# Relationship history for MSHA mine 3501041

Current hierarchy: **Darrel A  Nelson → Freeman Rock Inc → FREEMAN PORTABLE CRUSHER**

- 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:** Acco Contractors Inc → FREEMAN PORTABLE CRUSHER; 1950-01-01 to 1977-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Acco Contractors → FREEMAN PORTABLE CRUSHER; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Acco Contractors → Acco Contractors Inc; 1950-01-01 to 1977-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Freeman Rock Inc → FREEMAN PORTABLE CRUSHER; 1977-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ted L  Freeman Jr → FREEMAN PORTABLE CRUSHER; 1977-04-01 to 2016-02-25; source msha-controller-operator-history
- **controller_controls_operator:** Ted L  Freeman Jr → Freeman Rock Inc; 1977-04-01 to 2016-02-25; source msha-controller-operator-history
- **controller_controls_mine:** Darrel A  Nelson → FREEMAN PORTABLE CRUSHER; 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