# Relationship history for MSHA mine 4100072

Current hierarchy: **United States Lime & Minerals Inc → Texas Lime Company → 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Texas Lime Company → Plant & Quarry; 1950-01-01 to 1989-08-19; source msha-controller-operator-history
- **controller_controls_mine:** Rangaire Corp → Plant & Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rangaire Corp → Texas Lime Company; 1950-01-01 to 1989-08-19; source msha-controller-operator-history
- **operator_operates_mine:** Texas Lime Company → Plant & Quarry; 1989-08-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** United States Lime & Minerals Inc → Plant & Quarry; 1989-08-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** United States Lime & Minerals Inc → Texas Lime Company; 1989-08-20 to current/open; source msha-controller-operator-history