# Relationship history for MSHA mine 3607720

Current hierarchy: **Fourway Participation Company B V → Ridgewood Mining Inc → Spillway Site**

- 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:** Revere Coal Reclamation Inc → Spillway Site; 1985-07-01 to 1987-08-16; source msha-controller-operator-history
- **controller_controls_mine:** Cambell Tommye-David A Leytze Et Al → Spillway Site; 1985-07-01 to 1987-08-16; source msha-controller-operator-history
- **controller_controls_operator:** Cambell Tommye-David A Leytze Et Al → Revere Coal Reclamation Inc; 1985-07-01 to 1987-08-16; source msha-controller-operator-history
- **operator_operates_mine:** Uniontech Partners Inc → Spillway Site; 1987-08-17 to 1989-05-18; source msha-controller-operator-history
- **controller_controls_mine:** Karsnak George → Spillway Site; 1987-08-17 to 1989-05-18; source msha-controller-operator-history
- **controller_controls_operator:** Karsnak George → Uniontech Partners Inc; 1987-08-17 to 1989-05-18; source msha-controller-operator-history
- **operator_operates_mine:** Ridgewood Mining Inc → Spillway Site; 1989-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fourway Participation Company B V → Spillway Site; 1989-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fourway Participation Company B V → Ridgewood Mining Inc; 1989-05-19 to current/open; source msha-controller-operator-history