# Relationship history for MSHA mine 1510307

Current hierarchy: **Potter Gordon → G P Coal Company → Rockhouse Dock**

- 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:** G P Coal Company → Rockhouse Dock; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Potter Gordon → Rockhouse Dock; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Potter Gordon → G P Coal Company; 1977-03-01 to current/open; source msha-controller-operator-history