# Relationship history for MSHA mine 1510757

Current hierarchy: **Hugh  Holbrook → Holbrook Mining Company Inc → No 9 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:** Hugh  Holbrook → No 9 Mine; 1976-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B H & L Coals Inc → No 9 Mine; 1977-09-01 to 1978-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Lewis Lonnie B & Estill Blair → No 9 Mine; 1977-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lewis Lonnie B & Estill Blair → B H & L Coals Inc; 1977-09-01 to 1978-06-22; source msha-controller-operator-history
- **operator_operates_mine:** Holbrook Mining Company Inc → No 9 Mine; 1978-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hugh  Holbrook → Holbrook Mining Company Inc; 1978-06-23 to current/open; source msha-controller-operator-history