# Relationship history for MSHA mine 3503446

Current hierarchy: **Darrell C  Hayden → Quality Rock Company → HAYDEN 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

- **controller_controls_mine:** Darrell C  Hayden → HAYDEN QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Quality Rock Company → HAYDEN QUARRY; 1997-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darrell C  Hayden → Quality Rock Company; 1997-08-01 to current/open; source msha-controller-operator-history