# Relationship history for MSHA mine 2200728

Current hierarchy: **Imerys S A → Kentucky-Tennessee Clay Company → Rooker Mine**

- 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:** Hecla Mining Company → Rooker Mine; 1986-06-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky-Tennessee Clay Company → Rooker Mine; 1999-03-01 to 2001-03-27; source msha-controller-operator-history
- **controller_controls_operator:** Hecla Mining Company → Kentucky-Tennessee Clay Company; 1999-03-01 to 2001-03-27; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky-Tennessee Clay Company → Rooker Mine; 2001-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → Rooker Mine; 2001-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A → Kentucky-Tennessee Clay Company; 2001-03-28 to current/open; source msha-controller-operator-history