# Relationship history for MSHA mine 2601548

Current hierarchy: **Burrows Thomas J → Frieberg Mining Corp → Frieberg Mine & Mill**

- 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:** Willow Creek Exploration Inc → Frieberg Mine & Mill; 1979-01-01 to 1980-03-06; source msha-controller-operator-history
- **controller_controls_mine:** Silberman Mark → Frieberg Mine & Mill; 1979-01-01 to 1980-03-06; source msha-controller-operator-history
- **controller_controls_operator:** Silberman Mark → Willow Creek Exploration Inc; 1979-01-01 to 1980-03-06; source msha-controller-operator-history
- **operator_operates_mine:** Frieberg Mining Corp → Frieberg Mine & Mill; 1980-03-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Burrows Thomas J → Frieberg Mine & Mill; 1980-03-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burrows Thomas J → Frieberg Mining Corp; 1980-03-07 to current/open; source msha-controller-operator-history