# Relationship history for MSHA mine 4400029

Current hierarchy: **H D Crowder & Sons Inc → F & M CONSTRUCTION CORP → NO. 2 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** H D Crowder & Sons Inc → NO. 2 PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** F & M Construction Corp → NO. 2 PIT; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** H D Crowder & Sons Inc → F & M Construction Corp; 1981-04-01 to current/open; source msha-controller-operator-history