# Relationship history for MSHA mine 4202453

Current hierarchy: **Dena  Christensen → Christensen Const and Gravel Inc → Christensen  Wash Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Dena  Christensen → Christensen  Wash Plant; 1983-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Christensen Const and Gravel Inc → Christensen  Wash Plant; 2006-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dena  Christensen → Christensen Const and Gravel Inc; 2006-08-01 to current/open; source msha-controller-operator-history