# Relationship history for MSHA mine 4604807

Current hierarchy: **Occidental Petroleum Corp → Island Creek Coal Company → 17 Junior Ramp**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Occidental Petroleum Corp → 17 Junior Ramp; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Island Creek Coal Company → 17 Junior Ramp; 1975-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Occidental Petroleum Corp → Island Creek Coal Company; 1975-07-15 to current/open; source msha-controller-operator-history