# Relationship history for MSHA mine 1401301

Current hierarchy: **R B  Killough → Killough Quarries Inc → Princeton Quarry (20)**

- 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

- **controller_controls_mine:** N R  Hamm → Princeton Quarry (20); 1950-01-01 to 2012-02-08; source msha-controller-operator-history
- **controller_controls_mine:** R B  Killough → Princeton Quarry (20); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Killough Quarries Inc → Princeton Quarry (20); 1979-10-01 to 1980-09-09; source msha-controller-operator-history
- **controller_controls_operator:** R B  Killough → Killough Quarries Inc; 1979-10-01 to 1980-09-09; source msha-controller-operator-history
- **operator_operates_mine:** N R Hamm Quarry Inc → Princeton Quarry (20); 1980-09-10 to 1984-10-03; source msha-controller-operator-history
- **controller_controls_operator:** N R  Hamm → N R Hamm Quarry Inc; 1980-09-10 to 1984-10-03; source msha-controller-operator-history
- **operator_operates_mine:** Killough Quarries Inc → Princeton Quarry (20); 1984-10-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R B  Killough → Killough Quarries Inc; 1984-10-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Princeton Quarry (20); 2012-02-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → N R Hamm Quarry Inc; 2012-02-09 to 1984-10-03; source msha-controller-operator-history