# Relationship history for MSHA mine 1800754

Current hierarchy: **Raymond C  Ryczek; Thomas A  Ryczek → Ryczek Stone Quarry → RYCZEK 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:** Ryczek Stone Quarry → RYCZEK QUARRY; 2001-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Raymond C  Ryczek et al → RYCZEK QUARRY; 2001-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Raymond C  Ryczek et al → Ryczek Stone Quarry; 2001-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas A  Ryczek et al → Ryczek Stone Quarry; 2001-07-01 to current/open; source msha-controller-operator-history