# Relationship history for MSHA mine 2102912

Current hierarchy: **Abear Robert L → Pequot Sand & Gravel → Swenson 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:** Pequot Sand & Gravel → Swenson Pit; 1983-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Abear Robert L → Swenson Pit; 1983-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Abear Robert L → Pequot Sand & Gravel; 1983-08-01 to current/open; source msha-controller-operator-history