# Relationship history for MSHA mine 1517237

Current hierarchy: **Evans John M & Phillip → Olympic Energy Inc → Surface #2**

- 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:** Olympic Energy Inc → Surface #2; 1992-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Evans John M & Phillip → Surface #2; 1992-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Evans John M & Phillip → Olympic Energy Inc; 1992-05-01 to current/open; source msha-controller-operator-history