# Relationship history for MSHA mine 0203143

Current hierarchy: **Zachary  Stam; Miguel  Burrola → Southern Arizona Sand and Gravel LLC. → Padilla Crush and Screening Plant**

- 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:** Arizona General Engineering Contracting Inc → Padilla Crush and Screening Plant; 2006-10-23 to 2020-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Laurence  Harvey → Padilla Crush and Screening Plant; 2006-10-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Laurence  Harvey → Arizona General Engineering Contracting Inc; 2006-10-23 to 2020-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Southern Arizona Sand and Gravel LLC. → Padilla Crush and Screening Plant; 2020-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Zachary  Stam et al → Padilla Crush and Screening Plant; 2020-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zachary  Stam et al → Southern Arizona Sand and Gravel LLC.; 2020-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Miguel  Burrola et al → Southern Arizona Sand and Gravel LLC.; 2020-09-01 to current/open; source msha-controller-operator-history