# Relationship history for MSHA mine 2902079

Current hierarchy: **E B  Pollister → E B Pollister → PORTABLE SCREEN PLT**

- 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:** Steve Bell Construction → PORTABLE SCREEN PLT; 1992-01-01 to 1997-04-07; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Bell → PORTABLE SCREEN PLT; 1992-01-01 to 1997-04-07; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Bell → Steve Bell Construction; 1992-01-01 to 1997-04-07; source msha-controller-operator-history
- **operator_operates_mine:** E B Pollister → PORTABLE SCREEN PLT; 1997-04-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** E B  Pollister → PORTABLE SCREEN PLT; 1997-04-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** E B  Pollister → E B Pollister; 1997-04-08 to current/open; source msha-controller-operator-history