Cauldron bottom

{
  "id": "MLC-T-IND-001009",
  "term": "Cauldron bottom",
  "field": "Industrial and trades",
  "definition": "A smooth, rounded mass of rock, in many cases the cast of a fossil tree stump, embedded in the roof of a coal seam and surrounded by glossy slickensided surfaces. Because it is poorly bonded to the surrounding rock, it can drop out without warning, so it is a recognised roof hazard in underground coal mining. In Britain the same feature is also called a pot bottom or kettle bottom.",
  "synonyms": [
    "cauldron arse"
  ],
  "subject": "Shop talk and trade slang",
  "references": [
    "Mining: Vocabulary (ISO)"
  ],
  "translations": {
    "de": "Kesselrund",
    "es": "fondo de caldera",
    "fr": "fond de chaudron"
  },
  "url": "https://mlchart.com/terminology/industrial/cauldron-bottom/"
}