# Relationship history for MSHA mine 4606751

Current hierarchy: **Patriot Coal Corporation → Apogee Coal Company LLC → Ruffner**

- 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:** Diamond Shamrock Corp → Ruffner; 1981-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Amherst Coal Company → Ruffner; 1984-03-01 to 1987-07-13; source msha-controller-operator-history
- **controller_controls_operator:** Diamond Shamrock Corp → Amherst Coal Company; 1984-03-01 to 1987-07-13; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Ruffner; 1987-05-19 to 2005-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Apogee Coal Company LLC → Ruffner; 1987-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Apogee Coal Company LLC; 1987-07-14 to 2005-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Magnum Coal Company → Ruffner; 2006-01-01 to 2008-07-22; source msha-controller-operator-history
- **controller_controls_operator:** Magnum Coal Company → Apogee Coal Company LLC; 2006-01-01 to 2008-07-22; source msha-controller-operator-history
- **controller_controls_mine:** Patriot Coal Corporation → Ruffner; 2008-07-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Patriot Coal Corporation → Apogee Coal Company LLC; 2008-07-23 to current/open; source msha-controller-operator-history