# Relationship history for MSHA mine 4102894

Current hierarchy: **D N  Chambers Jr → Chambco Inc → Brazos Construction Materials-Plant B**

- 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:** Brazos Construction Materials → Brazos Construction Materials-Plant B; 1979-01-01 to 1984-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Chambco Inc-Adams Equipment Co Et Al → Brazos Construction Materials-Plant B; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chambco Inc-Adams Equipment Co Et Al → Brazos Construction Materials; 1979-01-01 to 1984-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Chambco Inc → Brazos Construction Materials-Plant B; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** D N  Chambers Jr → Brazos Construction Materials-Plant B; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** D N  Chambers Jr → Chambco Inc; 1985-01-01 to current/open; source msha-controller-operator-history