# Relationship history for MSHA mine 1401087

Current hierarchy: **R B  Killough → Killough Quarries Inc → Lawrence Quarry And Mill No 16**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Killough Quarries Inc → Lawrence Quarry And Mill No 16; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** R B  Killough → Lawrence Quarry And Mill No 16; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R B  Killough → Killough Quarries Inc; 1950-01-01 to current/open; source msha-controller-operator-history