# Relationship history for MSHA mine 0401801

Current hierarchy: **Hanson PLC → Kaiser Sand & Gravel Company → Windsor Plant No 3**

- 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:** Quarry Products Inc → Windsor Plant No 3; 1950-01-01 to 1984-06-14; source msha-controller-operator-history
- **controller_controls_mine:** Mary  Bottoms → Windsor Plant No 3; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mary  Bottoms → Quarry Products Inc; 1950-01-01 to 1984-06-14; source msha-controller-operator-history
- **operator_operates_mine:** Piombo Corp → Windsor Plant No 3; 1984-06-15 to 1986-06-20; source msha-controller-operator-history
- **controller_controls_mine:** Centennial Savings & Loan Association → Windsor Plant No 3; 1984-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Centennial Savings & Loan Association → Piombo Corp; 1984-06-15 to 1986-06-20; source msha-controller-operator-history
- **operator_operates_mine:** Piombo Construction Company → Windsor Plant No 3; 1986-06-21 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_mine:** Felix H  Siri → Windsor Plant No 3; 1986-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Felix H  Siri → Piombo Construction Company; 1986-06-21 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Kaiser Sand & Gravel Company → Windsor Plant No 3; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Windsor Plant No 3; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Kaiser Sand & Gravel Company; 1988-11-14 to current/open; source msha-controller-operator-history