# Relationship history for MSHA mine 2002798

Current hierarchy: **Walter L  Hazen → CHIPPEWA STONE & GRAVEL INC → PIONEER PLANT**

- 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:** Daniel J Hazen → PIONEER PLANT; 1988-02-01 to 1989-08-01; source msha-controller-operator-history
- **controller_controls_mine:** Daniel J  Hazen → PIONEER PLANT; 1988-02-01 to 1989-08-01; source msha-controller-operator-history
- **controller_controls_operator:** Daniel J  Hazen → Daniel J Hazen; 1988-02-01 to 1989-08-01; source msha-controller-operator-history
- **operator_operates_mine:** Chippewa Stone & Gravel Inc → PIONEER PLANT; 1989-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Walter L  Hazen → PIONEER PLANT; 1989-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walter L  Hazen → Chippewa Stone & Gravel Inc; 1989-08-02 to current/open; source msha-controller-operator-history