# Relationship history for MSHA mine 0405136

Current hierarchy: **Mariposa County-Ca → Mariposa County Department Of Public Works → Yosemite Slate Quarry**

- 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:** Mariposa County Department Of Public Works → Yosemite Slate Quarry; 1991-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mariposa County-Ca → Yosemite Slate Quarry; 1991-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mariposa County-Ca → Mariposa County Department Of Public Works; 1991-02-01 to current/open; source msha-controller-operator-history