# Relationship history for MSHA mine 4003538

Current hierarchy: **Michael  Hollingshead → SRM Materials, LLC → Smyrna 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 → Smyrna Quarry; 2013-12-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** SRM Materials, LLC → Smyrna Quarry; 2020-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Hollingshead et al → SRM Materials, LLC; 2020-05-04 to current/open; source msha-controller-operator-history