# Relationship history for MSHA mine 4607765

Current hierarchy: **B W  McDonald → Opportunity Coal Company Inc → Mine No 4**

- 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:** Michael C  Castle → Mine No 4; 1988-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big South Mining & Construction Company Inc → Mine No 4; 1989-09-01 to 1994-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Michael C  Castle → Big South Mining & Construction Company Inc; 1989-09-01 to 1994-11-13; source msha-controller-operator-history
- **controller_controls_mine:** B W  McDonald → Mine No 4; 1990-02-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Opportunity Coal Company Inc → Mine No 4; 1994-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** B W  McDonald → Opportunity Coal Company Inc; 1994-11-14 to current/open; source msha-controller-operator-history