# Relationship history for MSHA mine 1510449

Current hierarchy: **Curtis  Francis → Big Hill Mining Inc → 1a**

- 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:** Ora Mae Coal Company Inc → 1a; 1977-06-01 to 1987-01-20; source msha-controller-operator-history
- **controller_controls_mine:** Massey Energy Company → 1a; 1977-06-01 to 1987-01-20; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Ora Mae Coal Company Inc; 1977-06-01 to 1987-01-20; source msha-controller-operator-history
- **controller_controls_mine:** Curtis  Francis → 1a; 1982-03-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** A & A Francis Energy Inc → 1a; 1987-01-21 to 1990-04-11; source msha-controller-operator-history
- **controller_controls_mine:** Dean  Francis → 1a; 1987-01-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dean  Francis → A & A Francis Energy Inc; 1987-01-21 to 1990-04-11; source msha-controller-operator-history
- **operator_operates_mine:** Big Hill Mining Inc → 1a; 1990-04-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Curtis  Francis → Big Hill Mining Inc; 1990-04-12 to current/open; source msha-controller-operator-history