text": "How do water content and consistency vary across depth and location, including beneath any surface crust?",
                    "kind": "measurement",
                    "id": "representative-mud-body-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "loading-and-disturbance",
            "name": "Loading and disturbance",
            "description": "Describe deformation and resistance under conditions relevant to the proposed interaction.",
            "findings": [
              {
                "id": "response-to-specified-force",
                "name": "Response to specified force",
                "description": "Record the response to loading or shearing without assigning a universal strength from appearance.",
                "questions": [
                  {
                    "text": "What resistance to shear or penetration has been measured, under which drainage and sample disturbance conditions?",
                    "kind": "measurement",
                    "id": "response-to-specified-force-q01"
                  },
                  {
                    "text": "For the proposed contact pressure, duration and motion, what additional evidence is needed to assess sinking, displacement or loss of support?",
                    "kind": "action",
                    "id": "response-to-specified-force-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "handling-and-destination-fitness",
        "name": "Handling and destination fitness",
        "description": "Connect the mud's measured condition and constituent evidence to a particular handling method and destination.",
        "rationale": "Whether mud can be moved or used depends on its current consistency, inclusions and the requirements of the receiving process or place.",
        "layers": [
          {
            "id": "movement-and-conditioning",
            "name": "Movement and conditioning",
            "description": "Assess practical transfer methods and any necessary changes to water content or particle mixture.",
            "findings": [
              {
                "id": "handling-method-fit",
                "name": "Handling method fit",
                "description": "Match observed behaviour to scooping, excavation, pumping or placement requirements and identify conditioning trials.",
                "questions": [
                  {
                    "text": "Which observed consistency, coarse inclusions or debris constrain the proposed scoop, excavator, pump or container?",
                    "kind": "action",
                    "id": "handling-method-fit-q01"
                  },
                  {
                    "text": "What small-scale trial would establish whether mixing, screening or water removal makes the mud suitable for the intended transfer?",
                    "kind": "action",
                    "id": "handling-method-fit-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "contact-reuse-and-removal",
            "name": "Contact, reuse and removal",
            "description": "Record the evidence needed for a named exposure, reuse or receiving destination.",
            "findings": [
              {
                "id": "destination-specific-suitability",
                "name": "Destination-specific suitability",
                "description": "Keep material identification separate from a supported decision about contact, use or disposal.",
                "questions": [
                  {
                    "text": "Which constituent or contaminant measurements are required by the intended contact, reuse process or receiving destination, and which remain missing?",
                    "kind": "measurement",
                    "id": "destination-specific-suitability-q01"
                  },
                  {
                    "text": "Given those requirements and available results, is the proposed route supported, conditional on further work or unresolved?",
                    "kind": "action",
                    "id": "destination-specific-suitability-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "evidence-and-external-alignment",
        "name": "Evidence and external alignment",
        "description": "What the world already says about this thing, gathered so the model can be checked against it.",
        "rationale": "A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.",
        "layers": [
          {
            "id": "reported-evidence",
            "name": "Reported evidence",
            "description": "Findings from the breadth pass, kept separate from the structural claims.",
            "findings": [
              {
                "id": "evidence-kinds",
                "name": "Kinds and varieties",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  "Clayey mud and silty mud (textural classes used in sedimentology and geotechnics)",
                  "Fluid mud (high-concentration near-bed suspension in estuaries, harbours and navigation channels)",
                  "Drilling mud (engineered circulating fluid: water-, oil- or synthetic-based)",
                  "Red mud / bauxite residue from the Bayer process",
                  "Carbonate lime mud (silt- and clay-sized calcium carbonate sediment)",
                  "Peloid / therapeutic mud used in balneology",
                  "Earthen-construction mud (adobe, cob, wattle-and-daub)",
                  "Organic-rich anoxic mud (black harbour, lagoon and salt-marsh mud)"
                ],
                "questions": [
                  {
                    "id": "evidence-kinds-q01",
                    "text": "Which of these kinds and varieties hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-identifiers",
                "name": "Identifiers and schemes",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  {
                    "scheme": "Wikidata",
                    "value_or_pattern": "Q170378",
                    "note": "Item for mud as a material; confirm on the live item before treating the Q-id as canonical in a catalogue."
                  },
                  {
                    "scheme": "Wentworth / Folk grain-size class",
                    "value_or_pattern": "mud = sediment with a dominant fraction <62.5 µm (4 φ); Folk prefixes silty-/clayey- from the silt:clay ratio",
                    "note": "Descriptive class, not a registry code."
                  },
                  {
                    "scheme": "ISO 14688 particle-size fractions",
                    "value_or_pattern": "clay Cl <0.002 mm; silt Si 0.002-0.063 mm; together the fines that constitute mud",
                    "note": "European geotechnical identification, not a product SKU."
                  },
                  {
                    "scheme": "Unified Soil Classification System (ASTM D2487)",
                    "value_or_pattern": "CL, CH, ML, MH, OL, OH (and dual symbols with sand)",
                    "note": "Engineering group symbols for fine-grained soils that behave as mud when saturated."
                  },
                  {
                    "scheme": "EU List of Waste",
                    "value_or_pattern": "01 03 09 (red mud from alumina production); 17 05 06 (dredging spoil other than 17 05 05*)",
                    "note": "Waste codes for two industrial/harbour occurrences of mud, not for natural sediment in place."
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-identifiers-q01",
                    "text": "Which of these identifiers and schemes hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-standards-and-regulation",
                "name": "Standards and regulation",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  "ISO 14688-1 and ISO 14688-2 (International Organization for Standardization) - identification and classification of soil, including silt and clay.",
                  "ASTM D2487 Unified Soil Classification System and ASTM D4318 Atterberg limits (ASTM International) - engineering classification and plasticity of fine-grained soils.",
                  "EN 1997 Eurocode 7 (CEN) - geotechnical design on soft fine-grained ground.",
                  "API Spec 13A / ISO 13500 and API RP 13B-1 / ISO 10414-1 (American Petroleum Institute / ISO) - materials and field testing of drilling mud.",
                  "ASTM E2392 (ASTM International) - design of earthen wall building systems (adobe and related mud construction).",
                  "London Convention 1972 and London Protocol 1996 (IMO) - dumping of dredged mud at sea.",
                  "U.S. Clean Water Act section 404 and EPA/USACE dredged-material rules - excavation, placement and testing of estuarine and harbour mud.",
                  "Seveso-type major-accident and mining-waste rules (EU and national) - storage of red mud / bauxite residue after incidents such as Ajka (2010)."
                ],
                "questions": [
                  {
                    "id": "evidence-standards-and-regulation-q01",
                    "text": "Which of these standards and regulation hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-real-world-use",
                "name": "Real-world use",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  "Accumulates on tidal flats, river floodplains, lake beds, deltas and harbour basins, where it is mapped, dredged or left as habitat.",
                  "Carries and stores contaminants in ports; dredged mud is tested, confined, or reused as fill.",
                  "Used as the body of adobe bricks, cob walls and wattle-and-daub in dryland building.",
                  "Circulated as drilling mud to cool the bit, carry cuttings and control formation pressure in boreholes.",
                  "Applied as peloid in spas and as a raw feed in some ceramic and brick plants.",
                  "Red mud is stored in residue disposal areas at alumina refineries and is researched as a secondary raw material.",
                  "Forms the bed that fishing, aquaculture and wading-bird habitat occupy on muddy coasts.",
                  "Creates trafficability and foundation problems for roads, pipelines and light structures on soft ground."
                ],
                "questions": [
                  {
                    "id": "evidence-real-world-use-q01",
                    "text": "Which of these real-world use hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-measurements",
                "name": "Typical measurements",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  {
                    "quantity": "Particle size (sand-fines boundary / percent finer than 63 µm)",
                    "typical_range": "muds are typically >50 percent finer than 63; clay-sized fraction often 10-60",
                    "unit": "µm"
                  },
                  {
                    "quantity": "Gravimetric water content (mass water / dry solids)",
                    "typical_range": "plastic natural mud about 20-80; fluid mud commonly 100-400",
                    "unit": "%"
                  },
                  {
                    "quantity": "Bulk density",
                    "typical_range": "fluid mud about 1.03-1.30; plastic to firm natural mud about 1.3-1.8",
                    "unit": "g/cm³"
                  },
                  {
                    "quantity": "Undrained shear strength",
                    "typical_range": "very soft mud <12; soft about 12-25; firm mud higher",
                    "unit": "kPa"
                  },
                  {
                    "quantity": "Plasticity index (liquid limit minus plastic limit)",
                    "typical_range": "low-plasticity silty mud about 5-15; high-plasticity clay mud often 20-50 or more",
                    "unit": "%"
                  },
                  {
                    "quantity": "Yield stress (fluid mud)",
                    "typical_range": "order 0.1-10 in navigable fluid-mud layers, higher in gelled beds",
                    "unit": "Pa"
                  },
                  {
                    "quantity": "Organic-matter or organic-carbon content",
                    "typical_range": "mineral muds often <2-5 percent organic carbon; harbour and marsh muds higher",
                    "unit": "%"
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-measurements-q01",
                    "text": "Which of these typical measurements hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-failure-modes-and-hazards",
                "name": "Failure modes and hazards",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  "Slope failure and mudflows (including volcanic lahars) when saturated fines lose strength.",
                  "Quick-clay collapse in glaciated terrains (Fennoscandia, eastern Canada) after leaching of marine pore water.",
                  "Bearing-capacity failure, large settlement and loss of trafficability under foundations, plant and vehicles.",
                  "People and livestock trapped or drowned on tidal mudflats; poor rescue access.",
                  "Siltation and \"fluid-mud\" nautical-depth error in channels, causing grounding.",
                  "Remobilisation of bound metals, nutrients and persistent organics from contaminated harbour mud.",
                  "Hydrogen sulphide, anoxia and odour from reducing organic mud.",
                  "Caustic, high-pH release and dam failure of red-mud reservoirs.",
                  "Lost circulation, kicks and well-control failure when drilling mud density or chemistry is wrong.",
                  "Airborne silica and other dust from dried, trafficked mud."
                ],
                "questions": [
                  {
                    "id": "evidence-failure-modes-and-hazards-q01",
                    "text": "Which of these failure modes and hazards hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-regional-variation",
                "name": "Regional variation",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  "In petroleum English worldwide, \"mud\" primarily means drilling fluid, not natural sediment.",
                  "Sedimentologists internationally treat mud as silt plus clay below ~63 µm; U.S. engineering practice more often says \"fines\", \"silt\" or \"clay\" and reserves \"mud\" for field description.",
                  "German North Sea usage distinguishes Schlick (tidal-flat mud) from Schlamm (sludge-like mud); Dutch waterway practice uses slib for suspended/bed fines versus everyday modder.",
                  "Fluid-mud research and nautical-depth practice are especially developed on European hypertidal estuaries (e.g. Ems, Loire, Severn).",
                  "Adobe and mudbrick are living building systems in the Middle East, the Sahel, Andean and southwestern North American drylands; codes and mixes differ.",
                  "Red mud is an alumina-industry term (Australia, Brazil, China, Europe, Gulf) rather than a sedimentological class.",
                  "Quick-clay hazards and naming are concentrated in Norway, Sweden, Finland and eastern Canada."
                ],
                "questions": [
                  {
                    "id": "evidence-regional-variation-q01",
                    "text": "Which of these regional variation hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-neighbours",
                "name": "Neighbouring kinds and how to tell them apart",
                "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.",
                "evidence": [
                  {
                    "name": "Sand",
                    "difference": "Sand is coarser than 63 µm (ISO) or 62.5 µm (Wentworth); a wet handful of sand does not form a plastic ribbon, whereas mud does."
                  },
                  {
                    "name": "Silt (as a separate grade)",
                    "difference": "Silt is the 2-63 µm (or 4-62.5 µm) grade alone; mud is the combined silt-plus-clay population, often cohesive because of the clay."
                  },
                  {
                    "name": "Clay",
                    "difference": "Clay is either the <2 µm (ISO) or <4 µm (Wentworth) grade, or a clay-mineral suite; mud is a texture that may be clay-poor if silt dominates."
                  },
                  {
                    "name": "Soil",
                    "difference": "Soil has pedological structure, horizons and a living profile; mud is the unconsolidated wet sediment or remoulded fines without that organisation."
                  },
                  {
                    "name": "Sludge",
                    "difference": "Sludge is an organic-rich process residue (sewage, pulp, water-treatment); distinguish by origin, high volatile solids and treatment-plant context, not by grain size alone."
                  },
                  {
                    "name": "Slurry",
                    "difference": "Slurry is an engineered suspension (often of sand, tailings or cement) made to be pumped; mud may be natural and is defined by fines content and plasticity, not by being a designed mix."
                  },
                  {
                    "name": "Ooze",
                    "difference": "Pelagic ooze is deep-sea biogenic silt- and clay-sized sediment (calcareous or siliceous); lime mud on shelves is terrigenous-carbonate and is classified with the depositional setting and composition, not water depth alone."
                  },
                  {
                    "name": "Peat / mire",
                    "difference": "Peat is an organic wetland deposit that remains fibrous or humified plant matter; oven-dry organic content and von Post humification separate it from mineral mud with accessory organics."
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-neighbours-q01",
                    "text": "Which of these neighbouring kinds and how to tell them apart hold for the sense of mud this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  },
  "openQuestions": [
    "Which operational definition of mud should this registry adopt, and should it set any particle size or solids concentration boundaries?",
    "Does the registry intend mud to include engineered drilling mud and strongly organic mixtures, or should those uses link to neighbouring models?",
    "Which consistency and mechanical tests offer useful comparisons across mud types without implying that one test predicts every handling condition?",
    "How should the model represent transitions from muddy water to mud and from mud to dried material while preserving the identity of a tracked body?",
    "Which existing Vercy models own soil, sediment, slurry and sludge, and where would linking to them avoid duplicate coverage?"
  ],
  "statistics": {
    "bundles": 5,
    "layers": 9,
    "findings": 16,
    "questions": 24
  }
}
