# Relationship history for MSHA mine 1509538

Current hierarchy: **Hibbard Jack → Du Page Coal Corp → Processing 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:** Laurel Fuel Company Inc → Processing Plant; 1976-05-01 to 1982-06-08; source msha-controller-operator-history
- **controller_controls_mine:** Boyce John E → Processing Plant; 1976-05-01 to 1982-06-08; source msha-controller-operator-history
- **controller_controls_operator:** Boyce John E → Laurel Fuel Company Inc; 1976-05-01 to 1982-06-08; source msha-controller-operator-history
- **operator_operates_mine:** East Bernstadt Processing Inc → Processing Plant; 1982-06-09 to 1985-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Green Walt-Harold Baldwin Et Al → Processing Plant; 1982-06-09 to 1985-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Green Walt-Harold Baldwin Et Al → East Bernstadt Processing Inc; 1982-06-09 to 1985-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Hibbard Jack → Processing Plant; 1985-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Du Page Coal Corp → Processing Plant; 1985-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hibbard Jack → Du Page Coal Corp; 1985-08-23 to current/open; source msha-controller-operator-history