# Relationship history for MSHA mine 1510983

Current hierarchy: **MAPCO Inc → Pontiki Coal Corp → Pontiki No 1 Prep Plant**

- 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

- **controller_controls_mine:** MAPCO Inc → Pontiki No 1 Prep Plant; 1975-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pontiki Coal Corp → Pontiki No 1 Prep Plant; 1977-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MAPCO Inc → Pontiki Coal Corp; 1977-10-01 to current/open; source msha-controller-operator-history