# Relationship history for MSHA mine 0102915

Current hierarchy: **Mann Henry → Abyss Sand & Gravel Inc → Baker Mann**

- 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:** Abyss Sand & Gravel Inc → Baker Mann; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mann Henry → Baker Mann; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mann Henry → Abyss Sand & Gravel Inc; 1991-07-01 to current/open; source msha-controller-operator-history