# Relationship history for MSHA mine 4405447

Current hierarchy: **Blankenship Ralph → Comanche Coal Corp → No 4 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:** Patrick Petroleum Corp Of Michigan → No 4 Mine; 1978-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Patrick Coal Corp → No 4 Mine; 1980-06-01 to 1981-11-24; source msha-controller-operator-history
- **controller_controls_operator:** Patrick Petroleum Corp Of Michigan → Patrick Coal Corp; 1980-06-01 to 1981-11-24; source msha-controller-operator-history
- **controller_controls_mine:** Blankenship Ralph → No 4 Mine; 1980-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hammer Coal Company Inc → No 4 Mine; 1981-11-25 to 1984-08-06; source msha-controller-operator-history
- **controller_controls_mine:** Holmes James P → No 4 Mine; 1981-11-25 to 1984-08-06; source msha-controller-operator-history
- **controller_controls_operator:** Holmes James P → Hammer Coal Company Inc; 1981-11-25 to 1984-08-06; source msha-controller-operator-history
- **controller_controls_mine:** Potter Hersel E → No 4 Mine; 1982-02-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Yogi Mining Company Inc → No 4 Mine; 1984-08-07 to 1986-11-23; source msha-controller-operator-history
- **controller_controls_operator:** Potter Hersel E → Yogi Mining Company Inc; 1984-08-07 to 1986-11-23; source msha-controller-operator-history
- **operator_operates_mine:** Comanche Coal Corp → No 4 Mine; 1986-11-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blankenship Ralph → Comanche Coal Corp; 1986-11-24 to current/open; source msha-controller-operator-history