# Relationship history for MSHA mine 1401811

Current hierarchy: **Summit Materials LLC → Hamm Companies → Metso Portable Plant**

- 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:** N R  Hamm → Metso Portable Plant; 1950-01-01 to 2012-02-08; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Metso Portable Plant; 2012-02-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hamm Companies → Metso Portable Plant; 2020-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** N R  Hamm → Hamm Companies; 2020-03-12 to 2012-02-08; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Hamm Companies; 2020-03-12 to current/open; source msha-controller-operator-history