# Relationship history for MSHA mine 4100997

Current hierarchy: **R C  Soares → R L White Company → Smyth 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:** Azrock Industries Inc → Smyth Quarry; 1950-01-01 to 1984-11-27; source msha-controller-operator-history
- **controller_controls_mine:** Clark William K → Smyth Quarry; 1950-01-01 to 1984-11-27; source msha-controller-operator-history
- **controller_controls_operator:** Clark William K → Azrock Industries Inc; 1950-01-01 to 1984-11-27; source msha-controller-operator-history
- **controller_controls_mine:** R C  Soares → Smyth Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R L White Company → Smyth Quarry; 1984-11-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R C  Soares → R L White Company; 1984-11-28 to current/open; source msha-controller-operator-history