# Relationship history for MSHA mine 3606557

Current hierarchy: **Shearer Joseph H → Shearer Development Corp → Shearer Strip**

- 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:** Shearer Joseph H → Shearer Strip; 1974-09-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Shearer Development Corp → Shearer Strip; 1977-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shearer Joseph H → Shearer Development Corp; 1977-08-01 to current/open; source msha-controller-operator-history