# Relationship history for MSHA mine 2001047

Current hierarchy: **David  Mattila; Lisa  Mattila → Superior Sand & Gravel, Inc. → Superior Wash 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Superior Sand & Gravel Inc → Superior Wash Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thomas R  Thornton → Superior Wash Plant; 1950-01-01 to 2017-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Thomas R  Thornton → Superior Sand & Gravel Inc; 1950-01-01 to 2017-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Lisa  Mattila et al → Superior Wash Plant; 2018-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lisa  Mattila et al → Superior Sand & Gravel Inc; 2018-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Mattila et al → Superior Sand & Gravel Inc; 2018-01-01 to current/open; source msha-controller-operator-history