# Relationship history for MSHA mine 3606551

Current hierarchy: **Lingenfelter John F → Spring Valley Coal Company Inc → Valley Strip**

- 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:** Spring Valley Coal Company Inc → Valley Strip; 1977-10-01 to 1982-01-12; source msha-controller-operator-history
- **controller_controls_mine:** Lingenfelter John F → Valley Strip; 1977-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lingenfelter John F → Spring Valley Coal Company Inc; 1977-10-01 to 1982-01-12; source msha-controller-operator-history
- **operator_operates_mine:** Red Line Mining Corp → Valley Strip; 1982-01-13 to 1984-08-08; source msha-controller-operator-history
- **controller_controls_mine:** Blue Line Coal Company Inc → Valley Strip; 1982-01-13 to 1984-08-08; source msha-controller-operator-history
- **controller_controls_operator:** Blue Line Coal Company Inc → Red Line Mining Corp; 1982-01-13 to 1984-08-08; source msha-controller-operator-history
- **operator_operates_mine:** Josh Mining Company → Valley Strip; 1984-08-09 to 1987-10-26; source msha-controller-operator-history
- **controller_controls_mine:** Giron James & David Hillegas → Valley Strip; 1984-08-09 to 1987-10-26; source msha-controller-operator-history
- **controller_controls_operator:** Giron James & David Hillegas → Josh Mining Company; 1984-08-09 to 1987-10-26; source msha-controller-operator-history
- **operator_operates_mine:** Spring Valley Coal Company Inc → Valley Strip; 1987-10-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lingenfelter John F → Spring Valley Coal Company Inc; 1987-10-27 to current/open; source msha-controller-operator-history