# Relationship history for MSHA mine 1514873

Current hierarchy: **Hill Zelma → Shevon Coal Inc → No 4 Mine**

- 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:** Hill Zelma → No 4 Mine; 1984-02-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Shevon Coal Inc → No 4 Mine; 1984-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hill Zelma → Shevon Coal Inc; 1984-09-01 to current/open; source msha-controller-operator-history