# Relationship history for MSHA mine 4503382

Current hierarchy: **Douglas  Schermer → Schermer Construction Inc → Crusher Plant #1**

- 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

- **controller_controls_mine:** Douglas  Schermer → Crusher Plant #1; 1994-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Schermer Construction Inc → Crusher Plant #1; 1999-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas  Schermer → Schermer Construction Inc; 1999-01-01 to current/open; source msha-controller-operator-history