# Relationship history for MSHA mine 3602120

Current hierarchy: **Adams Robert L → H A T Coal Company → No 2 Slope**

- 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:** 4 D Coal Company → No 2 Slope; 1950-01-01 to 1981-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Derck Robert-Robert Adams Et Al → No 2 Slope; 1950-01-01 to 1981-10-18; source msha-controller-operator-history
- **controller_controls_operator:** Derck Robert-Robert Adams Et Al → 4 D Coal Company; 1950-01-01 to 1981-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Adams Robert L Et Al → No 2 Slope; 1981-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** H A T Coal Company → No 2 Slope; 1981-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Adams Robert L Et Al → H A T Coal Company; 1981-10-19 to current/open; source msha-controller-operator-history