# Relationship history for MSHA mine 4103097

Current hierarchy: **Mid America Materials Company → Hallett Construction Company → Brazos River 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:** Hallett Construction Company → Brazos River Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Construction Company → Brazos River Plant; 1981-09-01 to 1986-10-13; source msha-controller-operator-history
- **controller_controls_operator:** Hallett Construction Company → Hallett Construction Company; 1981-09-01 to 1986-10-13; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Construction Company → Brazos River Plant; 1986-10-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mid America Materials Company → Brazos River Plant; 1986-10-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mid America Materials Company → Hallett Construction Company; 1986-10-14 to current/open; source msha-controller-operator-history