# Relationship history for MSHA mine 3600927

Current hierarchy: **Custom Coals Penna; Custom Coals Holdings → Custom Coals-Dilltown → Dilltown Preparation Facility**

- 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:** Oneida Mining Company → Dilltown Preparation Facility; 1950-01-01 to 1976-03-12; source msha-controller-operator-history
- **controller_controls_mine:** NACCO Industries Inc → Dilltown Preparation Facility; 1950-01-01 to 1976-03-12; source msha-controller-operator-history
- **controller_controls_operator:** NACCO Industries Inc → Oneida Mining Company; 1950-01-01 to 1976-03-12; source msha-controller-operator-history
- **operator_operates_mine:** Pennsylvania Mines Corp → Dilltown Preparation Facility; 1976-03-13 to 1993-11-17; source msha-controller-operator-history
- **controller_controls_mine:** Pennsylvania Power & Light Company → Dilltown Preparation Facility; 1976-03-13 to 1993-11-17; source msha-controller-operator-history
- **controller_controls_operator:** Pennsylvania Power & Light Company → Pennsylvania Mines Corp; 1976-03-13 to 1993-11-17; source msha-controller-operator-history
- **operator_operates_mine:** Custom Coals-Dilltown → Dilltown Preparation Facility; 1993-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Custom Coals Holdings et al → Dilltown Preparation Facility; 1993-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Custom Coals Holdings et al → Custom Coals-Dilltown; 1993-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Custom Coals Penna et al → Custom Coals-Dilltown; 1993-11-18 to current/open; source msha-controller-operator-history