# Relationship history for MSHA mine 3600111

Current hierarchy: **Richard E  Pierson → R.E. Pierson Materials Corp → Rheems 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:** Union Quarries Inc → Rheems Quarry; 1950-01-01 to 2002-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Mumma Robert M (Estate) & Max C Hempt → Rheems Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mumma Robert M (Estate) & Max C Hempt → Union Quarries Inc; 1950-01-01 to 2002-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Richard E  Pierson → Rheems Quarry; 1990-02-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Donegal Rock Products → Rheems Quarry; 2002-04-01 to 2008-11-23; source msha-controller-operator-history
- **controller_controls_mine:** Gerald P  Spearing  et al → Rheems Quarry; 2002-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gerald P  Spearing  et al → Donegal Rock Products; 2002-04-01 to 2008-11-23; source msha-controller-operator-history
- **operator_operates_mine:** R.E. Pierson Materials Corp → Rheems Quarry; 2008-11-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard E  Pierson → R.E. Pierson Materials Corp; 2008-11-24 to current/open; source msha-controller-operator-history