# Relationship history for MSHA mine 3401453

Current hierarchy: **Martin Marietta Materials Inc → Meridian Aggregates Co LP → WILLIS**

- 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 → WILLIS; 1979-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Boorhem-Fields Inc → WILLIS; 1984-05-01 to 1993-03-14; source msha-controller-operator-history
- **controller_controls_operator:** William  Boorhem  et al → Boorhem-Fields Inc; 1984-05-01 to 1993-03-14; source msha-controller-operator-history
- **controller_controls_mine:** Meridian Aggregates Company LP → WILLIS; 1991-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Meridian Aggregates Company → WILLIS; 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 Co LP → WILLIS; 2001-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → WILLIS; 2001-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Meridian Aggregates Co LP; 2001-04-03 to current/open; source msha-controller-operator-history