# Relationship history for MSHA mine 4503481

Current hierarchy: **Walt  Miles → Miles Sand & Gravel Company → Boulder Hill Pit**

- 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:** Walt  Miles et al → Boulder Hill Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Walt  Miles et al → Boulder Hill Pit; 1983-04-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Concrete Nor'West → Boulder Hill Pit; 2001-05-01 to 2016-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Walt  Miles et al → Concrete Nor'West; 2001-05-01 to 2016-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Miles Sand & Gravel Company → Boulder Hill Pit; 2016-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walt  Miles et al → Miles Sand & Gravel Company; 2016-06-01 to current/open; source msha-controller-operator-history