# Relationship history for MSHA mine 4201970

Current hierarchy: **George A  Thompson → Bryce Valley Builders → BRYCE VALLEY BUILDERS**

- 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:** Bryce Valley Builders → BRYCE VALLEY BUILDERS; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** George A  Thompson → BRYCE VALLEY BUILDERS; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George A  Thompson → Bryce Valley Builders; 1986-03-01 to current/open; source msha-controller-operator-history