# Relationship history for MSHA mine 1515925

Current hierarchy: **Martin Graham → Arnold Fork Coal Company → #2**

- 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:** Random Coal Company Inc → #2; 1987-02-01 to 1987-07-19; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Terry → #2; 1987-02-01 to 1987-07-19; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Terry → Random Coal Company Inc; 1987-02-01 to 1987-07-19; source msha-controller-operator-history
- **operator_operates_mine:** Arnold Fork Coal Company → #2; 1987-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Graham → #2; 1987-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Graham → Arnold Fork Coal Company; 1987-07-20 to current/open; source msha-controller-operator-history