# Relationship history for MSHA mine 1515462

Current hierarchy: **Florida Progress Corporation → Kentucky May Coal Company Inc → Dredge No 1**

- 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:** Sunnyside Coal → Dredge No 1; 1985-12-01 to 1986-04-13; source msha-controller-operator-history
- **controller_controls_mine:** Sammons James Et Al → Dredge No 1; 1985-12-01 to 1986-04-13; source msha-controller-operator-history
- **controller_controls_operator:** Sammons James Et Al → Sunnyside Coal; 1985-12-01 to 1986-04-13; source msha-controller-operator-history
- **operator_operates_mine:** V & W Dredging → Dredge No 1; 1986-04-14 to 1989-11-19; source msha-controller-operator-history
- **controller_controls_mine:** Clevenger Mark → Dredge No 1; 1986-04-14 to 1993-01-14; source msha-controller-operator-history
- **controller_controls_operator:** Clevenger Mark → V & W Dredging; 1986-04-14 to 1989-11-19; source msha-controller-operator-history
- **controller_controls_mine:** Florida Progress Corporation → Dredge No 1; 1989-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky May Coal Company Inc → Dredge No 1; 1989-11-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Florida Progress Corporation → Kentucky May Coal Company Inc; 1989-11-20 to current/open; source msha-controller-operator-history