# Relationship history for MSHA mine 1514868

Current hierarchy: **Brown Denver & Glen York → D B & Y Construction → No 1**

- 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

- **operator_operates_mine:** D B & Y Construction → No 1; 1984-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brown Denver & Glen York → No 1; 1984-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brown Denver & Glen York → D B & Y Construction; 1984-09-01 to current/open; source msha-controller-operator-history