# Relationship history for MSHA mine 3503577

Current hierarchy: **Nathan  Marple → Nathan Marple Excavation → Marple Gravel**

- 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:** Nathan Marple Excavation → Marple Gravel; 2003-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nathan  Marple → Marple Gravel; 2003-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nathan  Marple → Nathan Marple Excavation; 2003-05-19 to current/open; source msha-controller-operator-history