# Relationship history for MSHA mine 1601100

Current hierarchy: **Summers Mark → A & M Construction Inc → Pit #1**

- 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:** Johnny F Smith Truck & Dragline Service Inc → Pit #1; 1986-08-01 to 1993-06-27; source msha-controller-operator-history
- **controller_controls_mine:** Johnny L  Smith → Pit #1; 1986-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnny L  Smith → Johnny F Smith Truck & Dragline Service Inc; 1986-08-01 to 1993-06-27; source msha-controller-operator-history
- **operator_operates_mine:** A & M Construction Inc → Pit #1; 1993-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Summers Mark → Pit #1; 1993-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Summers Mark → A & M Construction Inc; 1993-06-28 to current/open; source msha-controller-operator-history