# Relationship history for MSHA mine 3503629

Current hierarchy: **Darrel A  Nelson → FREEMAN ROCK, INC. → PORTABLE POWERSCREEN**

- 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

- **controller_controls_mine:** Ted L  Freeman Jr → PORTABLE POWERSCREEN; 1977-04-01 to 2016-02-25; source msha-controller-operator-history
- **operator_operates_mine:** FREEMAN ROCK, INC. → PORTABLE POWERSCREEN; 2006-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ted L  Freeman Jr → FREEMAN ROCK, INC.; 2006-02-14 to 2016-02-25; source msha-controller-operator-history
- **controller_controls_mine:** Darrel A  Nelson → PORTABLE POWERSCREEN; 2016-02-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darrel A  Nelson → FREEMAN ROCK, INC.; 2016-02-26 to current/open; source msha-controller-operator-history