# Relationship history for MSHA mine 4604539

Current hierarchy: **Burton Billy → B D S Coal Company Inc → 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:** H & M Coal Company → No 1 Mine; 1975-01-01 to 1975-06-23; source msha-controller-operator-history
- **controller_controls_mine:** Hall Jack → No 1 Mine; 1975-01-01 to 1975-06-23; source msha-controller-operator-history
- **controller_controls_operator:** Hall Jack → H & M Coal Company; 1975-01-01 to 1975-06-23; source msha-controller-operator-history
- **operator_operates_mine:** B D S Coal Company Inc → No 1 Mine; 1975-06-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Burton Billy → No 1 Mine; 1975-06-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burton Billy → B D S Coal Company Inc; 1975-06-24 to current/open; source msha-controller-operator-history