# Relationship history for MSHA mine 4103042

Current hierarchy: **Strain Carl S → Strain Brothers Inc → Project Ac-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

- **controller_controls_mine:** Strain Carl S Et Al → Project Ac-1; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Strain Brothers Inc → Project Ac-1; 1980-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Strain Carl S Et Al → Strain Brothers Inc; 1980-11-01 to current/open; source msha-controller-operator-history