# Relationship history for MSHA mine 1516875

Current hierarchy: **MAPCO Inc → Race Fork Coal Corp → K-2a**

- 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:** MAPCO Inc → K-2a; 1989-10-25 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Race Fork Coal Corp → K-2a; 1990-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MAPCO Inc → Race Fork Coal Corp; 1990-05-01 to current/open; source msha-controller-operator-history