# Relationship history for MSHA mine 0503217

Current hierarchy: **Anderson Duane → Mt Harris Coal Company → Mt Harris Coal Company**

- 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:** Mt Harris Coal Company → Mt Harris Coal Company; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Anderson Duane → Mt Harris Coal Company; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Anderson Duane → Mt Harris Coal Company; 1978-08-01 to current/open; source msha-controller-operator-history