# Relationship history for MSHA mine 1508679

Current hierarchy: **Greene John W → Century Inc → No 1 Surface**

- 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:** Keck John M → No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Brushy Creek Coal Inc → No 1 Surface; 1975-08-12 to 1975-12-08; source msha-controller-operator-history
- **controller_controls_operator:** Keck John M → Brushy Creek Coal Inc; 1975-08-12 to 1975-12-08; source msha-controller-operator-history
- **operator_operates_mine:** Century Inc → No 1 Surface; 1975-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Greene John W → No 1 Surface; 1975-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Greene John W → Century Inc; 1975-12-09 to current/open; source msha-controller-operator-history