# Relationship history for MSHA mine 1513173

Current hierarchy: **B W  McDonald → Opportunity Coal Company Inc → Opportunity Coal Co Inc Mine #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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** D F D Company Inc → Opportunity Coal Co Inc Mine #1; 1981-10-01 to 1990-02-12; source msha-controller-operator-history
- **controller_controls_mine:** Davis Floyd D → Opportunity Coal Co Inc Mine #1; 1981-10-01 to 1990-02-12; source msha-controller-operator-history
- **controller_controls_operator:** Davis Floyd D → D F D Company Inc; 1981-10-01 to 1990-02-12; source msha-controller-operator-history
- **operator_operates_mine:** Opportunity Coal Company Inc → Opportunity Coal Co Inc Mine #1; 1990-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** B W  McDonald → Opportunity Coal Co Inc Mine #1; 1990-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** B W  McDonald → Opportunity Coal Company Inc; 1990-02-13 to current/open; source msha-controller-operator-history