# Relationship history for MSHA mine 1513325

Current hierarchy: **Frost Ranny B → Rand Energy Inc → Frost Coal No 28 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Rand Energy Inc → Frost Coal No 28 Strip; 1982-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Frost Ranny B → Frost Coal No 28 Strip; 1982-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frost Ranny B → Rand Energy Inc; 1982-01-01 to current/open; source msha-controller-operator-history