# Relationship history for MSHA mine 4103777

Current hierarchy: **Hammack Billy J-Steve Carrow → B K S Sand & Gravel → Doggert 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:** B K S Sand & Gravel → Doggert Pit; 1993-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hammack Billy J-Steve Carrow Et Al → Doggert Pit; 1993-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hammack Billy J-Steve Carrow Et Al → B K S Sand & Gravel; 1993-06-01 to current/open; source msha-controller-operator-history