# Relationship history for MSHA mine 0503502

Current hierarchy: **Roaring Fork Coal Corp & Lark Mng Corp → Snowmass Coal Company → Unit Train Loadout Facility**

- 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:** Roaring Fork Coal Corp & Lark Mng Corp → Unit Train Loadout Facility; 1978-12-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Snowmass Coal Company → Unit Train Loadout Facility; 1979-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roaring Fork Coal Corp & Lark Mng Corp → Snowmass Coal Company; 1979-10-01 to current/open; source msha-controller-operator-history