# Relationship history for MSHA mine 4102781

Current hierarchy: **Eagle Materials Inc & Heidelberger Zement Ag → Texas Lehigh Cement Company LP → Texas-Lehigh Cement Plant & Quarry**

- 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

- **operator_operates_mine:** Texas Cement Company → Texas-Lehigh Cement Plant & Quarry; 1978-03-09 to 1986-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Eagle Materials Inc → Texas-Lehigh Cement Plant & Quarry; 1978-03-09 to 1986-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Eagle Materials Inc → Texas Cement Company; 1978-03-09 to 1986-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Texas Lehigh Cement Company LP → Texas-Lehigh Cement Plant & Quarry; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Eagle Materials Inc & Heidelberger Zement Ag → Texas-Lehigh Cement Plant & Quarry; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eagle Materials Inc & Heidelberger Zement Ag → Texas Lehigh Cement Company LP; 1986-07-01 to current/open; source msha-controller-operator-history