# Relationship history for MSHA mine 4801546

Current hierarchy: **Christensen C Eric & Kelly G Melvin → Hardrock Concrete Lc → HARDROCK CONCRETE WASH PLANT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Hardrock Concrete Lc → HARDROCK CONCRETE WASH PLANT; 1998-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Christensen C Eric & Kelly G Melvin → HARDROCK CONCRETE WASH PLANT; 1998-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christensen C Eric & Kelly G Melvin → Hardrock Concrete Lc; 1998-03-01 to current/open; source msha-controller-operator-history