# Relationship history for MSHA mine 3607567

Current hierarchy: **Alfred J  Brown → S B M Coal → Big Rock Drift**

- 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:** Harner Alfred R Et Al → Big Rock Drift; 1983-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** H & T Coal Company → Big Rock Drift; 1984-04-01 to 1985-07-16; source msha-controller-operator-history
- **controller_controls_operator:** Harner Alfred R Et Al → H & T Coal Company; 1984-04-01 to 1985-07-16; source msha-controller-operator-history
- **operator_operates_mine:** S B M Coal → Big Rock Drift; 1985-07-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Alfred J  Brown → Big Rock Drift; 1985-07-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alfred J  Brown → S B M Coal; 1985-07-17 to current/open; source msha-controller-operator-history