# Relationship history for MSHA mine 3303302

Current hierarchy: **Calvin Harley E & William H → Harley E Calvin & Company → Oak Hill 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:** Calvin Harley E & William H → Oak Hill Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Harley E Calvin & Company → Oak Hill Strip; 1974-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Calvin Harley E & William H → Harley E Calvin & Company; 1974-05-01 to current/open; source msha-controller-operator-history