# Relationship history for MSHA mine 0101543

Current hierarchy: **French Robert B Jr → Blackstone Coal Company → Blackstone No 1**

- 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:** Philip Hales Coal Sales → Blackstone No 1; 1976-08-01 to 1977-03-03; source msha-controller-operator-history
- **controller_controls_mine:** Hales Philip → Blackstone No 1; 1976-08-01 to 1977-03-03; source msha-controller-operator-history
- **controller_controls_operator:** Hales Philip → Philip Hales Coal Sales; 1976-08-01 to 1977-03-03; source msha-controller-operator-history
- **operator_operates_mine:** Blackstone Coal Company → Blackstone No 1; 1977-03-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** French Robert B Jr → Blackstone No 1; 1977-03-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** French Robert B Jr → Blackstone Coal Company; 1977-03-04 to current/open; source msha-controller-operator-history