# Relationship history for MSHA mine 3401882

Current hierarchy: **Adrion Dell  Watkins → Watkins Sand Co. Inc. → Rickner 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

- **controller_controls_mine:** Frank D  Watkins → Rickner Pit; 1950-01-01 to 2023-06-20; source msha-controller-operator-history
- **operator_operates_mine:** Watkins Sand Co. Inc. → Rickner Pit; 2002-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frank D  Watkins → Watkins Sand Co. Inc.; 2002-01-29 to 2023-06-20; source msha-controller-operator-history
- **controller_controls_mine:** Adrion Dell  Watkins → Rickner Pit; 2023-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Adrion Dell  Watkins → Watkins Sand Co. Inc.; 2023-06-21 to current/open; source msha-controller-operator-history