# Relationship history for MSHA mine 4102818

Current hierarchy: **Holcim Ltd → Holcim (US), Inc → Baca Plant**

- 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:** Ideal Basic Industries Inc → Baca Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Baca Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Thorstenberg Materials Company Inc → Baca Plant; 1979-01-01 to 1989-06-08; source msha-controller-operator-history
- **controller_controls_operator:** Ideal Basic Industries Inc → Thorstenberg Materials Company Inc; 1979-01-01 to 1989-06-08; source msha-controller-operator-history
- **operator_operates_mine:** Holnam Inc → Baca Plant; 1989-06-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Holnam Inc; 1989-06-09 to current/open; source msha-controller-operator-history