# Relationship history for MSHA mine 3200667

Current hierarchy: **Joel  Schriock; Hallie  Lock; William Todd  Schriock → Gravel Products Inc → C-6 Portable 1560 Omnicone**

- 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:** William  Schriock Jr → C-6 Portable 1560 Omnicone; 1950-01-01 to 2021-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Gravel Products Inc → C-6 Portable 1560 Omnicone; 1983-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Schriock Jr → Gravel Products Inc; 1983-07-01 to 2021-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Hallie  Lock et al → C-6 Portable 1560 Omnicone; 2021-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hallie  Lock et al → Gravel Products Inc; 2021-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William Todd  Schriock et al → Gravel Products Inc; 2021-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joel  Schriock et al → Gravel Products Inc; 2021-04-03 to current/open; source msha-controller-operator-history