# Relationship history for MSHA mine 2700304

Current hierarchy: **Michael  Therrien → Therrien & Sons → PORTABLE CRUSHER**

- 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:** Therrien & Sons → PORTABLE CRUSHER; 1995-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Therrien → PORTABLE CRUSHER; 1995-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Therrien → Therrien & Sons; 1995-03-01 to current/open; source msha-controller-operator-history