# Relationship history for MSHA mine 1510492

Current hierarchy: **Thornberry Rennie - Earl → Kentucky Gem Coal Company Inc → Clay County No 1 Surface**

- 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:** Thornberry Rennie - Earl Et Al → Clay County No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ibex Inc Et Al → Clay County No 1 Surface; 1976-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Gem Coal Company-A Joint Venture → Clay County No 1 Surface; 1977-06-01 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Ibex Inc Et Al → Kentucky Gem Coal Company-A Joint Venture; 1977-06-01 to 1981-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Gem Coal Company Inc → Clay County No 1 Surface; 1981-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thornberry Rennie - Earl Et Al → Kentucky Gem Coal Company Inc; 1981-07-01 to current/open; source msha-controller-operator-history