# Relationship history for MSHA mine 1511975

Current hierarchy: **Paramount Drilling Corp → King Coal Company → No 7**

- 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

- **controller_controls_mine:** Paramount Drilling Corp → No 7; 1976-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William N  Rich → No 7; 1978-12-28 to 1980-07-29; source msha-controller-operator-history
- **operator_operates_mine:** Zephyr Mining Company → No 7; 1979-07-01 to 1979-09-25; source msha-controller-operator-history
- **controller_controls_operator:** William N  Rich → Zephyr Mining Company; 1979-07-01 to 1979-09-25; source msha-controller-operator-history
- **operator_operates_mine:** King Coal Company → No 7; 1979-09-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paramount Drilling Corp → King Coal Company; 1979-09-26 to current/open; source msha-controller-operator-history