# Relationship history for MSHA mine 2401731

Current hierarchy: **Schmidt Willard-Jeffrey Smith → Highland Quarters Company → Highland Quarters**

- 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:** Highland Quarters Company → Highland Quarters; 1983-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Schmidt Willard-Jeffrey Smith Et Al → Highland Quarters; 1983-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schmidt Willard-Jeffrey Smith Et Al → Highland Quarters Company; 1983-07-01 to current/open; source msha-controller-operator-history