# Relationship history for MSHA mine 2700271

Current hierarchy: **David G  Foster → Foster Materials Inc → Foster Materials 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Hopkinton Construction Company Inc → Foster Materials Inc; 1987-05-01 to 1989-10-12; source msha-controller-operator-history
- **controller_controls_mine:** Foster Bernard → Foster Materials Inc; 1987-05-01 to 1989-10-12; source msha-controller-operator-history
- **controller_controls_operator:** Foster Bernard → Hopkinton Construction Company Inc; 1987-05-01 to 1989-10-12; source msha-controller-operator-history
- **operator_operates_mine:** Foster Materials Inc → Foster Materials Inc; 1989-10-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David G  Foster → Foster Materials Inc; 1989-10-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David G  Foster → Foster Materials Inc; 1989-10-13 to current/open; source msha-controller-operator-history