# Relationship history for MSHA mine 4500844

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials → Pacific 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

- **controller_controls_mine:** Martin Marietta Materials Inc → Pacific Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pacific Quarries Inc → Pacific Quarry; 1950-01-01 to 1987-12-07; source msha-controller-operator-history
- **controller_controls_mine:** Michael G  Brown → Pacific Quarry; 1950-01-01 to 1987-12-07; source msha-controller-operator-history
- **controller_controls_operator:** Michael G  Brown → Pacific Quarries Inc; 1950-01-01 to 1987-12-07; source msha-controller-operator-history
- **controller_controls_mine:** Burlington Resources Inc → Pacific Quarry; 1981-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company → Pacific Quarry; 1987-12-08 to 1991-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Burlington Resources Inc → Meridian Aggregates Company; 1987-12-08 to 1991-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company → Pacific Quarry; 1991-03-01 to 2001-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Meridian Aggregates Company LP → Pacific Quarry; 1991-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Meridian Aggregates Company LP → Meridian Aggregates Company; 1991-03-01 to 2001-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company LP → Pacific Quarry; 2001-04-03 to 2008-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Pacific Quarry; 2001-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Meridian Aggregates Company LP; 2001-04-03 to 2008-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials → Pacific Quarry; 2009-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials; 2009-01-01 to current/open; source msha-controller-operator-history