# Relationship history for MSHA mine 1510973

Current hierarchy: **Swanton Corp → T C Bell Inc → No 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:** T C Bell Inc → No 1 Surface; 1977-12-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Billy Ray  Carroll → No 1 Surface; 1977-12-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Billy Ray  Carroll → T C Bell Inc; 1977-12-01 to 1978-07-31; source msha-controller-operator-history
- **operator_operates_mine:** T C Bell Inc → No 1 Surface; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Swanton Corp → No 1 Surface; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Swanton Corp → T C Bell Inc; 1978-08-01 to current/open; source msha-controller-operator-history