# Relationship history for MSHA mine 4502603

Current hierarchy: **Scott & Associates-Miles Sand & Gravel → Day Break Rock → Day Break Rock**

- 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:** Paul Zimmerly Rock Products → Day Break Rock; 1978-03-09 to 1987-07-28; source msha-controller-operator-history
- **controller_controls_mine:** David  Zimmerly → Day Break Rock; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Zimmerly → Paul Zimmerly Rock Products; 1978-03-09 to 1987-07-28; source msha-controller-operator-history
- **operator_operates_mine:** Day Break Rock → Day Break Rock; 1987-07-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Scott & Associates-Miles Sand & Gravel Et Al → Day Break Rock; 1987-07-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Scott & Associates-Miles Sand & Gravel Et Al → Day Break Rock; 1987-07-29 to current/open; source msha-controller-operator-history