# Relationship history for MSHA mine 3607211

Current hierarchy: **Harner Roy E & Delbert L Artz → Part Time Coal Company → Legal Silt Bank**

- 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:** Part Time Coal Company → Legal Silt Bank; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harner Roy E & Delbert L Artz → Legal Silt Bank; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harner Roy E & Delbert L Artz → Part Time Coal Company; 1981-09-01 to current/open; source msha-controller-operator-history