# Relationship history for MSHA mine 4100300

Current hierarchy: **James W  Thomas → Bricktech Corp Of America → Mason**

- 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

- **operator_operates_mine:** Southwestern Brick Inc → Mason; 1950-01-01 to 1983-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Martin Ray → Mason; 1950-01-01 to 1983-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Martin Ray → Southwestern Brick Inc; 1950-01-01 to 1983-06-19; source msha-controller-operator-history
- **operator_operates_mine:** Southwestern Brick Inc → Mason; 1983-06-20 to 1984-02-27; source msha-controller-operator-history
- **controller_controls_mine:** Kramer John → Mason; 1983-06-20 to 1984-02-27; source msha-controller-operator-history
- **controller_controls_operator:** Kramer John → Southwestern Brick Inc; 1983-06-20 to 1984-02-27; source msha-controller-operator-history
- **operator_operates_mine:** Southwestern Brick Inc → Mason; 1984-02-28 to 1997-08-24; source msha-controller-operator-history
- **controller_controls_mine:** Hatten E T → Mason; 1984-02-28 to 1997-08-24; source msha-controller-operator-history
- **controller_controls_operator:** Hatten E T → Southwestern Brick Inc; 1984-02-28 to 1997-08-24; source msha-controller-operator-history
- **operator_operates_mine:** Bricktech Corp Of America → Mason; 1997-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James W  Thomas Et Al → Mason; 1997-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James W  Thomas Et Al → Bricktech Corp Of America; 1997-08-25 to current/open; source msha-controller-operator-history