# Relationship history for MSHA mine 0503929

Current hierarchy: **Sundance Oil Company → Sundance Coal Company → Helen #2 (Strip)**

- 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

- **controller_controls_mine:** Sundance Oil Company → Helen #2 (Strip); 1982-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sundance Coal Company → Helen #2 (Strip); 1984-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sundance Oil Company → Sundance Coal Company; 1984-01-01 to current/open; source msha-controller-operator-history