# Relationship history for MSHA mine 4701556

Current hierarchy: **James  Baumhardt → Baumhardt Sand & Gravel Company → Portable Crusher**

- 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:** Baumhardt Sand & Gravel Company → Portable Crusher; 1950-01-01 to 2026-03-08; source msha-controller-operator-history
- **controller_controls_mine:** Baumhardt Joseph → Portable Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Baumhardt Joseph → Baumhardt Sand & Gravel Company; 1950-01-01 to 2026-03-08; source msha-controller-operator-history
- **operator_operates_mine:** Baumhardt Sand & Gravel Company → Portable Crusher; 2026-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James  Baumhardt → Portable Crusher; 2026-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Baumhardt → Baumhardt Sand & Gravel Company; 2026-03-09 to current/open; source msha-controller-operator-history