# Relationship history for MSHA mine 4502695

Current hierarchy: **Schwartz Dave & Roger Olson → Chelatchie Rock Products → Park Pit #2**

- 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

- **controller_controls_mine:** Schwartz Dave & Roger Olson → Park Pit #2; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Delhur Inc → Park Pit #2; 1979-01-01 to 1981-08-26; source msha-controller-operator-history
- **controller_controls_mine:** Samuel G  Hurworth → Park Pit #2; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Samuel G  Hurworth → Delhur Inc; 1979-01-01 to 1981-08-26; source msha-controller-operator-history
- **operator_operates_mine:** Chelatchie Rock Products → Park Pit #2; 1981-08-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schwartz Dave & Roger Olson → Chelatchie Rock Products; 1981-08-27 to current/open; source msha-controller-operator-history