# Relationship history for MSHA mine 1509377

Current hierarchy: **Texas Pioneer Coal Co & Kentucky Diamond Energies → Kentucky Diamond Energies Company Inc → #4 Hollow 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

- **operator_operates_mine:** Kentucky Diamond Energies Company Inc → #4 Hollow Surface; 1975-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Texas Pioneer Coal Co & Kentucky Diamond Energies → #4 Hollow Surface; 1975-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Texas Pioneer Coal Co & Kentucky Diamond Energies → Kentucky Diamond Energies Company Inc; 1975-11-01 to current/open; source msha-controller-operator-history