# Relationship history for MSHA mine 3603983

Current hierarchy: **Glenn  Krach; Alvin  Gearhart → Krach & Gearhart Coal Company → Alvin Gearhart**

- 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:** Alvin Gearhart → Alvin Gearhart; 1973-01-01 to 1997-01-05; source msha-controller-operator-history
- **controller_controls_mine:** Gearhart Alvin → Alvin Gearhart; 1973-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gearhart Alvin → Alvin Gearhart; 1973-01-01 to 1997-01-05; source msha-controller-operator-history
- **operator_operates_mine:** Krach & Gearhart Coal Company → Alvin Gearhart; 1997-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Alvin  Gearhart et al → Alvin Gearhart; 1997-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alvin  Gearhart et al → Krach & Gearhart Coal Company; 1997-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Glenn  Krach et al → Krach & Gearhart Coal Company; 1997-01-06 to current/open; source msha-controller-operator-history