# Relationship history for MSHA mine 1518308

Current hierarchy: **Kenneth L  Stacy → Coal Extraction LLC → Polly 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:** Sapphire Mining Inc → Polly Surface; 2000-12-01 to 2004-04-25; source msha-controller-operator-history
- **controller_controls_mine:** Michael K  Cook et al → Polly Surface; 2000-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael K  Cook et al → Sapphire Mining Inc; 2000-12-01 to 2004-04-25; source msha-controller-operator-history
- **controller_controls_operator:** Randy A  Cook et al → Sapphire Mining Inc; 2000-12-01 to 2004-04-25; source msha-controller-operator-history
- **operator_operates_mine:** Coal Extraction LLC → Polly Surface; 2004-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kenneth L  Stacy → Polly Surface; 2004-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth L  Stacy → Coal Extraction LLC; 2004-04-26 to current/open; source msha-controller-operator-history