# Relationship history for MSHA mine 2501170

Current hierarchy: **Don  Rogert → Mallard Sand & Gravel Company → ROGERT SAND PIT #4**

- 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:** Don  Rogert → ROGERT SAND PIT #4; 1993-08-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mallard Sand & Gravel Company → ROGERT SAND PIT #4; 1996-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don  Rogert → Mallard Sand & Gravel Company; 1996-08-01 to current/open; source msha-controller-operator-history