# Relationship history for MSHA mine 1515023

Current hierarchy: **Polly James → Polly Coal Company → Mine 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

- **operator_operates_mine:** Black Dollar Coal Company → Mine No 1; 1984-12-01 to 1987-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Polly Roger → Mine No 1; 1984-12-01 to 1987-01-04; source msha-controller-operator-history
- **controller_controls_operator:** Polly Roger → Black Dollar Coal Company; 1984-12-01 to 1987-01-04; source msha-controller-operator-history
- **operator_operates_mine:** Branch Coal Company → Mine No 1; 1987-01-05 to 1987-10-08; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Robert → Mine No 1; 1987-01-05 to 1987-10-08; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Robert → Branch Coal Company; 1987-01-05 to 1987-10-08; source msha-controller-operator-history
- **operator_operates_mine:** Polly Coal Company → Mine No 1; 1987-10-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Polly James → Mine No 1; 1987-10-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Polly James → Polly Coal Company; 1987-10-09 to current/open; source msha-controller-operator-history