# Relationship history for MSHA mine 4001046

Current hierarchy: **Imerys S A → Kentucky-Tennessee Clay Company → Gleason Mines**

- 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:** Kentucky-Tennessee Clay Company → Gleason Mines; 1950-01-01 to 1983-03-28; source msha-controller-operator-history
- **controller_controls_mine:** Chester  Gulick → Gleason Mines; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chester  Gulick → Kentucky-Tennessee Clay Company; 1950-01-01 to 1983-03-28; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky-Tennessee Clay Company → Gleason Mines; 1983-03-29 to 1988-01-03; source msha-controller-operator-history
- **controller_controls_mine:** Ranchers Exploration & Development Corp → Gleason Mines; 1983-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ranchers Exploration & Development Corp → Kentucky-Tennessee Clay Company; 1983-03-29 to 1988-01-03; source msha-controller-operator-history
- **controller_controls_mine:** Hecla Mining Company → Gleason Mines; 1986-06-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky-Tennessee Clay Company → Gleason Mines; 1988-01-04 to 2001-03-27; source msha-controller-operator-history
- **controller_controls_operator:** Hecla Mining Company → Kentucky-Tennessee Clay Company; 1988-01-04 to 2001-03-27; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky-Tennessee Clay Company → Gleason Mines; 2001-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → Gleason Mines; 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