# Relationship history for MSHA mine 2500427

Current hierarchy: **Michael  Werner → Nichols Construction Company → Blue Valley Pit**

- 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:** Nichols Construction Company → Blue Valley Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Philip F  Werner Jr et al → Blue Valley Pit; 1950-01-01 to 2025-03-25; source msha-controller-operator-history
- **controller_controls_operator:** Philip F  Werner Jr et al → Nichols Construction Company; 1950-01-01 to 2025-03-25; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Werner → Blue Valley Pit; 2025-03-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Werner → Nichols Construction Company; 2025-03-26 to current/open; source msha-controller-operator-history