# Relationship history for MSHA mine 2501101

Current hierarchy: **Gene  Gregg → Gregg Sand & Gravel → PORTABLE DREDGE #2**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Gene  Gregg → PORTABLE DREDGE #2; 1987-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gregg Sand & Gravel → PORTABLE DREDGE #2; 1988-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gene  Gregg → Gregg Sand & Gravel; 1988-06-01 to current/open; source msha-controller-operator-history