# Relationship history for MSHA mine 4602242

Current hierarchy: **Biglow Corp → F & F Mining Corp → #1 Surface**

- 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:** F & F Mining Corp → #1 Surface; 1950-01-01 to 1985-11-26; source msha-controller-operator-history
- **controller_controls_mine:** G B  Frederick → #1 Surface; 1950-01-01 to 1985-11-26; source msha-controller-operator-history
- **controller_controls_operator:** G B  Frederick → F & F Mining Corp; 1950-01-01 to 1985-11-26; source msha-controller-operator-history
- **operator_operates_mine:** F & F Mining Corp → #1 Surface; 1985-11-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Biglow Corp → #1 Surface; 1985-11-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Biglow Corp → F & F Mining Corp; 1985-11-27 to current/open; source msha-controller-operator-history