# Relationship history for MSHA mine 1511273

Current hierarchy: **Hess Jimmie Leon → Big Buck Coal Company Inc → 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

- **operator_operates_mine:** Big Buck Coal Company → No 1; 1978-05-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Varney Barry & Garry → No 1; 1978-05-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Varney Barry & Garry → Big Buck Coal Company; 1978-05-01 to 1978-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Big Buck Coal Company Inc → No 1; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hess Jimmie Leon Et Al → No 1; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hess Jimmie Leon Et Al → Big Buck Coal Company Inc; 1978-08-01 to current/open; source msha-controller-operator-history