# Relationship history for MSHA mine 1509406

Current hierarchy: **Spangler Fred R → B & F 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:** J & J Coal Company Inc → No 1 Mine; 1975-07-03 to 1977-04-17; source msha-controller-operator-history
- **controller_controls_mine:** Collins Jimmy & John Sexton → No 1 Mine; 1975-07-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Collins Jimmy & John Sexton → J & J Coal Company Inc; 1975-07-03 to 1977-04-17; source msha-controller-operator-history
- **operator_operates_mine:** B & F Coal Company → No 1 Mine; 1977-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Spangler Fred R Et Al → No 1 Mine; 1977-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Spangler Fred R Et Al → B & F Coal Company; 1977-04-18 to current/open; source msha-controller-operator-history