# Relationship history for MSHA mine 4605515

Current hierarchy: **Pierce Ernest G → Pierce Coal & Construction Inc → No 2 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Pierce Ernest G → No 2 Surface; 1976-07-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pierce Coal & Construction Inc → No 2 Surface; 1977-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pierce Ernest G → Pierce Coal & Construction Inc; 1977-05-01 to current/open; source msha-controller-operator-history