# Relationship history for MSHA mine 2302193

Current hierarchy: **Chris L  Schroeder; Doug L  Friesen → Triple L Gravel Inc → Triple  L Gravel, Inc.**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Triple L Gravel Inc → Triple  L Gravel, Inc.; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ruth W  Latham → Triple  L Gravel, Inc.; 1999-11-01 to 2004-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Ruth W  Latham → Triple L Gravel Inc; 1999-11-01 to 2004-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Chris L  Schroeder et al → Triple  L Gravel, Inc.; 2004-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chris L  Schroeder et al → Triple L Gravel Inc; 2004-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doug L  Friesen et al → Triple L Gravel Inc; 2004-10-01 to current/open; source msha-controller-operator-history