# Relationship history for MSHA mine 1507477

Current hierarchy: **Harrison Bruce & Larry → Chippewa Coal Co → No 1 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

- **operator_operates_mine:** Chippewa Coal Co → No 1 Mine; 1974-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harrison Bruce & Larry → No 1 Mine; 1974-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harrison Bruce & Larry → Chippewa Coal Co; 1974-01-29 to current/open; source msha-controller-operator-history