# Relationship history for MSHA mine 2601651

Current hierarchy: **Hilberg S T → S T Hilberg Consulting → Canyon Milling**

- 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:** Canyon Milling Inc → Canyon Milling; 1980-06-01 to 1983-03-23; source msha-controller-operator-history
- **controller_controls_mine:** Carlstrom D F → Canyon Milling; 1980-06-01 to 1983-03-23; source msha-controller-operator-history
- **controller_controls_operator:** Carlstrom D F → Canyon Milling Inc; 1980-06-01 to 1983-03-23; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Bernie E → Canyon Milling; 1981-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Valley Aggregate Inc → Canyon Milling; 1983-03-24 to 1984-11-01; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Bernie E → Valley Aggregate Inc; 1983-03-24 to 1984-11-01; source msha-controller-operator-history
- **operator_operates_mine:** S T Hilberg Consulting → Canyon Milling; 1984-11-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hilberg S T → Canyon Milling; 1984-11-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hilberg S T → S T Hilberg Consulting; 1984-11-02 to current/open; source msha-controller-operator-history