# Relationship history for MSHA mine 3004121

Current hierarchy: **Karl  Bach → Bach & Co → Bach & Co Boulder Mine**

- 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:** Karl  Bach → Bach & Co Boulder Mine; 1980-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bach & Co → Bach & Co Boulder Mine; 2024-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Karl  Bach → Bach & Co; 2024-03-28 to current/open; source msha-controller-operator-history