# Relationship history for MSHA mine 1102644

Current hierarchy: **Riggs Earl → Riggs Mine Company → Riggs No 2 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Riggs Mine Company → Riggs No 2 Mine; 1978-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Riggs Earl → Riggs No 2 Mine; 1978-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Riggs Earl → Riggs Mine Company; 1978-06-01 to current/open; source msha-controller-operator-history