# Relationship history for MSHA mine 1509791

Current hierarchy: **Sexton Willis → Little Block Coal Company → No 1**

- 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

- **controller_controls_mine:** Sexton Bill → No 1; 1976-03-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B & S Coal Co → No 1; 1976-06-28 to 1977-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Sexton Bill → B & S Coal Co; 1976-06-28 to 1977-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Little Block Coal Company → No 1; 1977-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sexton Willis → No 1; 1977-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sexton Willis → Little Block Coal Company; 1977-02-01 to current/open; source msha-controller-operator-history