# Relationship history for MSHA mine 2300788

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Aggregates → BARNHART 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Martin Marietta Materials Inc → BARNHART QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William E  Witaker → BARNHART QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** West Lake Quarry & Material Company → BARNHART QUARRY; 1980-07-01 to 1992-12-06; source msha-controller-operator-history
- **controller_controls_operator:** William E  Witaker → West Lake Quarry & Material Company; 1980-07-01 to 1992-12-06; source msha-controller-operator-history
- **operator_operates_mine:** Barnhart Limestone Inc → BARNHART QUARRY; 1992-12-07 to 1998-07-29; source msha-controller-operator-history
- **controller_controls_mine:** Louis A  Griesemer et al → BARNHART QUARRY; 1992-12-07 to 1998-07-29; source msha-controller-operator-history
- **controller_controls_operator:** Louis A  Griesemer et al → Barnhart Limestone Inc; 1992-12-07 to 1998-07-29; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → BARNHART QUARRY; 1998-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1998-07-30 to current/open; source msha-controller-operator-history