# Relationship history for MSHA mine 1512391

Current hierarchy: **Randy  Johnson → Westerman 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:** Minerals Development Company → No 1 Mine; 1980-07-01 to 1983-05-22; source msha-controller-operator-history
- **controller_controls_mine:** Nelson R Joy Et Al → No 1 Mine; 1980-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nelson R Joy Et Al → Minerals Development Company; 1980-07-01 to 1983-05-22; source msha-controller-operator-history
- **operator_operates_mine:** Richland Contracting Company → No 1 Mine; 1983-05-23 to 1984-02-08; source msha-controller-operator-history
- **controller_controls_mine:** Blair Douglas L → No 1 Mine; 1983-05-23 to 1984-02-08; source msha-controller-operator-history
- **controller_controls_operator:** Blair Douglas L → Richland Contracting Company; 1983-05-23 to 1984-02-08; source msha-controller-operator-history
- **operator_operates_mine:** Westerman Coal Company Inc → No 1 Mine; 1984-02-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Randy  Johnson et al → No 1 Mine; 1984-02-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Randy  Johnson et al → Westerman Coal Company Inc; 1984-02-09 to current/open; source msha-controller-operator-history