# Relationship history for MSHA mine 3606639

Current hierarchy: **Will Howard D → Will'S Construction → Will'S Construction Strip**

- 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:** Will'S Construction → Will'S Construction Strip; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Will Howard D → Will'S Construction Strip; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Will Howard D → Will'S Construction; 1978-04-01 to current/open; source msha-controller-operator-history