# Relationship history for MSHA mine 2901915

Current hierarchy: **Siegrist Construction Company → Burnett Construction Company → Burnett Construction Crusher**

- 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:** Siegrist Construction Company Et Al → Burnett Construction Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Burnett Construction Company → Burnett Construction Crusher; 1983-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Siegrist Construction Company Et Al → Burnett Construction Company; 1983-06-01 to current/open; source msha-controller-operator-history