# Relationship history for MSHA mine 0504489

Current hierarchy: **Carl  Strohecker → Strohecker Asphalt & Paving, Inc. → 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Daves Excavation → PORTABLE CRUSHER; 1992-06-01 to 1993-07-13; source msha-controller-operator-history
- **controller_controls_mine:** Dave  Powers → PORTABLE CRUSHER; 1992-06-01 to 1993-07-13; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Powers → Daves Excavation; 1992-06-01 to 1993-07-13; source msha-controller-operator-history
- **operator_operates_mine:** Glen Wells Construction Inc → PORTABLE CRUSHER; 1993-07-14 to 1995-03-26; source msha-controller-operator-history
- **controller_controls_mine:** Glen  Wells → PORTABLE CRUSHER; 1993-07-14 to 1995-03-26; source msha-controller-operator-history
- **controller_controls_operator:** Glen  Wells → Glen Wells Construction Inc; 1993-07-14 to 1995-03-26; source msha-controller-operator-history
- **operator_operates_mine:** High-Tech Fab Inc → PORTABLE CRUSHER; 1995-03-27 to 2000-02-27; source msha-controller-operator-history
- **controller_controls_mine:** Jerry  Dunno → PORTABLE CRUSHER; 1995-03-27 to 2000-02-27; source msha-controller-operator-history
- **controller_controls_operator:** Jerry  Dunno → High-Tech Fab Inc; 1995-03-27 to 2000-02-27; source msha-controller-operator-history
- **operator_operates_mine:** Strohecker Asphalt & Paving, Inc. → PORTABLE CRUSHER; 2000-02-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Carl  Strohecker → PORTABLE CRUSHER; 2000-02-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carl  Strohecker → Strohecker Asphalt & Paving, Inc.; 2000-02-28 to current/open; source msha-controller-operator-history