# Relationship history for MSHA mine 4500574

Current hierarchy: **Taiheiyo Cement Corp → Smokey Point Concrete → Smokey Point Pit**

- 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:** Arlington Sand & Gravel → Smokey Point Pit; 1950-01-01 to 1984-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Michael G  Brown → Smokey Point Pit; 1950-01-01 to 1984-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Michael G  Brown → Arlington Sand & Gravel; 1950-01-01 to 1984-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Arlington Sand & Gravel Inc → Smokey Point Pit; 1984-06-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Jane A  Hallock → Smokey Point Pit; 1984-06-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Jane A  Hallock → Arlington Sand & Gravel Inc; 1984-06-01 to 1990-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Arlington Sand & Gravel → Smokey Point Pit; 1990-10-01 to 1992-03-23; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → Smokey Point Pit; 1990-10-01 to 1992-03-23; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → Arlington Sand & Gravel; 1990-10-01 to 1992-03-23; source msha-controller-operator-history
- **operator_operates_mine:** Smokey Point Concrete Inc → Smokey Point Pit; 1992-03-24 to 2014-03-04; source msha-controller-operator-history
- **controller_controls_mine:** Mark D  Crawford → Smokey Point Pit; 1992-03-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark D  Crawford → Smokey Point Concrete Inc; 1992-03-24 to 2014-03-04; source msha-controller-operator-history
- **operator_operates_mine:** Smokey Point Concrete → Smokey Point Pit; 2014-03-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → Smokey Point Pit; 2014-03-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → Smokey Point Concrete; 2014-03-05 to current/open; source msha-controller-operator-history