# Relationship history for MSHA mine 1516798

Current hierarchy: **Daugherty William S → Daugherty Petroleum Inc → Durham Ridge Mine**

- 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

- **operator_operates_mine:** Daugherty Petroleum Inc → Durham Ridge Mine; 1989-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Daugherty William S → Durham Ridge Mine; 1989-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Daugherty William S → Daugherty Petroleum Inc; 1989-10-01 to current/open; source msha-controller-operator-history