# Relationship history for MSHA mine 3600518

Current hierarchy: **Heidelberg Materials AG → Hanson Aggregates BMC Inc → Rich Hill Quarry**

- 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:** Commercial Stone Company Inc → Rich Hill Quarry; 1950-01-01 to 1999-10-03; source msha-controller-operator-history
- **controller_controls_mine:** Joseph H  Shearer → Rich Hill Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph H  Shearer → Commercial Stone Company Inc; 1950-01-01 to 1999-10-03; source msha-controller-operator-history
- **controller_controls_mine:** USS Holdings Inc → Rich Hill Quarry; 1996-03-09 to 2003-07-18; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates BMC Inc → Rich Hill Quarry; 1999-10-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USS Holdings Inc → Hanson Aggregates BMC Inc; 1999-10-04 to 2003-07-18; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Rich Hill Quarry; 2003-07-19 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates BMC Inc; 2003-07-19 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Rich Hill Quarry; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Hanson Aggregates BMC Inc; 2007-08-23 to current/open; source msha-controller-operator-history