# Relationship history for MSHA mine 3401267

Current hierarchy: **Grayson Larry & J T → Grayson Sand & Gravel → Kenneth Kern Sand 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:** Grayson Sand & Gravel → Kenneth Kern Sand Pit; 1980-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grayson Larry & J T → Kenneth Kern Sand Pit; 1980-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grayson Larry & J T → Grayson Sand & Gravel; 1980-02-01 to current/open; source msha-controller-operator-history