# Relationship history for MSHA mine 1516340

Current hierarchy: **Florida Progress Corporation → Kentucky May Coal Company Inc → #1 Surface 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

- **operator_operates_mine:** Tebco Inc → #1 Surface Mine; 1988-03-01 to 1989-12-20; source msha-controller-operator-history
- **controller_controls_mine:** Ballard Tom → #1 Surface Mine; 1988-03-01 to 1989-12-20; source msha-controller-operator-history
- **controller_controls_operator:** Ballard Tom → Tebco Inc; 1988-03-01 to 1989-12-20; source msha-controller-operator-history
- **controller_controls_mine:** Florida Progress Corporation → #1 Surface Mine; 1989-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky May Coal Company Inc → #1 Surface Mine; 1989-12-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Florida Progress Corporation → Kentucky May Coal Company Inc; 1989-12-21 to current/open; source msha-controller-operator-history