# Relationship history for MSHA mine 1700880

Current hierarchy: **Mark A  Leighton → Leighton's Excavation → M-T Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Leighton's Excavation → M-T Pit; 2011-06-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark A  Leighton → M-T Pit; 2011-06-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark A  Leighton → Leighton's Excavation; 2011-06-02 to current/open; source msha-controller-operator-history