# Relationship history for MSHA mine 4202377

Current hierarchy: **DC Transport & Excavating Inc → DC Sand & Gravel → Portable/various locations**

- 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:** DC Sand & Gravel → Portable/various locations; 2004-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** DC Transport & Excavating Inc → Portable/various locations; 2004-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** DC Transport & Excavating Inc → DC Sand & Gravel; 2004-01-06 to current/open; source msha-controller-operator-history