# Relationship history for MSHA mine 2000731

Current hierarchy: **Amber  Hoover; Amy  Watson; James  Sturrus Jr → High Grade Materials Co. → Linden 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:** Grand Valley Gravel Company → Linden Pit; 1950-01-01 to 2000-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Fenske Steven → Linden Pit; 1950-01-01 to 2000-07-30; source msha-controller-operator-history
- **controller_controls_operator:** Fenske Steven → Grand Valley Gravel Company; 1950-01-01 to 2000-07-30; source msha-controller-operator-history
- **controller_controls_mine:** James P  Sturrus → Linden Pit; 1998-05-01 to 2019-04-30; source msha-controller-operator-history
- **operator_operates_mine:** High Grade Materials Co. → Linden Pit; 2000-07-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James P  Sturrus → High Grade Materials Co.; 2000-07-31 to 2019-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Amber  Hoover et al → Linden Pit; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amber  Hoover et al → High Grade Materials Co.; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Sturrus Jr et al → High Grade Materials Co.; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amy  Watson et al → High Grade Materials Co.; 2019-05-01 to current/open; source msha-controller-operator-history