# Relationship history for MSHA mine 3300058

Current hierarchy: **T L  Darlington → Waterloo Coal Company Inc → DIAMOND STONE**

- 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:** Diamond Stone Quarries Inc → DIAMOND STONE; 1950-01-01 to 1988-02-29; source msha-controller-operator-history
- **controller_controls_mine:** W E  Engle → DIAMOND STONE; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W E  Engle → Diamond Stone Quarries Inc; 1950-01-01 to 1988-02-29; source msha-controller-operator-history
- **controller_controls_mine:** T L  Darlington → DIAMOND STONE; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Waterloo Coal Company Inc → DIAMOND STONE; 1988-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** T L  Darlington → Waterloo Coal Company Inc; 1988-03-01 to current/open; source msha-controller-operator-history