# Relationship history for MSHA mine 0900588

Current hierarchy: **Duncan Edgar Olen → J M Duncan Quarry Company → Duncan Quarry**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Buchanan Flagstone Quarry → Duncan Quarry; 1950-01-01 to 1979-03-27; source msha-controller-operator-history
- **controller_controls_mine:** Hallman  Buchanan → Duncan Quarry; 1950-01-01 to 1979-08-20; source msha-controller-operator-history
- **controller_controls_operator:** Hallman  Buchanan → Buchanan Flagstone Quarry; 1950-01-01 to 1979-03-27; source msha-controller-operator-history
- **operator_operates_mine:** J M Duncan Quarry Company → Duncan Quarry; 1979-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Duncan Edgar Olen → Duncan Quarry; 1979-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Duncan Edgar Olen → J M Duncan Quarry Company; 1979-03-28 to current/open; source msha-controller-operator-history