# Relationship history for MSHA mine 0901244

Current hierarchy: **Michael  Hollingshead → SRM Materials, LLC → SRM Materials - Savannah 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

- **controller_controls_mine:** Michael  Hollingshead et al → SRM Materials - Savannah Quarry; 2013-12-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** BACA SAND LLC → SRM Materials - Savannah Quarry; 2017-12-01 to 2020-08-13; source msha-controller-operator-history
- **controller_controls_mine:** Miguel  Baca → SRM Materials - Savannah Quarry; 2017-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Miguel  Baca → BACA SAND LLC; 2017-12-01 to 2020-08-13; source msha-controller-operator-history
- **operator_operates_mine:** SRM Materials, LLC → SRM Materials - Savannah Quarry; 2020-08-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Hollingshead et al → SRM Materials, LLC; 2020-08-14 to current/open; source msha-controller-operator-history