# Relationship history for MSHA mine 3602152

Current hierarchy: **Bernard J  Sudol → Bernard J Sudol → Port Trevorton Dredge**

- 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:** Keller Coal Company → Port Trevorton Dredge; 1950-01-01 to 1979-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Keller J Henry → Port Trevorton Dredge; 1950-01-01 to 1979-04-29; source msha-controller-operator-history
- **controller_controls_operator:** Keller J Henry → Keller Coal Company; 1950-01-01 to 1979-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Bernard J  Sudol → Port Trevorton Dredge; 1973-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kratzer Coal Corp → Port Trevorton Dredge; 1979-04-30 to 1983-06-05; source msha-controller-operator-history
- **controller_controls_mine:** Fisher W Donald → Port Trevorton Dredge; 1979-04-30 to 1983-06-05; source msha-controller-operator-history
- **controller_controls_operator:** Fisher W Donald → Kratzer Coal Corp; 1979-04-30 to 1983-06-05; source msha-controller-operator-history
- **controller_controls_mine:** Keller G Flanders → Port Trevorton Dredge; 1982-08-01 to 1996-06-27; source msha-controller-operator-history
- **operator_operates_mine:** G Flanders Keller → Port Trevorton Dredge; 1983-06-06 to 1983-11-01; source msha-controller-operator-history
- **controller_controls_operator:** Keller G Flanders → G Flanders Keller; 1983-06-06 to 1983-11-01; source msha-controller-operator-history
- **operator_operates_mine:** J Henry Keller → Port Trevorton Dredge; 1983-11-02 to 1985-06-04; source msha-controller-operator-history
- **controller_controls_mine:** Keller J Henry → Port Trevorton Dredge; 1983-11-02 to 1985-06-04; source msha-controller-operator-history
- **controller_controls_operator:** Keller J Henry → J Henry Keller; 1983-11-02 to 1985-06-04; source msha-controller-operator-history
- **operator_operates_mine:** Bernard J Sudol → Port Trevorton Dredge; 1985-06-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bernard J  Sudol → Bernard J Sudol; 1985-06-05 to current/open; source msha-controller-operator-history