# Relationship history for MSHA mine 1519473

Current hierarchy: **John T  Quintrell → Smoky Quartz → Advantage No. 1 Air Shaft**

- 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

- **controller_controls_mine:** United  Company → Advantage No. 1 Air Shaft; 2004-11-15 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Metinvest B V → Advantage No. 1 Air Shaft; 2009-04-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sapphire Coal Company → Advantage No. 1 Air Shaft; 2010-03-15 to 2021-08-04; source msha-controller-operator-history
- **controller_controls_operator:** Metinvest B V → Sapphire Coal Company; 2010-03-15 to 2021-08-04; source msha-controller-operator-history
- **controller_controls_operator:** United  Company → Sapphire Coal Company; 2010-03-15 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** John T  Quintrell → Advantage No. 1 Air Shaft; 2021-07-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Smoky Quartz → Advantage No. 1 Air Shaft; 2021-08-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John T  Quintrell → Smoky Quartz; 2021-08-05 to current/open; source msha-controller-operator-history