# Relationship history for MSHA mine 2602289

Current hierarchy: **Christensen Milton → Environmental Health Science Llc → ENVIROMENTAL HLTH 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:** Environmental Health Science Llc → ENVIROMENTAL HLTH MINE; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Christensen Milton → ENVIROMENTAL HLTH MINE; 2013-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christensen Milton → Environmental Health Science Llc; 2013-10-28 to current/open; source msha-controller-operator-history