# Relationship history for MSHA mine 2200401

Current hierarchy: **Boyd C A → Mississippi-Alabama Sand Company → Pit No 1**

- 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:** Mississippi-Alabama Sand Company → Pit No 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Boyd C A → Pit No 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boyd C A → Mississippi-Alabama Sand Company; 1950-01-01 to current/open; source msha-controller-operator-history