# Relationship history for MSHA mine 4104467

Current hierarchy: **Daniel Marcus  Frost → Frost Crushed Stone → Portable #3**

- 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:** Daniel Marcus  Frost → Portable #3; 1992-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Frost Crushed Stone → Portable #3; 2004-04-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Daniel Marcus  Frost → Frost Crushed Stone; 2004-04-19 to current/open; source msha-controller-operator-history