# Relationship history for MSHA mine 0600791

Current hierarchy: **John F Hychko; Gary  Hychko → LEVEL DEVELOPMENT CORPORATION → WATERVILLE  MATERIALS**

- 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:** Level Development Corporation → WATERVILLE  MATERIALS; 2016-03-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Hychko et al → WATERVILLE  MATERIALS; 2016-03-02 to 2023-09-17; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Hychko et al → Level Development Corporation; 2016-03-02 to 2023-09-17; source msha-controller-operator-history
- **controller_controls_operator:** John F  Hychko et al → Level Development Corporation; 2016-03-02 to 2023-09-17; source msha-controller-operator-history
- **controller_controls_mine:** Gary  Hychko et al → WATERVILLE  MATERIALS; 2023-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Hychko et al → Level Development Corporation; 2023-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John F Hychko et al → Level Development Corporation; 2023-09-18 to current/open; source msha-controller-operator-history