# Relationship history for MSHA mine 1900002

Current hierarchy: **James E  Bristol Jr → Bates Brothers Seam-Face Granite Company → Walpole 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:** Bates Brothers Seam-Face Granite Company → Walpole Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James E  Bristol Jr → Walpole Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James E  Bristol Jr → Bates Brothers Seam-Face Granite Company; 1950-01-01 to current/open; source msha-controller-operator-history