# Relationship history for MSHA mine 1510689

Current hierarchy: **Brock Larry W → Blue Ridge Coal Company → No 1**

- 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:** Swartwood T Marshall → No 1; 1975-06-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Coal Fuels Inc → No 1; 1977-08-01 to 1987-02-02; source msha-controller-operator-history
- **controller_controls_operator:** Swartwood T Marshall → Coal Fuels Inc; 1977-08-01 to 1987-02-02; source msha-controller-operator-history
- **operator_operates_mine:** Blue Ridge Coal Company → No 1; 1987-02-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brock Larry W → No 1; 1987-02-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brock Larry W → Blue Ridge Coal Company; 1987-02-03 to current/open; source msha-controller-operator-history