# Relationship history for MSHA mine 1512499

Current hierarchy: **Nichols Mark → Nafco Energy Corp → No 1 Surface**

- 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

- **operator_operates_mine:** Nafco Energy Corp → No 1 Surface; 1980-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nichols Mark → No 1 Surface; 1980-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nichols Mark → Nafco Energy Corp; 1980-08-01 to current/open; source msha-controller-operator-history