# Relationship history for MSHA mine 1505173

Current hierarchy: **Lea Coal Company → Lea Coal Company → No 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Island Creek Coal Company → No 1-Mine; 1950-01-01 to 1973-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Occidental Petroleum Corp → No 1-Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Occidental Petroleum Corp → Island Creek Coal Company; 1950-01-01 to 1973-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Lea Coal Company → No 1-Mine; 1973-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lea Coal Company → No 1-Mine; 1973-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lea Coal Company → Lea Coal Company; 1973-08-01 to current/open; source msha-controller-operator-history