# Relationship history for MSHA mine 4201983

Current hierarchy: **Brent L  Christensen → Christensen Brothers Rock Products Inc → Christensen Brothers 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

- **operator_operates_mine:** Christensen Brothers Rock Products Inc → Christensen Brothers Pit; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brent L  Christensen et al → Christensen Brothers Pit; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brent L  Christensen et al → Christensen Brothers Rock Products Inc; 1986-07-01 to current/open; source msha-controller-operator-history