# Relationship history for MSHA mine 1506670

Current hierarchy: **Bevins Willie → Big Lump Coal Company → No 1 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

- **operator_operates_mine:** Big Lump Coal Co → No 1 Mine; 1950-01-01 to 1975-03-20; source msha-controller-operator-history
- **controller_controls_mine:** Carter Mike → No 1 Mine; 1950-01-01 to 1975-03-20; source msha-controller-operator-history
- **controller_controls_operator:** Carter Mike → Big Lump Coal Co; 1950-01-01 to 1975-03-20; source msha-controller-operator-history
- **controller_controls_mine:** Bevins Willie → No 1 Mine; 1974-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big Lump Coal Company → No 1 Mine; 1975-03-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bevins Willie → Big Lump Coal Company; 1975-03-21 to current/open; source msha-controller-operator-history