# Relationship history for MSHA mine 3304140

Current hierarchy: **Marilyn J Simak → Simak Trucking & Excavating Inc → Simak Trucking Inc**

- 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:** Simak Trucking & Excavating Inc → Simak Trucking Inc; 1988-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Marilyn J Simak → Simak Trucking Inc; 1988-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marilyn J Simak → Simak Trucking & Excavating Inc; 1988-07-01 to current/open; source msha-controller-operator-history