# Relationship history for MSHA mine 0504962

Current hierarchy: **Sasha B  Sittner; Jeff G  Schlabach → Substratum Excavation → Quinn's Quarry**

- 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:** Substratum Excavation → Quinn's Quarry; 2010-07-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sasha B  Sittner et al → Quinn's Quarry; 2010-07-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sasha B  Sittner et al → Substratum Excavation; 2010-07-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeff G  Schlabach et al → Substratum Excavation; 2010-07-13 to current/open; source msha-controller-operator-history