# Relationship history for MSHA mine 0504083

Current hierarchy: **Colas S A → Simon Contractors → PORTABLE #1 Fort Collins**

- 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:** Don  Kehn → PORTABLE #1 Fort Collins; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Don Kehn Construction Inc → PORTABLE #1 Fort Collins; 1985-08-01 to 2023-05-03; source msha-controller-operator-history
- **controller_controls_operator:** Don  Kehn → Don Kehn Construction Inc; 1985-08-01 to 2023-05-03; source msha-controller-operator-history
- **controller_controls_mine:** Colas S A → PORTABLE #1 Fort Collins; 1995-01-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simon Contractors → PORTABLE #1 Fort Collins; 2023-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Colas S A → Simon Contractors; 2023-05-04 to current/open; source msha-controller-operator-history