# Relationship history for MSHA mine 2302521

Current hierarchy: **John R Escobar → Ozark Mountain Materials → 376 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:** Ozark Mountain Crushing & Screening, LLC → 376 Quarry; 2017-07-01 to 2020-06-18; source msha-controller-operator-history
- **controller_controls_mine:** John R Escobar → 376 Quarry; 2017-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John R Escobar → Ozark Mountain Crushing & Screening, LLC; 2017-07-01 to 2020-06-18; source msha-controller-operator-history
- **operator_operates_mine:** Ozark Mountain Materials → 376 Quarry; 2020-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John R Escobar → 376 Quarry; 2020-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John R Escobar → Ozark Mountain Materials; 2020-06-19 to current/open; source msha-controller-operator-history