# Relationship history for MSHA mine 1511847

Current hierarchy: **Hensley Keith → Silver Diamond Energy 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Tony Smith Coal Company → No 1 Surface; 1979-04-01 to 1979-10-30; source msha-controller-operator-history
- **controller_controls_mine:** Smith Tony Et Al → No 1 Surface; 1979-04-01 to 1979-10-30; source msha-controller-operator-history
- **controller_controls_operator:** Smith Tony Et Al → Tony Smith Coal Company; 1979-04-01 to 1979-10-30; source msha-controller-operator-history
- **operator_operates_mine:** Silver Diamond Energy Inc → No 1 Surface; 1979-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hensley Keith → No 1 Surface; 1979-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hensley Keith → Silver Diamond Energy Inc; 1979-10-31 to current/open; source msha-controller-operator-history