# Relationship history for MSHA mine 2901119

Current hierarchy: **Eric  Knezevich → Howard's Sand & Gravel → Tecolote 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Howard's Sand & Gravel → Tecolote Pit; 1988-02-01 to 2021-01-03; source msha-controller-operator-history
- **controller_controls_mine:** Dorothy  Knezevich → Tecolote Pit; 1988-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dorothy  Knezevich → Howard's Sand & Gravel; 1988-02-01 to 2021-01-03; source msha-controller-operator-history
- **operator_operates_mine:** Howard's Sand & Gravel → Tecolote Pit; 2021-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Eric  Knezevich → Tecolote Pit; 2021-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eric  Knezevich → Howard's Sand & Gravel; 2021-01-04 to current/open; source msha-controller-operator-history