# Relationship history for MSHA mine 3401634

Current hierarchy: **Martin Marietta Materials Inc → Meridian Aggregates Company, a Limited Partnership → SAWYER**

- 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:** William  Boorhem  et al → SAWYER; 1979-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Oklahoma Stone Inc → SAWYER; 1988-02-01 to 1991-02-13; source msha-controller-operator-history
- **controller_controls_mine:** Wallace T  Langston → SAWYER; 1988-02-01 to 1991-02-13; source msha-controller-operator-history
- **controller_controls_operator:** Wallace T  Langston → Oklahoma Stone Inc; 1988-02-01 to 1991-02-13; source msha-controller-operator-history
- **operator_operates_mine:** Amrock Inc → SAWYER; 1991-02-14 to 1992-12-22; source msha-controller-operator-history
- **controller_controls_mine:** American Rock Products Inc → SAWYER; 1991-02-14 to 1992-12-22; source msha-controller-operator-history
- **controller_controls_operator:** American Rock Products Inc → Amrock Inc; 1991-02-14 to 1992-12-22; source msha-controller-operator-history
- **controller_controls_mine:** Meridian Aggregates Company LP → SAWYER; 1991-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Boorhem-Fields Inc → SAWYER; 1992-12-23 to 1993-03-14; source msha-controller-operator-history
- **controller_controls_operator:** William  Boorhem  et al → Boorhem-Fields Inc; 1992-12-23 to 1993-03-14; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company → SAWYER; 1993-03-15 to 2001-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Meridian Aggregates Company LP → Meridian Aggregates Company; 1993-03-15 to 2001-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company, a Limited Partnership → SAWYER; 2001-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → SAWYER; 2001-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Meridian Aggregates Company, a Limited Partnership; 2001-04-03 to current/open; source msha-controller-operator-history