# Relationship history for MSHA mine 4604771

Current hierarchy: **Massey Energy Company → Rockridge Coal Company Inc → Toler Custom Cleaning Plant**

- 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:** Clear Fork Coal Company Inc → Toler Custom Cleaning Plant; 1975-06-01 to 1977-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Carroll Preston W → Toler Custom Cleaning Plant; 1975-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carroll Preston W → Clear Fork Coal Company Inc; 1975-06-01 to 1977-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Clear Fork Coal Company Inc → Toler Custom Cleaning Plant; 1977-07-01 to 1986-08-17; source msha-controller-operator-history
- **controller_controls_mine:** C-M Resources → Toler Custom Cleaning Plant; 1977-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** C-M Resources → Clear Fork Coal Company Inc; 1977-07-01 to 1986-08-17; source msha-controller-operator-history
- **operator_operates_mine:** Rockridge Coal Company Inc → Toler Custom Cleaning Plant; 1986-08-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Massey Energy Company → Toler Custom Cleaning Plant; 1986-08-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Rockridge Coal Company Inc; 1986-08-18 to current/open; source msha-controller-operator-history