# Relationship history for MSHA mine 4502574

Current hierarchy: **Richard N  Christopherson → Ace Paving Company Inc → Dickey Pit**

- 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:** Richard N  Christopherson → Dickey Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ace Paving Company Inc → Dickey Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard N  Christopherson → Ace Paving Company Inc; 1978-03-09 to current/open; source msha-controller-operator-history