# Relationship history for MSHA mine 1508140

Current hierarchy: **4-N Coal Co → 4-N Coal Company → No 2 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

- **controller_controls_mine:** 4-N Coal Co → No 2 Mine; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** 4-N Coal Company → No 2 Mine; 1975-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** 4-N Coal Co → 4-N Coal Company; 1975-06-15 to current/open; source msha-controller-operator-history