# Relationship history for MSHA mine 0504186

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Inc. → Rich Pit**

- 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 → Rich Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Southwest Ready-Mix Inc → Rich Pit; 1986-10-01 to 1998-01-29; source msha-controller-operator-history
- **controller_controls_mine:** Estate of Henry T. Southway Jr. → Rich Pit; 1986-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Estate of Henry T. Southway Jr. → Southwest Ready-Mix Inc; 1986-10-01 to 1998-01-29; source msha-controller-operator-history
- **controller_controls_mine:** Redland Plc → Rich Pit; 1988-11-14 to 1998-02-10; source msha-controller-operator-history
- **operator_operates_mine:** Western Mobile Southern Inc → Rich Pit; 1998-01-30 to 1998-02-10; source msha-controller-operator-history
- **controller_controls_operator:** Redland Plc → Western Mobile Southern Inc; 1998-01-30 to 1998-02-10; source msha-controller-operator-history
- **operator_operates_mine:** Western Mobile Southern Inc → Rich Pit; 1998-02-11 to 2020-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Rich Pit; 1998-02-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Western Mobile Southern Inc; 1998-02-11 to 2020-09-14; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Inc. → Rich Pit; 2020-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Inc.; 2020-09-15 to current/open; source msha-controller-operator-history