# Relationship history for MSHA mine 0503173

Current hierarchy: **Mallory Donald C → Rockcastle Company → Grassy Gap Coal Company #1 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

- **controller_controls_mine:** Mallory Donald C → Grassy Gap Coal Company #1 Mine; 1975-09-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rockcastle Company → Grassy Gap Coal Company #1 Mine; 1978-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mallory Donald C → Rockcastle Company; 1978-07-01 to current/open; source msha-controller-operator-history