# Relationship history for MSHA mine 2501173

Current hierarchy: **Nosal Darold F → Nosal Sand & Gravel → NOSAL 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Richard J Nosal → NOSAL PIT; 1997-05-01 to 2002-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Richard J Nosal → NOSAL PIT; 1997-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard J Nosal → Richard J Nosal; 1997-05-01 to 2002-05-01; source msha-controller-operator-history
- **operator_operates_mine:** Nosal Sand & Gravel → NOSAL PIT; 2002-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nosal Darold F → NOSAL PIT; 2002-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nosal Darold F → Nosal Sand & Gravel; 2002-05-02 to current/open; source msha-controller-operator-history