# Relationship history for MSHA mine 3401872

Current hierarchy: **Joseph L  Parker Jr → Anchor Stone Co → 81ST STREET SAND PLANT**

- 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:** Joseph L  Parker Jr → 81ST STREET SAND PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Anchor Stone Co → 81ST STREET SAND PLANT; 2001-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph L  Parker Jr → Anchor Stone Co; 2001-08-01 to current/open; source msha-controller-operator-history