# Relationship history for MSHA mine 1800296

Current hierarchy: **Aggregate Industries PLC → Rockville Crushed Stone Inc → Aggregate Industries-Div/Rockville Crush**

- 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:** Lone Star Industries Inc → Aggregate Industries-Div/Rockville Crush; 1950-01-01 to 1980-11-18; source msha-controller-operator-history
- **controller_controls_mine:** Lone Star Industries Inc → Aggregate Industries-Div/Rockville Crush; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lone Star Industries Inc → Lone Star Industries Inc; 1950-01-01 to 1980-11-18; source msha-controller-operator-history
- **operator_operates_mine:** Aggregate Industries Inc → Aggregate Industries-Div/Rockville Crush; 1980-11-19 to 1986-06-27; source msha-controller-operator-history
- **controller_controls_mine:** Day Francis O Iii → Aggregate Industries-Div/Rockville Crush; 1980-11-19 to 1986-06-27; source msha-controller-operator-history
- **controller_controls_operator:** Day Francis O Iii → Aggregate Industries Inc; 1980-11-19 to 1986-06-27; source msha-controller-operator-history
- **operator_operates_mine:** Rockville Crushed Stone Inc → Aggregate Industries-Div/Rockville Crush; 1986-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Aggregate Industries-Div/Rockville Crush; 1986-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Rockville Crushed Stone Inc; 1986-06-28 to current/open; source msha-controller-operator-history